WO2005004419A1 - 通信システム、マルチキャスト対応ルータ、送信端末、受信端末及び通信方法 - Google Patents
通信システム、マルチキャスト対応ルータ、送信端末、受信端末及び通信方法 Download PDFInfo
- Publication number
- WO2005004419A1 WO2005004419A1 PCT/JP2004/009663 JP2004009663W WO2005004419A1 WO 2005004419 A1 WO2005004419 A1 WO 2005004419A1 JP 2004009663 W JP2004009663 W JP 2004009663W WO 2005004419 A1 WO2005004419 A1 WO 2005004419A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- address
- multicast
- message
- unit
- transfer
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L45/00—Routing or path finding of packets in data switching networks
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/02—Details
- H04L12/16—Arrangements for providing special services to substations
- H04L12/18—Arrangements for providing special services to substations for broadcast or conference, e.g. multicast
- H04L12/185—Arrangements for providing special services to substations for broadcast or conference, e.g. multicast with management of multicast group membership
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L45/00—Routing or path finding of packets in data switching networks
- H04L45/16—Multipoint routing
Definitions
- the present invention relates to a communication system, a multicast-capable router, a transmitting terminal, a receiving terminal, and a communication method.
- PIM-SM Multicast-Sparse Mode
- MIP-BT Mobile IP Bi-Directional Tunneling
- a transmitting terminal that transmits a multicast packet moves and its address changes.
- the transmitting terminal that has moved to a foreign network (Foreign Network) transfers the transmitted multicast packets via a home agent (Home Agent) to maintain communication.
- Home Agent Home Agent
- multicast packets can be transferred unless all routers are multicast-compatible routers that support multicast protocol. Did not. That is, in the conventional communication system, when a multicast-capable router and a non-multicast-capable router that do not support the multicast protocol coexist, the multicast packet cannot be transferred.
- an object of the present invention is to set an appropriate multicast tree and transfer multicast packets even if a non-multicast-capable router exists in the communication system.
- the communication system of the present invention includes a multicast-capable router and a transmission terminal.
- the multicast-capable router includes a transfer destination holding unit that holds a transfer destination address to which the multicast-capable router transfers the multicast packet, and a transfer destination address of another multicast-capable router as a transfer destination address in association with the transmission terminal address and the multicast group address.
- a transfer destination registration unit for registering an address in the transfer destination holding unit, and a join request message requesting that the address of the multicast-capable router be added to the destination address to which the sending terminal transmits the multicast packet to the sending terminal address.
- the transmitting terminal includes a destination holding unit that holds the destination address, and a destination registering unit that registers the address of the multicast-capable router in the destination holding unit as the destination address based on the participation request message. Including.
- the transfer destination address is an address to which a multicast-capable router transfers a multicast packet.
- the destination address is the address where the transmitting terminal transmits the multicast packet.
- the transmitting terminal address is the address of the transmitting terminal.
- the multicast group address is an address indicating a multicast group.
- an address of another multicast-capable router is registered as a transfer destination address in a transfer destination holding unit that holds a transfer destination address in association with a transmission terminal address and a multicast group address;
- a join request message requesting that the address of the multicast-capable router be added to the destination address is sent to the sending terminal address.
- the transmitting terminal registers the address of the multicast-capable router as a destination address in a destination holding unit that holds the destination address.
- a multicast-capable router is
- the router address can be stored.
- the sending terminal is The address of the multicast-capable router can be held as the destination address. Therefore, an appropriate multicast tree in which the multicast packet is transferred from the transmitting terminal to the receiving terminal via the multicast-capable router is set.
- a non-multicast-capable router existing between a transmitting terminal and a multicast-capable router or between multicast-capable routers only needs to transfer multicast packets by unicast.
- the communication system can set up an appropriate multicast tree and transfer multicast packets even if there is a non-multicast-capable router.
- UMP Unicast Extension Multicast Protocol
- FIG. 1 is a diagram showing a configuration of a communication system according to a first embodiment of the present invention.
- FIG. 2 is a block diagram showing a configuration of a UR according to the first embodiment of the present invention.
- FIG. 3 is a diagram showing an entry holding unit of a UR according to the first embodiment of the present invention.
- FIG. 4 is a block diagram showing a configuration of a transmitting terminal according to the first embodiment of the present invention.
- FIG. 5 is a diagram showing an entry holding unit of the transmitting terminal according to the first embodiment of the present invention.
- FIG. 6 is a flowchart showing an operation procedure when a UR receives a packet according to the first embodiment of the present invention.
- FIG. 7 is a flowchart showing a procedure of processing a multicast packet performed by the UR according to the first embodiment of the present invention.
- FIG. 8 is a flowchart showing a Join message processing procedure performed by a UR according to the first embodiment of the present invention.
- FIG. 9 is a flowchart showing a procedure of processing a Prune message performed by the UR according to the first embodiment of the present invention.
- FIG. 10 is a sequence diagram showing a procedure when a transmission of a multicast packet is requested by the receiving terminal according to the first embodiment of the present invention.
- FIG. 11 is a diagram showing a communication system when a transmission of a multicast packet is requested by the receiving terminal according to the first embodiment of the present invention.
- FIG. 12 is a sequence diagram showing a multicast packet transfer procedure according to the first embodiment of the present invention.
- FIG. 13 is a diagram showing transfer of a multicast packet according to the first embodiment of the present invention.
- FIG. 14 is a sequence diagram showing a procedure for a receiving terminal to participate in a multicast tree according to the first embodiment of the present invention.
- FIG. 15 is a diagram showing participation of a receiving terminal in a multicast tree according to the first embodiment of the present invention.
- FIG. 16 is a diagram showing transfer of a multicast packet according to a newly set multicast tree according to the first embodiment of the present invention.
- FIG. 17 is a diagram showing transfer of a multicast packet in a state where a plurality of receiving terminals are participating in a multicast tree according to the first embodiment of the present invention.
- FIG. 18 is a diagram showing a communication system when a multicast tree according to the first embodiment of the present invention has transitioned to a stable state.
- FIG. 19 is a flowchart showing a procedure for leaving a multicast tree according to the first embodiment of the present invention.
- FIG. 20 is a diagram showing a communication system at the time of leaving a multicast tree according to the first embodiment of the present invention.
- FIG. 21 is a diagram showing transfer of a multicast packet after leaving according to the first embodiment of the present invention.
- FIG. 22 is a diagram showing a configuration of a communication system according to a second exemplary embodiment of the present invention.
- FIG. 23 is a sequence diagram showing a procedure for a receiving terminal to participate in a multicast tree according to the second embodiment of the present invention.
- FIG. 24 shows how a receiving terminal according to the second embodiment of the present invention participates in a multicast tree.
- FIG. 25 is a diagram showing transfer of a multicast packet according to a newly set multicast tree according to the second embodiment of the present invention.
- FIG. 26 is a sequence diagram showing a procedure for a receiving terminal to participate in a multicast tree according to the third embodiment of the present invention.
- FIG. 27 is a diagram showing participation of a receiving terminal in a multicast tree according to the third embodiment of the present invention.
- FIG. 28 is a diagram showing transfer of a multicast packet according to a newly set multicast tree according to the third embodiment of the present invention.
- FIG. 29 is a diagram showing an operation in the communication system when the transmitting terminal according to the fourth embodiment of the present invention moves.
- FIG. 30 is a diagram showing a communication system according to a fifth embodiment of the present invention.
- FIG. 31 is a diagram showing processing in an initial state of a multicast tree according to a fifth embodiment of the present invention.
- FIG. 32 is a diagram showing participation of a receiving terminal in an initial state of a multicast tree according to the fifth embodiment of the present invention.
- FIG. 33 is a diagram showing a process in a stable state of the multicast tree according to the fifth embodiment of the present invention.
- FIG. 34 is a diagram showing participation of receiving terminals in a stable state of the multicast tree according to the fifth embodiment of the present invention.
- FIG. 35 is a flowchart showing a processing procedure at the time of receiving a Join message according to the fifth embodiment of the present invention.
- FIG. 36 is a flowchart showing a processing procedure at the time of receiving a Prune message according to the fifth embodiment of the present invention.
- FIG. 37 is a sequence diagram showing a multicast packet transfer procedure according to a fifth embodiment of the present invention.
- FIG. 38 is a diagram showing a state immediately after the transmission terminal of the communication system according to the sixth embodiment of the present invention has moved.
- FIG. 39 is a block diagram showing a configuration of a receiving terminal according to a sixth embodiment of the present invention.
- FIG. 40 is a diagram showing an entry holding unit of the receiving terminal according to the sixth embodiment of the present invention.
- FIG. 41 is a diagram illustrating a state in which multicast trees coexist before and after a transmission terminal address change according to a sixth embodiment of the present invention.
- FIG. 42 is a diagram showing a state where only the multicast library after the transmission terminal address is changed is maintained according to the sixth embodiment of the present invention.
- FIG. 43 is a flowchart showing an UR operation procedure according to the sixth embodiment of the present invention.
- FIG. 44 is a flowchart showing an operation procedure of the receiving terminal according to the sixth embodiment of the present invention.
- the communication system 1 includes a transmitting terminal 10, a plurality of UMP routers (UMP Routers, hereinafter referred to as "UR") 20a to 20h, and a plurality of non-UMP routers (Non-UMP Routers, hereinafter). 30a to 30f, and a plurality of receiving terminals 40a to 40d.
- the transmitting terminal 10, UR20a-20h, and NR30a-30f are hierarchically connected.
- the transmitting terminal 10 is arranged at the most upstream, and the UR 20f 20h and the NR 30d 30f are arranged at the most downstream.
- the transmitting terminal 10 is provided with a transmitting terminal address "S". Addresses “R1”, “R2”, “R3”, and “R4” are assigned to the receiving terminals 40a, 40b, 40c, and 40d, respectively. UR20a, 20b, 20c, 20d, 20e, 20f, 20g, 20h have addresses UR1, UR2, UR3, UR4, UR5, UR6, UR7, and UR8, respectively. Is given. Addresses “NR1,” “NR2,” “NR3,” “NR4,” and “NR5” are assigned to the NRs 30a, 3 Ob, 30c, 30d, 30e, 30f, and 30g, respectively. Note that the communication system 1 may use IPv4 which uses IPv6.
- the transmitting terminal 10 transfers the multicast packet to the destination address.
- the receiving terminals 40a and 40d receive the multicast packet.
- the UR 20a-20h and the NR 30a-30f send the multicast to the transfer destination address according to the multicast packet transfer path set between the transmitting terminal 10 and the receiving terminals 40a-40d (hereinafter referred to as "multicast tree"). Forward the packet.
- the UR 20a-20e can act as a branching nolator for forwarding multicast packets to multiple forwarding addresses.
- the receiving terminals 40a-40d and UR20f, 20g, 20h, NR30d, 30e, 30f perform wireless communication.
- the transmitting terminal 10, the URs 20a-20h, and the receiving terminals 40a 40d set a multicast tree.
- the configuration of the UR will be described using the UR20a as an example.
- the UR2 Oa includes an entry holding unit 21a, a receiving unit 22, a transfer unit 23, a transfer control unit 24, a message processing unit 25, and a message providing unit 26.
- UR20b-20h has the same configuration as UR20a.
- the receiving unit 22 receives the transmitting terminal 10, other URs and NRs, the receiving terminals 40a and 40d, and other multicast packets and control messages.
- the multicast packet includes data from the transmitting terminal 10.
- a multicast packet is encapsulated and transmitted between the transmitting terminal and the UR, and between the URs.
- the control message is a message related to the control of the multicast tree, such as setting, maintaining, and changing the multicast tree.
- a Join message In the control message, a Join message, a Membership Report, and a Stable option are set.
- a Join message (hereinafter, referred to as a "Stable Join message”), and a Membership Report with the Stable option set (hereinafter, referred to as a "Stable Membership Report”).
- Prune message 1 ⁇ Leave roup message, Redirect message 1 ⁇ , Bmamg Update message (hereinafter referred to as "BU message”), Location Update message (hereinafter referred to as "LU message”), etc.
- BU message Bmamg Update message
- LU message Location Update message
- the Join message or Membership Report is a join request message requesting that the transmitting terminal 10 add an address to the destination address to which the multicast packet is transmitted or the UR 20a 20h to the destination address to which the multicast packet is transferred. is there. That is, the participation request message is a control message requesting the transmitting terminal 10 to transmit a multicast packet.
- the multicast tree has an initial state and a stable state. The multicast tree transitions from an initial state to a stable state. When the number of newly joining receiving terminals decreases, the multicast tree is judged to have shifted to a stable state.
- the Join message and Members Hip Report will be a maintenance request message for maintaining the multicast tree transmitted in the initial state of the multicast tree.
- the Stable Join message and the Staple Membership Report are maintenance request messages for maintaining the multicast tree transmitted after the multicast tree has transitioned to the stable state.
- the Prune message and the Leave Group message are leave request messages requesting to leave the multicast tree.
- the UR20a 20h and the receiving terminals 40a-40d transmit the Join message and the Prune message.
- the Membership Report and Leave Group messages are transmitted by the receiving terminals 40a to 40d.
- the Redirect message is a join / withdrawal request message requesting that an address be added to a destination address or a transfer destination address, and that the address be deleted from the destination address or the transfer destination address.
- the Redirect message includes a Join message and a Prune message.
- the Ridirect message includes an address requesting addition to the transfer destination address or the transmission destination address, and an address requesting deletion from the transfer destination address or the transmission destination address.
- the BU message is a change notification message for notifying the destination address of the change of the transmission terminal address when the transmission terminal address is changed.
- the LU message is a location update message that notifies the receiving terminal of the changed transmitting terminal address when the transmitting terminal address is changed. For example, when the sending terminal address is changed due to movement of the sending terminal 10, the LU message notifies the receiving terminal by associating the sending terminal address before the change with the changed sending terminal address, and notifies the receiving terminal. Notification of the move.
- the sending terminal adds the LU message to a multicast packet that can be sent by itself and transfers it.
- Receiving section 22 determines whether the message is a control message or a multicast packet based on an option of the header.
- the receiving unit 22 transmits the control message to the message processing unit 25. To enter.
- the receiving unit 22 inputs the multicast packet to the transfer control unit 24. At this time, if the multicast packet is encapsulated, the receiving unit 22 converts the multicast packet into a deep cell and inputs the extracted multicast packet. Note that the receiving unit 22 inputs a packet not addressed to the UR 20a itself to the transfer unit 23 as it is.
- the transfer unit 23 transfers the control message to the transmitting terminal 10, other URs and NRs, and the receiving terminals 40a and 40d.
- the transfer unit 23 transfers the multicast packet to another UR, NR, or receiving terminal 40a 40d.
- the transfer unit 23 obtains a multicast packet from the reception unit 22 or the transfer control unit 24.
- the transfer unit 23 acquires a control message from the message processing unit 25 and the message providing unit 26.
- the entry holding unit 21a is a transfer destination holding unit that holds a transfer destination address. As shown in FIG. 3, the entry holding unit 21a stores a transfer destination address, a KAT (Keep Alive Timer) in association with a table type, a transmission terminal address, a multicast address, a tunnel source address, and a previous tunnel source address. ), JT (Join Timer) is held.
- KAT Keep Alive Timer
- JT Join Timer
- the table types include a multicast control table (Multicast Control Table, hereinafter referred to as "MCT”) and a multicast forwarding table (Multicast Forwarding Table, hereinafter referred to as "MFT").
- MCT Multicast Control Table
- MFT Multicast Forwarding Table
- the transmitting terminal address may be changed due to the movement of the transmitting terminal 10 or the like. Therefore, the entry holding unit 21a can hold the MCT entry or MFT entry of the current transmitting terminal address at the current position of the transmitting terminal 10, and the MCT entry or MFT entry of the transmitting terminal address before the change.
- a multicast tree or a multicast packet can specify which multicast group from which transmitting terminal 10 relates to which multicast group by the combination of the transmitting terminal address and the multicast group address.
- a multicast group to which the transmitting terminal 10 forwards the multicast packet is assigned a multicast group address “G”.
- the entry holding unit 21a associates the transmission terminal address with the multicast gnope address. Attach and hold.
- the entry held by the entry holding unit 21a can be specified by a combination of the transmission terminal address and the multicast group address.
- the entry holding unit 21a holds an entry regarding the multicast stream in which the UR 20a is participating. I do.
- the tunnel source address is a source address used for encapsulating a multicast packet received by the UR. Therefore, for example, the tunnel source address registered in the entry holding unit 21a of the UR 20a is the transmission terminal address “S”.
- the previous tunnel source address is the tunnel source address before the change when the tunnel source address is changed.
- the transfer destination address is an address indicating a transfer destination to which the UR transfers the multicast packet.
- KAT is a timer value for measuring a holding time of a transfer destination address or a transmission destination address.
- the KAT is held in association with the transfer destination address.
- the holding time is a time during which the transmitting terminal 10 or the UR 20a-20f holds the transfer destination address or the transmission destination address.
- KAT (UR3) indicates the KAT of the transfer destination address “UR3”
- KAT (UR2) indicates the KAT of the transfer destination address “UR2”.
- the transfer destination address whose KAT has expired is deleted from the entry holding unit 21a.
- JT is a timer value that measures the time until the start of transmitting the Join message.
- a Join message is sent upon expiration of JT.
- JT will be restarted upon expiration of JT.
- JT is held in association with the transmitting terminal address and the multicast gnorape address. If the table type is MCT, it is not necessary to hold the tunnel source address, previous tunnel source address, and JT.
- the transfer control unit 24 controls the transfer of the multicast packet based on the transfer destination address. Specifically, the transfer control unit 24 acquires a multicast packet from the receiving unit 22. The transfer control unit 24 searches the entry holding unit 21a and obtains a transfer destination address associated with the transmission terminal address and the multicast group address included in the obtained multicast packet.
- the transfer control unit 24 sets the entry holding unit 21a to Refer to and duplicate the multicast packet so that the multicast packet has the number of forwarding addresses. It should be noted that the transfer control unit 24 does not need to perform duplication when there are several transfer destination addresses.
- the transfer control unit 24 compares the destination address of the decapsulated multicast packet with the transfer destination address held by the entry holding unit 21a, and when the destination address and the transfer destination address are different, The multicast packet is encapsulated at the destination address. Specifically, the transfer control unit 24 sets the transfer destination address acquired from the entry holding unit 21a as the destination address, sets the address of the UR 20a itself as the source address, and encapsulates the multicast packet. . The transfer control unit 24 inputs the encapsulated multicast bucket to the transfer unit 23.
- the transfer control unit 24 can perform encapsulation using, for example, an encapsulation technique indicated in “IP in IP Tunneling” (RFC1853) or “Generic Packet Tunneling in Ipv6 Specification J (RFC2473)”.
- the transfer control unit 24 compares the destination address of the decapsulated multicast packet with the transfer destination address held by the entry holding unit 21a, and when the transfer destination address is the same as the destination address, Then, the multicast packet is directly input to the transfer unit 23.
- the message processing unit 25 processes the control message.
- the message processing unit 25 functions as a transfer destination registration unit that registers the address of another multicast-capable router (UR) in the transfer destination holding unit as a transfer destination address in association with the transmission terminal address and the multicast group address.
- the message processing unit 25 acquires the control message received by the UR 20a from the receiving unit 22.
- the message processing unit 25 registers the information in the entry holding unit 21a based on the type of the control message, the destination address and the source address of the control message, and the information held by the entry holding unit 21a. Update or delete the information that is retained.
- the message processing unit 25 When registering a new transfer destination address, the message processing unit 25 generates an MFT entry or an MCT entry. Specifically, the message processing unit 25 sets MFT or MCT as the table type of the entry holding unit 21a, and generates an MFT entry or an MCT entry for each transmission terminal address and multicast group address. For example, the message processing unit 25 sends a message to the transmitting terminal that is newly received by the UR 20a and specified by the join message. Generate MFT entry or MCT entry for each address and multicast group address. The MFT entry or MCT entry generated in this way functions as an MFT or MCT.
