Path computation element communication protocol (PCEP) extensions for stateful label switched path management

• US 8,885,463 B1
• Filed: 12/13/2011
• Issued: 11/11/2014
• Est. Priority Date: 10/17/2011
• Status: Active Grant

• Current Assignee: Juniper Networks Incorporated
• Original Assignee: Juniper Networks Incorporated
• Inventors: Medved, Jan, Ward, David, Varga, Robert
• Primary Examiner(s): Rutkowski, Jeffrey M
• Assistant Examiner(s): Ohri, Romani
• Application Number:
  US13/324,861
• Time in Patent Office: 1,064 Days
• Field of Search: 370/255, 370/228, 370/390, 370/235, 370/238, 370/328, 709/224
• US Class Current: 370/228
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/38 Flow based routing
• CPC Class Codes: H04L 45/50 using label swapping, e.g. multi-protocol label switch [MPLS]

Abstract

In general, techniques are described for extending a path computation element (PCE) communication protocol (PCEP) to support messages that enable PCEs to actively modify Multi-Protocol Label Switching (MPLS) for Traffic Engineering Label Switched Paths (TE LSPs) in and across network domains. In one example, an LSP database of a router includes configuration data for one or more LSPs configured in the router and further includes LSP state information specifying a current state of all LSPs of the router. A path computation client (PCC) of a router establishes an extended PCEP session and synchronizes LSP state information to a stateful PCE using the extended PCEP session. Subsequently, the stateful PCE sends an LSP update request to the PCC in the extended PCEP session, wherein the LSP update request includes one or more updated parameters for the LSP. The PCC then re-signals the LSP through the network according to the updated parameters.

Claims

1. A method comprising:

establishing an extended path computation element communication protocol (PCEP) session with a stateful path computation element (PCE) to a path computation client (PCC) of a network router of a packet-switched network;

receiving, with the stateful PCE, label switched path (LSP) state information that specifies a current state of an existing LSP previously signaled by the PCC; and

sending, from the stateful PCE to the PCC using the extended PCEP session, an LSP update request that includes one or more updated parameters for the existing LSP and directs the PCC to re-signal the existing LSP according to the updated parameters.

2. The method of claim 1,

wherein the LSP state information includes one or more of a status, a setup priority, a hold priority, a number of hops, a reserved bandwidth, a metric, or a path for the existing LSP.

3. The method of claim 1, further comprising:

receiving, with the stateful PCE in the extended PCEP session, an association between an LSP identifier that identifies the existing LSP in extended PCEP messages for the extended PCEP session and a symbolic LSP name that is unique within the PCC for the existing LSP; and

associating the LSP state information received by the stateful PCE with the LSP identifier and the symbolic LSP name.

4. The method of claim 3, further comprising:

receiving, with the stateful PCE, a resource request message that includes the symbolic LSP name;

identifying, with the stateful PCE, LSP state information for the existing LSP using the symbolic LSP name; and

providing the LSP state information in response to the resource request message.

5. The method of claim 1, wherein the stateful PCE sends the LSP update request only when the stateful PCE is delegated control of the existing LSP from the PCC.

6. The method of claim 1, further comprising:

receiving, by the stateful PCE, an LSP state report message in the extended PCEP session that delegates control of the existing LSP from the PCC to the stateful PCE.

7. The method of claim 6, further comprising:

sending, from the stateful PCE to the PCC, an LSP update request message in the extended PCEP session that returns the delegated control of the existing LSP to the PCC.

8. The method of claim 1, wherein the updated parameters for the existing LSP include one or more of an LSP status and an LSP reserved bandwidth.

9. The method of claim 1, wherein the existing LSP is a first LSP, the method further comprising:

receiving, with the stateful PCE, LSP state information for a second LSP previously signaled by the PCC;

determining, according to a network policy stored by the stateful PCE, an optimal ordering of setting up the first and second LSPs;

sending the LSP update request in the extended PCEP session to direct the PCC to re-signal the first LSP according to the optimal ordering;

according to the determined ordering, sending a subsequent LSP update request in the extended PCEP session to direct the PCC to re-signal the second LSP according to the optimal ordering after setting up the first LSP.

10. The method of claim 9, wherein the network policy includes one of a total throughput and bandwidth allocation fairness.

11. The method of claim 1, further comprising:

executing a routing protocol to receive traffic engineering information with the stateful PCE from routers of the network; and

determining the updated parameters for the existing LSP using the traffic engineering information.

12. The method of claim 1, wherein the LSP update request specifies a priority that directs the PCC to prioritize the LSP update request among a set of received LSP update requests.

13. The method of claim 1, further comprising:

receiving, with the stateful PCE, an LSP state report message subsequent to sending the LSP update request indicating whether the PCC successfully re-signaled the existing LSP according to the updated parameters.

14. The method of claim 1, further comprising:

receiving, with the stateful PCE, an initialization message from the PCC indicating the PCC allows modification of parameters for the existing LSP.

15. A path computation element (PCE) comprising:

a control unit having one or more processors;

a client interface of the control unit that establishes an extended path computation element communication protocol (PCEP) session to a path computation client (PCC) of a network router of a packet-switched network; and

a label switched path (LSP) state database that stores LSP state information for one or more LSPs owned by the PCC,

wherein the client interface receives LSP state information that specifies a current state of an existing LSP previously signaled by the PCC and stores the LSP state information to the LSP state database, and

wherein the client interface sends, to the PCC using the extended PCEP session, an LSP update request that includes one or more updated parameters for the existing LSP and directs the PCC to re-signal the existing LSP according to the updated parameters.

16. The PCE of claim 15, further comprising:

a delegation database that specifies LSPs in the LSP state information database that are controlled by the PCE,

wherein the client interface receives an LSP state report message in the extended PCEP session that delegates control of the existing LSP from the PCC to the PCE and stores the delegation to the delegation database.

