Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS20020001310 A1
Publication typeApplication
Application numberUS 09/893,634
Publication dateJan 3, 2002
Filing dateJun 29, 2001
Priority dateJun 29, 2000
Also published asUS8898320, US20060242311, US20150106477, WO2002003614A2, WO2002003614A3
Publication number09893634, 893634, US 2002/0001310 A1, US 2002/001310 A1, US 20020001310 A1, US 20020001310A1, US 2002001310 A1, US 2002001310A1, US-A1-20020001310, US-A1-2002001310, US2002/0001310A1, US2002/001310A1, US20020001310 A1, US20020001310A1, US2002001310 A1, US2002001310A1
InventorsKhanh Mai, Roland Noll, Tom Grimes, Tom Dong
Original AssigneeKhanh Mai, Roland Noll, Tom Grimes, Tom Dong
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Virtual multicasting
US 20020001310 A1
Abstract
A method and system of virtual multicasting content is disclosed. The method and system disclosed enable the receipt of virtual multicast content without requiring the expensive investment in the infrastructure necessary for a network to be multicast enabled. The virtual multicasting may be performed according to a method of virtual multicasting multicast content on non-multicast enabled networks, comprising the steps of determining if an attached network is multicast enabled, if the attached network is not totally multicast enabled, querying for virtual multicast requests for the multicast content from non-multicast enabled client computers, listening for virtual multicast requests, and determining, based on the virtual multicast requests, which client computers request the multicast content, from the unicast addresses, and the requested methods of delivery for the multicast content. The network includes client computers that have unicast addresses and the at least one virtual multicast request includes a unicast address identifying a client computer of the network and a requested method of delivery for the multicast content.
Images(13)
Previous page
Next page
Claims(36)
What is claimed is:
1. A method of virtual multicasting (VMC) multicast content on non-multicast enabled networks, comprising the steps of:
determining if an attached network is multicast enabled, wherein the network includes client computers that have unicast addresses;
if the attached network is not totally multicast enabled, querying for virtual multicast requests for the multicast content from non-multicast enabled client computers;
listening for virtual multicast requests, wherein at least one virtual multicast request includes a unicast address identifying a client computer of the network and a requested method of delivery for the multicast content; and
determining, based on the virtual multicast requests, which client computers request the multicast content, from the unicast addresses, and the requested methods of delivery for the multicast content.
2. The method of claim 1, further comprising the step of:
building a table of requesting client computers based on the requesting client computers determined from the determining step.
3. The method of claim 2, further comprising the steps of:
receiving the multicast content, wherein the multicast content comprises a plurality of packets;
replicating the packets and addressing the packets per the table of requesting client computers; and
transmitting the replicated and addressed packets to the requesting client computers.
4. The method of claim 3, wherein:
the building step builds a VMC client table (VCT) file that includes the identities of the requesting client computers and the unicast addresses of the requesting clients; and
the method further comprises:
reading the VCT file for the identities of the requesting client computers and the unicast addresses of the requesting clients, wherein the replicating step addresses the packets per the unicast addresses of the requesting clients.
5. The method of claim 1, further comprising the steps of:
selecting an optimal upstream virtual router; and
forwarding a multicast request for the multicast content to the selected upstream virtual router.
6. The method of claim 5, wherein the selecting step comprises the steps of:
determining a router load on upstream virtual routers;
determining a round trip time on the upstream virtual routers; and
balancing the determined router loads and round trip times for the upstream virtual routers, wherein the selecting step selects the upstream virtual router with the best balance of router load and round trip time.
7. The method of claim 1, wherein the determining if the attached network is multicast enabled comprises the step of:
listening for Internet Group Management Protocol (IGMP) queries.
8. The method of claim 1, wherein the querying step comprises the step of:
issuing virtual IGMP (VIGMP) queries, wherein VIGMP queries query client computers for VIGMP reports that request unicast or multicast delivery of the multicast content.
9. The method of claim 8, wherein the VIGMP reports that request unicast delivery of the multicast content include a unicast address for a requesting client computer and a multicast address for the multicast content.
10. The method of claim 1, wherein the listening step listens for virtual multicast requests from downstream virtual routers.
11. The method of claim 10, wherein the listening step listens for virtual multicast requests from downstream virtual routers by listening for Virtual Multicast Registration protocol (VMCRP) reports from the downstream virtual routers.
12. The method of claim 11, wherein the VMCRP reports include a unicast address for a requesting downstream virtual router and a multicast address for the multicast content.
13. A computer-readable medium comprising instructions for virtual multicasting (VMC) multicast content on non-multicast enabled networks, by:
determining if an attached network is multicast enabled, wherein the network includes client computers that have unicast addresses;
if the attached network is not totally multicast enabled, querying for virtual multicast requests for the multicast content from non-multicast enabled client computers;
listening for virtual multicast requests, wherein at least one virtual multicast request includes a unicast address identifying a client computer of the network and a requested method of delivery for the multicast content; and
determining, based on the virtual multicast requests, which client computers request the multicast content, from the unicast addresses, and the requested methods of delivery for the multicast content.
14. The computer-readable medium of claim 13, further comprising instructions for:
building a table of requesting client computers based on the requesting client computers determined from the determining step.
15. The computer-readable medium of claim 14, further comprising instructions for:
receiving the multicast content, wherein the multicast content comprises a plurality of packets;
replicating the packets and addressing the packets per the table of requesting client computers; and
transmitting the replicated and addressed packets to the requesting client computers.
16. The computer-readable medium of claim 15, wherein:
the building instruction builds a VMC client table (VCT) file that includes the identities of the requesting client computers and the unicast addresses of the requesting clients; and
the computer-readable medium further comprises instructions for:
reading the VCT file for the identities of the requesting client computers and the unicast addresses of the requesting clients, wherein the replicating instruction addresses the packets per the unicast addresses of the requesting clients.
17. The computer-readable medium of claim 13, further comprising instructions for:
selecting an optimal upstream virtual router; and
forwarding a multicast request for the multicast content to the selected upstream virtual router.
18. The computer-readable medium of claim 17, wherein the selecting instruction comprises instructions for:
determining a router load on upstream virtual routers;
determining a round trip time on the upstream virtual routers; and
balancing the determined router loads and round trip times for the upstream virtual routers, wherein the selecting instruction selects the upstream virtual router with the best balance of router load and round trip time.
19. The computer-readable medium of claim 13, wherein the determining if the attached network is multicast enabled instruction comprises instructions for:
listening for Internet Group Management Protocol (IGMP) queries.
20. The computer-readable medium of claim 13, wherein the querying instruction comprises instructions for:
issuing virtual IGMP (VIGMP) queries, wherein VIGMP queries query client computers for VIGMP reports that request unicast or multicast delivery of the multicast content.
21. The computer-readable medium of claim 20, wherein the VIGMP reports that request unicast delivery of the multicast content include a unicast address for a requesting client computer and a multicast address for the multicast content.
22. The computer-readable medium of claim 13, wherein the listening instruction listens for virtual multicast requests from downstream virtual routers.
23. The computer-readable medium of claim 22, wherein the listening instruction listens for virtual multicast requests from downstream virtual routers by listening for Virtual Multicast Registration protocol (VMCRP) reports from the downstream virtual routers.
24. The computer-readable medium of claim 23, wherein the VMCRP reports include a unicast address for a requesting downstream virtual router and a multicast address for the multicast content.
25. A system for virtual multicasting (VMC) multicast content on non-multicast enabled networks, comprising:
a virtual router;
an attached network associated with the virtual router, wherein the attached network includes a plurality of client computers that have unicast addresses; and
wherein the virtual router includes software comprising instructions for:
determining if the attached network is multicast enabled;
if the attached network is not totally multicast enabled, querying for virtual multicast requests for the multicast content from non-multicast enabled client computers;
listening for virtual multicast requests, wherein at least one virtual multicast request includes a unicast address identifying a client computer of the network and a requested method of delivery for the multicast content; and
determining, based on the virtual multicast requests, which client computers request the multicast content, from the unicast addresses, and the requested methods of delivery for the multicast content.
26. The system of claim 25, wherein the virtual router software further comprises instructions for:
building a table of requesting client computers based on the requesting client computers determined from the determining step.
27. The system of claim 26, wherein the virtual router software further comprises instructions for:
receiving the multicast content, wherein the multicast content comprises a plurality of packets;
replicating the packets and addressing the packets per the table of requesting client computers; and
transmitting the replicated and addressed packets to the requesting client computers.
28. The system of claim 27, wherein:
the building instruction builds a VMC client table (VCT) file that includes the identities of the requesting client computers and the unicast addresses of the requesting clients; and
the virtual router software further comprises instructions for:
reading the VCT file for the identities of the requesting client computers and the unicast addresses of the requesting clients, wherein the replicating instruction addresses the packets per the unicast addresses of the requesting clients.