- the message processing unit 25 registers the generated MFT entry in association with the transmission terminal address, the multicast group address, the tunnel source address, the previous tunnel source address, the transfer destination address, KAT, and JT.
- the message processing unit 25 registers the generated MCT entry in association with the transmission terminal address, the multicast group address, the transfer destination address, and ⁇ .
- the message processing unit 25 inputs the received control message to the message providing unit 26.
- the message providing unit 26 generates a control message and provides it to the transmitting terminal 10 and other URs.
- the message providing unit 26 functions as a router message providing unit that provides a participation request message requesting that the address of the multicast-capable router be added to the transmission destination address to the transmission terminal address.
- the message providing unit 26 acquires the control message received by the UR 20a from the message processing unit 25.
- the message providing unit 26 generates a control message based on the acquired control message and the information held by the entry holding unit 2la.
- the message providing unit 26 inputs the generated control message to the transfer unit 23, and provides the control message to the transmission terminal 10 and other URs via the transfer unit 23.
- the transmitting terminal 10 includes an entry holding unit 11, a receiving unit 12, a transmitting unit 13, a message processing unit 14, and a packet generating unit 15.
- the receiving unit 12 receives a control message from the UR 20a 20h.
- the receiving unit 12 inputs the received control message to the message processing unit 14.
- the entry holding unit 11 is a destination holding unit that holds a destination address. As shown in FIG. 5, the entry holding unit 11 holds a destination address and a KAT in association with a table type, a transmission terminal address, and a multicast group address. Since the transmitting terminal 10 does not use anything other than the MFT, “MFT” is set in the table type.
- the destination address is This is the address to which the transmitting terminal 10 transmits the multicast packet.
- the destination address held by the transmitting terminal 10 is the address of the multicast-capable router (UR address) or the address of the receiving terminal.
- KAT indicates the KAT of the destination address “UR1”.
- the transmitting terminal address may be changed due to the movement of the transmitting terminal 10 or the like. Therefore, the entry holding unit 11 can hold the MFT entry of the current transmitting terminal address at the current position of the transmitting terminal 10 and the MFT entry of the transmitting terminal address before the change.
- the message processing unit 14 processes the control message.
- the message processing unit 14 functions as a destination registration unit that registers the address of the multicast-capable router (UR) as a destination address in the destination holding unit based on the participation request message.
- the message processing unit 14 acquires the control message received by the transmitting terminal 10 from the receiving unit 12.
- the message processing unit 14 registers information in the entry holding unit 11 and updates information held in the entry holding unit 11 based on the type of the control message, the source address of the control message, and the information held by the entry holding unit 11. And delete.
- Message processing unit 14 sets MFT as the table type of entry holding unit 11, and generates an MFT entry for each transmission terminal address and multicast group address. For example, the message processing unit 14 generates an MFT entry for each transmission terminal address and multicast group address newly received by the transmission terminal 10 specified by a Join message or a Redirect message. The message processing unit 14 registers the generated MFT entry in association with the transmission terminal address, the multicast group address, the transmission destination address, and the KAT.
- the packet generation unit 15 generates a multicast packet including data.
- the packet generator 15 generates a control message such as a BU message or an LU message, or a multicast packet to which an LU message is added, as necessary.
- the packet generator 15 generates a multicast packet based on the destination address.
- the packet generation unit 15 acquires the transmission destination address from the entry holding unit 11. Further, the packet generation unit 15 obtains data based on an input from the application unit or an external input.
- the packet generation unit 15 adds a transmission terminal address as a transmission source address, Generate a multicast packet with the multicast group address added as the destination address.
- the packet generation unit 15 refers to the entry holding unit 11 and copies the generated multicast packet so that the number of the multicast packet is equal to the number of destination addresses. Note that the packet generation unit 15 does not need to perform duplication when the number of destination addresses is one.
- the packet generation unit 15 sets the transmission terminal address as the transmission source address, sets the transmission destination address as the destination address, and encapsulates the multicast packet.
- the packet generator 15 inputs the encapsulated multicast packet to the transmitter 13.
- Transmitting section 13 transmits a multicast packet or a control message to UR 20a 20h or NR 30a-30f, and to receiving terminals 40a-40d.
- the transmitting unit 13 obtains the encapsulated multicast packet from the packet generating unit 15 and obtains a control message from the message processing unit 14.
- Figure 6 shows the operation procedure when receiving a packet.
- the receiving unit 22 of the UR 20a-20h receives a packet from an adjacent UR or NR (S101).
- the receiving unit 22 determines whether a special option is set in the received packet (S102).
- the Hop-by-Hop option specified in RFC2460 can be used.
- the Router Alert option specified in RFC2113 can be used. This allows the URs 20a-20h to notify other URs and the transmitting terminal 10 that the packet is a special control message.
- data indicating that the message should not be discarded even if the option cannot be interpreted For example, in the case of the Hop_by_Hop option, an option that starts with the option type starting with "00" is added. Can be added.
- step (S102) if no special option is set, the receiving unit 22 determines whether the destination address of the packet is the UR itself (S103). On the other hand, in the case of a control message in which a special option is set in step (S102), the receiving unit 22 inputs the control message to the message processing unit 25 (S108).
- step (SI03) if the destination address of the packet is not the UR itself, the receiving unit 22 inputs the packet to the transfer unit 23 (S104). On the other hand, if the destination address of the packet is the UR itself in step (S103), the receiving unit 22 determines whether the packet is encapsulated (S105). If the packet is encapsulated, the receiving unit 22 decapsulates and extracts the packet (S106).
- the receiving unit 22 determines whether the received packet itself or a packet extracted by decapsulation is a multicast packet or a control message (S107). If the packet is a multicast packet in step (SI07), the receiving unit 22 inputs the multicast packet to the transfer control unit 24 (S108). On the other hand, if the packet is determined to be a control message in step (S107), the receiving unit 22 inputs the control message to the message processing unit 25 (S109).
- UR20a-20h repeats the procedure shown in Fig. 6 every time it receives a packet.
- FIG. 7 shows a processing procedure when the UR 20a receives a multicast packet.
- the receiving unit 22 receives the multicast packet (S201).
- the receiving unit 22 decapsulates the encapsulated multicast packet.
- the receiving unit 22 inputs the extracted multicast packet and the source address set in the encapsulated multicast packet to the transfer control unit 24.
- the transfer control unit 24 sets the source address of the encapsulated multicast packet as the tunnel source address of the entry holding unit 21a (S202).
- step (S202) when the tunnel source address is different from the already set tunnel source address, the transfer control unit 24 stores the already set tunnel source address in the previous tunnel of the entry holding unit 21a. You may set it to the original address. According to this, when the receiving unit 22 subsequently receives a multicast packet from the previous tunnel source address, the message providing unit 26 explicitly transmits a Prune message to the previous tunnel source address. By doing so, duplicate reception of multicast packets can be prevented.
- the transfer control unit 24 searches the entry holding unit 21a and determines whether or not there is an entry including the transmission terminal address “S” and the multicast group address “G” included in the multicast packet acquired from the reception unit 22 (S203).
- the transfer control unit 24 determines whether or not the destination address of the multicast packet is included in the transfer destination address of the entry (S204). If the destination address is not included in the transfer destination address, the transfer control unit 24 stably checks the multicast tree specified by the transmission terminal address “S” and the multicast group address “G” included in the multicast packet. It is determined whether or not (S205).
- the transfer control unit 24 determines whether or not there are a plurality of transfer destination addresses in the entry including the transmission terminal address “S” and the multicast group address “G” of the entry holding unit 21a. Is determined (S206). If there is no plurality of transfer destination addresses, the transfer control unit 24 instructs the message providing unit 26 to generate a Redirect message.
- the message providing unit 26 generates a Redirect message for the tunnel source address of the multicast packet, and transmits the message to the transfer unit 23 (S207).
- the Redirect message includes a Prune message requesting that the UR receiving the multicast packet leave itself, and a Join message requesting that the UR join the transfer destination address held in the entry holding unit 21a.
- the transfer control unit 24 encapsulates the multicast packet with the transfer destination address. (S208). At this time, the transfer control unit 24 duplicates the multicast packet so as to have the number of transfer destination addresses, and encapsulates each multicast packet using the transfer destination address. The transfer control unit 24 inputs the encapsulated multicast packet to the transfer unit 23. Then, the transfer unit 23 transfers the multicast packet based on the destination address (S209).
- step (S204) when the destination address is included in the transfer destination address, the transfer control unit 24 inputs the received multicast packet to the transfer unit 23 as it is. Then, the transfer unit 23 converts the received multicast packet based on the destination address. It is transferred as it is (S209). In this way, the transfer control unit 24 controls the transfer of the multicast packet based on the transfer destination address by performing encapsulation using the transfer destination address. On the other hand, if there is no entry in step (S203), the transfer control unit 24 discards the acquired multicast packet (S210).
- FIG. 8 and FIG. 9 show a processing procedure when the UR 20a 20h receives a control message.
- FIG. 8 shows the case of the control message 3 ⁇ 4oin message.
- the receiving unit 22 receives the Join message and inputs it to the message processing unit 25 (S301).
- the message processing unit 25 searches the entry holding unit 21a and determines whether or not there is an entry including the transmission terminal address “S” and the multicast group address “G” included in the obtained and obtained oin message (S302). If an entry exists, the message processing unit 25 determines whether there is a plurality of transfer destination addresses in the entry including the transmission terminal address “S” and the multicast group address “G” in the entry holding unit 21a. (S303).
- the message processing unit 25 determines whether the transfer destination address includes the source address of the Join message (S304). When determining that the message is included, the message processing unit 25 determines whether or not the received oin message is a Stable Join message with the Stable option set (S305). When determining that the Stable option is set, the message processing unit 25 inputs the received ⁇ Join message to the transfer unit 23. The transfer unit 23 transfers the received ⁇ Join message as it is upstream (S306).
- (S304) if the message processing unit 25 determines that the transfer destination address of the MFT entry does not include the source address of the Join message, the MFT held by the entry holding unit 21a The source address is added to the transfer destination address of the entry (S308). Then, the message processing unit 25 discards the Join message (S309). Further, the message processing unit 25 activates the KAT for the transfer destination address added to the entry holding unit 21a (S310).
- step (S303) when the message processing unit 25 determines in step (S303) that there are a plurality of transfer destination addresses, it determines whether or not the transfer destination address includes the source address of the Join message (S307). . The message processing unit 25 determines that the transfer destination address is included. If the connection has been disconnected, the processing of steps (S309) and (S310) is performed. When determining that the transfer destination address is not included, the message processing unit 25 performs the processing of steps (S308) to (S310).
- the message processing unit 25 determines whether the received message is a Stable Join message in which the join message power Stable option is set. (S311). If the message processing unit 25 determines that the S table option has not been set and determines that the S table option has not been set, the source address of the Join message is transferred to the transmission terminal address “S” and the multicast group address “G” included in the Join message. Generate a new MFT entry associated with the address. The message processing unit 25 registers the generated MFT entry in the entry holding unit 21a. Then, the message processing unit 25 activates the JT of the registered transfer destination address (S312). Further, the message processing unit 25 activates the KAT of the registered transfer destination address (S313).
- the message processing unit 25 discards the Join message (S314). Further, the message processing unit 25 instructs the message providing unit 26 to generate a Join message.
- the message provider 26 sets the UR's own address as the source address and sets the source terminal address as the destination address, and generates a Join message. Then, the message providing unit 26 inputs the generated oin message to the transfer unit 23, and the transfer unit 23 transmits a Join message (S315).
- step (S 311) when the message processing unit 25 determines that the multicast tree is stable, the message processing unit 25 inputs the received oin message to the transfer unit 23 as it is.
- the transfer unit 23 transfers the Join message directly to the upstream based on the transmission terminal address included in the Join message (S316).
- the message processing unit 25 sets the transfer destination address in association with the transmission terminal address "S" and the multicast group address "G". Is registered in the entry holding unit 21a.
- the message providing unit 26 provides a Join message (participation request message) requesting to add the UR address to the destination address of the transmitting terminal 10 to the transmitting terminal address.
- the Join message is a message that the UR requests to transmit a multicast packet from, for example, the receiving terminal 40a 40d, that is, a Join message requesting to join the multicast tree. Generated in response to the message, and transmitted to the transmission terminal 10 located upstream. Also, the UR itself sets the address of the UR itself as the source address and transmits an oin message, and the other UR registers the transfer destination address in the entry holding unit 21a based on the Join message. Therefore, the message processing unit 25 can register the address of another UR as the transfer destination address in the entry holding unit 21a.
- FIG. 9 shows the case of the control message power SPmne message.
- the message processing unit 25 acquires a Prune message from the receiving unit 22 (S401).
- the message processing unit 25 searches the entry holding unit 21a and determines whether or not there is an entry including the transmission terminal address “S”, the multicast group address “G”, and the transfer destination address included in the acquired Prune message. Is determined (S402).
- the message processing unit 25 deletes the transfer destination address included in the Prune message from the entry (S403). On the other hand, when the entry does not exist, the message processing unit 25 discards the Prune message (S410). The message processing unit 25 determines whether or not the entry disappears as a result of deleting the transfer destination address in step (S403) (S404). The entry disappears when the transfer destination address becomes 0.
- the message processing unit 25 instructs the message providing unit 26 to generate a Prune message.
- the message providing unit 26 sets the UR's own address as the transmission source address, and generates a Prune message in which the transmission terminal address is set as the destination address (S405).
- the message providing unit 26 inputs the generated Prune message to the transfer unit 23 (S409).
- the Prune message is transmitted to the transmitting terminal 10 in order for the UR to explicitly leave the multicast tree.
- the message processing unit 25 determines that the multicast tree specified by the transmission terminal address “S” and the multicast group address “G” included in the Prune message has stabilized. It is determined whether or not it is (S406). If the multicast tree is stable, the message processing unit 25 determines whether there is a plurality of transfer destination addresses in the entry including the transmission terminal address “S” and the multicast group address “G” (S407). ).
- the message processing unit 25 determines that the UR itself is not a duplication point for duplicating the multicast packet received by the UR.
- the message processing unit 25 instructs the message providing unit 26 to generate a Redirec message.
- the message providing unit 26 generates a Redirect message (S408).
- the message providing unit 26 sets the address of the UR itself as the source address of the Redirect message.
- the message providing unit 26 deletes the UR itself from the transfer destination address or the transmission destination address, and generates a Redeirect message requesting that the transfer destination address remaining in the entry be added to the transfer destination address or the transmission destination address.
- the Redirect message is transmitted from the UR itself when the UR receives a message requesting withdrawal of the multicast tree from the receiving terminals 40a and 40d and other URs when the multicast tree is in a stable state.
- This can also be used as a change request message that instructs the upstream UR or transmission terminal 10 to change the information held by the entry holding units n and 21a.
- the transfer unit 23 transfers the Prune message or the Redirect message based on the transmission terminal address included in the Prune message or the Redirect message. If the multicast tree is not stable in step (S406), or if there are a plurality of transfer destination addresses in step (S407), the message processing unit 25 ends the process.
- FIGS. Fig. 10 shows the procedure
- Fig. 11 shows the communication system 1.
- the entry holding units 21a to 21h of the UR 20a 20h and the entry holding unit 11 of the transmission terminal 10 will be described as necessary. However, for the sake of simplicity, only the table type, the transmission terminal address, the multicast group address, the transfer destination address or the transmission destination address are shown in the information retained by the entry storage units 11, 21a and 21h. .
- the transmission terminal address, the multicast group address, the transfer destination address or the transmission destination address are represented by (transmission terminal address, multicast group address): [transmission destination address or transmission destination address].
- Notation. (Sending terminal address, multicast group address) can specify the multicast tree or multicast packet related to which multicast group from which sending terminal. Also, the transmission terminal 10 will be described as the most upstream.
- the receiving terminal 40a transmits a participation request message to the UR 20f (S501). If the router to which the receiving terminal 40a is connected via a wireless link is a UR, the receiving terminal 40a uses IGMPv2 (Internet Management Protocol Version 2) or MLDv2 (Multicast Listener Discovery Version 2, "draft—vida—mid—v2 — See xx.txt ”) to request the transmission of multicast packets and request to join the multicast tree. Specifically, receiving terminal 40a transmits Membership Report2 to UR20f. Note that the receiving terminal 40a follows the MLDv2 when using IPv6, but transmits the Membership Report2 according to IGMPv3 when using IPv4.
- the message processing unit 25 of the UR20f based on the transmission terminal multicast address "G" set in Membership Report 2, associates the transmission terminal address "S" with the M: and the transfer destination address "G” by associating the MFT. Generate an entry.
- This MFT entry indicates that the receiving terminal 40a that desires to receive the multicast packet specified by the combination of the transmitting terminal address “S” and the multicast address “G” exists under the UR 20f itself. That is, when the transfer destination address is the multicast group address “G”, it indicates that the receiving terminal 40a that desires to receive the multicast packet specified by (S, G) is connected to the UR 20f.
- the transfer unit 23 of the UR 20f transmits the multicast packet decapsulated by the transfer control unit 24 to the receiving terminal 40a connected to the UR 20f itself.
- the message processing unit 25 registers the generated MFT entry in the entry holding unit 21f (S502).
- the message providing unit 26 of the UR 20f generates a Join message 3 requesting that the address of the UR 20f be added to the destination address of the transmitting terminal 10, and transmits the joining message 3 via the transfer unit 23. It is provided to the address (S503). Specifically, the message providing unit 26 sets the transmission terminal address “S” as the destination address, the address “UR6” of the UR20f as the source address, specifies the multicast group address “G”, and generates the oin message 3 I do. The UR and the transmitting terminal 10 existing upstream from the UR 20f can detect that the received packet is a Join message by the special option set in the Join message 3. The transfer unit 23 transfers the Join message 3 based on the transmission terminal address “S” set in the destination address.
- the UR 20d connected to the UR 20f and located upstream of the UR 20f receives the Join message 3.
- the message processing unit 25 of the UR 20d transmits the multicast address “S”, the multicast address “G”, and the multicast address “G6” based on the source address “UR6” and the multicast Generate an MFT entry that associates the address “G” with the transfer destination address “UR6”.
- the message processing unit 25 registers the generated MFT entry in the entry holding unit 21d (S504).
- the message providing unit 26 of the UR 20d sets the transmission terminal address “S” as the destination address, the UR 20d address “UR4” as the transmission source address, specifies the multicast group address “Gj”, and sends the oin message 3 It is generated and provided to the transmission terminal address via the transfer unit 23 (S505).
- the message providing unit 26 of the UR20b sets the transmission terminal address "S" as the destination address, the UR20b address "UR2" as the transmission source address, specifies the multicast group address "GJ", and sends the oin message 3 It is generated and provided to the transmission terminal address via the transfer unit 23 (S507).
- the NR 30a existing between the UR 20b and the UR 20a located upstream of the UR 20b sends a Join message 3 based on the transmission terminal address "S" set as the transmission destination address, to the unit. Transfer by casting.
- the UR 20a located upstream of the UR 20b receives the Join message 3.
- the message processing unit 25 of the UR 20a generates an MFT entry in which the transmission terminal address “S”, the multicast address “G”, and the transfer destination address “UR2” are associated based on the Join message 3.
- the message processing unit 25 registers the generated MFT entry in the entry holding unit 21a (S508).
- the message providing unit 26 of the UR 20a sets the transmission terminal address "S" as the destination address, the UR 20a address "UR1" as the transmission source address, specifies the multicast group address "GJ", and sends the oin message 3 It is generated and provided to the transmission terminal address via the transfer unit 23 (S509).
- the message processing unit 14 of the transmission terminal 10 transmits the transmission terminal address "S" based on the transmission terminal address "S" set in the Join message 3, the multicast address "G", and the source address "UR1". An MFT entry that associates “S” with the multicast address “G” and the destination address “UR1” is generated.
