|Publication number||US20050226247 A1|
|Application number||US 11/099,413|
|Publication date||Oct 13, 2005|
|Filing date||Apr 4, 2005|
|Priority date||Feb 10, 2000|
|Also published as||US6678273, US20040218584, US20090016326|
|Publication number||099413, 11099413, US 2005/0226247 A1, US 2005/226247 A1, US 20050226247 A1, US 20050226247A1, US 2005226247 A1, US 2005226247A1, US-A1-20050226247, US-A1-2005226247, US2005/0226247A1, US2005/226247A1, US20050226247 A1, US20050226247A1, US2005226247 A1, US2005226247A1|
|Original Assignee||Garth Brown|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (14), Referenced by (5), Classifications (13)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This disclosure relates generally to communications systems and in particular to managing connections between enterprises and subscribers.
Enterprises (e.g., corporations) need to establish communication channels to various subscribers (e.g., employees). These communication channels may be through various service providers, such as the public telephone switching network, Internet service providers (“ISP”), frame relay carriers, and digital subscriber line (“DSL”) carriers. The cost of maintaining a communication channel to each service provider can be very expensive for an enterprise.
The complexity and actual dollar cost of connecting to such service providers can be very high. More importantly, the time delay in establishing a connection to a service provider can be even more costly. Accordingly, it would be desirable to have a communications network that would help reduce the actual cost of the physical connections and in which connections to various service providers can be provided in a timely manner.
A managed private network system for allowing enterprises to connect to various subscribers through service providers without a need to establish a direct physical connection to each service provider is provided. The managed private network (“MPN”) system allows an enterprise to connect to multiple service providers through a single physical connection terminating at the enterprise. This physical connection is between the enterprise and an MPN system. In one embodiment, the physical connection may be a high-speed line, such as a T3 line, and the communications between the enterprise and the MPN system is conducted using the asynchronous transfer mode (“ATM”) protocol. (The ATM protocol is described in “Hands-On ATM” by McDysan and Spohn and published by McGraw-Hill in 1998, which is hereby incorporated by reference.) When the MPN system receives data via the physical connection from the enterprise, the MPN system causes the data to be routed to the appropriate service provider. The service provider then forwards that data to the intended subscriber. Similarly, when a subscriber sends data to a service provider, that service provider routes the data to the MPN system. The MPN system then forwards the data to the appropriate enterprise. Multiple enterprises may be connected to the MPN system. The data of each enterprise is kept separate and distinct from the data of other enterprise using, for example, a virtual connection for each enterprise. Each enterprise may have its own physical connection to the MPN system. Also, each subscriber would typically be assigned to a single enterprise.
The MPN system maintains various connections to service providers. When an enterprise wants to establish a connection to a service provider that is already connected to the MPN system, the MPN system can be reconfigured to route data received via the physical connection from the enterprise to that service provider. In this way, the enterprise can use the previously established physical connection with the MPN system to transmit data to a new service provider. In addition, the MPN system may provide additional services to the enterprise. For example, the MPN system may be coupled to an archival data storage system. The enterprise may back up its data onto the archival storage system. Also, an enterprise may use the MPN system to provide primary or backup access to the public telephone network.
In one embodiment, the MPN system comprises an aggregating ATM component, a switching ATM component, and an intermediary LAN component. Each enterprise is connected to the switching ATM via a high-speed physical communications line. Each service provider is connected to the aggregating ATM component via a physical communications line. The aggregating ATM component may receive data generated by subscribers and send data generated by the enterprise to the subscriber via a subscriber virtual connection dedicated to the subscriber by the aggregating ATM component. The aggregating ATM component maps each subscriber virtual connection to an enterprise/MPN virtual connection that is dedicated to the enterprise to which the subscriber is assigned. The enterprise/MPN virtual connection connects the aggregating ATM component to the switching ATM component. When the switching ATM component receives data from a subscriber via the enterprise/MPN virtual connection, the switching ATM component forwards the data to the intermediary LAN component. The intermediary LAN component decides how to process the data. For example, the intermediary LAN component may decide to send the data back to the switching ATM component so that it can be forwarded to the enterprise. When the switching ATM component receives data from an enterprise via an enterprise virtual connection dedicated to the enterprise, it forwards the data to the intermediary LAN component. Again, the intermediary LAN component decides how to process the data. The intermediary LAN component may decide to send the data to the switching ATM component so that it can be forwarded via the enterprise/MPN virtual connection to the aggregating ATM component. The aggregating ATM component can then forward the data to the intended subscriber via the subscriber virtual connection. The intermediary LAN component may process the data in ways other than forwarding the data. If the data is destined for a server which is connected to the intermediary LAN component via a LAN, such as an Ethernet VLAN, the intermediary LAN component may forward the data to a LAN or virtual LAN dedicated to the enterprise. The switching ATM component may forward data to and receive data from the intermediary LAN component via virtual connections dedicated to each enterprise. Thus, the MPN system uses a series of virtual connections (each virtual connection in the series dedicated to a single enterprise) to send data between that enterprise and the aggregating ATM. In this way, the data of an enterprise can be kept separate and distinct from that data of other enterprises.
