Dense virtual router packet switching

• US 20020099849A1
• Filed: 10/19/2001
• Published: 07/25/2002
• Est. Priority Date: 01/25/2001
• Status: Active Grant

• Current Assignee: Ericsson AB (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Crescent Networks, Inc.
• Inventors: Tingley, Chase T., Alfieri, Stephen M.
• Granted Patent: US 7,039,720 B2
• Time in Patent Office: Days
• US Class Current: 709/243
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/52 Multiprotocol routers
• CPC Class Codes: H04L 45/586 of virtual routers
• CPC Class Codes: H04L 45/76 Routing in software-defined topologies, e.g. routing between virtual machines

Abstract

A dense virtual router packet switching system includes a memory divided into context areas for a set of virtual private routed networks (VPRNs). Each context area includes a routing table and routing protocol state information for a corresponding VPRN. Each of a set of different routing tasks operates with a separate routing table and separate routing protocol state information to realize a corresponding virtual router. Context selection logic selectively couples the routing tasks to the different context areas of the memory to realize a set of virtual routers for all the VPRNs. The system supports a large number of routes by exploiting the segmentation of the VPRNs. Rather than having a single large routing table and associated routing process, which can load hardware resources in proportion to the square of the number of routes in the routing table, routes are distributed among a number of VPRNs having generally smaller tables and correspondingly less processing demand.

Claims

1. A virtual routing system, comprising:

a memory divided into a configurable number of context areas for a corresponding set of virtual private routed networks (VPRNs), each context area including a routing table and associated routing protocol state information for the corresponding VPRN, each VPRN employing a respective routing protocol and network address space;

a set of one or more routing tasks, the set including at least one routing task for each different type of routing protocol employed in the set of VPRNs, each routing task being operable only with a separate routing table and with separate routing protocol state information to realize a corresponding virtual router to carry out associated routing operations in a VPRN; and

context selection logic operative to selectively couple the routing tasks to the different context areas of the memory to realize a set of virtual routers, each virtual router being associated with a corresponding one of the VPRNs.

2. A virtual routing system according to claim 1, wherein the set of routing tasks includes at least one Open Shortest Path First (OSPF) routing task and at least one Border Gateway Protocol (BGP) routing task.

3. A virtual routing system according to claim 1, further comprising a set of virtual interfaces operative to translate between generic interface identifiers used by the virtual routers and physical interface information for physical network links to which the virtual routing system is connected.

4. A virtual routing system according to claim 3, wherein the physical network links to which the virtual routing system is connected employ label switched paths, and wherein the set of virtual interfaces include virtual interfaces containing information for encapsulating and attaching labels to packets on the label switched paths.

5. A virtual routing system according to claim 1, wherein the selective coupling of the routing tasks to the different context areas of the memory is performed at the rate at which protocol packets for the various VPRNs are received by the virtual routing system.

6. A method of operating a routing system, comprising:

maintaining a number of context areas in a memory for a corresponding set of virtual private routed networks (VPRNs), each context area including a routing table and associated routing protocol state information for the corresponding VPRN, each VPRN employing a respective routing protocol and network address space;

executing a set of one or more routing tasks, the set including at least one routing task for each different type of routing protocol employed in the set of VPRNs, each routing task being operable only with a separate routing table and with separate routing protocol state information to realize a corresponding virtual router to carry out associated routing operations in a VPRN; and

selectively coupling the routing tasks to the different context areas of the memory to realize a set of virtual routers, each virtual router being associated with a corresponding one of the VPRNs.

7. A method according to claim 6, wherein the set of routing tasks includes at least one Open Shortest Path First (OSPF) routing task and at least one Border Gateway Protocol (BGP) routing task.

8. A method according to claim 6, further comprising maintaining a set of virtual interfaces operative to translate between generic interface identifiers used by the virtual routers and physical interface information for physical network links to which the virtual routing system is connected.

9. A method according to claim 8, wherein the physical network links to which the virtual routing system is connected employ label switched paths, and wherein the set of virtual interfaces include virtual interfaces containing information for encapsulating and attaching labels to packets on the label switched paths.

10. A method according to claim 6, wherein the selective coupling of the routing tasks to the different context areas of the memory is performed at the rate at which protocol packets for the various VPRNs are received by the virtual routing system.