29. The system of claim 25, further comprising a plurality of upstream virtual routers, wherein the virtual router software further comprises instructions for:
selecting an optimal upstream virtual router; and
forwarding a multicast request for the multicast content to the selected upstream virtual router.
30. The system of claim 29, wherein the selecting instruction comprises instructions for:
determining a router load on upstream virtual routers;
determining a round trip time on the upstream virtual routers; and
balancing the determined router loads and round trip times for the upstream virtual routers, wherein the selecting instruction selects the upstream virtual router with the best balance of router load and round trip time.
31. The system of claim 25, wherein the determining if the attached network is multicast enabled instruction comprises instructions for:
listening for Internet Group Management Protocol (IGMP) queries.
32. The system of claim 25, wherein the querying instruction comprises instructions for:
issuing virtual IGMP (VIGMP) queries, wherein VIGMP queries query client computers for VIGMP reports that request unicast or multicast delivery of the multicast content.
33. The system of claim 32, wherein the VIGMP reports that request unicast delivery of the multicast content include a unicast address for a requesting client computer and a multicast address for the multicast content.
34. The system of claim 25, wherein system further comprises one or more downstream virtual routers and the listening instruction listens for virtual multicast requests from downstream virtual routers.
35. The system of claim 34, wherein the listening instruction listens for virtual multicast requests from downstream virtual routers by listening for Virtual Multicast Registration protocol (VMCRP) reports from the downstream virtual routers.
36. The system of claim 35, wherein the VMCRP reports include a unicast address for a requesting downstream virtual router and a multicast address for the multicast content.
Description
    CROSS REFERENCE TO RELATED APPLICATIONS
  • [0001]
    This application hereby claims the benefit of the priority of U.S. Provisional Patent Application, Serial No. 60/214,752, filed Jun. 29, 2000, which is hereby incorporated by reference. This application also hereby incorporates by reference U.S. Patent Application, Serial No. 09/835,529, entitled “Channel Dancer” and filed Apr. 17, 2001, U.S. Patent Application, Serial No. 09/878,232, entitled “Personal Content Manager” and filed Jun. 12, 2001, and U.S. Patent Application entitled “Digital Rights Management”, invented by Khanh Mai, Roland Noll, and Tom Grimes and filed on the same date, under separate cover, as the present application.
  • BACKGROUND
  • [0002]
    1. Technical Field
  • [0003]
    The present invention is related to Internet Protocol (“IP”) multicasting, and more particularly to IP multicasting over a non-IP multicast supported network.
  • [0004]
    2. Description of Related Art
  • [0005]
    Over the past ten years, the bandwidth capacity available to consumers for receiving content from the Internet and other networks has increased ten-fold and more. The increased bandwidth capacity has enabled consumers to download larger and larger files and other content, including rich media and multimedia content such as audio clips, video clips, songs, programs, and movies. This increased bandwidth capacity has increased Internet usage and the potential for enjoyable and productive usage.
  • [0006]
    The content may be delivered to users, for example, as real-time IP multicast or unicast streams. IP multicasting is a method to send a single message to multiple recipients belonging to a multicast group. To multicast content, a multicast group is created by a multicast router and Internet Group Management Protocol (IGMP) queries for the multicast content are sent out to clients via the router's network. Clients that want to receive the multicast content send a IGMP report, in response to the IGMP query to the multicast router and are added to the multicast group. Any client that is a member of the multicast group receives the multicast content. The IP multicasting method can reduce the unnecessary network load caused by the unicasting method, which sends out multiple copies of the same message to multiple recipients. Despite the increased bandwidth capacity, however, most networks, especially Internet Service Provider (“ISP”) networks, are not IP multicast enabled. Enabling IP multicasting in a network requires equipment upgrades. Also, broadcasting of heavily requested content may be bandwidth prohibitive for many networks. Unfortunately, the necessary equipment upgrades are often not undertaken by many networks. Many networks do not make the necessary equipment upgrades because the equipment upgrades are not cost efficient.
  • [0007]
    What is needed is a mechanism for delivering IP multicast content to users via a non-multicast enabled network.
  • SUMMARY OF THE INVENTION
  • [0008]
    An advantage of the present invention is that it overcomes the disadvantages and shortcomings of the prior art. Another advantage of the present invention is that it provides a method and a system for simulating multicasting over non-multicast enabled networks. Another advantage of the present invention is that it provides a system that is able to distribute multicast/unicast packets to multiple end-users through non-multicast enabled networks with multicast efficiency. Another advantage of the present invention is that it does not require changes on the pre-existing infrastructure of the networks. The potential beneficiaries of the present invention include applications involving fan-out distribution of packets, content distribution to multiple isolated (non-multicast enabled in between) networks, and last stop distribution of packets (see FIGS. 1, 7, and 8).
  • [0009]
    These and other advantages of the present invention are achieved by a method of virtual multicasting multicast content on non-multicast enabled networks, comprising the steps of determining if an attached network is multicast enabled, if the attached network is not totally multicast enabled, querying for virtual multicast requests for the multicast content from non-multicast enabled client computers, listening for virtual multicast requests, and determining, based on the virtual multicast requests, which client computers request the multicast content, from the unicast addresses, and the requested methods of delivery for the multicast content. The network includes client computers that have unicast addresses and the at least one virtual multicast request includes a unicast address identifying a client computer of the network and a requested method of delivery for the multicast content.
  • [0010]
    These and other advantages of the present invention are also achieved by a computer-readable medium comprising instructions for virtual multicasting (VMC) multicast content on non-multicast enabled networks, by determining if an attached network is multicast enabled, if the attached network is not totally multicast enabled, querying for virtual multicast requests for the multicast content from non-multicast enabled client computers, listening for virtual multicast requests, and determining, based on the virtual multicast requests, which client computers request the multicast content, from the unicast addresses, and the requested methods of delivery for the multicast content. The network includes client computers that have unicast addresses and the at least one virtual multicast request includes a unicast address identifying a client computer of the network and a requested method of delivery for the multicast content.
  • [0011]
    These and other advantages of the present invention are also achieved by a system for virtual multicasting (VMC) multicast content on non-multicast enabled networks, comprising a virtual router and an attached network, associated with the virtual router, that includes a plurality of client computers that have unicast addresses. The virtual router includes software comprising instructions for determining if the attached network is multicast enabled, if the attached network is not totally multicast enabled, querying for virtual multicast requests for the multicast content from non-multicast enabled client computers, listening for virtual multicast requests, and determining, based on the virtual multicast requests, which client computers request the multicast content, from the unicast addresses, and the requested methods of delivery for the multicast content. The at least one virtual multicast request includes a unicast address identifying a client computer of the network and a requested method of delivery for the multicast content.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • [0012]
    The detailed description will refer to the following drawings, in which like numbers refer to like items, and in which:
  • [0013]
    [0013]FIG. 1 is a schematic diagram of an exemplary embodiment of a virtual multicasting system.
  • [0014]
    [0014]FIGS. 2a-2 c are block diagrams illustrating exemplary hardware components of an embodiment of the virtual multicasting system.
  • [0015]
    [0015]FIGS. 3a-3 b are flowcharts illustrating an exemplary method of virtual multicasting.
  • [0016]
    [0016]FIG. 4 is a schematic diagram of a virtual network tree.
  • [0017]
    [0017]FIGS. 5a-5 b are block diagrams illustrating an exemplary implementation of the virtual multicasting system.
  • [0018]
    [0018]FIG. 6 is a block diagram of an exemplary implementation of the virtual multicasting system. FIGS. 7 and 8 are schematic diagrams of exemplary embodiments of the virtual multicasting system.
  • DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
  • [0019]
    [0019]FIG. 1 is a schematic diagram of an exemplary application of a Virtual Multicasting (VMC) system according to the present invention. The embodiment shown in FIG. 1 is a virtual network 10 including a plurality of sub-networks (networks A-F). The virtual network 10 in FIG. 1 provides a fan-out distribution of packets. The VMC system includes software routing applications as well as computer hardware for hosting these applications. The components of the VMC system are listed as follows:
  • [0020]
    VMC System Hardware Components
  • [0021]
    Virtual Routers (VRs) 12, which preferably are standard computers with networking capabilities. Except for client components, the VMC software resides on the VRs.
  • [0022]
    Clients 14, which preferably are standard computers for end-users that comprise client software, including certain VMC software components, and receive content delivered by the VMC system over the virtual network 10. Clients 14 are the end-recipients of content distribution. Clients 14 preferably also include a network interface card/adapter and necessary networking software such as TCP/IP.