- the message processing unit 14 registers the generated MFT entry in the entry holding unit 11 (S510). As described above, the message processing unit 14 registers the address “U R1” of the UR 20a located at the most upstream position in the entry holding unit 11 when the transmission terminal address “S” is set to the upstream of the multicast tree.
- FIG. 12 shows the procedure
- FIG. 13 shows the state of the communication system 1.
- the packet generation unit 15 of the transmission terminal 10 refers to the entry holding unit 11 and sets the transmission terminal address "S" as the transmission source address and the multicast group address "G" as the destination address in the data. Generate a multicast packet. Then, the packet generation unit 15 sets the transmission terminal address “S” as the transmission source address and the destination address “UR1” held by the entry holding unit 11 as the destination address in the generated multicast packet, and The multicast packet is encapsulated. Then, the transmitting unit 13 of the transmitting terminal 10 transmits the encapsulated multicast packet 5a to the UR 20a based on the destination address “UR1” (S601).
- the receiving unit 22 of the UR 20a decapsulates the encapsulated multicast packet 5a.
- the receiving unit 22 inputs the extracted multicast packet and the source address “S” set in the encapsulated multicast packet 5a to the transfer control unit 24.
- the transfer control unit 24 sets the source address “S” of the encapsulated multicast packet 5a as the tunnel source address of the entry holding unit 21a.
- the transfer control unit 24 of the UR 20a refers to the entry holding unit 21a, and since the transfer destination address "UR2" is different from the destination address "G" of the decapsulated multicast packet, the address of the UR 20a itself is determined as the source address. Encapsulate by setting "UR1" and the transfer destination address "UR2" as the destination address. Then, the transfer unit 23 transfers the encapsulated multicast packet 5b to the UR 20b based on the destination address “UR2” (S602).
- the NR 30a existing on the path between the UR 20a and the UR 20b can be transferred by a normal unicast process based on the destination address "UR2" without being aware that the multicast packet 5a is a multicast packet. .
- the receiving unit 22 of the UR 20b decapsulates the encapsulated multicast packet 5b.
- the transfer control unit 24 of the UR 20b sets the source address “UR1” of the multicast packet 5b that has been force-packaged to the tunnel source address of the entry holding unit 21b.
- the transfer control unit 24 of the UR2 Ob refers to the entry holding unit 21b and, because the transfer destination address “UR4” and the destination address “G” of the decapsulated multicast packet are different, the transfer address of the UR20b itself is used as the source address.
- the address "UR2" and the transfer destination address "UR4" as the destination address are set and encapsulated.
- the transfer unit 23 transfers the encapsulated multicast packet 5c to the UR 20d based on the destination address “UR4” (S603).
- the receiving unit 22 of the UR 20d decapsulates the encapsulated multicast packet 5c.
- the transfer control unit 24 of the UR 20d sets the source address “UR2” of the multicast packet 5c that has been force-packaged to the tunnel source address of the entry holding unit 21d.
- the transfer control unit 24 of the UR2 Od refers to the entry holding unit 21d, and sets the transfer destination address "UR6" and the directory. Since the destination address “G” of the encapsulated multicast packet is different, the UR20d's own address “UR4” is set as the source address, and the transfer destination address “UR6” is set as the destination address for encapsulation. Then, the transfer unit 23 transfers the encapsulated multicast packet 5d to the UR 20f based on the destination address “UR6” (S604).
- the receiving unit 22 of the UR 20f decapsulates the encapsulated multicast packet 5d and extracts the multicast packet 5e.
- the transfer control unit 24 of the UR 20f sets the source address “UR4” of the encapsulated multicast packet 5d as the tunnel source address of the entry holding unit 21f.
- the transfer control unit 24 of the UR 20f refers to the entry holding unit 21f, and determines that the transfer destination address “G” is the same as the destination address “G” of the decapsulated multicast packet.
- the transfer unit 23 transmits the multicast packet 5e to the receiving terminal 40a by multicast based on the destination address “G” (S605).
- the multicast packet is transferred from transmitting terminal 10 to receiving terminal 40a according to the set multicast tree.
- the multicast packets 5a-5d are encapsulated by the transmission destination address and the transmission destination address (UR1, UR2, UR4, UR6). Therefore, the NR 30a existing between the transmitting terminal 10 and the UR 20f can transfer the multicast packet by a normal unicast without being aware that the received packet is a multicast packet.
- FIGS. 15 and 17 the states of the entry holding units 21a, 21b, and 21e before the update are stored in the entry holding units 21a, 21b, and 21e. Shown as parts 21 la, 211b, 211e.
- receiving terminal 40b transmits Membership Report 2 to UR 20g, and requests participation in the multicast tree (S701).
- the message processing unit 25 of the UR 20g based on the transmission terminal address "S" set in the Membership Report 2 and the multicast address "G", transmits the transmission terminal address "S"
- the message processing unit 25 registers the generated MFT entry in the entry holding unit 21g (S702).
- the message providing unit 26 of the UR20g sets the transmission terminal address "S" as the destination address, the UR20g address "UR7" as the transmission source address, specifies the multicast group address "G", and generates the oin message 3 I do.
- the transfer unit 23 transfers the Join message 3 based on the transmission terminal address “S” set as the destination address (S703).
- the NR30b existing between the UR20g and the UR20b located upstream of the UR20g transfers the Join message 3 by multicast based on the transmission terminal address "S" set in the transmission destination address. .
- UR20b located upstream of UR20g receives Join message 3.
- the message processing unit 25 of the UR 20b updates the entry holding unit 21b based on the received join message 3 and the entry held by the entry holding unit 21b.
- the message processing unit 25 determines, based on the transfer destination address "UR4" held by the pre-update entry holding unit 21lb and "UR7" set as the source address of the ijoin message 3, A new MFT entry is created in which the transmission terminal address “S”, the multicast address “G”, and the transfer destination address “UR4, UR7” are associated with each other.
- the message processing unit 25 registers the newly generated MFT entry in the entry holding unit 21b, thereby changing the state of the entry holding unit 21b from the state of the pre-update entry holding unit 211b to the state of the entry holding unit 21b shown in FIG. Update (S704).
- the multicast packet is transferred to the receiving terminal 40a via the transmitting terminal 10, UR20a, UR20b, UR20d, and UR20f, and the transmitting terminal 10, UR20a,
- the multicast tree to which the receiving terminal 40b (this multicast packet is transferred) is set via the UR20b, UR20d, and UR20g.
- the packet generation unit 15 of the transmission terminal 10 refers to the entry holding unit 11 and sets the transmission terminal address “S” as the transmission source address and the multicast group address “G” as the destination address in the data. Generate a multicast packet. Then, the packet generator 15 The source terminal address “S” is set as the source address in the generated multicast packet, and the destination address “UR1” held by the entry holding unit 11 is set as the destination address, and the multicast packet is encapsulated. Then, the transmitting unit 13 of the transmitting terminal 10 transmits the encapsulated multicast packet 5a to the UR 20a based on the destination address “UR1”.
- the receiving unit 22 of the UR 20a decapsulates the encapsulated multicast packet 5a.
- the receiving unit 22 inputs the extracted multicast packet and the source address “S” set in the encapsulated multicast packet 5a to the transfer control unit 24.
- the transfer control unit 24 sets the source address “S” of the encapsulated multicast packet 5a as the tunnel source address of the entry holding unit 21a.
- the transfer control unit 24 of the UR 20a refers to the entry holding unit 21a, and since the transfer destination address "UR2" is different from the destination address "G" of the decapsulated multicast packet, the address of the UR 20a itself is determined as the source address. Encapsulate by setting "UR1" and the transfer destination address "UR2" as the destination address. Then, the transfer unit 23 transfers the encapsulated multicast packet 5b to the UR 20b based on the destination address “UR2”.
- the receiving unit 22 of the UR 20b decapsulates the encapsulated multicast packet 5b.
- the transfer control unit 24 of the UR 20b refers to the entry holding unit 21b and duplicates the decapsulated multicast packet so that there are two transfer destination addresses, so that the number of multicast packets becomes two.
- the transfer control unit 24 compares the transfer destination address "UR4, UR7J" with the destination address "G" of the decapsulated multicast packet. Since each transfer destination address is different from the destination address, the transfer control unit 24 sets the address “UR2” of the UR20b itself as the source address, and sets the transfer destination address “UR4” as the destination address of one multicast packet. Then, the transfer destination address “UR7” is set as the destination address of the other multicast packet, and the packet is encapsulated.
- the transfer unit 23 transfers the encapsulated multicast packet 5c to the UR 20d based on the destination address "UR4". Further, the transfer unit 23 transfers the encapsulated multicast packet 5f to the UR 20g based on the destination address “UR7”. [0119] The UR20d and UR20f transfer the multicast packets 5d and 5e in the same manner as in Figs. The receiving unit 22 of the UR 20g decapsulates the encapsulated multicast packet 5f to extract the multicast packet 5e.
- the transfer control unit 24 of the UR 20g refers to the entry holding unit 21g, and since the transfer destination address “G” is the same as the destination address “G” of the decapsulated multicast packet, the transfer unit 24 Enter 23.
- the transfer unit 23 transmits the multicast packet 5e to the receiving terminal 40b by multicast based on the destination address “G”. As described above, the multicast packet is transferred from the transmitting terminal 10 to the receiving terminals 40a and 40b according to the set multicast packet.
- FIG. 17 shows a multicast tree newly set by receiving terminals 40c and 40d participating in the multicast tree shown in FIG. Since the receiving terminal 40c is connected to the NR 30e, the receiving terminal 40c detects that the router connected to the NR 30e via the wireless link is the NR. The receiving terminal 40c can detect the presence or absence of the Membership Query. For example, when the receiving terminal 40c cannot receive the Membership Query for a specified time or longer, it can determine that there is no UR transmitting the Membership Query, and can detect that it is connected to the NR.
- the receiving terminal 40c can determine that there is no UR capable of processing the Membership Report even in a case where the multicast packet cannot be received even after the lapse of the specified time, and the receiving terminal 40c connects to the NR. Can be detected.
- the receiving terminal 40c When connected to the NR, the receiving terminal 40c transmits a Join message 3 requesting participation in the multicast stream specified by (S, G). Since a special option is set for the Join message 3 transmitted by the receiving terminal 40c, the NR 30e does not discard the Join message 3 and the UR existing on the route from the receiving terminal 40c to the transmitting terminal 10 is a Join message. 3 can be received.
- the receiving terminal 40c sets the transmission terminal address “S” as the destination address, sets the address “R3” of the receiving terminal 40c as the source address, specifies the multicast group address “G”, and transmits the fcjoin message 3 . In this case, in the UR, the UR 20e, which is the most downstream in the path from the receiving terminal 40c to the transmitting terminal 10, receives the Join message 3.
- the UR20a becomes Also need to transfer multicast packets. Therefore, the message processing unit 25 of the UR 20a changes the entry held by the entry holding unit 21a from the entry (S, G): [UR2] in the pre-update entry holding unit 21 la to the entry (S, G): [ UR2, UR3]. Also, the UR 20c needs to transfer a multicast packet to the UR 20e. Therefore, the message processing unit 25 of the UR 20c registers the entry (S, G): [UR5] in the entry holding unit 21c.
- the message processing unit 25 of the UR 20e registers the entry (S, G): [R3] as shown in the pre-update entry holding unit 21le in the entry holding unit 21e.
- the UR 20e needs to transfer the multicast packet also to the UR 20h. Therefore, the message processing unit 25 of the UR 20e converts the entry held by the entry holding unit 21e from the entry (S, G): [R3] of the pre-update entry holding unit 211e to the entry (S, G): [R3, UR8 To]. Further, the message processing unit 25 of the UR 20h registers the entry (S, G): [G] in the entry holding unit 21h. Thereby, a multicast tree in which the multicast packet is transferred from the transmitting terminal 10 to the plurality of receiving terminals 40a to 40e is set.
- Transfer of a multicast packet according to this multicast tree is performed as follows.
- the packet generation unit 15 of the transmission terminal 10 refers to the entry holding unit 11 and sets the transmission terminal address “S” as the source address and the multicast group address “G” as the destination address in the data, and sets the multicast packet.
- the packet generation unit 15 sets the transmission terminal address “S” as the source address and the destination address “UR1” held by the entry holding unit 11 as the destination address in the generated multicast packet, and encapsulates the multicast packet.
- the transmitting unit 13 of the transmitting terminal 10 transmits the multicast packet 5a converted into a packet to the UR 20a based on the destination address “UR1”.
- the receiving unit 22 of the UR 20a decapsulates the encapsulated multicast packet 5a.
- the transfer control unit 24 of the UR 20a refers to the entry holding unit 21a and determines that the transfer destination address is Since there are two, duplicate the decapsulated multicast packet so that there are two multicast packets.
- the transfer control unit 24 compares the transfer destination address “UR2, UR3” with the destination address “G” of the decapsulated multicast packet. Since the transfer destination address of V and the deviation is also different from the destination address, the transfer control unit 24 sets the address “UR1” of the UR 20a itself as the transmission source address, and sets the destination address “UR1” in the destination address of one of the multicast packets.
- UR2 ” is set, and the destination address of the other multicast packet is set to the transfer destination address“ UR3 ”, and the packet is encapsulated.
- the transfer unit 23 transfers the encapsulated multicast packet 5b to the UR 20b based on the destination address "UR2". Further, the transfer unit 23 transfers the encapsulated multicast packet 5g to the UR 20c based on the destination address “UR3”.
- the receiving unit 22 of the UR 20b decapsulates the encapsulated multicast packet 5b.
- the transfer control unit 24 of the UR 20b refers to the entry holding unit 21b and duplicates the decapsulated multicast packet so that there are two transfer destination addresses, so that the number of multicast packets becomes two.
- the transfer control unit 24 compares the transfer destination address “UR4, UR7J” with the destination address “G” of the decapsulated multicast packet. Since each transfer destination address is different from the destination address, the transfer control unit 24 sets the address “UR2” of the UR20b itself as the source address, and sets the transfer destination address “UR4” as the destination address of one multicast packet. Then, the transfer destination address “UR7” is set as the destination address of the other multicast packet, and the packet is encapsulated.
- the transfer unit 23 transfers the encapsulated multicast packet 5c to the UR 20d based on the destination address "UR4". Further, the transfer unit 23 transfers the encapsulated multicast packet 5f to the UR 20g based on the destination address “UR7”.
- the UR20d and UR20f transfer the multicast packets 5d and 5e in the same manner as in Figs.
- the receiving unit 22 of the UR 20g decapsulates the encapsulated multicast packet 5f to extract the multicast packet 5e.
- the transfer control unit 24 of the UR 20g refers to the entry holding unit 21g, and since the transfer destination address “G” is the same as the destination address “G” of the decapsulated multicast packet, the transfer unit 24 Enter 23. transfer The unit 23 transmits the multicast packet 5e to the receiving terminal 40b by multicast based on the destination address “G”.
- the receiving unit 22 of the UR 20c decapsulates the encapsulated multicast packet 5g and extracts the multicast packet.
- the transfer control unit 24 of the UR 20c refers to the entry holding unit 21c, and since the transfer destination address ⁇ UR5 '' and the destination address ⁇ G '' of the decapsulated multicast bucket are different, the address UR20c itself as the source address is U R3 ”and the transfer destination address“ UR5 ”as the destination address are encapsulated. Then, the transfer unit 23 transfers the encapsulated multicast packet 5h to the UR 20e based on the destination address “UR5”.
- the receiving unit 22 of the UR 20e decapsulates the encapsulated multicast packet 5h.
- the transfer control unit 24 of the UR 20e refers to the entry holding unit 21e and, because there are two transfer destination addresses, duplicates the decapsulated multicast packet so that there are two multicast packets.
- the transfer control unit 24 compares the transfer destination address “R3, UR8” with the destination address “G” of the decapsulated multicast packet. Since each of the destination addresses is different from the destination address, the transfer control unit 24 sets the address “UR5” of the U R20e itself as the source address, and sets the destination address “R3” as the destination address of one of the multicast packets. Is set, and the destination address of the other multicast packet is set to the transfer destination address “UR8” for encapsulation.
- the transfer unit 23 transfers the encapsulated multicast packet 5j to the receiving terminal 40c based on the destination address "shaku3". Further, the transfer unit 23 transfers the encapsulated multicast packet 5i to the UR 20h based on the destination address “UR8”. In this way, the UR 20e forwards the multicast packet with “R3” set as the destination address to the receiving terminal 40c by unicast based on the entry (S, G): [R3, UR8]. The UR 20h decapsulates the multicast packet 5i, and transfers the extracted multicast packet 5e to the receiving terminal 40d by multicast.
- the multicast tree transitions from an initial state to a stable state.
- the multicast tree is in a stable state, for example, due to a decrease in newly joining receiving terminals. Transition. For example, after the start of the live broadcast, the number of newly participating receiving terminals decreases.
- the transmitting terminal 10 can determine that the number of newly participating receiving terminals has decreased, it can determine that the state has shifted to the stable state.
- the communication system 1 When the communication system 1 transitions to the stable state, the communication system 1 sets a multicast tree connecting the branch routers, which are the duplication points of the multicast packet. According to this, URs (such as UR20c) other than branch routers existing on the route of the multicast tree can treat multicast packets in the same way as unicast packets. As described above, since all the URs included in the communication system 1 do not need to process the multicast packet, the load on the entire communication system 1 is reduced.
- URs such as UR20c
- the bucket generating unit 15 of the transmitting terminal 10 when the multicast tree shifts to the stable state, the bucket generating unit 15 of the transmitting terminal 10 generates a multicast packet in which the Stable option indicating that the multicast tree has shifted to the stable state is generated. 13 sends. As a result, the transmitting terminal 10 notifies the participating receiving terminals 40a to 40d that the multicast tree has shifted to a stable state.
- the receiving terminals 40a to 40d transmit a Stable Membership Report or a Stable Joion message.
- the receiving terminal 40c transmits a Stable Join message with the destination address “S” and the source address “R3”.
- the URs 20c and 20d which are not branch routers, use the Stable Join message 3a only for registering or updating entries, and transfer them to the upstream URs 20a and 20b as they are.
- the stable join message 3a from the UR 20f passes through the UR 20d and is received by the UR 20b which is a branch router.
- the message processing unit 25 of the UR 20b adds “UR6” to the transfer destination address of the UR 20b based on the Stable Join message 3a from the UR 20f.
- the message processing unit 25 of the UR 20b converts the entry held by the entry holding unit 21b from the entry (S, G): [UR4, UR7] in the pre-update entry holding unit 212b to the entry in the migrating entry holding unit 312b.
- the UR 20b transfers the multicast packet received from the UR 20a to the UR 20d, UR 20f, and UR 20g.
- the message providing unit 26 of the UR 20d that has passed the Stable Join message 3a provides the Redirect message 4 to the UR 20b via the transfer unit 23.
- the Redirect message 4 is a message requesting that the address “UR4” of the UR 20d be deleted from the transfer destination address and the address “UR6” of the UR 20f be added to the transfer destination address.
- the destination address of the Redirect message 4 is set to the transmission terminal address “S”.
- the entry held by the entry 21b is updated to the entry (S, G): [UR4, UR6, UR7] and the entry (S, G): [UR6, UR7] in the entry-in-transition holding unit 312b.
- the UR20f has two routes: a route in which the UR20b transfers the multicast packet to the UR20d, a route in which the UR20d transfers the multicast packet to the UR20f, and a route in which the UR20b transfers the multicast packet directly to the UR20f. Therefore, it is possible to prevent the multicast packet from being received repeatedly.
- the Redirect message is It can be used as a change request message that instructs the upstream UR or transmitting terminal 10 to change the information held by the entry holding unit.
- the stable join message 3a from the UR 20e passes through the UR 20c and is received by the UR 20a that is a branch router.
- the message processor 25 of UR20a is the entry the entry holding portion 21 a is held
- E emissions tri the updated previous entry holding portion 212a (S, G): [ UR2, UR3] Power et al., Transition entry holding ⁇ ⁇ ⁇ ⁇ Entry (S, G) in B312a: Update to [UR2, UR3, UR5].
