Systems and methods for implementing second-link routing in packet switched networks

Abstract

A network ( 100 ) includes multiple gateways ( 135, 140 ) and a router ( 105 ) connected to at least one of the multiple gateways ( 135, 140 ). The router ( 105 ) is configured to receive packets that include multiple first virtual circuit identifiers associated with the multiple gateways in the network ( 100 ), assign second virtual circuit identifiers to the at least one connected gateway, and initiate transmission of a message to the at least one connected gateway informing the gateway of the first virtual circuit identifiers.

What is claimed is: 
     
         1 . A packet-based network comprising:
 a first gateway node communicatively coupled between a first routing node and a first local area network (LAN);   a second gateway node communicatively coupled between a second routing node and a second LAN; and   at least one virtual circuit established between the first gateway node and the second gateway node operable to communicate Internet Protocol (IP) traffic between the first LAN and the second LAN, wherein the virtual circuit is identified in memory of the first gateway node using information received from the first routing node, the information comprising a virtual circuit identifier associated with the second gateway node,   wherein the at least one virtual circuit is identified in memory of the second gateway node using information received from the second routing node, the information comprising a virtual circuit identifier associated with the first gateway node,   wherein each of the first and second routing nodes and the first and second gateway nodes each include a gateway forwarding table for storing the virtual circuit identifiers associated with each of the gateway nodes.   
     
     
         2 . The network as recited in  claim 1 , wherein the first routing node and the second routing node are operable to transmit one or more messages therebetween, the message to ultimately inform their respective connected gateway nodes of the virtual circuit identifiers associated with the other gateway node. 
     
     
         3 . The network as recited in  claim 1 , wherein the first routing node updates at least one virtual circuit table stored at the first routing node using both of the virtual circuit identifier associated with the first gateway node and the virtual circuit identifier associated with the second gateway node. 
     
     
         4 . The network as recited in  claim 1 , wherein the second routing node updates at least one virtual circuit table stored at the second routing node using both of the virtual circuit identifier associated with the first gateway node and the virtual circuit identifier associated with the second gateway node. 
     
     
         5 . A method comprising:
 receiving a packet at a node;   inspecting a header of the packet for an input virtual channel identifier (VCI in );   determining an output port number (PN out ) by referencing a virtual channel table stored on the node with the VCI in , the PN out  referencing a port on the node;   determining an output virtual channel identifier (VCI out ) by referencing the virtual channel table with the VCI in ;   replacing the VCI in  in the header of the packet with the determined VCI out ;   forwarding the packet to at least one of another node utilizing the VCI out  and sent via the determined PN out ; and   updating the virtual channel table at the node with one or more changes to the virtual channels associated with the one or more gateways;   wherein the virtual channel table includes a list of VCI out  identifiers that reference one or more virtual channels associated with one or more gateways communicably connected to the node, and   wherein the one or more gateways each include at least one virtual channel table for storing virtual channel entries associated with virtual channels utilized for incoming packets from one or more routers.   
     
     
         6 . The method as recited in  claim 5 , wherein the node and the at least one of another node each comprise at least one of a router, switch, or gateway. 
     
     
         7 . The method as recited in  claim 5 , further comprising the node initiating transmission of a packet to one or more neighboring routers, the packet informing the neighboring routers of the virtual channels associated with the one or more gateways. 
     
     
         8 . The method as recited in  claim 5 , wherein the one or more gateways each include at least one gateway forwarding table to store virtual channel identifiers associated with the one or more other gateways. 
     
     
         9 . The method as recited in  claim 5 , wherein the node includes at least one gateway forwarding table to store virtual channel identifiers associated with each of the one or more gateways. 
     
     
         10 . A node comprising:
 a virtual channel table to store one or more input virtual channel identifier (VCI in ) entries, one or more router output port (PN out ) entries, and one or more output virtual channel identifier (VCI out ) entries, wherein the one or more VCI out  entries reference one or more virtual channels associated with one or more gateways communicably connected to the node; and   a network interface operable to:
 receive a packet; 
 inspect a header of the packet for a VCI in  entry; 
 determine a PN out  entry by referencing the virtual channel table with the VCI in ; 
 determine a VCI out  entry by referencing the virtual channel table with the VCI in ; 
 replace the VCI in  in the header of the packet with the determined VCI out ; and 
 forward the packet to at least one of another node utilizing the VCI out  and sent via the determined PN out , 
   wherein the one or more gateways each include at least one gateway forwarding table to store virtual channel identifiers associated with the one or more other gateways, and wherein the one or more gateways each include at least one virtual channel table for storing virtual channel entries associated with virtual channels utilized for incoming packets from one or more router/switches.   
     
     
         13 . The node as recited in claim  12 , wherein the node and the at least one of another node each comprise at least one of a router, switch, or gateway. 
     
     
         14 . The node as recited in claim  12 , wherein the network interface is further operable to initiate transmission of a packet to one or more neighboring router/switches, the packet informing the neighboring router/switches of the virtual channels associated with the one or more gateways.