  • [0023]
    Content servers 16, which preferably are standard computers with networking, data-storage, and web hosting capabilities. Content preferably originates from the content servers 16. Content servers 16 may also serve as a web site, accessible via the Internet, hosting information about content availability.
  • [0024]
    VMC System Software Components
  • [0025]
    A Virtual Multicast Distribution protocol (VMCDP) that dictates how VRs 12 convert packets from multicast packets to unicast packets and vise versa, replicate packets for unicast clients 14 or downstream VRs 12 (VRs 12 located at virtual sub-networks downstream—e.g., VR22 is downstream from VR11), and deliver packets. The software conversion of packets from multicast to unicast may be accomplished by modifying destination IP of the packet at the IP layer. A standard multicast group is defined by an multicast IP address and a port. A unique value in the VMC system is how a channel is defined. A VMC channel map (see VMC file below) is created at the central location VR 12 (e.g., VR11) and fetched by all the downstream VRs 12. In the VMC system, a channel (or a multicast group in standard multicast) is defined by a port. When a VR 12 receives a unicast stream (destinated to the VR 12) at a port on the map, the VR 12 automatically knows what multicast group the unicast stream belongs to based on the VMC channel map. This is impossible for standard Transmission Control Protocol/Internet Protocol (TCP/IP) without adding more information (like the mutlicast IP address) to the packet. Another unique feature is that VMC system does not alter the original packet. The VMC system does not add information to the original packet. The VMC system always keeps the original sender's IP address for possible backlink service. The VMC protocols describe below are only used on VRs 12 for registration and distribution mechanisms.
  • [0026]
    A Virtual Multicast Registration protocol (VMCRP). The VMCRP is used by VRs 12 for dynamic registration of client 14 requests for VMC content, periodic probing and the addition/removal of clients 14 or downstream VRs 12 from VMC client table files (see below). VMCRP is a protocol used among VRs 12 to forward requests of VMC content on certain channels. Upon receiving a request from a client 14 or another VR 12 (forwarding requests), a VR 12 will send a short message to all the VRs 12 at its parent level on the Virtual Network Tree (see VNT file below) asking for the parent VR's 12 loads and distance (judging by round trip time (RTT) of an ICMP packet). After making an optimal selection of a parent VR 12 based these two factors, the VR 12 will add the parent VR 12 entry to its client table (for unicast request—see VCT file below) or the multicast flag will be turned on (for a multicast request) and forward the request to the selected parent VR 12. VRs 12 will periodically send a probing (in dynamic registration) message to all it clients 14. A client 14 which fails to answer the probing will be removed from the client table. So no unnecessary streams (for clients 14 that fail to 25 answer) will be send to that network. At the same time, clients 14 and VRs 12 may periodically send probing to their registered parent VRs 12. If a parent VR 12 fails to answer the probing, the client/VR will re-register all the content requests associated with the parent VR 12 with other parent VRs 12.
  • [0027]
    A Virtual IGMP protocol (VIGMP) for clients 14 to register requests for content with Virtual Routers 12. VIGMP reports generally indicate that the client 14 is requesting unicast delivery (the client 14 is not multicast enabled). Clients 14 in a multicast enabled portion of a network may transmit VIGMP reports requesting multicast delivery (the client 14 is multicast enabled). The VIGMP preferably is an application programming interface (API) for easy integration with client software.
  • [0028]
    VMC System Files
  • [0029]
    A Virtual Network Tree (VNT) File. The VNT file preferably contains a list of the VRs 12 on the entire virtual network 10. These VRs 12 are grouped by levels starting from root level VRs 12 at a central location (i.e., network A in FIG. 1). The VNT file describes the hierarchy of the virtual routers 12. For the example in FIG. 1, VR11 is at root level or level 1. VR21 and VR22 are at level 2 (i.e., level 2 VRs 12). VR31, VR32, and VR33 are at level 3 (i.e., level 3 VRs 12). The levels may represent regions, states, and cities, for example. The maximum number of VRs 12 at a certain level may be determined by the capacities of the VRs 12 at a higher level (i.e., closer to the root level).
  • [0030]
    The VNT file preferably also includes information about each VR 12 on the list. This information preferably includes an IP address of the VR 12 that is accessible by other VRs 12 and the full host name of the VR 12. The VNT file is preferably created at the central location and is preferably fetched by VRs 12 on the same virtual network 10 during the VR's 12 startup in order for the VRs 12 to determine their level (e.g., level 2) and to find the closest upstream VR 12.
  • [0031]
    A VMC Channel Map (VCM) File. The VCM file preferably includes a list of pairs of multicast IP addresses and port numbers supported by the specific VMC system. Each pair of addresses and port numbers defines a multicast channel for content distribution. The VCM file may be created at the central location and be fetched by VRs 12 on the same virtual network 10 during the VR's 12 startup in order for the VRs 12 to determine what multicast channels are available.
  • [0032]
    A VMC Client Table (VCT) File. Preferably, each VR 12 keeps a client table (the VCT file) for each available multicast channel (group). The VCT file contains a multicast flag and a list of unicast clients 14 for each supported multicast channel. The VCT file is created locally by the registration protocols VIGMP and VMCRP. The multicast flag for each supported multicast channel is turned on upon the VR 12 receiving of a VIGMP report for a multicast group (indicating that a client wants to receive the multicast content). The list of unicast clients 14 requesting content from each supported multicast channel is updated as follows: upon the VR 12 receiving a VIGMP/YMCRP unicast request from a client 14 or downstream VR 12 (the senders), the client's 14 or/and downstream VR's 12 IP address is added to the list of unicast clients in the VCT file, if the client 14 or VR 12 is not already on the list.
  • [0033]
    Function of the VMC System
  • [0034]
    The above VMC protocols (VMCDP, VMCRP and VIGMP) are built on top of standard TCP/IP protocols, such as UDP (user datagram protocol), IP (Internet Protocol), ICMP (Internet Control Message Protocol), and IGMP. Indeed, the messaging proscribed by the VMC protocols is identical to the underlying standard TCP/IP protocols. For example, the VIGMP reports are identical to IGMP reports.
  • [0035]
    Each VR 12 can receive/distribute multicast as well as unicast packets. The VRs 12 can also convert multicast packets to unicast packets, and vise-versa. Whether a VR 12 concerts multicast packets to unicast packet, or vice-versa, is determined by the VR 12 virtual multicast client table (VCT files) created by the registration protocol VMCRP requests. For example, if a client 14 sends a VIIGMP unicast request to the VR 12, the client's 14 IP address is added to the list of unicast clients in the VCT file and multicast packets for the requested multicast content group are converted to unicast packets for that client 14.
  • [0036]
    Referring to the exemplary application of the VMC system shown in FIG. 1, the virtual network 10 includes six sub-networks, networks A-F. Networks A-D are separate and connected only via the Internet, which is not (or at least not fully) multicast enabled. Network A is the central location where all the content packets (content for multicast distributing) originate in the virtual network 10. As shown, network A receives the content from the content server 16, which may be co-located with or remotely located from network A.
  • [0037]
    In the example illustrated in FIG. 1, virtual multicasting is achieved by running a virtual router 12 on each network A-F (in a similar way normal networks are configured with different routers) that requires virtual multicasting. The VNT file, which includes a virtual multicasting tree that describes the virtual network 10 and the sub-networks A-F, is built at the network A, the central location (the root of the tree). During the startup of each VR 12, each VR 12 communicates with VR11, the VR 12 at the central location, and fetches the VNT file and the VCM file. Each VR 12 uses the VNT file to determine their tree level and the closest upstream VR 12.
  • [0038]
    The VMC client 14 registration process is driven by client 14 requests for multicast content. Once a VR 12 detects the absence of a multicast enabled router (the absence of IGMP queries), the VR 12 periodically issues VIGMP queries using a control channel to the attached network A-F. The VIGMP queries are identical to IGMP queries for multicast clients. A user on a client 14 may review available multicast content on the content server 16 using a web browser, or other means. A multicast-enabled client 14, for example Client 1 on Network D, may request to join a multicast group for multicast content by sending out IGMP reports to the VR 12. A unicast client 14 wanting to receive the multicast content may use VIGMP reports to request unicast delivery (Unicast UDP) of the multicast packets. On a multicast-enabled network, where a regular router is issuing IGMP queries, the VR 12 preferably only listens to and processes the VIGMP reports.
  • [0039]
    A VR 12, for example VR31, that receives the VIGMP report adds the requesting unicast client 14 to the VCT file of the VR 12 (i.e., the VMC client table) for the requested multicast content group and forwards/registers the requested multicast group with one of the upstream VRs 12 using the registration protocol VMCRP. The upstream VR 12, with which the requested multicast group is registered, is preferably selected based on an optimal balance of the loading on each upstream VR 12 and the Round Trip Time (RTT) necessary for the registration to reach each upstream VR 12. The selected VR 12 (parent VR) forwards the registration to a further upstream VR 12 in a similar manner. This registration process preferably continues until the registration reaches the root VR 12 at the center location (network A).