- the message providing unit 26 of the UR20c that has passed the stable join message 3a deletes the address "UR3" of the UR20c from the transfer destination address and adds the address "UR5" of the UR20e to the transfer destination address.
- the message processing unit 25 of the UR 20a which has received the Reidirect message 4, converts the entry held by the entry holding unit 21a from the entry (S, G): [UR 2, UR3, UR5] in the migrating entry holding unit 312a to the entry ( S, G): Update to [UR2, UR5].
- FIG. 20 the state of the entry holding units 21a, 21b, and 21g before the update is stored in the entry holding units 21a, 21b, and 21g before the update. , 213b, 211g.
- Fig. 19 shows one injection of the operating hand, and Fig. 20 shows the communication system 1.
- the receiving terminal 40b transmits to the UR 20g a withdrawal request message requesting deletion from the transfer destination address or the transmission destination address. Specifically, the receiving terminal 40b transmits a Leave Group message 7 according to IGMPv2 or MLDv2. As a result, the receiving terminal 40b requests to leave the multicast tree, and requests to stop transmitting the multicast packet (S801).
- the message processing unit 25 of the UR 20g deletes the entry specified by the transmission terminal address "S" and the multicast group address "G" set in the Leave Group message 7 from the entry holding unit 21g. (S802). As a result, the entry holding unit 21g holds The entry to be updated is updated from the state of the pre-update entry holding unit 211g holding the entry (S, G): [G] to a state not holding the entry specified by (S, G).
- the message providing unit 26 of the U R20g transmits the Prune message 8 in order to leave the UR 20g itself from the multicast tree. It is generated and provided to the transmission terminal address via the transfer unit 23 (S803). Since a special option is set for Prune message 8, a UR located upstream from UR20g can detect that the received Prune message 8 is a special control message.
- the NR 30b existing between the UR 20g and the UR 20b upstream of the UR 20g transfers the received prune message 8 by unicast based on the transmission terminal address "S".
- the message processing unit 25 of the UR 20b stores the entry held by the entry holding unit 21b based on the received Prune message 8 in the entry (S, G) in the pre-update entry holding unit 213b: [UR6, UR7]. , Update to entry (S, G): [UR6]. That is, the transfer destination address UR7 is deleted (S804).
- the message processing unit 25 of the UR 20b checks that the transfer destination address held by the entry holding unit 21b is
- the message providing unit 26 Since it is one, it is determined that it is not a branch router. Therefore, the message providing unit 26 generates the Redirect message 4 and provides it to the transmission terminal address via the transfer unit 23 (S805).
- the Redirect message 4 is a message requesting that the address “UR2” of the UR20b be deleted from the transfer destination address and the address “UR6” of the UR20f be added to the transfer destination address.
- the transmission terminal address “S” is set as the destination address of the Redirect message 4.
- the NR 30a existing between the UR 20b and the UR 20a upstream of the UR 20b transfers the received Redirect message 4 by unicast based on the transmission terminal address "S".
- the message processing unit 25 of the UR 20a stores the entry held by the entry holding unit 21a in the entry (S, G) in the pre-update entry holding unit 213a: [UR2, UR5 ] To the entry (S, G): [UR6, UR5] (S806).
- the transfer unit 23 of the UR2 Oa transfers the Redirect message 4 to the transmission terminal 10 based on the transmission terminal address “S”.
- the message processing unit 14 of the transmitting terminal 10 searches the entry holding unit 11 based on the received Redirect message 4.
- the message processing unit 14 transmits the destination address “UR1” of the entry specified by the transmission terminal address “S” and the multicast group address “G” included in the Redirect message 4 and “UR2” included in the Redirect message 4 Therefore, the Redirect message 4 is discarded without updating the entry holding unit 11 (S808). As a result, the multicast tree is updated to the state shown in FIG. By requesting the receiving terminal 40b to stop the transmission of the multicast packet in this way, it is possible to limit the branch router serving as the duplication point of the multicast packet. Therefore, the load of the communication system 1 is dispersed.
- the transfer of the multicast packet according to the multicast tree shown in FIG. 20 is as shown in FIG.
- the transmitting terminal 10 transmits the multicast packet 5a to the UR 20a.
- the UR 20a forwards the multicast packet 5k with the source address set to "UR1" and the destination address set to "UR6" to the UR 20b.
- the UR 20b transfers the multicast packet 51 in which the source address is “UR2” and the destination address is “UR6” to the UR 20f.
- the UR 20f transfers the multicast packet 5e to the receiving terminal 40a.
- the UR 20a transfers the multicast packet 5m in which the source address is set to "UR1" and the destination address is set to "UR5" to the UR 20e.
- the UR 20e transfers the multicast packet 5j to the receiving terminal 40c, and transfers the multicast packet 5i to the UR 20h.
- the UR 20h transfers the multicast packet 5e to the receiving terminal 40d.
- the transmitting terminal 10 the URs 20a-20h, and the communication method
- the URs 20a-20h can hold another UR address as a transfer destination address.
- the transmitting terminal 10 can hold the UR address as the destination address. Therefore, an appropriate multicast is set to transfer the multicast packet from the transmitting terminal 10 to the receiving terminals 40a and 40d via the UR.
- the NR30a-f existing between the transmitting terminal 10 and the UR or between the URs only needs to transfer multicast packets by unicast.
- the communication system 1 can set an appropriate multicast tree and transfer the multicast packet. That is, even if UR20a 20h and NR30a-30f coexist in communication system 1, Multicast packets can be transferred. Therefore, by partially introducing the UR into the communication system 1, multicast packets can be easily transferred at low cost.
- the message processing units 25 and 24 also receive the entry holding units 11 and 21a to 21h based on the participation request messages such as the Membership Report 2 and the Join Message 3 of the receiving terminals 40a to 40d and the UR 20a to 20h. You can register your address in. Therefore, the receiving terminals 40a 40d and the URs 20a-20h can participate in the set multicast tree. As a result, the communication system 1 can transfer the multicast packet to the participating receiving terminals 40a to 40d and the UR 20a 2 Oh.
- the communication system 201 includes the transmitting terminal 10, the UR 20a 20i, the NRs 30a and 30f, and the receiving terminals 40a and 40d.
- the following description focuses on the differences from the communication system 1 shown in FIG. UR20d and UR20i are connected to the same sub-network 50.
- the subnetwork 50 includes, for example, Ethernet.
- UR20d and UR20i are connected to UR20b located upstream via subnetwork 50.
- FIG. 24 shows the procedure, and FIG. 24 shows an example of the communication system 201.
- the receiving terminal 40b transmits Membership Report2 to the UR 20g according to IGMPv2 or MLDv2 (S901).
- the message processing unit 25 of the UR 20g generates an entry in which the transmission terminal address "S", the multicast group address "G", and the transfer destination address "G" are associated based on the Membership Report2.
- the message processing unit 25 registers the generated entry in the entry holding unit 21g (S902).
- the message providing unit 26 of the UR 20g generates a Join message 3 for the UR 20g to join the multicast tree based on the received Membership Report 2, and provides the Join message 3 to the transmission terminal address via the transfer unit 23.
- the message provider 26 sets the destination address to " Set “S” and “UR7” as the source address, specify the multicast gnope address “G”, and generate an oin message 3.
- the transfer unit 23 transfers the Join message 3 based on the transmission terminal address “S” set as the destination address (S903).
- the message processing unit 25 of the UR 20i stores an entry in which the transmission terminal address "S", the multicast group address "G", and the transfer destination address "UR7" are associated. It is generated and registered in the entry holding unit 21i (S904).
- the message providing unit 26 of the UR 20i sets the destination address to "S”, sets the source address to "UR9”, specifies the multicast group address "G”, and generates the fcjoin message 3.
- the transfer unit 23 transfers the Join message 3 based on the transmission terminal address “S” set as the destination address (S905).
- the UR 20d connected to the same subnetwork 50 receives the multicast packet specified by the transmission terminal address "S" and the multicast group address "G", the UR 20i has a stable multicast tree. After that, Join message 3 is received like a branch router.
- the message processing unit 25 of the UR 20b receives: the UR 20d and the UR 20i that connect to the same subnet 50 based on the Join message 3 and the entry indicated in the pre-update entry holding unit 214b held by the entry holding unit 21b. Detects that it is requesting to send the same multicast packet. Then, the message processing unit 25 generates an entry in which the transmission terminal address “S”, the multicast group address “G”, and the transfer destination address “G” are associated with each other.
- the message processing unit 25 By registering the generated entry in the entry holding unit 21b, the message processing unit 25 stores the entry held by the entry holding unit 21b in the entry (S, G) in the pre-update entry holding unit 214b: [UR6] Is updated to entry (S, G): [G] (S906).
- the entry holding unit 21b holds a multicast gnope address as a transfer destination address.
- the message providing unit 26 of the UR 20b generates a Redirect message 4 to instruct update of the entry held by the transmitting terminal 10, and provides the Redirect message 4 to the transmitting terminal address via the transfer unit 23 (S907). .
- the message providing unit 26 transfers the address “UR6” of the UR20f to the transfer destination address. And generates a Redirect message 4 requesting that the address “UR2” of UR20b be added to the transfer destination address.
- the destination address of the Redirect message 4 is set to the transmission terminal address “S”.
- the NR 30a existing between the UR 20b and the UR 20a upstream of the UR 20b transfers the received Redirect message 4 by unicast based on the transmission terminal address "S".
- the message processing unit 25 of the UR 20a retrieves the entry held by the entry holding unit 21a from the entry (S, G) in the pre-update entry holding unit 214a: [UR6]. Entry (S, G): Update to [UR2] (S908).
- the transfer unit 23 of the UR 20a transfers the Redirect message 4 to the transmitting terminal 10 based on the destination address (S909).
- the message processing unit 14 of the transmitting terminal 10 stores the entry held by the entry holding unit n into the entry in the pre-update entry holding unit 111.
- the packet generation unit 15 of the transmission terminal 10 refers to the entry holding unit 11 and generates a multicast packet by setting the transmission terminal address “S” as the source address and the multicast group address “G” as the destination address in the data. . Then, the packet generation unit 15 sets the transmission terminal address “S” as the source address and the destination address “UR2” held by the entry holding unit 11 as the destination address in the generated multicast packet, and sets the multicast packet. To encapsulate. Then, the transmission unit 13 of the transmission terminal 10 transmits the encapsulated multicast packet 5n based on the destination address “UR2”.
- the receiving unit 22 of the UR 20b decapsulates the encapsulated multicast packet 5n.
- the transfer control unit 24 of the UR 20b refers to the entry holding unit 21b, and inputs the transfer destination address “G” and the destination address “G” of the decapsulated multicast packet to the transfer unit 23 as they are because the destination address “G” is the same as the decapsulated multicast packet. .
- the transfer unit 23 transfers the multicast packet 5e to the sub-network 50 by multicast based on the destination address “G”.
- the receiving unit 22 of the UR 20d receives the multicast packet 5e via the sub-network 50.
- the transfer control unit 24 of the UR 20d refers to the entry holding unit 21d, and since the transfer destination address “UR6” is different from the destination address “G” of the multicast packet 5e, the UR 20d own address ⁇ UR4 And set the transfer destination address "UR6" as the destination address and encapsulate it. Then, the transfer unit 23 transfers the encapsulated multicast packet 5d to the UR 20f based on the destination address “UR6”. The UR 20f decapsulates the multicast packet 5d and transfers the multicast packet 5e to the receiving terminal 4Oa by multicast.
- the receiving unit 22 of the UR 20i receives the multicast packet 5e via the sub-network 50.
- the transfer control unit 24 of the UR 20i refers to the entry holding unit 21i, and since the transfer destination address “UR7” is different from the destination address “G” of the multicast packet 5e, the UR20i's own address “UR9” is used as the source address. Then, the transfer destination address “UR7” is set as the destination address, and the packet is encapsulated. Then, the transfer unit 23 transfers the encapsulated multicast packet 5o to the UR 20g based on the destination address “UR7”. The UR 20g decapsulates the multicast packet 5o and transfers the multicast packet 5e to the receiving terminal 40b by multicast.
- Figs. 26 and 27 show an example in which the receiving terminal 40b joins the multicast tree when the resources of the UR 20b are insufficient when the receiving terminal 40a has already joined the multicast tree. explain.
- the states of the entry holding units 11 and 2 la before updating are distinguished from each other in order to distinguish the states before and after updating. Shown as 12, 215a.
- Receiving terminal 40b transmits Membership Report 2 to UR 20g, and requests participation in the multicast library (S1001).
- the message processing unit 25 of the UR 20g generates an entry in which the transmission terminal address “S”, the multicast group address “G”, and the transfer destination address “G” are associated based on the received Membership Report 2, and the entry It is registered in the holding unit 2lg (S1002).
- the message providing unit 26 of the UR 20g generates the Join message 3 and provides it to the transmission terminal address via the transfer unit 23.
- the message providing unit 26 sets the destination address to “S” and the source address to “UR7”, specifies the multicast group address “G”, and generates the fcjoin message 3.
- the transfer unit 23 transfers the Join message 3 based on the transmission terminal address “S” set as the destination address (S1003).
- the NR 30b existing between the UR 20g and the UR 20b upstream of the UR 20g transfers the received fcjoin message 3 by unicast based on the transmission terminal address "S". Further, the UR 20b transfers the Join message 3 as it is by the unicast based on the transmission terminal address “S” because the resource for performing the processing based on the received oin message 3 is insufficient. Further, the NR 30a existing between the UR 20b and the UR 20a upstream from the UR 20b transfers the received ⁇ Join message 3 by unicast based on the transmission terminal address "S".
- the UR 20a receives the Join message 3. Based on the received oin message 3 and the entry held by the entry holding unit 21a in the state shown in the before-update entry holding unit 215a, the message processing unit 25 of the UR 20a sends the transmission terminal address “S” and the multicast group address “ G ”and the transfer destination address“ UR6, UR7 ”. The message processing unit 25 registers the generated entry in the entry holding unit 21b, and stores the entry held by the entry holding unit 21b in the entry (S, G) in the pre-update entry holding unit 215b: [UR6]. The entry (S, G) is updated to [UR6, UR7] (S1004).
- the message providing unit 26 of the UR 20a generates a Redirect message 4 to instruct an update of the entry held by the transmitting terminal 10, and provides the Redirect message 4 to the transmitting terminal address via the transfer unit 23 (S1005). .
- the message providing unit 26 requests that the address “UR6” of the UR20f be deleted from the transfer destination address and the address “UR1” of the UR20a be added to the transfer destination address.
- Redirect message 4 is generated.
- the destination address of the Redirect message 4 is set to the transmission terminal address “S”.
- the message processing unit 14 of the transmitting terminal 10 retrieves the entry held by the entry holding unit n from the entry (S, G): [UR6] in the pre-update entry holding unit 112. , Entry (S, G): updated to [UR1] (S1006). As a result, a new multicast tree as shown in FIG. 27 is set.
- the packet generation unit 15 of the transmission terminal 10 refers to the entry holding unit 11 and refers to the transmission terminal address “S” as the source address of the multicast packet and the destination address “UR1” held by the entry holding unit 11 as the destination address. Is set, and the multicast packet is encapsulated. Then, the transmitting unit 13 of the transmitting terminal 10 transmits the encapsulated multicast packet 5a based on the destination address “UR1”.
- the receiving unit 22 of the UR 20a decapsulates the encapsulated multicast packet 5a and extracts the multicast packet.
- the transfer control unit 24 of the UR 20a refers to the entry holding unit 21a and duplicates the extracted multicast packet to make two since there are two transfer destination addresses.
- the transfer control unit 24 sets the address "UR1" of the UR20a itself as the source address. .
- the transfer control unit 24 sets the transfer destination address “UR6” as the destination address in one of the multicast packets, and sets the destination address “UR7” in the other multicast packet to encapsulate.
- the transfer unit 23 transfers the encapsulated multicast packets 5p and 5q to the destination TURs 20f and 20g based on the destination addresses “UR6” and “UR7”, respectively.
- the URs 20f and 20g decapsulate the manocast cast packets 5p and 5q, respectively, and transfer the multicast packet 5e to the receiving terminals 40a and 40b by multicast.
- the UR 20a-20h consigns processing of the control message to another UR by transferring the control message without processing the control message. it can.
- some URs process communication
- the load on the system 1 can be distributed, and the load on the entire communication system 1 can be reduced.
- the entry holding units 11, 21a and 21h are not updated before updating).
- the states of the entry holding units 113, 216a, 215b, 211c, 211d, 212e, 212g, 211f before update are respectively distinguished. , 211h.
- the transmitting terminal 10 moves from the home network 60a to the external network 60b using Mobile IPv6 (No, Handover). Then, the transmitting terminal 10 acquires, for example, a CoA (Care of Address) as the ISA “S ′” in the destination external network 60b.
- a CoA Care of Address
- the packet generation unit 15 of the transmitting terminal 10 sets the ISA "S '" as the source address, and sets the oISA "S" used in the home network 60a to the HA ⁇ (Home Address option) multicast. Generate a packet. Further, when the transmission terminal address changes and the transmission destination address is held by the transmission terminal 10, the packet generator 15 sets a special option.
- the packet generation unit 15 of the transmission terminal 10 refers to the entry holding unit 11 in the state of the pre-update entry holding unit 113, sets “UR1” as the destination address according to the entry before moving, and encapsulates the multicast packet. I do.
- the transmitting unit 13 transfers the encapsulated multicast packet 5r based on the destination address. If the entry holding unit 11 holds a plurality of destination addresses, the packet generating unit 15 sets the plurality of destination addresses without setting a special option.
- UR1 is generated.
- the message processing unit 14 registers the generated entry in the entry holding unit 11, and stores the entry held by the entry holding unit n from the entry (S, G): [UR1] in the pre-update entry holding unit 113 from the entry ( S / S, G): Update to [UR1].
- the transmitting terminal 10 receives the transmitted multicast packet 5r, for example, by the UR 20b. Since the special option is set, the receiving unit 22 of the UR 20b decapsulates the multicast packet 5r, sets the extracted multicast packet and the multicast packet 5r, and sets the multicast packet 5r.
- the destination address "UR1" and the source address "S '" are input to the message processing unit 25.
- the message processing unit 25 is based on the ISA "S '" set in the source address, the oISA "S” set in the HOA, and the entry holding unit 21b in the state of the pre-update entry holding unit 215b. There are, 13 and eight "3 '” and 0 13 eight "3", the multicast group address "G”, the transfer destination address before update E entry holding portion 215b holds "UR6, UR7" and an entry that associates Generate.
- the message processing unit 25 registers the generated entry in the entry holding unit 21b, and stores the entry held by the entry holding unit 21b in the entry (S, G) in the pre-update entry holding unit 215b: [UR6, UR7 ] To entry (S / S ', G): [UR6, UR7].
- the message processing unit 25 inputs the decapsulated multicast packet and the destination address “UR1” set in the multicast packet 5r to the transfer control unit 24.
- the transfer control unit 24 sets the destination address "UR1" set in the multicast packet 5r as the destination address of the extracted multicast packet, and sets the address "UR2" of the UR 20b as the source address.
- the transfer unit 23 transfers the encapsulated multicast packet 5s to the UR 20a based on the destination address.
- the transfer control unit 24 controls the transmission of the multicast packet to the transmission destination address “UR1” of the transmission terminal 10 before the change. As a result, the transfer unit 23 transmits the multi-key that the UR20b has received so far. Transfer the multicast packet 5s to the UR20a that is the source of the multicast packet.
- the transfer control unit 24 refers to the entry holding unit 21b and, because of the two transfer destination addresses, duplicates the multicast packet to make two. Since the transfer destination address “UR6, UR7” is different from the destination address “G” of the extracted multicast packet, the transfer control unit 24 sets the address “UR2” of the UR 20b itself as the source address. The transfer control unit 24 sets the transfer destination address “UR6” as the destination address for one of the multicast packets, and sets the destination address “UR7” for the other multicast packet to encapsulate. Then, the transfer unit 23 transfers the encapsulated multicast packets 5t and 5u to the URs 20f and 20g based on the destination addresses "UR6" and "UR7", respectively.