The virtual connections dedicated to an enterprise may correspond to a common network layer dedicated to the enterprise. The network layer may comply with layer 3 of the International Standards Organization (“ISO”) Open Systems Interconnection (“OSI”) protocol reference model. The various service providers may use different implementations of the sub-network layer. That is, the service providers may use different physical and data link layer implementations of the OSI model. The MPN system can aggregate data from multiple service providers regardless of their sub-network layer implementations.
In one embodiment, in the MPN system is implemented using the following components.
Functional Component Implementing Component Aggregating component Redback Networks SMS-1000 Intermediary LAN component Cisco Systems Catalyst 5513 Switching component Cisco Systems LightStream 1010
Tables 1-3 illustrate the configuration of the implementing components in one embodiment.
TABLE 1 Redback Networks SMS-1000 RB-CHAC-IS-1K Redback 1000 Chassis with AC input RB-PS-1K-AC AC power supply RB-PS-1K-AC AC power supply RB-CE1-1K-32MB Control Engine with 32MB RAM RB-FE-1K-8MB Forwarding Engine with 8MB RAM RB-EIM-1K-2TX 2x10/100 BaseT Ethernet I/O Module RB-AIM-1K-2DS3 2xATM DS-3 I/O Module RB-AIM-1K-20C3MM 2xATM OC-3 I/O Module RB-SW4000-1K-1.0 4000 subscriber AOS (access Operating System) Software License TABLE 2
Cisco Systems Catalyst 5513
Catalyst 5513 Chassis
Catalyst 5500 AC Power Supply
Redundant Catalyst 5500 AC Power
Catalyst 5500/5000 Supervisor Engine
Module w/NFFC II
Dual Port 100BaseFX MMF Uplink
Module for Supervisor
24 Port 10/100TX Backbone Switching
(FEC, 802.1Q/ISL, RJ-45)
Cisco Systems LightStream 1010
ATM Switch Processor with
LS1010 IISP and PNNI Feature Set
LightStream 1010 64 MB DRAM
Lightstream1 - 1 - /C5500 Carrier
Lightstream1 - 1 - /C5500 Carrier
4Port STS-3c/STM-1 Multimode Fiber
4 Port DS-3 Port Adaptor Modules
4 Port T1 (ATM) with RJ-48 Interface
4 Port STS-3c/STM-1 Single-Mode
The SMS component serves as a connection aggregation point that allows a large number of incoming physical and virtual connections from a variety of service providers to be terminated and segregated according to defined policies. For example, a single enterprise may have several hundred subscribers using DSLs through two different service providers and may have 50 locations using frame relay T1 lines through one service provider and 10 locations using point-to-point T1 lines through another service provider. These connections are directly attached to be SMS component. The SMS component binds (i.e., logically associates on an exclusive basis) each subscriber virtual connection to a SMS context (i.e., a logical secure partition within the SMS component). A current implementation of the SMS component may support 8000 incoming connections bound to as many as 40 different contexts. Future upgrades of the SMS component may provide for more connections and contexts.
The SMS component is connected to the LightStream component over one or more physical ATM connections (e.g., a multimode OC-3 connection). Each context of the SMS component forwards its data via a single enterprise/MPN virtual connection to the LightStream component. Thus, the segregation of enterprise data performed by the SMS component is extended to include the connection to the LightStream component and the remainder of the MPN system. This segregation provides a high level of security for an enterprise in that data packets for an enterprise are not intermingled with data packets of other enterprises on a single virtual connection.
The LightStream component receives data for each enterprise on a separate virtual connection from the SMS component. The LightStream component performs the following major functions:
The Catalyst component is an Ethernet switch with an ATM interface included in an ATM LANE module. Each LANE module provides an interconnection between an ATM virtual connection and an Ethernet virtual local area network (“VLAN”). A VLAN is logical partition of an Ethernet network. The connection from the SMS component via the LightStream component into the one LANE module is switched to either to a local Ethernet LAN or back onto the other LANE module bound to the enterprise.