  • [0040]
    The multicast content server 16 (which may be on the same network as the center location or remotely located from the center location) does not necessarily need to be multicasting since the root virtual router 12 can receive both multicast and unicast packets and convert them if necessary. With the distribution protocol VMCDP, once a VR 12 receives a multicast or unicast packet, the VR 12 checks against its VCT file (the VMC client table), conducts the necessary packet conversion and/or replication, and delivers a multicast packet to the attached network or/and multiple unicast packets to clients 14 on the attached network or/and downstream VRs 12.
  • [0041]
    A VR 12 preferably can send out a multicast packet and/or multiple unicast packets to clients 14 on the same network and/or to downstream VRs 12. For example, referring to the virtual network 10 in FIG. 1, VR21 may send a multicast packet to Network B if requested (by a multicast client, e.g. MC Client on Network B). In addition, VR21 replicates the packet and unicast the replicated packets to the unicast client (UC Client) on the attached network (Network B) and to downstream virtual routers VR31 and VR32.
  • [0042]
    The registration protocols VMCRP and VIGMP may be implemented dynamically. With the dynamic VMCRP and VIGMP, clients 14 and VRs 12 periodically re-register requests, check VCT files (the VMC client tables), and probe registered parent VRs 12. The probe may be to check if the registered parent VR 12 is still up. The registered parent VR 12 could be accidentally down or shut down for maintenance. The VR 12 or client 14 have the ability to switch to other parent VRs 12 for those channels already associated with the down parent VR 12. A client 14 in the VMC client table of a VR 12 is preferably removed from the VMC client table if the client 14 has not re-registered within a certain period of time. If the probe to a registered parent VR 12 fails, the current VR 12 re-registers with other upstream VR(s) 12 all the multicast content requests associated with the failed parent VR 12.
  • [0043]
    Exemplary VMC System Hardware Components FIGS. 2a through 2 c are block diagrams illustrating exemplary hardware components for implementing virtual multicasting and supporting a multicasting system.
  • [0044]
    Client 14 FIG. 2a illustrates an exemplary client 14. As shown, the client 14 preferably comprises a consumer PC/user machine 20 connected with a network 44 such as the Internet, a LAN or other network. Other clients, such as client 14′ may also be connected with network 44 and may include the same components as user machine 20.
  • [0045]
    User machine 20 illustrates typical components of a user machine. User machine 20 typically includes a memory 22, a secondary storage device 24, a processor 26, an input device 28, a display device 30, and an output device 32. Memory 22 may include random access memory (RAM) or similar types of memory, and it may store one or more applications 34, including client software 36 and VIGMP API 38, and a web browser 40, for execution by processor 26. Secondary storage device 24 may include a hard disk drive, floppy disk drive, CD-ROM drive, or other types of non-volatile data storage. Processor 26 may execute applications or programs stored in memory 22 or secondary storage 24, or received from the Internet or other network 44. The processor 26 may execute one or more applications 34, including client software 36 and VIGMP API 38, in order to provide the functions described in this specification. Input device 28 may include any device for entering information into user machine 20, such as a keyboard, mouse, cursor-control device, touch-screen, infrared, microphone, digital camera, video recorder or camcorder. Display device 30 may include any type of device for presenting visual information such as, for example, a computer monitor or flat-screen display. Output device 32 may include any type of device for presenting a hard copy of information, such as a printer, and other types of output devices include speakers or any device for providing information in audio form.
  • [0046]
    Web browser 40 is used to access the VMC system and to choose which broadband content the user wishes to view. The web browser 40 also is used to access the Internet 44, content servers 16 (e.g., a NOC) and ISPs. Examples of web browsers 40 include the Netscape Navigator™ program and the Microsoft Internet Explorer™ program. Any web browser, co-browser, or other application capable of retrieving content from a network (any wireline or wireless network may be used) and displaying pages or screens may be used. Content broadcast (multicast or unicast) and received by the client 14 may be displayed through the web-browser 40. The content may include “links”, for example, HyperText Transport Protocol (“HTTP”) hyperlinks to other content and/or Internet websites. Multimedia applications such as Microsoft Media Player™ and RealPlayer™ may be used to enable viewing of real-time multicast or unicast streams.
  • [0047]
    Examples of user machines for interacting within the system include personal computers, laptop computers, notebook computers, palm top computers, network computers, Internet appliances, set top terminals or any processor-controlled device capable of executing a web browser 40 or other type of application for interacting with the VMC system.
  • [0048]
    Content Server
  • [0049]
    [0049]FIG. 2b illustrates typical hardware components of a content server 16. Content server 16 typically includes a memory 50, a secondary storage device 52, a processor 54, an input device 56, a display device 58, and an output device 60. Memory 50 may include RAM or similar types of memory, and it may store one or more applications 64 for execution by processor 54. Secondary storage device 52 may include a hard disk drive, floppy disk drive, CD-ROM drive, or other types of non-volatile data storage. Processor 54 executes application(s), which are stored in memory 50 or secondary storage 52, or received from the broadband connection, the Internet or other network 44. Input device 56 may include any device for entering information into content server 16, such as a keyboard, mouse, cursor-control device, touch-screen, infrared, microphone, digital camera, video recorder or camcorder. Display device 58 may include any type of device for presenting visual information such as, for example, a computer monitor or flat-screen display. Output device 60 may include any type of device for presenting a hard copy of information, such as a printer, and other types of output devices include speakers or any device for providing information in audio form.
  • [0050]
    Content server 16 may store one or more database structures in secondary storage 52, for example, for storing and maintaining information regarding the clients 14. For example, it may maintain a relational, object-oriented or other client database for storing information concerning system users, the access rights of the users and their account status. The database structures may also include content databases. For example, the content server 16 may maintain a relational, object-oriented or other content database for storing content and/or information concerning the content.
  • [0051]
    Processing by the processors 54 may provide and support pages, windows and menus described in this specification and otherwise for display on display devices associated with the client 14. The pages, windows and menus may be formatted, for example, as web pages in HyperText Markup Language (HTML), Extensible Markup Language (XML) or in any other suitable form for presentation on a display device depending upon applications used by users of the clients 14.
  • [0052]
    Although only one content server 16 is shown, multiple servers may be used as necessary or desired to support and provide the content and may also use back-up or redundant servers to prevent network downtime in the event of a failure of a particular server.
  • [0053]
    Virtual Router FIG. 2c illustrates typical hardware components of a virtual router 12. A virtual router 12 is preferably a standard computer/server with networking functionality. Typically, the VR 12 includes a memory 70, a secondary storage device 72, a processor 74, a network input device 76, and a network output device 78. The memory 70, secondary storage device 72, and processor 74, are similar, in form and function to those of the content server 16 described above with reference to FIG. 2b. For example, the processor 74 may execute applications 80 stored in the memory 70 and/or secondary storage device 72, including VMCDP, VMCRP and VIMGP software described above, to perform the functions of the VMC system described herein. Likewise, the processor 74 may create and store files, including the VNT, VCM and VCT files described above, in the memory 70 and/or secondary storage device 72.
  • [0054]
    The network input device 76 and the network output device 78 may comprise network adaptors and/or network information cards (NIC). The network input device 76 and the network output device 78 are able input/output IP packets from/to the connected network (e.g., network A-F). The operating system on the VR 12 and the drivers on the network input device 76 and the network output device 78 support the standard TCP/IP protocols and can issue IP level protocols such as ICMP and IGMP. It is preferable for the operating system to support web-hosting protocols such as HTML, so the VR 12 may be configured and operated from remote sites.
  • [0055]
    In addition, although VR 12, client 14, and content server 16 are depicted with various components, one skilled in the art will appreciate that VR 12, client 14, and content server 16 can contain additional or different components. In addition, although aspects of an implementation consistent with the present invention are described as being stored in memory, one skilled in the art will appreciate that these aspects can also be stored on or read from other types of computer program products or computer-readable media, such as secondary storage devices, including hard disks, floppy disks, or CD-ROM; a carrier wave from the Internet or other network; or other forms of RAM or ROM. The computer-readable media may include instructions for controlling a computer system, such as VR 12, client 14, and content server 16, to perform a particular method.