- the message processing unit 25 of the UR20f, 20g also has the entry holding unit 21f,
- 21g is updated from the entry (S, G): [G] in the pre-update entry holding unit 21 If, 212g to the entry (S, G): [G]. Further, the message processing unit 25 of the UR 20d existing between the UR 20b and the UR 20f also stores the entry holding unit 21d from the entry (S, G): [UR6] in the entry holding unit 21 Id before updating. / S ,, G): Update to [UR6].
- the URs 20f and 20g decapsulate the multicast packets 5t and 5u, respectively, and receive the multicast packet 5y with the ISA "S '" set as the source address and the oISA "S" set with HAO as the receiving terminal 40a. , 40b ⁇ This Manorechicast ⁇ Transfer from here.
- the receiving unit 22 of the UR 20a receives the multicast packet 5s transferred to "UR1".
- the receiving unit 22 decapsulates the multicast packet 5s because a special option is set, and extracts the extracted multicast packet and the destination set in the multicast packet 5s (used for encapsulation).
- the address “UR1” and the source address “UR2” are input to the message processing unit 25.
- the message processing unit 25 of the UR 20a uses the source address "U R2" used for encapsulation and the entry holding unit 21a in the state of the pre-update entry holding unit 216a to send the U R20a to the multicast. Judge that it is not necessary to transfer the multicast packet to "UR2" which is the source of the packet. Therefore, the message processing unit 25 deletes “111 2” from the transfer destination address.
- the message processing unit 25 sends the ISA "S '" set to the source address to the HOA. Based on the set oISA “S”, the source address “UR2” used for encapsulation, and the entry holding unit 21a in the state of the entry holding unit 216a before update, the ISA “S '” and o Generate an entry corresponding to the ISA "S", the multicast group address "G", and the transfer destination address "UR5".
- the message processing unit 25 registers the generated entry in the entry holding unit 21a, and stores the entry held by the entry holding unit 21a in the entry (S, G) in the pre-update entry holding unit 215a: [UR2, UR5 ] To entry (SZS ', G): [UR5].
- the message processing unit 25 inputs the decapsulated multicast packet to the transfer control unit 24.
- the transfer control unit 24 of the UR 20a refers to the updated entry holding unit 21a and transfers the multicast packet 5v encapsulated by the transfer destination address "UR5" to the UR 20e.
- the UR 20a transfers the multicast packet 5v to the UR 20e obtained by removing the UR 20b that is the transfer source of the multicast packet 5s from the transfer destination address held by the entry holding unit 21a.
- the message processing unit 25 of the UR 20c existing between the UR 20a and the UR 20e also stores the entry holding unit 21c in the entry (S, G) in the pre-update entry holding unit 211c: the entry (S / S ') from [UR5]. , G): Update to [UR5].
- the message processing unit 25 of the UR 20e also updates the entry holding unit 2 le from the entry (S, G): [R3, UR8] in the pre-update entry holding unit 212 e to the entry (S ′, G): [R3, UR8]. I do.
- the transfer control unit 24 of the UR 20e transfers the encapsulated multicast packet 5w with the source address set to "UR5" and the destination address set to "R3" to the receiving terminal 40c according to the entry holding unit 21e. Further, the transfer control unit 24 sets the source address to “UR5” and sets the destination address to “UR8”, and transfers the encapsulated multicast packet 5x to the UR20h.
- the UR 20h updates the entry held by the entry holding unit 21h from the entry (S, G): [G] held by the pre-update entry holding unit 21 lh to an entry (SZS ', G): [G]. Then, the multicast packet 5y is transferred to the receiving terminal 40d by multicast.
- the receiving terminals 40a and 40d receive the multicast packet 5y in which ISA "S '" is set as the source address and oISA "S" is set in HAO.
- the receiving terminal 40c extracts the multicast packet 5y by decapsulating the multicast packet 5w. You.
- the receiving terminals 40a to 40d transmit the Membership Report 2 or the Join message 3 to the ISA “S ′”. This sets up a multicast tree with ISA "S '" upstream.
- the communication system 1 can appropriately transfer the multicast packet to the receiving terminals 40a-40d. . Therefore, the receiving terminals 40a to 40d need not detect the movement of the transmitting terminal 10 by themselves, and can omit the control based on the detection. Thus, the load that does not require changing the functions of the receiving terminals 40a to 40d can be reduced.
- the communication system 301 includes a transmitting terminal 10, URs 20a to 20c, NRs 30a 30c, and receiving terminals 40a to 40c.
- the communication system 301 differs from the communication system 1 shown in FIG. 1 in the number of URs, NRs, and reception terminals, and the connection relationship between the transmission terminals 10, UR20a-20c, NR30a-30c, and reception terminals 40a 40c has changed Other than that, it is substantially the same.
- UR20a 20c can be a branch router that forwards multicast packets to multiple forwarding addresses.
- the multicast packet is encapsulated and transmitted between the transmitting terminal and the branch router and between the branch routers.
- the receiving unit 22 of the UR 20a-20c determines whether or not the destination address of the encapsulated multicast packet matches the address of the UR 20a-20c itself.
- the receiving unit 22 inputs the multicast packet to the transfer control unit 24 when they match, because the UR 20a is a branch router. If these conditions are not met, the receiving unit 22 inputs them to the transmitting unit 23.
- the message processing unit 25 of the URs 20a to 20c functions as a determination unit that determines whether the UR is a branch router when the transmission terminal address is upstream of the multicast tree.
- the message processing unit 25 makes a determination based on the control message and the transfer destination address held by the entry holding units 21a and 21c. Further, when determining that the message processing unit 25 is to be a branch router, the message processing unit 25 also functions as a transfer destination registration unit that registers a plurality of transfer destination addresses in the transfer destination holding unit in association with the transmission terminal address. Specifically, when the message processing unit 25 determines that the UR 20a 20c is a branch router, it generates an MFT entry in the entry holding unit 21a-2lc and registers the transfer destination address.
- the message processing unit 25 stores the transfer destination address of the downstream branch router on the basis of the Redirect message 4 (participation / withdrawal request message) from the branch router downstream of the norators 20a-20c itself. 21a-21c, and the address of the downstream branch router is registered in the entry holding unit 21a-21c. As a result, an appropriate multicast tree in which the multicast packet is transferred from the transmitting terminal 10 to the receiving terminals 40a to 40c via the plurality of branch routers is set.
- the message processing unit 25 generates the MFT entry not only when the UR 20a-20c is determined to be a branch router, but also when the UR 20a-20c is a terminal nolator connected to the receiving terminals 40a-40c. Then, the transfer destination address is registered corresponding to the transmission terminal address and the multicast group address. As a result, an appropriate multicast tree in which the multicast packet is transferred from the transmitting terminal 10 to the receiving terminals 40a and 40c via the branch router and the terminal router is set. The message processing unit 25 generates an MCT entry and registers a transfer destination address unless the UR 20a-20c is a branch router or a terminal router.
- the message processing unit 25 determines whether the UR 20a 20c is a branch router or not. Then, it is determined whether a new control message should be generated and transmitted based on the received control message. If the message processing unit 25 does not become a branch router, it determines that the message is to be transmitted as it is, and inputs the received control message to the transfer unit 23. The message processing unit 25 determines that the message is to be newly generated when it becomes a branch router, and inputs the received control message to the message providing unit 26.
- the message providing unit 26 generates a control message.
- the message providing unit 26 generates a control message based on the control message received by the UR 20a-20c acquired from the message processing unit 25 and the information held by the entry holding units 21a 21c.
- the message providing unit 26 inputs the generated control message to the transfer unit 23.
- the entry holding unit 11 of the transmitting terminal 10 holds the address of any one of the branch router, the terminal router, and the receiving terminal as a destination address.
- the message processing unit 14 deletes the forwarding address of the branch router from the transmission destination holding unit based on the Redirect message, which is the participation Z withdrawal message, and registers the branch router address in the transmission destination holding unit. Functions as a destination registration unit.
- the multicast tree has an initial state and a stable state. For this reason, the processing in the initial state and the processing in the stable state will be described separately.
- the entry holding units 11 and 21a to 21c do not hold the transmission destination address or the transfer destination address.
- the receiving terminal 40a requests transmission of the multicast packet.
- the receiving terminal 40a can request transmission according to MLDv2 when the router to which the receiving terminal 40a is connected via a wireless link is a U R. Specifically, receiving terminal 40a transmits Membership 1 ⁇ 0112 to 111200.
- the receiving terminal 40a requests transmission of the multicast packet specified by the transmitting terminal address "S” and the multicast group address "G", that is, (S, G), using Membership Report2.
- Membership Report2 is multicast to destination address
- the address “R1” of the receiving terminal 40a is set as the group address “G” and the source address, and the designation of the multicast group address “G” is included.
- the UR 20c existing at the lowermost position on the route from the receiving terminal 40a to the transmitting terminal 10 receives the Member ship Report2.
- the message processing unit 25 of the UR 20c generates an MFT entry in the entry holding unit 21c because the UR 20c is a terminal router connected to the receiving terminal 40a.
- the message processing unit 25 registers (S, G): [G] in the MFT entry.
- the message processing unit 25 activates the KAT of the transfer destination address “G” and the JT related to (S, G).
- the message processing unit 25 of the UR 20c inputs the received Membership Report 2 to the message providing unit 26.
- the message providing unit 26 of the UR 20c generates a Join message 3 requesting the transmitting terminal 10 to transmit the multicast packet requested by the receiving terminal 40a using the Member ship Report2.
- the message providing unit 26 sets the transmission terminal address “S” as the destination address, sets the UR20c address “UR3” as the transmission source address, specifies the multicast group address “G”, and specifies Generate message 3.
- the message providing unit 26 of the UR 20c inputs the generated oin message 3 to the transfer unit 23, and the transfer unit 23 of the UR 20c transmits the Join message 3 to the transmission terminal 10. As a result, the UR 20c can transfer the Join message 3 to the URs 20b and 20a located further upstream.
- the UR 20b existing on the route from the UR 20c to the transmitting terminal 10 receives the Join message 3.
- the message processing unit 25 of the UR 20b refers to the entry holding unit 21b. Since the entry holding unit 21b does not hold the transfer destination address, the message processing unit 25 determines that the transfer destination address to which the UR 20b transfers the multicast packet is one received and determined by the oin message 3. I do. Therefore, the message processing unit 25 determines that the UR 20b does not become a branch router.
- the message processing unit 25 of the UR 20b generates an MCT entry in the entry holding unit 21b.
- the message processing unit 25 determines “UR3” set as the source address of the Join message 3 as the transfer destination address, and registers (S, G): [UR3] in the MCT entry.
- the message processing unit 25 activates the KAT of the transfer destination address “UR3”.
- URs that are not branch routers also retain the MCT.
- the message processing unit 25 inputs the received oin message 3 to the transfer unit 23 as it is.
- UR20b The transfer unit 23 transmits the Join message 3 to the transmitting terminal 10, and transfers the Join message to the UR 20a located further upstream.
- the UR 20a located further upstream in the route from the UR 20c to the transmitting terminal 10 receives the Join message 3.
- the message processing unit 25 of the UR 20a also generates an MCT entry in the entry holding unit 21a in the same manner as the UR 20b, registers (S, G): [UR3] in the MCT entry, and stores the transfer destination address “UR3” in the MCT entry. Start KAT. Since the NR 30a cannot interpret the special option, the NR 30a transfers the Join message 3 to the transmitting terminal 10 as a normal unicast packet.
- transmitting terminal 10 receives Join message 3.
- the message processing unit 14 generates an MFT entry in the entry holding unit 11.
- the message processing unit 14 determines that “UR3” set as the source address of the Join message 3 is the destination address, and registers (S, G): [UR3] in the MFT entry.
- the message processing unit 25 activates the KAT of the transmission destination address “UR3”.
- a multicast tree in which a multicast packet is transferred from the most upstream transmitting terminal 10 to the receiving terminal 40a via the UR 20c, which is the terminal router, is set.
- the receiving terminal 40a is participating in the multicast tree specified by (G) and (G)
- the receiving terminal 40b wants to start receiving a multicast packet transmitted by the transmitting terminal 10
- FIG. Join the multicast tree as shown.
- FIG. 32 the states of the entry holding units 11, 21a, and 21b are illustrated as pre-update entry holding units 114, 217a, and 216b.
- the receiving terminal 40b since the receiving terminal 40b is connected to the NR 30b, it detects that the router to which the receiving terminal 40b is connected via the wireless link is NR. Therefore, the receiving terminal 40b transmits a Join message 3 requesting participation in the multicast tree specified by (S, G). Since a special option is set for the Join message 3, the NR30bf and oin message 3 are not discarded, and the U existing in the route from the receiving terminal 40b to the transmitting terminal 10 R20b can receive Join message 3.
- the receiving terminal 40b sets the sending terminal address “S” as the destination address, sets the receiving terminal 40b address “R2” as the source address, specifies the multicast group address “G”, and sends a ⁇ Join message 3 Send.
- the UR 20b join message 3 existing at the lowermost position on the route from the receiving terminal 40b to the transmitting terminal 10 is received.
- the message processing unit 25 of the UR 20b refers to the pre-update entry holding unit 216b of the UR 20b.
- the message processing unit 25 determines that “UR3” already held as the transfer destination address corresponding to (S, G) by the pre-change entry holding unit 216b that holds the MCT entry and the received (S, G) Since the source address “R2” of the Join message 3 is different, the UR20b determines that there are multiple destination addresses “UR3” and “R2” for forwarding the multicast packet specified by (S, G). . Therefore, the message processing unit 25 determines that the UR 20b is a branch router. Thus, in the initial state, the MCT entry is used to determine the ability to become a branch router.
- the message processing unit 25 of the UR 20b which has determined to be the branch router, deletes the MCT entry from the pre-update entry holding unit 216b, and newly generates an MFT entry.
- the message processing unit 25 adds (S, G): [UR3, R2] to the MFT entry of the entry holding unit 21b based on the information held by the pre-update entry holding unit 216b and the received oin message 3.
- the message processing unit 25 activates the KAT of the transfer destination address “R2” and the JT related to (S, G). Further, the message processing unit 25 inputs the received: Join message 3 to the message providing unit 26 of the UR 20b.
- the message providing unit 26 of the UR 20b generates the Redirect message 4 based on the transfer destination address held by the entry holding unit 21b and the received fcjoin message 3. After generating the Redirect message 4, the message providing unit 26 receives and discards the join message 3.
- the message providing unit 26 of the UR 20b sends a Join message requesting that the address ⁇ UR2 '' of the UR 20b to be a branch router be added to the destination address, and the transfer destination address ⁇ UR3 '' of the UR 20b that is a branch router from the destination address.
- a Redirect message 4 including a Prune message requesting that “R2” be deleted is generated.
- the message providing unit 26 sets the transmission terminal address "S" as the destination address and the transmission source address. Set the address “UR2” of UR20b to the address, and use it as Redirect message 4 specifying the multicast group address “G”. Then, the message providing unit 26 of the UR 20b inputs the generated Redirect message 4 to the transfer unit 23, and the transfer unit 23 of the UR 20b transmits the Redirect message 4 to the transmission terminal 10. As a result, the UR 20b can transfer the Redirect message 4 to the UR 20a, which is further upstream.
- the transfer unit 23 provides the participation Z-leaving message to the transmission address requesting that the address of the branch router be added to the transmission destination address and the transfer destination address of the branch router be deleted from the transmission destination address. It functions as a router message providing unit to perform.
- the UR 20a existing on the route from the UR 20b to the transmitting terminal 10 receives the Redirect message 4.
- the message processing unit 25 of the UR 20a updates the entry holding unit 21a according to the Reidirect message 4. Specifically, the message processing unit 25 stores, as the transfer destination address, “UR3” of “UR3” and “R2” that have been instructed to delete from the MCT entry of the pre-update entry holding unit 217a. And delete the KAT, and register “UR2” for which the addition instruction has been received as the transfer destination address in the MCT entry.
- the message processing unit 25 activates the KAT of the transfer destination address “UR2”.
- the MCT entry in the entry holding unit 21a is updated to (S, G): [UR2].
- the UR located upstream of the branch router also adds the branch router address included in the Redirect message 4 to the transfer destination address, and deletes the branch router transfer destination address from the transfer destination address.
- the message processing unit 25 inputs the received Redirect message 4 to the transfer unit 23 as it is. Then, the transfer unit 23 of the UR 20a transmits the Redirect message 4 to the transmitting terminal 10, and transfers the NR 30a Redirect message 4 to the transmitting terminal 10 as a unicast packet.
- transmitting terminal 10 receives Redirect message 4.
- the message processing unit 14 updates the entry holding unit 11 according to the Reidirect message 4. Specifically, the message processing unit 14 holds, as the transmission destination address, of “UR3” and “R2” that have received the deletion instruction from the MFT entry of the pre-change entry holding unit 114. Delete “UR3” and its KAT, and register the address “UR2” of the branch router receiving the addition instruction as the destination address in the MFT entry. The message processing unit 14 sends the destination address "UR2" Start KAT. As a result, the MFT entry in the entry holding unit 11 is updated to (S, G): [UR2]. In this way, the message processing unit 14 deletes the forwarding address of the branch router from the destination holding unit based on the join / withdrawal message, and registers the destination address of the branch router in the destination holding unit. Functions as a registration unit.
- the multicast packet is transferred from the most upstream transmitting terminal 10 to the receiving terminal 40a via the UR 20b which is a branch router and the UR 20c which is a terminal router, and the receiving terminal 40b is transmitted via the UR 20b.
- new receiving terminals join the multicast tree one after another. Then, each time there is a new participation, the multicast tree is changed and set.
- the receiving terminal 40b, the UR20c that has become the terminal router, and the UR20b that has become the branch router respectively transmit a Join message 3 to the UR20b that is a branch router and the transmitting terminal 10 at regular intervals. Also, the receiving terminal 40a periodically transmits Membership Report2 to the UR 20c which is the terminal router. The transmitting terminal 10 and the UR 20b receive the Join message 3 and the UR 20c receives the Membership Report 2 to maintain the destination address and the transfer destination address of the entry holding channels 11, 21a and 21c.
- the message providing unit 26 of the UR20b that has become a branch router has an entry holding unit.
- a Join message 3 with the destination address “S” and the source address “UR2” is generated. Then, the transfer unit 23 of the UR 20b transmits the generated oin message 3.
- the message processing unit 14 of the transmitting terminal 10 refers to the entry holding unit 11 and, when the KAT of the destination address “UR2” expires, sends the entry address “UR2” corresponding to (S, G) from the entry holding unit 11. ". On the other hand, within the holding time when the KAT of the destination address “UR2” expires, the message processing unit 14 transmits the Join message 3 with the source address of “UR2” from the When receiving, restart the KAT of the destination address "UR2" to extend the holding time.
- the message processing unit 25 of the UR 20b which has become a branch router, refers to the entry holding unit 21b and deletes the MFT entry of the entry holding unit 21b when the KAT of the transfer destination address "UR3" expires. To create an MCT entry and register the transfer destination address "R2".
- the message processing unit 25 determines that the UR20b power branching router has become a non-branching router (hereinafter, referred to as a “non-branching router”) because the transfer destination address is “R2”. Then, the message processing unit 25 instructs the message providing unit 26 to generate the Redirect message 4.
- the message providing unit 26 adds the transfer destination address “R2” of the UR20b that has become a non-branch router to the destination address, and deletes the address “UR2” of the UR20b that has become a non-branch router from the destination address. Generate a Redirect message 4 requesting Then, the transfer unit 23 transmits the Redirect message 4 to the transmission terminal address “S”.