The CPE generated cell then arrives at the SMS component 603 of a specific ATM virtual connection, which may be one of many virtual connections carried on a single physical layer ATM line and where each virtual connection is established for each CPE. The SMS component associates the PDU with a bridging group associated with the enterprise to which the subscriber is assigned. The PDU is then the segmented and reassembled to strip away the AAL5 SNAP header information so that the type of payload (e.g., bridge to ethernet packet) contained with in the cell can be determined. The SMS component then forwards the Ethernet frames to the virtual connection to the destination MAC address specified in the Ethernet frame header, which could be other customer premise equipment or the LightStream component.
A bridging group is a transparent bridge using IEEE 802 protocol family encapsulation for Ethernet frames. Each bridging group holds a bridging table of known MAC addresses (acquired locally or using a spanning tree protocol from adjacent devices) and switches traffic outbound across the virtual connection closest to the destination MAC address if the MAC address is contained in the bridging table. Any traffic destination for an unknown MAC address is flooded outbound on all virtual connections within the bridging group.
The SMS component then the segments and reassembles the Ethernet frame into ATM cell that is tagged as a 1483 PDU in the payload field of the CPCS PDU of the AAL5 and that is then injected into the enterprise/MPN virtual connection over physical connection 603A. The cell is forwarded over the enterprise/MPN virtual connection dedicated to the enterprise's traffic to the LightStream component 604.
When the LightStream component receives the cell on the enterprise/MPN virtual connection, it switches the cell onto a virtual connection dedicated to the enterprise that is statically mapped to a virtual connection over physical connection 604A bound to a LANE module of the Catalyst component 605. There is a one-to-one relationship between the enterprise/MPN virtual connection for an enterprise and the virtual connection for enterprise on the LANE module. When the cell is received at the LANE module, the module segments and reassembles it back into an Ethernet frame with an associated destination MAC address. The LANE module then decides whether to forward to the cell to a VLAN or to the enterprise. If the cell is to be routed onto a VLAN, it is directed to a RFC 802.1q or Cisco ISL VLAN which is directly associated with the incoming virtual connection on a one-to-one basis. This VLAN is terminated directly on an 802.3 Ethernet port on the Catalyst component. If the cell is destined to the enterprise, then the Catalyst component forwards the cell to the other LANE module on a virtual connection dedicated to the enterprise that is statically mapped to the virtual connection for the enterprise. The Catalyst component segments and reassembles the frame and tags it as a 1483 PDU in the payload field of the CPCS PDU of the AAL5 SNAP header and then injects it into the virtual connection dedicated to the enterprise.
The LightStream component receives the cell and switches it to a single enterprise virtual connection that is mapped on a one-to-one basis to a physical ATM connection connected to an enterprise. This enterprise virtual connection is terminated at a CPE device located at the enterprise's main data center or the enterprise's LAN location. The CPE device receives the cell and segments and reassembles it back an Ethernet frame. The CPE device then injects the frame according to the IEEE 802 protocol standards onto the local area network at the enterprise.
From the foregoing, it will be appreciated that although specific embodiments of the MPN system have been described for purposes of illustration, various modifications may be made without deviating from the spirit and the scope of the invention. For example, a virtual connection can be extended from an enterprise to a service provider by either providing a physical ATM connection from the service provider to the LightStream component or providing a physical Ethernet connection from a service provider to the Catalyst component. That is, the functions of the various components can be located at or controlled by different entities (e.g., service providers). Also, the functions provided by the various components can be even further divided among more components or consolidated into fewer components. For example, the function associated with the connection to each LANE module of the Catalyst component could be performed by different LightStream components. Also, each component may be replaced by multiple components (arranged as a network or hierarchy) to facilitate scalability of the MPN system. For example, the SMS component can be replaced by multiple SMS components in a hierarchical or non-hierarchical arrangement. Also, the enterprises and subscribers may be any entity including a corporation, division, branch, employee and so on. Accordingly, the invention is not limited except by the following claims.
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|International Classification||H04L12/28, H04L12/66, H04L12/56|
|Cooperative Classification||H04L12/66, H04L2012/5638, H04L2012/5617, H04L12/5601, H04L2012/5621, H04L2012/5671, H04L2012/5665|
|European Classification||H04L12/66, H04L12/56A|