  • [0056]
    An Exemplary VMC Method
  • [0057]
    [0057]FIGS. 3a-3 b illustrate an exemplary method 90 of virtual multicasting. Method 90 may be implemented, for example, with software modules for execution by processor 74, processor 26, or a combination of the two processors. In this implementation, multicast content (e.g., broadband content) is broadcast to a network(s) and offered to multiple network users (e.g., clients, other virtual routers, etc.). As shown, the method preferably comprises the steps of: determining if an attached network (e.g., network A-D) is multicast enabled 92; querying for virtual multicast requests 94; listening for virtual multicast requests from clients and downstream virtual routers 96; determining which clients and/or downstream virtual routers request multicast content and the requested delivery method 98; building a table of requesting clients and virtual routers 100; selecting an optimal upstream router 102 (only applicable for downstream VRs 12); forwarding multicast request to upstream virtual router 104 (only applicable for downstream VRs 12); receiving the requested multicast content 106; replicating and addressing packets per table 108; and transmitting packets to requesting multicast clients and unicast clients and downstream virtual routers 110.
  • [0058]
    A VR 12 is preferably associated with a network (e.g., network B) and preferably determines whether the attached network is multicast enabled, step 92, by listening for IGMP queries 921 (e.g., on the network control channel). If no IGMP queries are received within a certain period of time, the VR 12 determines that the attached network is not multicast enabled. If the network is not totally multicast enabled (e.g., a UNICAST UDP network) the VR 12 preferably queries for virtual multicast content requests (step 94) by issuing VIGMP queries 941 and listens for virtual multicast content requests from clients 14 and downstream VRs 12 (step 96) by listening for VIGMP reports 961 and listening for VMRCP reports 962. The VR 12 (e.g., VR 22 in FIG. 1) preferably determines (step 98) which clients 14 and/or downstream VRs 12 (e.g., VR 33) request the multicast content and the requested delivery method for the multicast content (e.g., multicast or unicast) for each request by reading VIGMP and IGMP reports 981 from clients 14 and reading VMCRP reports 982 from downstream VRs 12. The VIGMP reports indicate whether the requesting clients 14 are to get unicast or multicast delivery (clients 14 that will join the multicast group). The IGMP reports indicate that the requesting clients 14 are to get multicast delivery.
  • [0059]
    The virtual router preferably builds a table of requesting clients and virtual routers (step 100) by building a VCT file 1001 that comprises unicast addresses of the clients 14 and/or downstream VRs 12 that requested the content and an associated multicast address(es) that identifies the requested content. As described above, if the VR 12 is a downstream VR 12 (e.g., VR22 in FIG. 1), the VR 12 preferably selects an optimal upstream virtual router 102 by determining the upstream VR 12 (e.g., VR11 in FIG. 1) loads and round trip times (RTTs) 921 and balancing these two factors to select an optimal upstream VR 12. This step 102 is only performed when there is a plurality of upstream VRs 12 to choose from. The VR 12 may perform step 102 at startup.
  • [0060]
    The VR 12 preferably forwards the multicast request to the selected upstream VR 12 (step 104) by turning on the multicast flag in the VCT file 1041 and transmitting the VCT file to the upstream VR 12. As noted above, the multicast request (e.g., the VCT file) is forwarded upstream until it reaches the root level or central location VR 12 (e.g., VR11).
  • [0061]
    If the central location VR 12, the selected VR 12, and any intervening VRs 12 have received the multicast request, the multicast content is transmitted to the current VR 12 (preferably as unicast packets). The current VR 12 preferably receives the content (step 106) as a stream of packets. The VR 12 replicates the packets for each requesting network client 14 and downstream VR 12 addresses the replicated packets with the unicast addresses of the requesting network clients 14 and downstream VRs 12 (step 108) as determined by reading the VCT file for unicast clients 14, VRs 12 and their addresses 1081. If the VR 12 receives the content as multicast packets, the VR 12 converts the multicast packets to unicast packets. For clients requesting multicast delivery, the VR 12 simply transmits the packets as multicast packets in the normal manner. The VR 12 transmits the unicast packets to each requesting unicast client 14 and downstream VR 12 (step 110). If the virtual router determines that the network is multicast enabled, the content is multicast to the requesting network multicast users in a normal way (see above).
  • [0062]
    As noted above, if the network is multicast enabled, the VR 12 will only listen to VIGMP reports. As noted before, for multicast clients 14, VIGMP reports may be identical to IGMP reports. If the network is not multicast enabled, the VR 12 will periodically send out VIGMP queries after it detects the absence of IGMP query message. Clients 14 can use VIGMP to request for multicast delivery or unicast delivery of the content.
  • [0063]
    As noted above, a VR 12 may replicate multicast content to other VRs 12, as well as clients 14. Virtual routers 12 may be logically stacked or hierarchically located on top of one another. FIG. 4 illustrates the hierarchical structure of VRs 12 of the example in FIG. 1. A VR 12, therefore, may maintain a VMC client table (a VCT file) that comprises unicast addresses for clients 14 and other VRs 12. A VR 12 may register with any VRs 12 above it (closer to the root) by using VMCRP or similar routing protocols. As noted, the decision of which parent VR 12 to register with is made based on an optimal balance of the load of parent VRs and the round trip time (RTT) to reach them. Accordingly, a central VR 12 may be co-located with a multicast content server in order to convert multicast streams to virtual multicast streams, with unicast addressing, that are broadcast to other VRs 12 at multiple networks. Likewise, one VR 12 may act as a backup for another VR 12 below it in the hierarchical structure.
  • [0064]
    Sample Implementation 1 of VMC System FIGS. 5a and 5 b illustrate a sample implementation of the VMC system. The system 120 illustrated by FIG. 5 comprises one or more signal origination [or orientation] points 122 (e.g., network operation center or “NOC”), one or more transmission mediums 124 (e.g., transmitting satellite dish(es), satellite(s) and receiving satellite dish(es) and the Internet), and one or more central office (“CO”) servers 126 (e.g., ISP servers) that support a network 128 of one or more clients 14. One example of the central office server 126 is depicted in FIG. 5b as comprising a VR 12 and an ATM/DSLAM switch 130, with connections via various sub-networks (e.g., broadband digital subscriber line (DSL) or cable) of the network 128 to one or more clients 14. The VR 12 may be resident or loaded on the actual router (not shown). In operation, the NOC 122, comprising the content server 16, broadcasts multicast content via the transmission medium 124 to the central office servers 126. The central office servers 126 distribute the content to the clients 14.
  • [0065]
    In addition to the multicast content, the NOC 122 may also provide information about content availability to its users through other channels, such as on a web site accessible via the Internet or other network 44. Clients 14 can access the web site to check which multicast content is available. If the network 128 is multicast enabled, a client 14 can request certain multicast content by registering with the ATM/DSLAM switch 130. The ATM/DSLAM switch 130 builds a table comprising the client's 14 address and the multicast address of the content and sends an IGMP packet to the router. In response to the IGMP packet, the router transmits the multicast stream for the requested content to the ATM/DSLAM switch 130 The ATM/DSLAM switch 130 replicates the multicast stream packets of the requested content and transmits them to the client 14, and any other requesting clients 14, based on its table.
  • [0066]
    If the network 128 is not multicast enabled (e.g., the ATM/DSLAM switch 130 does not have multicasting capability), a client 13 can transmit a VIGMP packet through the ATM/DSLAM switch 130 to the VR 12 requesting for unicast delivery. Preferably, the VIGMP packet registers the client 14 with the VR 12 and tells the VR 12 that the network 130 or sub-network on which the client 14 is located is not multicast enabled and that the client 14 wants to receive multicast content. The client 14 may contact the NOC 122 via the Internet or other network 44 to determine where the closest VR 12 is located before sending the VIGMP. The VR 12 may build a virtual VMC table or dynamic routing table (the VCT file) with information about the client 14 (e.g., the client's unicast address) so that it can replicate and transmit content packets to the client 14 when the client 14 requests content. As the VR 12 receives multicast content, the VR 12 may convert the requested multicast content by replicating the content packets and transmitting to the client 14 at the client's unicast address. Note, that the VR 12 may receive the multicast content as a unicast stream, for example, if there is another VR 12 upstream (e.g., co-located with the NOC 122) from the VR 12 (located at a central office 126). The packets of the unicast stream may include the multicast address of the content so that the VR 12 can identify and properly route the content.