- the message processing unit 25 determines whether the UR changes from a branch router to a non-branch router. Then, if the message processing unit 25 determines that the non-branching router will be the non-branching router, the forwarding unit 23 adds the transfer destination address of the non-branching router to the destination address, and adds the address of the non-branching router from the destination address. A join / leave request message requesting deletion is sent to the sending terminal address. As a result, in the communication system 301, even if the UR that has once become a branch router changes to a non-branch router, it can be changed to an appropriate multicast tree.
- the message processing unit 25 of the UR 20b deletes the MCT entry in which the transfer destination address "R2" is registered from the entry holding unit 21b.
- the message processing unit 25 of the UR 20b sets the receiving unit 22 of the UR 20b to the terminal router UR 20c, the receiving terminal 40b power, and the source
- the KAT with the forwarding addresses “UR3” and “R2” is restarted to extend the holding time.
- the message processing unit 25 of the terminal router UR20c refers to the entry holding unit 21c, and when the KAT of the transfer destination address “G” expires, the message processing unit 25 of the entry holding unit 21c checks whether the MAT entry is in the MFT entry. Then, the transfer destination address “G” corresponding to (S, G) is deleted. Further, when the receiving unit 22 of the UR 20c receives the Membership Report 2 from the receiving terminal 40a, the message processing unit 25 of the UR 20c restarts the KAT of the transfer destination address “G”.
- Membership Report 4 can also function as a maintenance request message for maintaining the multicast tree.
- FIG. 33 taking the case of transition to the stable state in the state of the multicast tree shown in FIG. 32 as an example.
- the state of the entry holding unit 21a in FIG. 32 is shown in FIG. It is illustrated in FIG.
- the packet generating unit 15 of the transmitting terminal 10 When the multicast tree shifts to the stable state, the packet generating unit 15 of the transmitting terminal 10 generates a multicast packet in which the Stable option indicating the shift to the stable state is set, and the transmitting unit 13 transmits the multicast packet. As a result, the transmitting terminal 10 notifies the participating receiving terminals 40a and 40b that the multicast tree has shifted to a stable state.
- the receiving terminals 40a and 40b After receiving the multicast packet with the Stable option set, the receiving terminals 40a and 40b transmit a Stable Membership Report for the receiving terminal 40a and a Stable Join message 3a for the receiving terminal 40b.
- the receiving terminal 40b After receiving the multicast packet in which the Stable option is set, the receiving terminal 40b transmits a Stable Join message 3a having the destination address “S” and the source address “R2”.
- the URs 20b, 20c After receiving the Stable Join message 3a from the receiving terminals 40a, 40b or the downstream UR, the URs 20b, 20c transmit the Stable Join message 3a.
- the message provider 26 of the terminal router UR20c determines that when the JAT expires and there is at least one transfer destination address for which the KAT has not expired, the destination address is the transmission terminal address "S" and the transmission destination address is "S". Stable with source address "UR3" and multicast group address "G"
- UR20c transfer unit 23 Sends the generated stable join message 3a.
- the UR 20b existing on the route from the UR 20c to the transmitting terminal 10 receives the Stable Join message 3a from the UR 20c.
- the message processing unit 25 of the UR 20b refers to the entry holding unit 21b and determines whether the entry is an MFT entry or an MCT entry that holds the source address of the received stable join message 3a as a transfer destination address. . If the message processing unit 25 holds the transmission source address of the MFT entry force Stable Join message 3a as the transfer destination address, it extends the holding time of the transfer destination address.
- the message processing unit 25 does not extend the holding time when the source address of the MCT entry Stable Join message 3a is held as the transfer destination address. If the source address of the MFT entry force Stable Join message 3a is held as the transfer destination address, the UR20b will, of course, be in the stable state within the hold time immediately before the KAT of the transfer destination address expires. This means that Join message 3a has been received.
- the message processing unit 25 of the UR 20b Since the message processing unit 25 of the UR 20b holds the source address "UR3" of the received Stable Join message 3a of the MFT entry force of the entry holding unit 21b as the transfer destination address, the message processing unit 25 of the transfer destination address "UR3" Restart KAT and extend the hold time.
- the UR 20b existing on the path from the receiving terminal 40b to the transmitting terminal 10 receives the Stable Join message 3a from the receiving terminal 40b. Then, the message processing unit 25 of the UR 20b holds the source address “R2” of the received Stable Join message 3a of the MFT entry capability of the entry holding unit 21b as the transfer destination address, and thus stores the transfer destination address “R2”. Restart KAT and extend the hold time.
- the message processing unit 25 of the UR 20b instructs the message providing unit 26 to set a sta- ble option in a join message to be generated in the future. Then, if there is at least one transfer destination address where the KAT has not expired when the JT expires, the message providing unit 26 of the UR 20b determines that the destination address is the transmission terminal address “S” and the transmission source address is “ Generate a stable join3a message specifying "UR2" and "G" as the multicast group address. Then, the transfer unit 23 of the UR 20b transmits the generated stable join message 3a. In this way, after receiving the Stable Join message 3a, the branch router itself transmits the Stable Join message 3a.
- the UR20a existing on the route to the UR20b force transmitting terminal 10 receives the Stable Join message. Receives message 3a.
- the message processing unit 25 of the UR 20a refers to the pre-change entry holding unit 21la.
- the before-change entry holding unit 21 la does not hold the MCT entry and holds the transfer destination address registered in the MCT entry.
- the source address of the received stable join message 3a is “UR2 ,
- the KAT at the transfer destination address "UR2" must not be restarted and the hold time must be extended.
- the Sta- ble Join message 3a is not used for restarting the KAT of the transfer destination address held in the MCT entry.
- the message processing unit 25 of the UR 20a inputs the Stable Join message 3a to the transfer unit 23 as it is.
- the transfer unit 23 of the UR 20a transmits the stable join message 3a to the transmission terminal 10, and transfers the NR30a stable join message 3a to the transmission terminal 10 as a unicast packet.
- the KAT of the transfer destination address "UR3" held in the before-update entry holding unit 218a expires because it is not restarted.
- the message processing unit 25 of the UR 20a deletes the transfer destination address “UR2” for which the KAT has expired from the pre-update entry holding unit 218a.
- the entry holding unit 21a updates the state in which the MCT entry is discarded and the transfer destination address is not held.
- transmitting terminal 10 receives stable join message 3a.
- the source address ⁇ UR2 '' of the received stable join message 3a is held as the destination address, so the KAT of the destination address ⁇ UR2 '' is restarted and the holding time is extended. I do.
- the KAT of the forwarding address “G” held by the entry holding unit 21c of the UR20c which is the terminal router, is similar to the case of maintaining the multicast tree in the initial state, when the UR20c receives the Membership Report, as in the case of maintaining the multicast tree in the initial state.
- the message processing unit 25 restarts.
- the communication system 301 after the transition to the stable state, by using the Staple Join message 3a used only for extending the holding time of the transfer destination address held by the MFT entry of the entry holding unit 21a 21c. Only the transfer destination address held by the MFT entry of the entry holding units 21a-21c is held, and the transfer destination address held by the MCT entry is deleted. As a result, the UR20a-20c becomes the MFT entry of the entry holding unit 21a-21c. Only when is a branch router or end router that holds the forwarding address, the forwarding address can be kept and the multicast tree in a stable state can be maintained.
- the MCT is used for setting a multicast tree, and more specifically, for determining whether or not the UR is a branch router. Therefore, it is useful in the initial state of the multicast tree where the receiving terminal frequently participates. However, after the multicast tree transitions to the stable state, the number of receiving terminals newly joining the multicast tree decreases, so the opportunity to determine whether the UR becomes a branch router decreases, and the MCT entry becomes smaller. Opportunities are also reduced. Therefore, the transfer destination address held by the MCT entry is held only in the initial state, and is deleted after the multicast tree transitions to the stable state, thereby further reducing the load on the URs other than the branch router and the terminal nolator.
- the receiving terminal 40c wants to start receiving the multicast packet transmitted by the transmitting terminal 10, it joins the stable multicast tree as shown in FIG.
- the entry holding units 11 and 21a change from the state in FIG. 33 in which the receiving terminals 40a and 40b participate in the power S, the state in FIG. 34 in which the receiving terminal 40c participates, and the state in FIG. 33 from the state in FIG. 34, the states of the entry holding units 11 and 21a in FIG. 33 are shown as pre-update entry holding units 116 and 220a, and the entry holding units 11 and 21a in the transfer state are shown in FIG.
- This state is illustrated as a transition entry holding unit 115, 219a.
- the receiving terminal 40c since the receiving terminal 40c is connected to the NR 30c, similarly to the receiving terminal 40b, the receiving terminal 40c detects that the router to which the receiving terminal 40c is connected via a wireless link is NR, and Send message 3. At this time, the receiving terminal 40c participates in the multicast tree, and receives a multicast packet with the Stable option set. Therefore, the receiving terminal 40c transmits a normal Join message 3 in which the Stable option is not set. The receiving terminal 40c sets the transmission terminal address “S” as the destination address, sets the address “R3” of the receiving terminal 40c as the source address, specifies the multicast group address “G”, and transmits the oin message 3. .
- the UR 20a which is present at the most downstream of the path from the receiving terminal 40c to the transmitting terminal 10 Force Join message 3 is received.
- the message processing unit 25 of the UR 20a refers to the pre-update entry holding unit 220a of the UR 20a.
- the message processing unit 25 receives the normal Join message 3 which is not the Stable Join message 3a used by the pre-update entry holding unit 220a to hold the transfer destination address and to maintain the stable multicast tree.
- “R3” set as the source address of the received join message 3 is determined as the transfer destination address to which the UR 20a transfers the multicast packet.
- the message processing unit 25 determines that the UR 20a does not become a branch router.
- the message processing unit 25 of the UR 20a generates an MCT entry in the pre-update entry storage unit 220a, registers (S, G): [R3], and sets the state of the entry storage unit 219a during migration. You. Further, the message processing unit 25 inputs the received fcjoin message 3 as it is to the transfer unit 23 of the UR 20a, and the transfer unit 23 transmits the Join message 3 to the transmission terminal 10.
- Transmitting terminal 10 receives Join message 3. Since the pre-update entry holding unit 116 does not hold “R3” set as the source address of the received oin message 3, the message processing unit 14 sets “R3” as the new transfer destination address. to decide. The message processing unit 14 generates an MFT entry, adds the transfer destination address “R3”, and changes the entry storage unit 116 before updating to the state (S, G) of the entry storage unit 115 during migration: [UR2, R3]. Update. Thereby, a multicast tree in which the multicast packet is directly transferred from the transmitting terminal 10 to the receiving terminal 40c is once constructed.
- the UR 20b transmits a stable join message 3a in which the destination address is "S”, the source address is "UR2", and the multicast group address is "G”. Then, the UR 20a existing on the route from the UR 20b to the transmitting terminal 10 receives the stable join message 3a.
- the message processing unit 25 of the UR 20a refers to the in-transition entry holding unit 219a.
- the message processing unit 25 sends the “R3” already held as the transfer destination address corresponding to (S, G) by the entry storing unit 219a during migration, and the Stable Join message 3a related to the received (S, G).
- Join address 3 is different from the source address “UR2”, so it is determined that stable join message 3a is not used to maintain a stable multicast tree.
- message processing The unit 25 determines that the UR 20a is a branch router because the UR 20a forwards the multicast packet specified by (S, G) to a plurality of destination addresses “UR2” and “R3”.
- the message processing unit 25 of the UR 20a deletes the MCT entry from the in-transition entry holding unit 219a and newly generates an MFT entry.
- the message processing unit 25 registers (S, G): [UR2, R3] in the MFT entry of the entry holding unit 21a.
- the message providing unit 26 of the UR 20a is a join message requesting to add the address "1113 ⁇ 41" of the UR 20a to be a new branch router to the destination address, and a branch router from the destination address.
- a Redirect message 4 including a UR20a transfer destination address “UR2” and a Prune message requesting that the “R3” be deleted is generated.
- the message providing unit 26 sets the transmission terminal address “S” as the destination address, the UR20a address “UR1” as the source address, and the Redirect message 4 specifying the multicast group address “G”. I do.
- the transfer unit 23 of the UR 20a transmits the Redirect message 4 to the transmitting terminal 10.
- Transmission terminal 10 receives Redirect message 4.
- the message processing unit 14 updates the entry holding unit 11 according to the Redirect message 4. Specifically, the message processing unit 14 deletes “UR2” and “R3” that have been instructed to be deleted from the MFT entry of the entry-in-transition holding unit 115, and deletes the branching router that has been instructed to add. Register the address "UR1" as the destination address in the MFT entry. Thereby, the MFT entry of the entry holding unit 11 is updated to (S, G): [UR1].
- a multicast packet is transferred to the receiving terminal 40a via the UR20c, a multicast packet is transferred to the receiving terminal 40b via the UR20a and the UR20b, and a multicast packet is transferred to the receiving terminal 40c via the UR20a.
- a multicast tree is set up. In this way, a stable multicast tree is set.
- step (S1102) when the c message processing unit 25 of the UR 20a 20 determines that the entry does not exist, the c message processing unit 25 determines whether the received oin message is a Stable Join message with the Stable option set. (SI 103). When the message processing unit 25 of the UR 20a 20c determines that the message is a stable join message, the transfer unit 23 of the UR 20a-20c transfers the stable join message to the upstream (SI 106).
- step (S1103) when the message processing unit 25 of the UR 20a-20c determines that the message is a normal Join message rather than a Stable Join message, it generates an MCT entry in the entry holding units 21a-21c. (S1105). Further, the message processing unit 25 of the UR 20a-20c registers the source address of the received oin message in the generated MCT entry as a transfer destination address, and activates the KAT (S1107). Then, the transfer unit 23 of the UR 20a-20c transfers the Join message to the upstream (S1108).
- step (S1102) when the message processing unit 25 of the UR 20a-20c determines that an entry exists, the message processing unit 25 determines whether the entry is an MCT entry or an MFT entry (S1104). If it is determined that the MFT entry is an MFT entry, the message processing unit 25 of the UR 20a-20c sets the transmission terminal address and the multicast group address indicated by the Join message, that is, the transfer destination address of the MFT entry corresponding to (S, G) to: It is determined whether the source address of the Join message is included (S1109).
- the message processing unit 25 of the UR20a-20c determines that the source address of the Join message is not included in the transfer destination address of the MFT entry corresponding to (S, G) as the transfer destination address. It is registered in the MFT entry corresponding to (S, G) in the entry holding units 21a 21c (S1114). Then, the message processing unit 25 of the UR 20a 20c discards the received fcjoin message (SI 115). Furthermore, the message processing unit 25 of the UR20a-20c The KAT of the transfer destination address held by the MFT entry corresponding to the registered (S, G) is activated (S1118).
- step (S1109) when the message processing unit 25 of the UR 20a-20c determines that the message is included in the transfer destination address of the MFT entry corresponding to (S, G), Proceed to S1115) and discard the received fcjoin message. Further, the message processing unit 25 of the UR 20a-20c proceeds to step (SI 118), and restarts the KAT of the transfer destination address registered in the MFT entry corresponding to (S, G).
- step (S1104) if it is determined that the entry is an MCT entry, the message processing unit 25 of the UR 20a-20c sets the transmission terminal address indicated by the Join message and the multicast group address, that is, (S, G) It is determined whether the transfer destination address of the corresponding MCT entry includes the source address of the Join message (SI 110). If the message processing unit 25 of UR20a-20c determines that the message is not included in the MCT entry corresponding to (S, G), it generates an MFT entry corresponding to (S, G) (Sllll) ).
- the message providing unit 26 of the UR 20a-20c generates a Redirect message corresponding to (S, G), and the transfer unit 23 of the UR 20a-20c transmits the Redirect message to the transmission terminal address (S1113). . Then, the UR 20a-20c proceeds to steps (S1114) and (S1115), registers the source address as the transfer destination address in the generated MFT entry corresponding to (S, G), and discards the Join message. Further, the UR 20a-20c proceeds to step (S1118), and activates the KAT of the transfer destination address held as the MFT entry corresponding to the registered (S, G). In this case, UR20a-20c also activates JT.
- step (S1110) when the message processing unit 25 of the UR 20a-20c determines that the message is included in the transfer destination address of the MCT entry corresponding to (S, G), the message is received and joined. It is determined whether the message is a Stable Join message with the Stable option set (S1112). If the message processing unit 25 of the UR 20a 20c determines that the message is a stable join message, the transfer unit 23 of the UR 20a 20c transfers the stable join message to the upstream (S1116).
- step (S1112) if it is determined that the message processing unit 25 of the UR 20a-1 20c is a normal Join message instead of a Stable Join message, the transfer unit 23 of the UR 20a-20c transmits the Join message. Upstream After the transfer (S1117), the process proceeds to step (S118), and the KAT of the transfer destination address included in the MCT entry corresponding to (S, G) is restarted. Thus, the communication system 301 sets the multicast tree.
- the receiving unit 22 of the UR 20a-20c receives the Prune message (S1201).
- the message processing unit 25 of the UR 20a 20c determines whether the entry holding units 21a-21c hold the source address of the Prune message as the transfer destination address (S1202). If the message processing unit 25 of the UR 20a-1c determines that it does not hold the source address of the Prune message, it forwards the received Prune message upstream (S1208).
- step (S1202) if the message processing unit 25 of the UR 20a-20c determines that the source address of the Prune message is held, the MCT entry or MFT of the entry holding unit 21a-2lc is determined. It is determined whether the entry is retained as a deviation or not (S1203). When it is determined that the MCT entry is held as the MCT entry, the message processing unit 25 of the UR 20a-20c deletes the MCT entry from the entry holding unit 21a-21c (S1205). Then, the UR20a-20c proceeds to step (S1208).
- step (S1203) when the message processing unit 25 of the UR 20a-20c determines that the MFT entry is held, the MFT of the source address of the Prune message is stored in the MFT of the entry holding unit 21a-21c. Delete from the entry (S1204).
- step (S1204) the message processing unit 25 of the UR20a-20c determines whether the MFT entry changes to an MCT entry by deleting the source address of the Prune message from the MFT entry (S1206). .
- step (S1206) if the message processing unit 25 of the UR 20a 20c determines that the MCT entry is changed, the message processing unit 25 instructs the message providing unit 26 to generate a Redirect message.
- the message providing unit 26 of the UR 20a 20c generates the Redirect message 4, and the transmitting unit 23 transmits the Redirect message 4 to the transmitting terminal 10 (S1207).
- the message processing unit 25 of the UR 20a-20c discards the Prune message (S1209).
- step (S1206) the message processing unit 25 of the UR 20a-20c stores the MFT entry in the MCT entry even if the MFT entry holds a plurality of transfer destination addresses and the source address is deleted from the MFT entry. If it is determined that there is no change, the process proceeds to step (S1209).
- FIG. 37 shows a transfer method using the multicast tree in the initial state shown in FIG.
- transmitting terminal 10 sets a transmitting terminal address "S" as a source address and a multicast group address "G" as a destination address in data to generate a multicast packet. Then, the transmitting terminal 10 sets the transmitting terminal address “S” as the source address and the destination address “UR2” held by the entry holding unit 11 as the destination address in the generated multicast packet, and encapsulates the multicast packet. . Then, the transmitting terminal 10 transfers the encapsulated multicast packet 105a to the UR 20b, which is a branch router, by unicast (S1301).
- the NRs 30a and UR20a existing on the path between the transmitting terminal 10 and the UR 20b, which is a branch router, can be transferred by ordinary unicast processing without being aware that the multicast packet 105a is a multicast packet.
- the UR 20b sets the source address "S" of the encapsulated multicast packet 105a in the tunnel source address of the entry holding unit 21b, and decapsulates the encapsulated multicast packet 105a.
- the UR 20b copies the multicast packet using the transfer control unit 24 in order to transmit the multicast packet to the transfer destination addresses “UR3” and “R2” held by the entry holding unit 21b.
- the UR20b sets the address ⁇ UR2 '' of the UR20b itself as the source address, sets the transfer destination address ⁇ UR3 '' as the destination address, encapsulates it, and encapsulates the multicast packet 105b into a capsule.