17. The PCE of claim 15, further comprising:

a traffic engineering database (TED) that stores traffic engineering information for the network; and

a routing protocol with traffic engineering extensions listener of the control unit that executes one or more routing protocols to receive traffic engineering information and stores received traffic engineering information to the TED.

18. The PCE of claim 15, further comprising:

a network optimization engine; and

a policy and resource database that stores a network policy,

wherein the existing LSP is a first LSP,

wherein the client interfaces receives LSP state information for a second LSP previously signaled by the PCC,

wherein the network optimization engine determines, according to the network policy, an optimal ordering of setting up the first and second LSPs,

wherein the client interface sends the LSP update request in the extended PCEP session to direct the PCC to re-signal the first LSP according to the optimal ordering, and

wherein, according to the determined ordering, the client interface sends a subsequent LSP update request in the extended PCEP session to the direct to PCC to re-signal the second LSP according to the optimal ordering after setting up the first LSP.

19. A method comprising:

establishing an extended path computation element communication protocol (PCEP) session, with a path computation client (PCC) of a network router of a packet-switched network, to a stateful path computation element (PCE);

synchronizing, with the PCC, label switched path (LSP) state information that specifies a current state of an existing LSP previously signaled by the PCC to the stateful PCE using the extended PCEP session; and

receiving, with the PCC from the stateful PCE using the extended PCEP session, an LSP update request that includes one or more updated parameters for the existing LSP and directs the PCC to re-signal the existing LSP according to the updated parameters.

20. The method of claim 19, further comprising:

re-signaling the existing LSP with the PCC in response to receiving the LSP update request.

21. The method of claim 19, further comprising:

receiving, with the PCC, a subsequent LSP update request from the stateful PCE, wherein the subsequent LSP update request includes one or more updated parameters for the existing LSP; and

re-signaling, with the PCC, the existing LSP using the updated parameters included in the subsequent LSP update request without re-signaling the existing LSP using the updated parameters included in the LSP update request.

22. The method of claim 19,

wherein the LSP state information includes one or more of a status, a setup priority, a hold priority, a number of hops, a reserved bandwidth, a metric, and a path for the existing LSP.

23. The method of claim 19, further comprising:

generating, with the PCC, an LSP identifier that identifies the existing LSP in extended PCEP messages for the extended PCEP session; and

sending an association between the LSP identifier and a symbolic LSP name that is unique within the PCC for the existing LSP to the stateful PCE.

24. The method of claim 23, further comprising:

synchronizing the LSP state information using an LSP state report message that includes the LSP identifier.

25. The method of claim 19, further comprising:

sending an LSP state report message in the extended PCEP session to the stateful PCE, wherein the LSP state report message delegates control of the existing LSP to the stateful PCE.

26. The method of claim 25, further comprising:

receiving a subsequent LSP state report message in the extended PCEP session from the stateful PCE, wherein the subsequent LSP state report message returns control of the existing LSP to the PCC.

27. The method of claim 25, further comprising:

sending a subsequent LSP state report message in the extended PCEP session to the stateful PCE, wherein the subsequent LSP state report message revokes control of the existing LSP from the PCE.

28. The method of claim 19, further comprising:

re-signaling the existing LSP with the PCC in response to receiving the LSP update request only when the PCC has delegated control of the existing LSP to the stateful PCE.

29. The method of claim 19, further comprising:

synchronizing, with the PCC, LSP state information that specifies a current state of all LSPs of the PCC to the stateful PCE using the extended PCEP session.

30. The method of claim 19, wherein the PCC does not request path computation from the stateful PCE.

31. A router comprising:

a control unit having one or more processors;

a path computation client of the control unit having a path computation element (PCE) interface that establishes an extended path computation element communication protocol (PCEP) session to a stateful PCE; and

a label switched path (LSP) database that includes configuration data for one or more LSPs configured in the router and further includes LSP state information specifying a current state of all LSPs of the router,

wherein the PCE interface synchronizes the LSP state information to the stateful PCE using the extended PCEP session,

wherein the PCE interface receives, using the extended PCEP session, an LSP update request from the stateful PCE that includes one or more updated parameters for an existing LSP of the LSPs and directs the router to re-signal the existing LSP according to the updated parameters.

32. The router of claim 31, further comprising:

a routing protocol daemon that re-signals the existing LSP with the updated parameters.

33. The router of claim 31, wherein the LSP state information includes one or more of a status, a setup priority, a hold priority, a number of hops, a reserved bandwidth, a metric, and a path for the existing LSP.

34. The router of claim 31,

wherein the PCC generates an LSP identifier that identifies the existing LSP in extended PCEP messages for the extended PCEP session, and

wherein the PCE interface sends an association between the LSP identifier and a symbolic LSP name that is unique within the router for the existing LSP to the stateful PCE.

35. The router of claim 31,

wherein the configuration data specifies one or more delegable parameters for the existing LSP, and

wherein the PCE interface sends an LSP state report message in the extended PCEP session to the stateful PCE, wherein the LSP state report message delegates control of the delegable parameters for the existing LSP to the stateful PCE.

36. The router of claim 31, further comprising:

a routing protocol daemon,

wherein the configuration data specifies default parameters for the existing LSP, and

wherein the router directs the routing protocol daemon to re-signal the existing LSP using the default parameters when the extended PCEP session terminates.

37. The router of claim 31, further comprising:

a routing protocol daemon,

wherein the configuration data specifies default parameters for the existing LSP,

wherein the PCE interface receives an LSP update request message returning a delegation for the existing LSP, and

wherein the PCC, in response to the LSP update request message, directs the routing protocol daemon to re-signal the existing LSP using the default parameters.