  • [0067]
    Sample Implementation 2 of VMC System
  • [0068]
    [0068]FIG. 6 illustrates another sample implementation of the virtual multicasting system. The system 140 illustrated by FIG. 6 comprises one or more regional data center or edge of net content servers 162, one or more central office servers 126 supporting networks 128 of clients 14, one or more transmission mediums 124 (e.g., landlines, DSL, cable, etc.) connecting the regional data center or edge of net content servers 162 to the central office servers 126, a plurality of clients 14 and broadband transmission mediums 128 connecting the central office servers 126 and the clients 14. The regional data center or edge of net content servers 162 may be co-located with a VR 12 so that the content broadcast by the content servers 16 may be virtually multicast. The VR 12 may convert multicast streams from the content servers 16 to unicast streams and broadcast them to central office servers 126 based on a central routing table comprising addresses for the central offices servers 126 with networks 128 of clients 14 that requested the content. For example, a movie that is requested by fifty thousand (50,000) clients 14 located on various central office networks 128 may be transmitted from a content server 16 to a VR 12 co-located with it at a regional data center 142, converted from a multicast stream to a unicast stream, replicated (as necessary) and broadcast across a landline(s) 124 to the various central office servers 126 and replicated and broadcast to the fifty thousand requesting clients 14 by VRs 12 at the central office servers 126. Since the content may be broadcast from the regional data center 142 as a unicast stream, the virtual multicasting provides a substantial bandwidth saving between the regional data center 142 and the central offices 126.
  • [0069]
    It is further noted that content that has been virtual multicast, as unicast, may be converted back to or re-broadcast as multicast. For example, in the system 140 shown in FIG. 6, if any of the central office servers 126 supported multicast enabled networks 128, the unicast stream received by the VR 12 at such central office servers 126 may be sent through to the ATM/DSLAM switch 130 and multicast to the clients 140, since the packets comprise the actual multicast address of the content. Likewise, if the network 128 receiving the virtual multicast stream is a LAN, the stream may be re-broadcast as a actual multicast stream since multicasting is supported within the LAN.
  • [0070]
    As noted above, the virtual network 10 in FIG. 1 is an application of the VMC system that may be used for fan-out distribution of packets. FIGS. 7 and 8 are schematic diagrams of additional exemplary applications of the VMC system according to the present invention. The exemplary virtual networks 150 and 160 shown in FIGS. 7 and 8 comprise VRs 12, clients 14, content servers 16, center networks 152 (corresponding to central location or root level network A in FIG. 1) and remote networks 154 (corresponding to networks B-F at levels 2 and below in FIG. 1). The virtual network 150 in FIG. 7 is a bridging-islands network. The virtual network 160 in FIG. 8 is a last-stop conversion network. The virtual networks 150 and 160 perform virtual multicasting as described above, with the center networks 152 fulfilling the role of the central location or center office server.
  • [0071]
    It is also noted that certain portions of networks may be multicast enabled while other portions are not. Consequently, a virtual router may conduct virtual multicasting simultaneously with a co-located router conducting true multicasting.
  • [0072]
    The terms and descriptions used herein are set forth by way of illustration only and are not meant as limitations. Those skilled in the art will recognize that numerous variations are possible within the spirit and scope of the invention.
Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US5331637 *Jul 30, 1993Jul 19, 1994Bell Communications Research, Inc.Multicast routing using core based trees
US5959989 *Jun 25, 1997Sep 28, 1999Cisco Technology, Inc.System for efficient multicast distribution in a virtual local area network environment
US6085238 *Apr 22, 1997Jul 4, 2000Matsushita Electric Works, Ltd.Virtual LAN system
US6088333 *Nov 14, 1997Jul 11, 2000Electronics And Telecommunications Research InstituteMulticast routing method using path overlapping efficiency in VP-based on ATM networks
US6154463 *Aug 26, 1997Nov 28, 2000Lucent Technologies, Inc.System and method for multicast conferencing and online discussion groups
US6163810 *Jun 2, 1998Dec 19, 2000At&T Corp.System and method for managing the exchange of information between multicast and unicast hosts
US6181697 *Mar 31, 1998Jan 30, 2001At&T Corp.Method for a unicast endpoint client to access a multicast internet protocol (IP) session and to serve as a redistributor of such session
US6185210 *Sep 30, 1997Feb 6, 2001Bbn CorporationVirtual circuit management for multi-point delivery in a network system
US6226686 *Sep 28, 1999May 1, 2001HearmeServer-group messaging system for interactive applications
US6259701 *Sep 11, 1997Jul 10, 2001At&T Corp.Method and system for a unicast endpoint client to access a multicast internet protocol (IP) session
US6331983 *May 6, 1997Dec 18, 2001Enterasys Networks, Inc.Multicast switching
US6370142 *Apr 2, 1997Apr 9, 2002Nortel Networks LimitedMethod and apparatus for performing per-port IP multicast pruning
US6457059 *Oct 13, 1998Sep 24, 2002Fujitsu LimitedMethod and apparatus for transmitting multicast data in a switched LAN environment
US6463447 *Dec 16, 1998Oct 8, 2002Rstar CorporationOptimizing bandwidth consumption for document distribution over a multicast enabled wide area network
US6523069 *Mar 13, 2000Feb 18, 2003Yahoo! Inc.Transmission of multicast media between networks
US6563830 *Mar 28, 2000May 13, 20033Com CorporationMulticast registration of all multicast flows in an asynchronous transfer mode based emulated LAN
US6567929 *Jul 13, 1999May 20, 2003At&T Corp.Network-based service for recipient-initiated automatic repair of IP multicast sessions
US6611872 *Jun 1, 1999Aug 26, 2003Fastforward Networks, Inc.Performing multicast communication in computer networks by using overlay routing
US6654371 *Apr 15, 1999Nov 25, 2003Nortel Networks LimitedMethod and apparatus for forwarding multicast data by relaying IGMP group membership
US6741575 *Feb 26, 1999May 25, 2004Hughes Electronics CorporationApparatus and method for efficient delivery of multicast data over personal access communications system (PACS)
US6748447 *Apr 7, 2000Jun 8, 2004Network Appliance, Inc.Method and apparatus for scalable distribution of information in a distributed network
US6785704 *Jul 3, 2000Aug 31, 2004Fastforward NetworksContent distribution system for operation over an internetwork including content peering arrangements
US6873627 *Jul 30, 1999Mar 29, 2005The Fantastic CorporationSystem and method for sending packets over a computer network
US6914907 *Aug 5, 1999Jul 5, 2005Alcatel Canada Inc.Method and apparatus for providing multi-cast transmissions using a distributed router
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US7065577 *Mar 27, 2002Jun 20, 2006AlcatelFacilitating IP-based multicasting control connections
US7149195Nov 29, 2001Dec 12, 2006Nokia CorporationApparatus, and associated method, for multicasting data in a radio communications system
US7263099 *Aug 14, 2002Aug 28, 2007Juniper Networks, Inc.Multicast packet replication
US7266095 *Nov 19, 2001Sep 4, 2007AlcatelAddressing method for use in an access network or a satellite infrastructure network that can support data transfer in non-connected mode
US7281058Oct 9, 2002Oct 9, 2007Juniper Networks, Inc.Delivering and receiving multicast content across a unicast network
US7391767 *Mar 7, 2003Jun 24, 2008Electronics And Telecommunications Research InstituteMethod for providing IP multicast service using virtual LAN
US7420972Aug 3, 2007Sep 2, 2008Juniper Networks, Inc.Multicast packet replication
US7606228 *Oct 20, 2009Electronics And Telecommunications Research InstituteHome gateway system for providing optical communication packet data interface function and home broadcast service providing method using the same
US7647619 *Jan 12, 2010Sony CorporationScalable filtering table
US7710889 *Nov 30, 2005May 4, 2010Kddi CorporationCommunication system, delay insertion server, backup server and communication control apparatus
US7716714Dec 1, 2004May 11, 2010At&T Intellectual Property I, L.P.System and method for recording television content at a set top box
