MPLS virtual rings

• US 7,623,446 B1
• Filed: 11/14/2005
• Issued: 11/24/2009
• Est. Priority Date: 11/14/2005
• Status: Expired due to Fees

• Current Assignee: RPX Clearinghouse LLC (RPX Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Ashwood Smith, Peter, Allan, David
• Primary Examiner(s): Ryman, Daniel J.
• Assistant Examiner(s): CRUTCHFIELD, CHRISTOPHER M
• Application Number:
  US11/271,939
• Time in Patent Office: 1,471 Days
• Field of Search: 370/223, 370/258
• US Class Current: 370/223
• CPC Class Codes: H04L 1/22 using redundant apparatus to increase reliability
• CPC Class Codes: H04L 12/42 Loop networks
• CPC Class Codes: H04L 12/4637 Interconnected ring systems
• CPC Class Codes: H04L 12/4641 Virtual LANs, VLANs, e.g. virtual private networks [VPN] LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272
• CPC Class Codes: H04L 41/20 Network management software packages
• CPC Class Codes: H04L 45/04 Interdomain routing, e.g. hierarchical routing
• CPC Class Codes: H04L 45/507 Label distribution

Abstract

A virtual ring representing a community of interest is constructed from an interconnected mesh of nodes in a packet network. The virtual ring instantiates ring labels in respective forwarding tables for each node in the virtual ring and then advertises the ring labels to all other nodes in the virtual ring, for example by flooding BGP advertisements. Data packets entering the ring are assigned a ring label which is then stripped off when exiting the ring. The data packets are forwarded around the virtual ring using the ring labels. The virtual ring can operate using BGP/LDP Multi Protocol Label Switching (MPLS). Multiple virtual rings can be bridged together using a central hub or alternatively multiple virtual rings can be redundantly bridged together using tandem hubs.

Claims

1. A method of constructing a virtual ring from a plurality of nodes in a packet network, the method comprising the steps of:

defining a community of interest by selecting nodes from an interconnected mesh of nodes in the packet network;

determining inter-node connectivity for each node in the community of interest with respect to all other nodes in the community of interest;

computing an optimal virtual ring to connect all the nodes in the community of interest;

advertising ring labels to all nodes in the community of interest;

determining neighboring nodes in the community of interest for each node in the community of interest and selecting east and west labels for the neighboring nodes from a set of advertisements received at each node in the community of interest, wherein the step of determining east and west labels comprises the step of first determining eastbound and westbound directions according to a lowest BGP next hop identifier and its closest next hop identifier; and

instantiating the ring labels in respective forwarding tables for each node in the community of interest to enable efficient forwarding of data packets to nodes in the community of interest.

2. The method as claimed in claim 1 wherein the packet network uses Multi Protocol Label Switching (MPLS) to forward data packets to Label Switching Routers linked together as the nodes of the virtual ring.

3. The method as claimed in claim 1 wherein the advertising step comprises a step of flooding the ring with BGP advertisements having identifiers for identifying the community of interest.

4. The method as claimed in claim 1 further comprising the step of configuring a node as a hub for bridging multiple rings together.

5. The method as claimed in claim 1 further comprising the step of configuring two adjacent nodes as tandem hubs to redundantly bridge multiple rings together.

6. A method of forwarding data packets through a virtual ring of nodes that connect a community of interest in a packet network, the method comprising the steps of:

computing the virtual ring connecting all nodes of the community of interest;

advertising ring labels to the nodes in the community of interest;

determining neighboring nodes in the community of interest for each node in the community of interest and selecting east and west labels for the neighboring nodes from a set of advertisements received at each node in the community of interest, wherein selecting east and west labels comprises determining eastbound and westbound directions according to a lowest BGP next hop identifier and its closest next hop identifier;

instantiating the ring labels in forwarding tables at each node in the community of interest;

assigning a ring label identifier to each data packet entering the virtual ring at an originating node;

forwarding the data packet through the virtual ring; and

stripping the ring label identifier from the data packet when the data packet exits the virtual ring at the originating node.

7. The method as claimed in claim 6 wherein the advertising step comprises a step of flooding the ring with BGP advertisements.

8. The method as claimed in claim 6 wherein the forwarding is performed using MPLS.

9. The method as claimed in claim 6 further comprising the step of configuring one of the nodes in the community of interest as a hub for bridging together a plurality of virtual rings.

10. The method as claimed in claim 6 further comprising the step of configuring two adjacent nodes in the community of interest as tandem hubs to redundantly bridge together a plurality of virtual rings.

11. A virtual ring for transporting data packets to one or more nodes that form part of a community of interest within a packet network, the virtual ring comprising:

a plurality of networked nodes connected together to define the virtual ring linking the community of interest;

a forwarding table at each node in the virtual ring, the forwarding table including ring labels for all other nodes in the ring, the ring labels having being advertised to other nodes in the community of interest to determine east and west labels for neighboring nodes for constructing the virtual ring, wherein determining the east and west labels comprises determining eastbound and westbound directions according to a lowest BGP next hop identifier and its closest next hop identifier;

packet-labeling means for assigning ring label identifiers to data packets entering the virtual ring;

means for forwarding data packets around the virtual ring; and

label-stripping means for stripping the ring label identifiers from data packets exiting the ring.

12. The virtual ring as claimed in claim 11 wherein the ring labels are advertised by flooding BGP advertisements to neighboring nodes.

13. The virtual ring as claimed in claim 11 wherein the means for forwarding data packets implements an MPLS forwarding paradigm for forwarding data packets to Label Switching Routers connected together as the nodes in the virtual ring.

14. The virtual ring as claimed in claim 11 wherein one of the nodes in the community of interest is designated to be a hub for bridging a plurality of virtual rings.

15. The virtual ring as claimed in claim 11 wherein two adjacent nodes in the community of interest are designated to be tandem hubs for redundantly bridging a plurality of virtual rings.