Resilient provider link state bridging (PLSB) virtual private LAN service (VPLS) interworking

• US 8,565,244 B2
• Filed: 12/12/2008
• Issued: 10/22/2013
• Est. Priority Date: 02/09/2008
• Status: Expired due to Fees

• Current Assignee: RPX Clearinghouse LLC (RPX Corporation)
• Original Assignee: Rockstar Consortium US LP (Rockstar Consortium Inc.)
• Inventors: Bragg, Nigel L., Allan, David, Ashwood Smith, Peter, Ungehagen, Paul
• Primary Examiner(s): Blanton, John
• Assistant Examiner(s): Patel, Jay P
• Application Number:
  US12/334,013
• Publication Number:
  US 20090201937A1
• Time in Patent Office: 1,775 Days
• Field of Search: 370/401, 370/256, 370/389
• US Class Current: 370/401
• CPC Class Codes: H04L 12/4625 Single bridge functionality, e.g. connection of two networks over a single bridge
• CPC Class Codes: H04L 45/12 Shortest path evaluation
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 47/125 by balancing the load, e.g. traffic engineering

Abstract

A method of peer interfacing a Link-State controlled network domain with an Ethernet Bridging controlled network domain. A pair of peer attachment points are provided between the Link-State controlled network domain and the Ethernet Bridging domain. The peer attachment points are respective endpoints of a set of one or more LAN segments defined within the Ethernet Bridging domain. The set of LAN segments are represented as a virtual node in the Link-State controlled network domain. The virtual node is represented in the Link-State controlled network domain as connected to each of the peer attachment points via a respective virtual link. The virtual links are configured such that frames to or from an address in the Link-State controlled network domain are forwarded over a tree passing through only one of the peer attachments points.

Claims

1. A method of peer interfacing a Link-State controlled network domain with an Ethernet Bridging controlled network domain, the method comprising;

providing a pair of peer attachment points between the Link-State controlled network domain and the Ethernet Bridging domain, the peer attachment points being respective endpoints of a set of one or more LAN segments defined within the Ethernet Bridging domain;

representing the set of LAN segments as a virtual node in the Link-State controlled network domain;

defining, in the Link-State controlled network domain, a respective virtual link connecting the virtual node to each peer attachment point; and

configuring, in the Link-State controlled network domain, the virtual links such that frames to or from an address in the Link-State controlled network domain are forwarded over a tree passing through only one of the peer attachments points.

2. The method of claim 1, wherein the set of LAN segments comprises at least one LAN segment that is dual-homed on both of the peer attachment points.

3. The method of claim 1, wherein the Link-State controlled network domain is a Provider Link State Bridging (PLSB) domain, and the Ethernet Bridging controlled network domain is a Virtual Private LAN Service (VPLS) network domain.

4. The method of claim 3, wherein each attachment point comprises a PLSB gateway connected to a VPLS gateway, the PLSB gateway being an endpoint of at least an unicast path of the PLSB domain, and the VPLS gateway being an endpoint of the set of the LAN segments.

5. The method of claim 1, wherein configuring the virtual links comprises assigning a respective predetermined cost to each virtual link, such that every path on the shortest path tree computed by the Link-State controlled network domain between the set of LAN segments and every address in the Link-State controlled network domain traverses only one of the peer attachment points.

6. The method of claim 5, wherein configuring each virtual link comprises;

setting the predetermined cost assigned to a first virtual link connected to a selected one of the attachment points based on an available capacity of the set of LAN segments; and

setting the predetermined cost assigned to a second virtual link artificially high, such that, under fault free conditions a shortest path computed in the Link-State controlled network domain will never traverse the attachment point connected to the second virtual link.

7. The method of claim 1, wherein the pair of peer attachment points are selected from among a plurality of attachment points between the Link-State controlled network domain and the Ethernet Bridging domain.

8. The method of claim 7, wherein two or more virtual nodes are provided, each virtual node being connected via virtual links to a respective pair of peer attachment points and representing in the Link-State controlled network domain a respective set of LAN segments.

9. The method of claim 8, wherein at least one of the plurality of attachment points is a member of at least two pairs of peer attachment points.