US7720994 *Jan 13, 2005May 18, 2010Cisco Technology, Inc.Method for suppression of multicast join/prune messages from extranet receivers
US7751394 *Jul 6, 2010Hitachi Communication Technologies, Ltd.Multicast packet relay device adapted for virtual router
US7768913Aug 8, 2007Aug 3, 2010Juniper Networks, Inc.Delivering and receiving multicast content across a unicast network
US7787436Nov 16, 2007Aug 31, 2010Ruckus Wireless, Inc.Communications throughput with multiple physical data rate transmission determinations
US7827304 *May 28, 2002Nov 2, 2010ZooinnetMethod and system for virtual multicast networking
US7840651 *Aug 3, 2007Nov 23, 2010Luchiana CinghitaClient-server emulation supporting multicast transmissions of media objects
US7864769Aug 18, 2008Jan 4, 2011Juniper Networks, Inc.Multicast packet replication
US7873102Jan 18, 2011At&T Intellectual Property I, LpVideo quality testing by encoding aggregated clips
US7908621Oct 31, 2007Mar 15, 2011At&T Intellectual Property I, L.P.System and apparatus for local video distribution
US7908627Jun 22, 2005Mar 15, 2011At&T Intellectual Property I, L.P.System and method to provide a unified video signal for diverse receiving platforms
US7986641 *Sep 10, 2007Jul 26, 2011Nippon Telegraph And Telephone CorporationMulticast data communication method, multicast data communication system, repeater, repeating method, and medium for storing repeating programs
US8027262 *Sep 27, 2011Fujitsu LimitedMethod and apparatus for keeping track of virtual LAN topology in network of nodes
US8054849Nov 8, 2011At&T Intellectual Property I, L.P.System and method of managing video content streams
US8086261Dec 27, 2011At&T Intellectual Property I, L.P.System and method for providing digital network access and digital broadcast services using combined channels on a single physical medium to the customer premises
US8089949Mar 8, 2010Jan 3, 2012Ruckus Wireless, Inc.Distributed access point for IP based communications
US8098576 *Jan 17, 2012Huawei Technologies Co., Ltd.Method and apparatus for providing a multicast service with multiple types of protection and recovery
US8116312 *Feb 8, 2006Feb 14, 2012Solarflare Communications, Inc.Method and apparatus for multicast packet reception
US8125975Nov 16, 2007Feb 28, 2012Ruckus Wireless, Inc.Communications throughput with unicast packet transmission alternative
US8144690 *Jun 8, 2001Mar 27, 2012Thomson Licensing S.A.ATM multicasting for delivering information over a network
US8179891 *May 15, 2012Vectormax CorporationMethod and apparatus for interdomain multicast routing
US8190688Jul 11, 2005May 29, 2012At&T Intellectual Property I, LpSystem and method of transmitting photographs from a set top box
US8214859Jul 3, 2012At&T Intellectual Property I, L.P.Automatic switching between high definition and standard definition IP television signals
US8228224Jul 24, 2012At&T Intellectual Property I, L.P.System and method of using a remote control and apparatus
US8230097 *Oct 5, 2005Jul 24, 2012Vectormax CorporationMethod and system for broadcasting multimedia data
US8282476Oct 9, 2012At&T Intellectual Property I, L.P.Multimedia-based video game distribution
US8355343Jan 15, 2013Ruckus Wireless, Inc.Determining associations in a mesh network
US8365218Jan 29, 2013At&T Intellectual Property I, L.P.Networked television and method thereof
US8390744Mar 5, 2013At&T Intellectual Property I, L.P.System and method of displaying a video stream
US8392593 *Mar 5, 2013Juniper Networks, Inc.Multiple control channels for multicast replication in a network
US8434116Apr 30, 2013At&T Intellectual Property I, L.P.Device, system, and method for managing television tuners
US8462620Feb 1, 2010Jun 11, 2013Kddi CorporationCommunication system, delay insertion server, backup server and communication control apparatus
US8526432 *Mar 16, 2009Sep 3, 2013Ralink Technology Corp.Packet processing system for a network packet forwarding device and method thereof
US8535151Aug 28, 2012Sep 17, 2013At&T Intellectual Property I, L.P.Multimedia-based video game distribution
US8547899Jul 28, 2008Oct 1, 2013Ruckus Wireless, Inc.Wireless network throughput enhancement through channel aware scheduling
US8584257Aug 10, 2004Nov 12, 2013At&T Intellectual Property I, L.P.Method and interface for video content acquisition security on a set-top box
US8619662Nov 2, 2010Dec 31, 2013Ruckus Wireless, Inc.Unicast to multicast conversion
US8634402Nov 17, 2011Jan 21, 2014Ruckus Wireless, Inc.Distributed access point for IP based communications
US8635659Jun 24, 2005Jan 21, 2014At&T Intellectual Property I, L.P.Audio receiver modular card and method thereof
US8638708Mar 7, 2010Jan 28, 2014Ruckus Wireless, Inc.MAC based mapping in IP based communications
US8706897Oct 31, 2012Apr 22, 2014Juniper Networks, Inc.Multiple control channels for multicast replication in a network
US8780760Jan 7, 2013Jul 15, 2014Ruckus Wireless, Inc.Determining associations in a mesh network
US8817784Jan 10, 2012Aug 26, 2014Solarflare Communications, Inc.Method and apparatus for multicast packet reception
US8824357Jul 13, 2012Sep 2, 2014Ruckus Wireless, Inc.Throughput enhancement by acknowledgment suppression
US8830955 *Mar 19, 2010Sep 9, 2014Interval Licensing LlcMulticast system using client forwarding
US8839314Mar 15, 2013Sep 16, 2014At&T Intellectual Property I, L.P.Device, system, and method for managing television tuners
US8843970Jan 31, 2011Sep 23, 2014Chanyu Holdings, LlcVideo distribution systems and methods for multiple users
US8893199Jun 22, 2005Nov 18, 2014At&T Intellectual Property I, L.P.System and method of managing video content delivery
US8904458Jul 29, 2004Dec 2, 2014At&T Intellectual Property I, L.P.System and method for pre-caching a first portion of a video file on a set-top box
US8966563Feb 7, 2011Feb 24, 2015At&T Intellectual Property, I, L.P.System and method to provide a unified video signal for diverse receiving platforms
US9019886Dec 13, 2013Apr 28, 2015Ruckus Wireless, Inc.Unicast to multicast conversion
US9066152Jan 21, 2014Jun 23, 2015Ruckus Wireless, Inc.Distributed access point for IP based communications
US9071942Nov 14, 2013Jun 30, 2015Ruckus Wireless, Inc.MAC based mapping in IP based communications
US9083539Aug 19, 2014Jul 14, 2015Solarflare Communications, Inc.Method and apparatus for multicast packet reception
US9100323 *Dec 9, 2013Aug 4, 2015Juniper Networks, Inc.Deadlock-resistant fabric tree replication in a network device
US9167241Dec 7, 2010Oct 20, 2015At&T Intellectual Property I, L.P.Video quality testing by encoding aggregated clips
US9178743Sep 23, 2011Nov 3, 2015At&T Intellectual Property I, L.P.System and method of managing video content streams
US9240868Nov 4, 2005Jan 19, 2016Ruckus Wireless, Inc.Increasing reliable data throughput in a wireless network
US9271327Sep 16, 2013Feb 23, 2016Ruckus Wireless, Inc.Wireless network throughput enhancement through channel aware scheduling
US9278283Nov 15, 2012Mar 8, 2016At&T Intellectual Property I, L.P.Networked television and method thereof
US9319347Jul 31, 2015Apr 19, 2016Juniper Networks, Inc.Deadlock-resistant fabric tree replication in a network device
US9338490Jan 16, 2015May 10, 2016At&T Intellectual Property I, L.P.System and method to provide a unified video signal for diverse receiving platforms
US20020087999 *Aug 22, 2001Jul 4, 2002Sony CorporationScalable filtering table
US20020089943 *Nov 19, 2001Jul 11, 2002AlcatelAddressing method for use in an access network or a satellite infrastructure network that can support data transfer in non-connected mode
US20030043786 *Nov 29, 2001Mar 6, 2003Jan KallApparatus, and associated method, for multicasting data in a radio communications system
US20040037280 *Dec 4, 2001Feb 26, 2004Georg HeinMethod for multicasting information via at least one communications network
US20040076162 *Mar 7, 2003Apr 22, 2004Jong-Kuk LeeMethod for providing IP multicast service using virtual LAN
US20040125818 *Jun 8, 2001Jul 1, 2004Richardson John WilliamAtm multicasting for delivering information over a network
US20050002398 *Jun 28, 2004Jan 6, 2005AlcatelIGMP on NT architecture
US20050076207 *May 28, 2002Apr 7, 2005Hyunje ParkMethod and system for virtual multicast networking
US20050097612 *Oct 29, 2003May 5, 2005Sbc Knowledge Ventures, L.P.System and method for local video distribution
US20050111474 *Dec 30, 2004May 26, 2005Fujitsu LimitedIP multicast communication system
US20050149988 *Jan 6, 2004Jul 7, 2005Sbc Knowledge Ventures, L.P.Delivering interactive television components in real time for live broadcast events