- the UR 20c decapsulates the encapsulated multicast packet 105b, extracts the multicast packet 105c, and transfers it to the receiving terminal 40a (S1303).
- the UR20b sets the address "UR2" of the UR20b itself as the source address, sets another transfer destination address "R2" as the destination address, encapsulates the packet, and encapsulates the multicast packet 105d. Is transferred to the receiving terminal 40b (S1304). In this way, data can be multicast-distributed to a plurality of destinations, the receiving terminal 40a and the receiving terminal 40b.
- UR20a-20 c holds a plurality of transfer destination addresses and becomes a duplication point only when it is determined that the branch router forwards the multicast packet transmitted by the transmitting terminal 10 to the plurality of transfer destination addresses. Further, when the UR20a-20c becomes a branch router, the UR20a-20c adds the address of the UR20a-20c to the destination address and deletes the transfer destination address of the branch router from the destination address, such as a Redirect message. By sending the join request message to the sending terminal address, the UR or sending terminal 10 upstream from itself can add the branch router address to the transfer destination address and destination address, and branch. You can request that the forwarding address of the router be deleted from the forwarding address or destination address.
- the upstream UR or the transmitting terminal 10 holds the address of the downstream branch router as the transfer destination address / the destination address, and deletes the transfer destination address of the downstream branch router from the transfer destination address and the destination address. it can.
- the UR20a 20c force can be a branch router as appropriate. That is, in the communication system 301, the branch router is dynamically determined. Then, an appropriate multicast tree in which the multicast packet is transferred from the transmitting terminal 10 to the receiving terminals 40a to 40c via the branch router is set. Of the UR20a-20c and NR30a-30c, only the branch router holds the forwarding address and forwards multicast packets to multiple forwarding destinations. Therefore, the UR and NR existing between the transmitting terminal 10 and the branch router need only transfer the encapsulated multicast packet by unicast.
- the load on the URs other than the branch routers is reduced, and even when the routers other than the branch routers are NRs, multicasting can be realized as the entire communication system 301.
- multicasting can be realized as the entire communication system 301.
- the load on the entire communication system could not be sufficiently reduced.
- an appropriate multicast tree is set without increasing the load on the communication system 301, and even when there is an NR between the transmitting terminal and the branch router or between the branch routers. To achieve marcasting.
- the message processing units 14 and 25 determine that the KAT of the transmission destination address or the transfer destination address has expired. In this case, the destination address and transfer destination address are deleted from the entry holding units 11 and 21a-21c, and the Join message 3 or the Stable Join message 3a (maintenance request) using the transfer destination address and destination address as the source address are deleted. If the sending terminal 10 or UR20a 20c receives the message) before the KAT expires, the KAT is restarted. Therefore, by maintaining the multicast tree until the KAT expires, the communication system 301 can always use an appropriate multicast tree even when the network topology changes. In addition, the communication system 301 can maintain the multicast tree as long as necessary by using the Join message 3 and the Stable Join message 3a (maintenance request message).
- the communication system 401 includes a transmitting terminal 10, URs 20a to 20f, NRs 30a and 30b, and receiving terminals 40a to 40c.
- the communication system 401 differs from the communication system 1 shown in FIG. 1 in the number of URs, NRs, and number of receiving terminals, and differs from the transmitting terminal 10, the URs 20a to 20f, the N30a and 30b, and the receiving terminals 40a to 40c. It is substantially the same except that the connection relation of S has changed. It is assumed that the transmitting terminal 10 moves on the network and the transmitting terminal address changes from “S” to “S ′”.
- the receiving terminal 40a includes an entry holding unit 41, a receiving unit 42, a transmitting unit 43, a packet processing unit 44, and a message providing unit 45.
- the receiving terminals 40b and 40c have the same configuration as the receiving terminal 40a.
- the receiving unit 42 receives a control message and a multicast packet from the UR 20a 20f, the NRs 30a and 30b, and the transmitting terminal 10.
- the receiving unit 42 inputs the received control message and multicast packet to the packet processing unit 44.
- the entry holding unit 41 is an address holding unit that holds the ISA, that is, the transmission terminal address and the multicast gnole address. As shown in FIG. 40, the entry holding unit 41 includes IS A, multicast group address, oISA, MPT (Message Pending Timer), ST ( Stale Timer). The entry holding unit 41 holds ISA and oISA in association with each other.
- MPT is a timer value for measuring a message suppression time for suppressing transmission of a Prune message or a Leave Group message. While the MPT has expired and is off, a Prune message or a Leave Group message is transmitted. While the MPT is on, no Prune or Leave Group messages are sent.
- ST is a timer value that measures the oISA retention time. The ST is held in association with the oISA. When the ST expires, the corresponding oISA is deleted from the entry holding unit 41.
- the packet processing unit 44 processes the control message and the multicast packet.
- the packet processing unit 44 acquires the control message and the multicast packet received by the receiving terminal 40a from the receiving unit 42.
- the packet processing unit 44 sets the ISA “S” currently held by the entry holding unit 41 to the oISA of the entry holding unit 41, Start the ST. Further, the packet processing unit 44 sets the ISA “S ′” included in the LU message to the ISA of the entry holding unit 41.
- the packet processing unit 44 refers to the entry holding unit 41, and determines whether or not the source address of the multicast packet is oISA. When the source address is oISA, the packet processing unit 44 refers to the entry holding unit 41 and determines whether the MPT is on or off. When the MPT is off, the packet processing unit 44 instructs the message providing unit 45 to generate a Prune message or Leave Group message specifying oISA. Further, the packet processing unit 44 activates the MPT of the entry holding unit 41. Further, the packet processing unit 44 deletes the oISA whose ST has expired from the entry holding unit 41.
- the message providing unit 45 generates a control message and provides it via the transmitting unit 43.
- the message providing unit 45 acquires the ISA and the multicast group address from the entry holding unit 41.
- the message providing unit 45 generates a Join message, a Membership Report, a Stable Join message, and the like by using the acquired ISA and multicast gnope address.
- the message providing unit 45 generates a Prune message or a Leave Group message in accordance with an instruction from the packet processing unit 44 to generate a Prune message or a Leave Group message specifying oISA.
- the message providing unit 45 stores the generated control message Input to the transmitter 43.
- the message providing unit 45 determines whether the transmitting terminal 10 is based on the location update message (LU message) that notifies the changed transmitting terminal address. Provision of a participation request message (Cioin message or Membership Report) requesting that the address of the receiving terminal be added to the destination address of the multicast packet transmission to the new transmitting terminal address (ISA) Providing a receiving terminal message Functions as a unit. Further, when the receiving terminal 40a connects to the NR, the message providing unit 45 provides a participation request message to which data for instructing not to discard the participation request message is added. Specifically, the message providing unit 45 generates the Join message 3 and provides it via the transmitting unit 43.
- LU message location update message
- ISA new transmitting terminal address
- Transmitting section 43 transmits a control message to URs 20a-20f, NRs 30a and 30b, and transmitting terminal 10.
- the transmitting unit 43 acquires the control message from the message providing unit 45 and transmits it.
- FIG. 38 shows a state immediately after the transmitting terminal 10 has moved from oISA “S” to ISA “S ′”. Therefore, in FIG. 38, the entry holding units 21a to 21f hold the forwarding address in the multicast tree specified by (S, G) using oISA “S”.
- the transmitting terminal 10 exists in the oISA “S”
- the multicast tree is set to be optimal when the oISA “S” is located upstream of the multicast tree. Also, all of the receiving terminals 40a-40c participate in the multicast tree.
- the entry holding unit 11 of the transmitting terminal 10 holds (S, G): [UR1], the entry holding unit 21a of UR20a holds (S, G): [UR3, UR6] as MFT entries, and UR20c
- the entry holding unit 21c holds (S, G): [UR4, UR5] as an MFT entry, and is a branch router.
- the entry holding units 21d to 21f of the UR 20d to 20f hold (S, G): [G] as an MFT entry, and serve as a terminal nolator. [0303]
- the packet generation unit 15 When the transmitting terminal 10 moves from oISA "S" to ISA "S '", the packet generation unit 15 generates a BU message 6 in which oISA "S" is associated with ISA "S'".
- the packet generator 15 sets the destination address of the BU message 6 to “UR1” according to the entry holding unit 11. Then, the packet generator 15 provides the BU message 6 to the UR 20a via the transmitter 13.
- the message processing unit 25 of the UR 20a holds the ISA "S '" and the oISA "S” in association with each other based on the BU message 6 received by the reception unit 22. Then, the message processing unit 25 of the UR 20a causes the transfer unit 23 to transfer the control message addressed to the oISA “S” received by the reception unit 22 to the ISA “S ′”. In this way, the UR 20a establishes a tunnel (
- Bi-Directional Tunneling 9 to function as a home agent.
- transmitting section 13 of transmitting terminal 10 transmits multicast packet 105 to UR 20a based on entry holding section 11, and transmits using multicast tree specified by (S, G).
- the multicast tree specified by (S, G) includes redundant paths because it is set to be optimal when oISA “S” is upstream of the multicast tree. Therefore, the communication system 201 needs to reset the multicast tree specified by (S ′, G) based on the ISA “S ′”. Therefore, the packet generator 15 generates the multicast packet 105 in which the “Stable” option is not set.
- the packet generation unit 15 adds, to the multicast packet 105, an LU message notifying an ISA in which oISA “S” is associated with 138 “3 ′”.
- the packet generating unit 15 provides such a multicast packet 105 to the receiving terminals 40a to 40c via the transmitting unit 13, and the transmitting terminal 10 changes the oISA "S" to the ISA "S '" to the receiving terminals 40a to 40c. Notify that it has moved.
- the packet generation unit 15 when the transmission terminal address is changed, first, the packet generation unit 15 provides a transfer destination update message (BU message) for notifying the change of the transmission terminal address to the transmission destination address. I do. Furthermore, the packet generation unit 15 functions as an update notification unit that provides a position update message (LU message) for notifying the changed transmission terminal address to the reception terminals 40a and 40c that receive the multicast packet.
- BU message transfer destination update message
- LU message position update message
- the receiving terminals 40a and 40c transmit the Mem with the destination address set to ISA "S '" based on the LU message added to the received multicast packet 105.
- the packet holding unit 44 updates the entry holding unit 41 based on the SLU message.
- the message providing unit 45 generates the Membership Report 2 by using the ISA “S ′” held in the updated entry holding unit 41, and the transmitting unit 43 transmits.
- the receiving terminal transmits Membership Report 2 according to the congestion avoidance control specified in the MLD. According to this, it is possible to avoid congestion caused by all receiving terminals trying to join the multicast tree specified by the newly set (S ′, G).
- the message processing unit 25 of the UR20d-20f sends the received Membership Report2 as a message. Input it to the providing unit 26.
- the message providing unit 26 of the UR 20d 20f sets the destination address to IS A "S '" and generates an oin message 3.
- the transfer unit 23 of the UR 20d-20f transmits a Join message 3 addressed to the ISA “S ′”.
- the transmitting terminal 10 and the UR 20a-20f set the initial state multicast tree in the communication system 301 shown in Figs.
- the transfer destination address corresponding to (S ′, G) is stored in the entry holding units 11, 21a-21f so that the ISA “S ′” is optimal when it is located upstream of the multicast tree. I will register to.
- the message processing unit 25 of the UR 20a-20f determines that the UR 20a-20f is a branch router when the ISA "S '" which is the changed transmission terminal address is located upstream of the multicast tree. Judge whether it will be.
- the message processing unit 25 of the UR 20a 20f that has determined to be the branch router registers a plurality of transfer destination addresses in the entry holding unit 21a 21f in association with (S ′, G) using ISA “S ′”.
- the UR20a-2Of message providing unit 26 that is determined to be a branch router generates a Redirect message in which the destination address is set to ISA "S '", and provides it via the transfer unit 23.
- the entry holding unit 21b of the UR 20b that did not hold the transfer destination address holds (S ,, G): [UR3, UR4] as an MFT entry.
- (S ,, G) It becomes a branch router in the multicast tree specified more.
- the entry holding unit 21c of the UR20c holds (S, G): [UR5, UR6] as an MFT entry in addition to (S, G): [UR4, UR5], which was held as an MFT entry. , (S ', G), it is also a branch router in the multicast tree specified.
- the entry holding unit 21a of the UR 20a holds (S ′, G): [UR 6] as an MCT entry in addition to (S, G): [UR3, UR6] held as an MFT entry.
- the entry holding units 21d-21f of the UR20d-20f held the MFT entries.
- (S, G): [G] is retained as an MFT entry, and it becomes a terminal nolator in the multicast tree specified by (S,, G). Then, in addition to (S, G): [UR1] held by the entry holding unit 11 of the transmitting terminal 10, (S,, G): [UR2] is held.
- the message processing units 14, 24 of the transmitting terminal 10, UR20a-20f based on at least one of a Leave Group message and a Prune message, or at least a holding time of the destination address or the transfer destination address, It is preferable to delete the destination address and the destination address associated with the oISA “S” from the entry holding units 11, 21a-21f.
- the receiving terminals 40a to 40c that have received the LU message stop transmitting the Stable Join message specifying (S, G). Specifically, the message providing unit 45 of the receiving terminals 40a and 40c generates a Stable Join message using the ISA “S ′” of the entry holding unit 41. Therefore, after the ISA of the entry holding unit 41 is updated by the LU message, the message providing unit 45 does not generate a Stable Join message using “S” that has become an oISA.
- the receiving terminals 40a and 40c transmit the Stable Join message specifying (S ', G). Only send.
- the message processing units 14 and 25 restart only the KAT of the transmission destination address and the transfer destination address corresponding to (S ′, G), and extend the holding time. Therefore, only the MFT entry corresponding to (S, G) of the entry holding units 11 and 21a-21f is held, and the transmission destination address and the transfer destination address held by the MFT entry corresponding to (S, G) are deleted. Is done. Therefore, transmitting terminal 10, UR 20a-20f can delete the multicast list corresponding to (S, G) and continue to hold only the MFT entry corresponding to (S ′, G). Therefore, transmitting terminal 10, UR 20a-20f can maintain only the multicast tree corresponding to (S ′, G).
- receiving terminals 40a to 40c use oIS A "S" by using Leave Group message 7 or Prune message 8 without waiting for the expiration of KAT. You can explicitly leave the Manorecast Tree.
- the receiving terminals 40a to 40c After receiving the multicast packet from the multicast tree specified by (S ′, G), the receiving terminals 40a to 40c request the leave of the multicast tree power specified by (S, G) after receiving the multicast packet. 7 is sent to the terminal router, UR20d-20f.
- the message providing unit 45 of the receiving terminals 40a to 40c generates a Leave Group message 7 specifying oISA "S", and the transmitting unit 43 transmits the Leave Group message 7.
- the message processing unit 25 of the UR 20d-20f holds the entry holding units 21d-21f based on the Leave Group message 7 requesting withdrawal of the multicast tree power specified by (S, G) ( Delete the MFT entry corresponding to (S, G). Further, the message processing unit 25 inputs the received Leave Group message 7 to the message providing unit 26.
- the message provider 26 of the UR20d—20f sets the destination address to oISA “S” based on the Leave Group message 7, and requests the deletion of the MFT entry corresponding to (S, G) Prune message 8 is generated and provided via the transfer unit 23.
- the transfer unit 23 of UR20d-20f sends Prune message 8.
- the UR 20a transfers the Prune message 8 to the ISA "S '" through the tunnel 9 according to the correspondence between ISA "S'" and oISA "S”. In this way, the Prune message 8 reaches the UR 20a-20c or the transmitting terminal 10 located in the ISA “S ′”.
- the message processing unit 14 of the transmitting terminal 10 or the message processing unit 25 of the UR 20a-20c sends the MFT entry corresponding to (S, G) from the entry holding units 11, 21a-21c based on the Prune message 8. Remove.
- the transmission terminal 10 and the entry holding units 11, 21a 21f of the UR 20a-2Of can hold only the MFT entry corresponding to (S ′, G).
- UR20a Receiver of 20f-20f Receives multicast packets (S1401).
- the transfer control unit 24 of the UR 20a-20f acquires the tunnel source address from the multicast packet and temporarily stores it (S1402).
- the UR 20a-20f decapsulates the multicast packet (S1403).
- the UR 20a 20f determines whether the entry holding units 21a-21f hold the corresponding MFT entry or MCT entry based on the transmission terminal address and the multicast gnope address set in the multicast packet (S1404). If the UR 20a-20f determines that the packet is not held, the UR 20a-20f discards the multicast packet (S1406).
- step (S1404) if the message processing unit 25 of the UR 20a-20f determines that the message is stored, the message processing unit 25 determines whether the message is stored as an MCT entry or an MFT entry (S1405). . If it is determined that the UR20a-20f is provided as the MCT entry, the message providing unit 26 of the UR20a-20f adds the transfer destination address of the UR20a-20f to the destination address, and adds the address of the UR20a-20f itself from the destination address. Generate a Redirect message to the sending terminal address that has the Hop-by-Hop option set, requesting that it be deleted. Then, the transfer unit 23 transmits a Redirect message (S1412).
- step (S1405) if it is determined in step (S1405) that the packet is held as an MFT entry, the transfer control unit 24 of the UR 20a 20f sends the tunnel source address of the received multicast packet to the entry holding unit 21a 21f It determines the force that matches the tunnel source address held by the server (S1407).
- step (S1407) if the tunnel source addresses do not match, the transfer control unit 24 of the UR 20a-20f transmits the tunnel source address of the received multicast packet. It determines the force that matches the previous tunnel source address held by the entry holding units 21a-21f (SI 408). If the address matches the previous tunnel source address, the message providing unit 26 of the UR 20a-20f generates a Prune message without setting the Hop-by-Hop option, and the transfer unit 23 transfers the Prune message to the previous tunnel source address (S 1409).
- step (S1408) if it is determined in step (S1408) that the address does not match the previous tunnel source address, the transfer control unit 24 of the U R20a-20f transmits the tunnel source address currently held by the entry holding units 21a-21f. Is set to the previous tunnel source address of the entry holding units 21a-21f (S1410). At this time, the transfer control unit 24 may use the KAT of the entry holding units 21a and 21f as the ST, and set so that the previous tunnel source address is deleted when the ST expires. After that, the transfer control unit 24 of the UR 20a-20f registers the tunnel source address stored in step (S1402) in the entry holding units 21a-21f (S1411). UR20a-20f proceeds to step (S1413) after steps (S1409) and (S1411).
- step (S1407) when the tunnel source addresses match, when steps (S1409) and (S1411) are completed, the transfer control unit 24 of the UR20a-20f transmits the multicast packet destination. It is determined whether the address is included in the transfer destination address of the MFT entry (S1413). If the destination address is not included in the transfer destination address, the transfer control unit 24 encapsulates the multicast packet with the transfer destination address (S1414). When determining that the destination address is included in the transfer destination address in step (S1413), the transfer control unit 24 inputs the multicast packet to the transfer unit 23 as it is. The transfer control unit 24 inputs the multicast packet encapsulated in step (S1414) to the transfer unit 23. Then, the transfer unit 23 transfers the multicast packet acquired from the transfer control unit 24 (S1415). Steps (S1407) and (S1411) can be omitted.
- the receiving unit 42 of each of the receiving terminals 40a to 40c receives the multicast packet (S1501).
- the bucket processing unit 44 of each of the receiving terminals 40a to 40c refers to the entry holding unit 41 and determines whether the source address of the received multicast packet is ISA (S1502).
- the packet processing unit 44 of the receiving terminals 40a to 40c determines whether the entry holding unit 41 holds oISA or not ( SI 503). If the entry holding unit 41 holds the oISA, the packet processing unit 44 determines whether the MPT is on or off (S1504). When the MPT is off, the message providing unit 45 of each of the receiving terminals 40a to 40c generates a Prune message addressed to oISA with the Hop-by-Hop option set, and provides it via the transmitting unit 43. Alternatively, the message providing unit 45 generates a Leave Group message addressed to the oISA and provides it via the transmitting unit 43 (S1505). Further, the packet processing unit 44 activates the MPT of the entry holding unit 41 (S1506).