10. A method of overlaying a Link-State protocol on an Ethernet Bridging network domain, the method comprising;

providing a plurality of attachment points between a Link-State protocol domain and the Ethernet Bridging network domain;

defining a set of one or more LAN segments in the Ethernet Bridging network domain, each LAN segment extending between a unique set of two or more of the attachment points;

representing the set of LAN segments as a respective virtual node defined in the Link-State protocol domain; and

defining, in the Link-State protocol domain, a respective virtual link connecting the virtual node to each one of the unique set of two or more of the attachment points;

such that each LAN segment is treated, in the Link-State protocol domain, as a link of the Link-State protocol domain for the purpose of computing a shortest path between a source address in the Link-State protocol domain and a destination address in the Link-State protocol domain.

11. The method of claim 10, wherein the Link-State protocol domain is a Provider Link State Bridging (PLSB) domain, and the Ethernet Bridging network domain is a Virtual Private LAN Service (VPLS) network domain.

12. The method of claim 10, wherein each attachment point comprises a PLSB gateway connected to a VPLS gateway, the PLSB gateway being an endpoint of at least a unicast path of the PLSB domain, and the VPLS gateway being an endpoint of at least one of the VPLS LAN segments.

13. The method of claim 10, wherein the Link-State protocol domain comprises respective first and second Link-State protocol domains, and wherein the source address is in the first Link-State protocol domain, and the destination address is in the second Link-State protocol domain.

14. The method of claim 13, wherein each of the one or more LAN segments are attached to a subset of the attachment points in each Link-State protocol domain.

15. A system for peer interfacing a Link-State controlled network domain with an Ethernet Bridging controlled network domain, the system comprising;

a pair of peer attachment points between the Link-State controlled network domain and the Ethernet Bridging domain, the peer attachment points being respective endpoints of a set of one or more LAN segments defined within the Ethernet Bridging domain;

a virtual node defined in the Link-State controlled network domain for representing the set of LAN segments; and

a respective virtual link defined in the Link-State controlled network domain for connecting the virtual node to each peer attachment point

wherein the virtual links are configured, in the Link-State controlled network domain, such that frames to or from an address in the Link-State controlled network domain are forwarded over a tree passing through only one of the peer attachments points.

16. The system as claimed in claim 15, wherein the set of LAN segments comprises at least one LAN segment that is dual-homed on both of the peer attachment points.

17. The system as claimed in claim 15, wherein the Link-State controlled network domain is a Provider Link State Bridging (PLSB) domain, and the Ethernet Bridging controlled network domain is a Virtual Private LAN Service (VPLS) network domain.

18. The system as claimed in claim 17, wherein each attachment point comprises a PLSB gateway connected to a VPLS gateway, the PLSB gateway being an endpoint of at least an unicast path of the PLSB domain, and the VPLS gateway being an endpoint of the set of the LAN segments.

19. The system as claimed in claim 15, wherein configuring the virtual links comprises assigning a respective predetermined cost to each virtual link, such that every path on the shortest path tree computed by the Link-State controlled network domain between the set of LAN segments and every address in the Link-State controlled network domain traverses only one of the peer attachment points.

20. The system as claimed in claim 19, wherein configuring each virtual link comprises;

setting the predetermined cost assigned to a first virtual link connected to a selected one of the attachment points based on an available capacity of the set of LAN segments; and

setting the predetermined cost assigned to a second virtual link artificially high, such that, under fault free conditions a shortest path computed in the Link-State controlled network domain will never traverse the attachment point connected to the second virtual link.

21. The system as claimed in claim 15, wherein the pair of peer attachment points are selected from among a plurality of attachment points between the Link-State controlled network domain and the Ethernet Bridging domain.

22. The system as claimed in claim 21, wherein two or more virtual nodes are provided, each virtual node being connected via virtual links to a respective pair of peer attachment points and representing in the Link-State controlled network domain a respective set of LAN segments.

23. The system as claimed in claim 22, wherein at least one of the plurality of attachment points is a member of at least two pairs of peer attachment points.