US20050265356 *Feb 3, 2005Dec 1, 2005Fujitsu LimitedMethod and apparatus for keeping track of virtual LAN topology in network of nodes
US20060002391 *Jan 7, 2005Jan 5, 2006Hitachi Communication Technologies, Ltd.Multicast packet relay device adapted for virtual router
US20060037043 *Aug 10, 2004Feb 16, 2006Sbc Knowledge Ventures, L.P.Method and interface for managing movies on a set-top box
US20060037083 *Aug 10, 2004Feb 16, 2006Sbc Knowledge Ventures, L.P.Method and interface for video content acquisition security on a set-top box
US20060048178 *Aug 26, 2004Mar 2, 2006Sbc Knowledge Ventures, L.P.Interface for controlling service actions at a set top box from a remote control
US20060074968 *Oct 6, 2004Apr 6, 2006Gyetko Gregory EElectronic content distribution management methods and systems
US20060077921 *Oct 7, 2004Apr 13, 2006Sbc Knowledge Ventures, L.P.System and method for providing digital network access and digital broadcast services using combined channels on a single physical medium to the customer premises
US20060083253 *Dec 29, 2004Apr 20, 2006Park Wan KHome gateway system for providing optical communication packet data interface function and home broadcast service providing method using the same
US20060085553 *Oct 5, 2005Apr 20, 2006Jon RachwalskiMethod and system for broadcasting multimedia data
US20060114360 *Dec 1, 2004Jun 1, 2006Sbc Knowledge Ventures, L.P.Device, system, and method for managing television tuners
US20060117374 *Dec 1, 2004Jun 1, 2006Sbc Knowledge Ventures, L.P.System and method for recording television content at a set top box
US20060120396 *Nov 30, 2005Jun 8, 2006Kddi CorporationCommunication system, delay insertion server, backup server and communication control apparatus
US20060156372 *Jan 12, 2005Jul 13, 2006Sbc Knowledge Ventures, L.P.System, method and interface for managing content at a set top box
US20060158368 *Jan 20, 2005Jul 20, 2006Sbc Knowledge Ventures, L.P.System, method and interface for controlling multiple electronic devices of a home entertainment system via a single control device
US20060168047 *Jan 13, 2005Jul 27, 2006Jennifer LiMethod for suppression of multicast join/prune messages from extranet receivers
US20060168610 *Jan 26, 2005Jul 27, 2006Sbc Knowledge Ventures, L.P.System and method of managing content
US20060170582 *Feb 2, 2005Aug 3, 2006Sbc Knowledge Ventures, L.P.Remote control, apparatus, system and methods of using the same
US20060174279 *Nov 19, 2004Aug 3, 2006Sbc Knowledge Ventures, L.P.System and method for managing television tuners
US20060174309 *Jan 28, 2005Aug 3, 2006Sbc Knowledge Ventures, L.P.System and method of managing set top box memory
US20060179466 *Feb 4, 2005Aug 10, 2006Sbc Knowledge Ventures, L.P.System and method of providing email service via a set top box
US20060184991 *Feb 14, 2005Aug 17, 2006Sbc Knowledge Ventures, LpSystem and method of providing television content
US20060184992 *Feb 14, 2005Aug 17, 2006Sbc Knowledge Ventures, L.P.Automatic switching between high definition and standard definition IP television signals
US20060218590 *Mar 10, 2005Sep 28, 2006Sbc Knowledge Ventures, L.P.System and method for displaying an electronic program guide
US20060230421 *Mar 30, 2005Oct 12, 2006Sbc Knowledge Ventures, LpMethod of using an entertainment system and an apparatus and handset for use with the entertainment system
US20060236343 *Apr 14, 2005Oct 19, 2006Sbc Knowledge Ventures, LpSystem and method of locating and providing video content via an IPTV network
US20060268917 *May 27, 2005Nov 30, 2006Sbc Knowledge Ventures, L.P.System and method of managing video content streams
US20060282785 *Jun 9, 2005Dec 14, 2006Sbc Knowledge Ventures, L.P.System and method of displaying content in display windows
US20060290814 *Jun 24, 2005Dec 28, 2006Sbc Knowledge Ventures, LpAudio receiver modular card and method thereof
US20060294559 *Jun 22, 2005Dec 28, 2006Sbc Knowledge Ventures, L.P.System and method to provide a unified video signal for diverse receiving platforms
US20060294561 *Jun 22, 2005Dec 28, 2006Sbc Knowledge Ventures, LpSystem and method of managing video content delivery
US20060294568 *Jun 24, 2005Dec 28, 2006Sbc Knowledge Ventures, L.P.Video game console modular card and method thereof
US20070011133 *Jun 22, 2005Jan 11, 2007Sbc Knowledge Ventures, L.P.Voice search engine generating sub-topics based on recognitiion confidence
US20070011250 *Jul 11, 2005Jan 11, 2007Sbc Knowledge Ventures, L.P.System and method of transmitting photographs from a set top box
US20070021211 *Jun 24, 2005Jan 25, 2007Sbc Knowledge Ventures, LpMultimedia-based video game distribution
US20070086441 *Nov 7, 2006Apr 19, 2007Jan KallApparatus, and Associated Method, for Multicasting Data in a Radio Communications System
US20070171926 *Jan 25, 2007Jul 26, 2007Vectormax CorporationMethod and Apparatus for Interdomain Multicast Routing
US20070183418 *Feb 8, 2006Aug 9, 2007Level 5 Networks, Inc.Method and apparatus for multicast packet reception
US20080052747 *Oct 31, 2007Feb 28, 2008Sbc Knowledge Ventures, LpSystem and Apparatus for Local Video Distribution
US20080056256 *Aug 3, 2007Mar 6, 2008Luchiana CinghitaClient-server emulation supporting multicast transmissions of media objects
US20080069099 *Sep 10, 2007Mar 20, 2008Nippon Telegraph And Telephone CorporationMulticast data communication method, multicast data communication system, repeater, repeating method, and medium for storing repeating programs
US20080100492 *Oct 26, 2007May 1, 2008Sbc Knowledge VenturesSystem and Method of Using a Remote Control and Apparatus
US20080137681 *Nov 16, 2007Jun 12, 2008Kish William SCommunications throughput with unicast packet transmission alternative
US20080137682 *Nov 16, 2007Jun 12, 2008Kish William SCommunications throughput with multiple physical data rate transmission determinations
US20090028095 *Jul 28, 2008Jan 29, 2009Kish William SWireless Network Throughput Enhancement Through Channel Aware Scheduling
US20090113024 *Jun 22, 2005Apr 30, 2009Snigdha VermaMulticase Downloading Using Path Information
US20090115904 *Jan 6, 2009May 7, 2009At&T Intellectual Property I, L.P.System and method of displaying a video stream
US20090154346 *Feb 24, 2009Jun 18, 2009Huawei Technologies Co., Ltd.Method and apparatus for providing a multicast service with multiple types of protection and recovery
US20090180396 *Jul 16, 2009Kish William SDetermining associations in a mesh network
US20090238183 *Mar 16, 2009Sep 24, 2009Ralink Technology Corp.Packet processing system and method thereof
US20100142385 *Feb 1, 2010Jun 10, 2010Kddi CorporationCommunication system, delay insertion server, backup server and communication control apparatus
US20100172354 *Mar 19, 2010Jul 8, 2010Vulcan Patents LlcMulticast system using client forwarding
US20110075727 *Mar 31, 2011At&T Intellectual Property I, L.P.Video quality testing by encoding aggregated clips
US20110096712 *Nov 2, 2010Apr 28, 2011William KishUnicast to Multicast Conversion
US20110119401 *Nov 16, 2010May 19, 2011Kish William SDetermining Role Assignment in a Hybrid Mesh Network
US20110167442 *Jul 7, 2011At&T Intellectual Property I, L.P.System and Method to Provide a Unified Video Signal for Diverse Receiving Platforms
US20110216685 *Sep 8, 2011Kish William SMac based mapping in ip based communications
US20120072901 *Sep 16, 2011Mar 22, 2012Heidelberger Druckmaschinen AgMethod for combined unicast/multicast software transmission
US20150381377 *Jun 26, 2014Dec 31, 2015Qualcomm Technologies International, Ltd.Method and apparatus for managing addresses and connectivity arrangements for transporting multicast data in a wireless network
WO2003019828A2 *Aug 23, 2002Mar 6, 2003Nokia CorporationApparatus, and associated method, for multicasting data in a radio communications system
WO2003019828A3 *Aug 23, 2002Sep 25, 2003Nokia CorpApparatus, and associated method, for multicasting data in a radio communications system
WO2005025146A1 *Jun 30, 2004Mar 17, 2005AlcatelTransmission of multicast traffic in a communications network
WO2005077045A2 *Feb 7, 2005Aug 25, 2005Arris International, Inc.Method and system for replicating a video stream onto separate qam downstream channels
WO2005077045A3 *Feb 7, 2005Dec 7, 2006Arris Int IncMethod and system for replicating a video stream onto separate qam downstream channels
WO2008071111A1 *Nov 14, 2007Jun 19, 2008Huawei Technologies Co., Ltd.Method, system and router for forwarding multicast data
Classifications
U.S. Classification370/390, 370/432
International ClassificationH04L12/18, H04L12/56
Cooperative ClassificationH04L45/00, H04L67/1002, H04L45/16, H04L12/1836, H04L12/185
European ClassificationH04L12/18E, H04L45/00, H04L45/16