- step (S1502) if the source address of the multicast packet is not ISA, in step (S1503), if the entry holding unit 41 does not hold oISA, the MPT is When it is on, the receiving terminals 40a and 40c do not perform any special processing, and the packet processing unit 44 processes data included in the multicast packet.
- the transmitting terminal 10 sets the transmitting destination address to the transmitting destination address.
- a message providing unit 45 that provides a BU message for notifying the change of the ISA and provides an LU message for notifying the ISA "S '" to the receiving terminals 40a to 40c.
- the receiving terminals 40a to 40c include a message providing unit 45 for providing a Join message or a Members Hip Report to the ISA based on the LU message.
- the transmission terminal 10 transmits a BU message to the transmission destination address, so that the transmission terminal 10 and the UR of the transmission destination address are transmitted. A tunnel can be built. Therefore, the control message addressed to the oISA is transferred to the transmitting terminal 10.
- transmitting terminal 10 can notify receiving terminals 40a-40c of the change of the transmitting terminal address by the LU message. Then, the receiving terminals 40a and 40c can recognize the change of the transmitting terminal address by the LU message and transmit the Join message or the Membership Report to the ISA “S,”. Therefore, an appropriate multicast tree is newly set in ISA “S ′” triggered by a Join message or Membership Report addressed to ISA “S ′”. Therefore, even if the transmission terminal address changes, the communication system 401 can use an appropriate multicast tool. Multicast can be realized.
- the branch router holds a plurality of transfer destination addresses in association with ISA "S '".
- UR20a-20f clearly distinguishes between oISA "S”, ie, the multicast tree corresponding to (S, G), and ISA "S '", ie, the multicast tree corresponding to (S', G). it can
- the message providing unit 45 of the receiving terminals 40a to 40c provides a Leave Group message 7 and a Prune message 8 specifying the address of the transmitting terminal 10 before the change. Then, the message processing units 14 and 25 of the transmitting terminal 10 and the UR 20a-20f send oISA “S”, that is, The destination address and transfer destination address associated with (S, G) are deleted from the entry holding units 11 and 21a-21f.
- the communication system 401 can delete the multicast tree formed using the oISA "S” using the Leave Group message 7, the Prune message 8, the transmission destination address, and the holding time of the transmission destination address. Therefore, it is possible to suppress the duplicate transfer of the multicast packet due to the coexistence of the multicast tree using the oISA “S” and the multicast tree using the ISA “S,”.
- the receiving terminals 40a to 40c are formed using the oISA “S” specified by the Leave Group message or the Prune message without waiting for the holding time to expire. Can be explicitly removed from the Multicastle. Therefore, in the communication system 401, duplicate transfer can be further reduced.
- IP is connectionless communication
- a message may not reach a target node in some cases. For this reason, it is preferable that the communication system 1-401 take measures to ensure that the control message reaches the target node. That is, it is preferable to take measures against loss of the control message.
- the message providing unit 26 of the UR20a-20i or the message processing unit 1 of the transmitting terminal 10 4 is a join request message (Membership Report 2 or Join message 3), a leave request message (Leave Group message 7 or Prune message 8), a join / leave request message, or a change request message (Recirect message 4) received by the UR20a-20i.
- Acknowledgment can be provided to the source of control messages such as.
- the message providing unit 26 generates an entry to be registered in the entry holding unit 21a 21i based on the received control message, deletes an entry from the entry holding unit 21a-21i,
- a control message is generated based on the control message thus obtained, it is possible to explicitly provide an acknowledgment response to the source receiving terminals 40a and 40c and other URs.
- the message providing unit 26 can provide an acknowledgment to the transmitting receiving terminals 40a and 40c and other URs.
- the message processing unit 14 of the transmitting terminal 10 can provide an acknowledgment to the source of the control message even when generating an entry to be registered in the entry holding unit 11 or not deleting an entry from the entry holding unit 11. .
- the receiving terminal 40a—40c or UR20a—20i of the transmission source that transmitted the control message receives the confirmation response, so that only the transmission terminal 10 or the UR that received the control message received the control message.
- the UR existing between itself and the transmitting terminal 10 or the UR that has received the control message can also confirm that the control message has been received.
- the UR or transmission terminal 10 that has generated or deleted an entry or generated a control message based on the control message received as described above provides an acknowledgment response, thereby enabling the source reception terminal 40a
- the 40c and the UR 20a-20i can recognize that the control message provided by themselves has been appropriately processed and the entry holding units 11, 2 la-2 li held by the transmitting terminal 10 and the UR 20a-20i have been reliably updated.
- the receiving terminals 40a and 40c and the URs 20a and 20i which cannot receive the acknowledgment, can detect the loss of the control message and provide the control message again. Therefore, in the communication system 1-401, the control message can reliably reach the target node. Moreover, it is necessary to send the same control message many times for security, assuming the control message source. Accordingly, the load on the entire communication system 401 can be reduced.
- KAT is used as in the communication systems 301, 401. By doing so, it is possible to deal with the loss of the leave request message. If the Join message 3 related to the entry is received (within the holding time) before the KAT included in each entry expires, the UR20a—20i, the transmitting terminal 10 restarts the KAT and holds the KAT. Extend time. On the other hand, if the UR20a 20i and the transmitting terminal 10 do not receive a Join message before the expiration of the KAT included in each entry (within the holding time), the transmitting terminal 10 automatically checks the forwarding address and the destination address of the entry. Delete it.
- the UR 20a-20i or the receiving terminal 40a 40c that wants to be maintained in the entry transmits the Join message 3 to the transmitting terminal address before the expiration of the KAT of the corresponding entry, so that the UR 20a—20i It is necessary to restart the KAT of the terminal 10.
- the entry is automatically deleted from the forwarding address or destination address when the KAT expires. Therefore, the UR 20a 20i and the receiving terminals 40a to 40c that desire to stop the transmission of the multicast packet do not need to transmit the leaving request message many times, assuming that the leaving request message will be lost.
- the communication system 1-1 401 can increase the reliability of a multicast packet by using a technology such as TCP or SCTP (refer to RFC2960) for the transfer of the multicast packet.
- a technology such as TCP or SCTP (refer to RFC2960) for the transfer of the multicast packet.
- the transmitting terminal 10 or the URs 20a-20i immediately updated the entry holding units 11, 21a-21i based on a control message such as a Redirect message.
- a control message such as a Redirect message.
- multicast packet loss may occur.
- FIG. 24 when “UR6” is deleted from the entry holding unit 11 and the transfer route between the transmission terminal 10 and the UR 20f is deleted, a packet loss may occur in the UR 20f.
- the transmission is performed.
- the terminal 10 and the UR 20a 20i may retain the entry before the update for a predetermined period. That is, packet loss may be reduced by providing a certain grace period.
- the transmission terminal 10 directly transmits the UR20f before a predetermined period elapses.
- the multicast packet and the multicast packet transferred by the UR20b are received in duplicate.
- the pre-update entry is deleted from the transmitting terminal 10 after the elapse of the predetermined period, the transmission of the directly transmitted multicast packet is automatically stopped.
- the UR 20f transmits a Redirect message or the like that explicitly requests to stop transmission of the multicast packet to the transmission terminal 10. May be. According to this, the overlapping reception of the multicast packet can be stopped, and the multicast tree can be changed smoothly.
- the multicast packet is encapsulated using the transfer destination address or the transfer destination address and transferred, but the transmitting terminal 10, the UR20a-20i has the entry holding units 11, 2
- the method is not limited as long as the multicast packet is transferred according to the transmission destination address and the transmission destination address held by la-21i.
- the transmitting terminal 10 and the URs 20a-20i may use NAT (Network Address Translation) or IP Masquerade. In this case, overhead due to encapsulation can be reduced.
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/563,751 US7620045B2 (en) | 2003-07-07 | 2004-07-07 | Communication system, multicast-capable router, transmitter terminal, receiver terminal, and communication method |
CN2004800195413A CN1820467B (zh) | 2003-07-07 | 2004-07-07 | 通信系统、组播对应路由器、发送终端、接收终端以及通信方法 |
EP04747132A EP1667381A4 (en) | 2003-07-07 | 2004-07-07 | COMMUNICATION SYSTEM, MULTICAST OPERABLE ROUTER, TRANSMITTER TERMINAL, RECEIVER TERMINAL, AND COMMUNICATION METHOD |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2003193232A JP4474124B2 (ja) | 2003-07-07 | 2003-07-07 | マルチキャスト通信システム及びルータ |
JP2003-193232 | 2003-07-07 | ||
JP2004-024871 | 2004-01-30 | ||
JP2004024871A JP4481666B2 (ja) | 2004-01-30 | 2004-01-30 | 通信システム、ルータ、送信端末、受信端末及び通信方法 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2005004419A1 true WO2005004419A1 (ja) | 2005-01-13 |
Family
ID=33566770
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2004/009663 WO2005004419A1 (ja) | 2003-07-07 | 2004-07-07 | 通信システム、マルチキャスト対応ルータ、送信端末、受信端末及び通信方法 |
Country Status (3)
Country | Link |
---|---|
US (1) | US7620045B2 (ja) |
EP (1) | EP1667381A4 (ja) |
WO (1) | WO2005004419A1 (ja) |
Families Citing this family (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101044770B (zh) | 2004-08-16 | 2016-05-04 | 高通股份有限公司 | 用于管理群组通信中的群组成员资格的方法和装置 |
US8102846B2 (en) * | 2005-03-31 | 2012-01-24 | Alcatel Lucent | Method and apparatus for managing a multicast tree using a multicast tree manager and a content server |
JP2006295787A (ja) * | 2005-04-14 | 2006-10-26 | Matsushita Electric Ind Co Ltd | 情報処理システム、情報処理装置、及び情報処理方法 |
US8578479B2 (en) * | 2006-03-21 | 2013-11-05 | Riverbed Technology, Inc. | Worm propagation mitigation |
US8006306B2 (en) * | 2006-03-21 | 2011-08-23 | Riverbed Technology, Inc. | Exploit-based worm propagation mitigation |
US20070280140A1 (en) * | 2006-05-30 | 2007-12-06 | Thiruvengadam Venketesan | Self-optimizing network tunneling protocol |
US9680880B2 (en) * | 2006-07-11 | 2017-06-13 | Alcatel-Lucent Usa Inc. | Method and apparatus for supporting IP multicast |
JP4993202B2 (ja) * | 2007-12-10 | 2012-08-08 | 横河電機株式会社 | フィールドネットワークシステム |
EP2134029A1 (en) | 2008-06-09 | 2009-12-16 | THOMSON Licensing | Network device and method for obtaining terminal multicast status |
US9385877B2 (en) * | 2008-09-16 | 2016-07-05 | Adobe Systems Incorporated | Multicast systems, methods, and computer program products |
EP2510642B1 (en) * | 2009-12-10 | 2016-02-24 | Thomson Licensing | Protocol booster for sctp in multicast networks |
US20110149960A1 (en) * | 2009-12-17 | 2011-06-23 | Media Patents, S.L. | Method and apparatus for filtering multicast packets |
CN102547582B (zh) * | 2010-12-20 | 2014-12-10 | 中国移动通信集团公司 | 传输组播数据的方法、组播树的更新方法以及系统和装置 |
JP5636995B2 (ja) * | 2011-02-07 | 2014-12-10 | セイコーエプソン株式会社 | ネットワーク通信装置、方法、及びプログラム |
KR101808634B1 (ko) * | 2011-09-29 | 2018-01-19 | 한국전자통신연구원 | 멀티캐스트 트래픽의 이동성 지원 방법 |
US9363227B2 (en) * | 2012-08-17 | 2016-06-07 | Cisco Technology, Inc. | Multicast source in group address mapping |
US8929370B2 (en) * | 2012-08-24 | 2015-01-06 | Avaya Inc. | Mechanism for efficiently transmitting tunnel keep-alive messages |
US20180102965A1 (en) * | 2016-10-07 | 2018-04-12 | Alcatel-Lucent Usa Inc. | Unicast branching based multicast |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH11127199A (ja) * | 1997-10-20 | 1999-05-11 | Fujitsu Ltd | 異種中継機器混在網におけるパケット中継方法及び中継機器 |
JP2002094562A (ja) * | 2000-09-20 | 2002-03-29 | Nec Corp | Ipパケット・マルチキャスト方法 |
JP2002368751A (ja) * | 2001-06-12 | 2002-12-20 | Matsushita Electric Ind Co Ltd | マルチキャスト通信システム |
JP2002374276A (ja) * | 2001-06-14 | 2002-12-26 | Furukawa Electric Co Ltd:The | データ中継方法、その装置およびその装置を用いたデータ中継システム |
JP2003309601A (ja) * | 2002-04-17 | 2003-10-31 | Hitachi Ltd | マルチキャスト通信装置およびシステム |
JP2004172932A (ja) * | 2002-11-20 | 2004-06-17 | Hitachi Ltd | データ配信システム |
JP2004242063A (ja) * | 2003-02-06 | 2004-08-26 | Fujitsu Ltd | データ生成装置 |
JP2004253976A (ja) * | 2003-02-19 | 2004-09-09 | Nippon Telegr & Teleph Corp <Ntt> | マルチキャストデータ通信システム及びその方法 |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6947434B2 (en) * | 2000-11-16 | 2005-09-20 | Telefonaktiebolaget Lm Ericsson (Publ) | Subgroup multicasting in a communications network |
US20020143951A1 (en) * | 2001-03-30 | 2002-10-03 | Eyeball.Com Network Inc. | Method and system for multicast to unicast bridging |
KR20020023100A (ko) * | 2001-05-28 | 2002-03-28 | 박현제 | 가상 멀티캐스트 네트워크 구축을 위한 시스템 |
US7339903B2 (en) * | 2001-06-14 | 2008-03-04 | Qualcomm Incorporated | Enabling foreign network multicasting for a roaming mobile node, in a foreign network, using a persistent address |
AU2003223604A1 (en) * | 2002-04-15 | 2003-11-03 | Flarion Technologies, Inc. | Tunneling between different addressing domains |
JP4094537B2 (ja) | 2003-12-08 | 2008-06-04 | 日本電信電話株式会社 | マルチキャストデータ通信システム及び分岐装置並びにプログラム |
JP4194956B2 (ja) | 2004-01-28 | 2008-12-10 | 日本電信電話株式会社 | マルチキャストデータ通信システム、分岐装置、及び、コンピュータプログラム |
-
2004
- 2004-07-07 EP EP04747132A patent/EP1667381A4/en not_active Withdrawn
- 2004-07-07 WO PCT/JP2004/009663 patent/WO2005004419A1/ja active Application Filing
- 2004-07-07 US US10/563,751 patent/US7620045B2/en not_active Expired - Fee Related
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH11127199A (ja) * | 1997-10-20 | 1999-05-11 | Fujitsu Ltd | 異種中継機器混在網におけるパケット中継方法及び中継機器 |
JP2002094562A (ja) * | 2000-09-20 | 2002-03-29 | Nec Corp | Ipパケット・マルチキャスト方法 |
JP2002368751A (ja) * | 2001-06-12 | 2002-12-20 | Matsushita Electric Ind Co Ltd | マルチキャスト通信システム |
JP2002374276A (ja) * | 2001-06-14 | 2002-12-26 | Furukawa Electric Co Ltd:The | データ中継方法、その装置およびその装置を用いたデータ中継システム |
JP2003309601A (ja) * | 2002-04-17 | 2003-10-31 | Hitachi Ltd | マルチキャスト通信装置およびシステム |
JP2004172932A (ja) * | 2002-11-20 | 2004-06-17 | Hitachi Ltd | データ配信システム |
JP2004242063A (ja) * | 2003-02-06 | 2004-08-26 | Fujitsu Ltd | データ生成装置 |
JP2004253976A (ja) * | 2003-02-19 | 2004-09-09 | Nippon Telegr & Teleph Corp <Ntt> | マルチキャストデータ通信システム及びその方法 |
Non-Patent Citations (3)
Title |
---|
"HOP by HOP Multicast Routing Protocol", ACM SIGCOM, August 2001 (2001-08-01) |
See also references of EP1667381A4 |
SEOK JOO KOH; JUYOUNG PARK: "Overlay Multicast Control Protocol (OMCP", 1 February 2003, IETF, article "Framework of Overlay Multicast Control Protocol; draft-sjkoh-overlay-multicast- framework-00 .txt" |
Also Published As
Publication number | Publication date |
---|---|
US20070121574A1 (en) | 2007-05-31 |
US7620045B2 (en) | 2009-11-17 |
EP1667381A1 (en) | 2006-06-07 |
EP1667381A4 (en) | 2011-07-27 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
WO2005004419A1 (ja) | 通信システム、マルチキャスト対応ルータ、送信端末、受信端末及び通信方法 | |
US7339903B2 (en) | Enabling foreign network multicasting for a roaming mobile node, in a foreign network, using a persistent address | |
JP4066867B2 (ja) | 移動ノード、パケット中継装置、パケット転送方法 | |
US9871718B2 (en) | Method and device for registering multicast source and establishing multicast path | |
JP4817131B2 (ja) | Ipネットワークシステム | |
JP4503071B2 (ja) | マルチキャスト通信方法 | |
JP2004179811A (ja) | パケット中継装置 | |
JP2002044143A (ja) | 通信制御方式及びルータ及び通信制御方法 | |
JP2005244904A (ja) | マルチキャストネットワーク装置,マルチキャストネットワークシステムおよびマルチキャスト方法 | |
JP2002335281A (ja) | マルチキャストパケット配信方法及びシステム、パケットのアドレス構造、並びに移動機 | |
JP4820950B2 (ja) | モバイルネットワークノードにおける経路最適化マルチキャストトラフィック | |
JP2009118472A (ja) | Ipネットワークシステム | |
JP2006074132A (ja) | マルチキャスト通信方法及びゲートウェイ装置 | |
Schmidt et al. | Mobile multicast sender support in proxy mobile IPv6 (PMIPv6) domains | |
JP2009272803A (ja) | 通信方法および通信システム | |
JP2006324981A (ja) | マルチキャストパケット転送方式 | |
JP4481666B2 (ja) | 通信システム、ルータ、送信端末、受信端末及び通信方法 | |
CN1820467B (zh) | 通信系统、组播对应路由器、发送终端、接收终端以及通信方法 | |
JP2010147600A (ja) | マルチキャスト通信方法、通信システムおよび通信装置 | |
WO2002103540A1 (en) | Enabling foreign network multicasting for a roaming mobile node, in a foreign network, using a persistent address | |
JP2006067499A (ja) | マルチキャスト制御方法、マルチキャストエリア管理装置、及びマルチキャスト制御装置、並びにプログラム | |
JP2005175609A (ja) | マルチキャストデータ通信システム及び分岐装置並びにプログラム | |
JP2015156569A (ja) | 中継装置及びその制御方法、プログラム。 | |
JP2004173209A (ja) | 情報配信方法 | |
KR100576727B1 (ko) | 이동성 인터넷망에서 소스 기반 멀티캐스트 서비스를이용한 핸드오버 방법 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
WWE | Wipo information: entry into national phase |
Ref document number: 200480019541.3 Country of ref document: CN |
|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BW BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE EG ES FI GB GD GE GH GM HR HU ID IL IN IS KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NA NI NO NZ OM PG PH PL PT RO RU SC SD SE SG SK SL SY TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): BW GH GM KE LS MW MZ NA SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LU MC NL PL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
WWE | Wipo information: entry into national phase |
Ref document number: 2004747132 Country of ref document: EP |
|
WWP | Wipo information: published in national office |
Ref document number: 2004747132 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2007121574 Country of ref document: US Ref document number: 10563751 Country of ref document: US |
|
WWP | Wipo information: published in national office |
Ref document number: 10563751 Country of ref document: US |