Method and apparatus for dynamic exchange of capabilities between adjacent/neighboring networks nodes

• US 6,553,423 B1
• Filed: 05/27/1999
• Issued: 04/22/2003
• Est. Priority Date: 05/27/1999
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Chen, Enke
• Primary Examiner(s): Dinh, Dung C.
• Assistant Examiner(s): WOO, ISAAC M
• Application Number:
  US09/321,782
• Time in Patent Office: 1,426 Days
• Field of Search: 709/238, 709/230, 709/227, 709/228, 709/229, 709/231, 709/232, 709/233, 709/234, 370/401, 370/402, 370/389
• US Class Current: 709/230
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/033 by updating distance vector protocols
• CPC Class Codes: H04L 45/04 Interdomain routing, e.g. hierarchical routing
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures

Abstract

A technique to dynamically exchange or update routing capabilities between neighboring peer routers in a computer network without disruption to the operation of the routers. A dynamic capability parameter in an Open message of a Border Gateway Protocol (BGP) enables a router to announce a new capability, or revise or remove a previously announced capability, to a neighboring router when a peer connection is established between the routers. Once announced, the dynamic capability allows the router to exchange a capability message containing updates of capabilities without the need for resetting the existing peer connection. As a result, the technique allows non-disruptive configuration and enabling of capabilities in a manner that improves network stability, while reducing interruption of network services.

Claims

1. A method for dynamically exchanging or updating routing capabilities between neighboring peer routers in a computer network, the method comprising the steps of:

establishing a peer connection between one of the neighboring routers and another of the neighboring routers;

announcing the ability to support a new capability, or revise or remove a previously announced capability, from the one of the neighboring routers to the other of the neighboring routers while the peer connection is established; and

exchanging a capability message between the one of the neighboring routers and the other of the neighboring routers to thereby facilitate graceful capability changes between the routers without terminating the peer connection.

2. The method of claim 1 wherein the peer connection is a border gateway protocol (BGP) peer connection and wherein the step of establishing comprises the steps of:

exchanging transmission control protocol (TCP) segments between the neighboring routers; and

identifying the neighboring routers through the exchange of a BGP open message.

3. The method of claim 2 wherein the step of announcing comprises the step of providing a dynamic capability parameter stored within an optional parameters field of the open message.

4. The method of claim 3 wherein the step of providing a dynamic capability parameter comprises the step of embodying the dynamic capability parameter as a BGP capability parameter having a code and length that conforms to a format of a capabilities optional parameter.

5. The method of claim 4 wherein the step of announcing further comprises the step of announcing an ability to receive and properly handle the capability message after the BGP peer connection is established.

6. The method of claim 5 wherein the step of exchanging the capability message further comprises the step of providing a plurality of defined values for storage within a capability action code field of the capability message.

7. The method of claim 6 wherein one of the plurality of defined values comprises a defined value for adding a new capability.

8. The method of claim 7 wherein another of the plurality of defined values comprises a defined value for replacing a previous announced capability.

9. The method of claim 8 wherein yet another of the plurality of defined values comprises a defined value for deleting a previously announced capability.

10. A memory device for use in dynamically exchanging or updating routing capabilities between neighboring peer routers in a computer network, the memory device containing data structures comprising:

a transmission control protocol (TCP) segment;

an open message cooperating with the TCP segment to establish a peer connection between the neighboring routers; and

a dynamic capability parameter stored within an optional parameters field of the open message, the dynamic capability parameter announcing the ability of a neighboring peer router to receive and properly handle a capability message after the peer connection is established.

11. The memory device of claim 10 wherein the capability message comprises a capability action code field for storing one of a plurality of defined values.

12. The memory device of claim 11 wherein one of the plurality of defined values comprises a defined value for adding a new capability.

13. The memory device of claim 12 wherein another of the plurality of defined values comprises a defined value for replacing a previous announced capability.

14. The memory device of claim 13 wherein yet another of the plurality of defined values comprises a defined value for deleting a previously announced capability.

15. Apparatus for dynamically exchanging or updating routing capabilities between neighboring peer routers in a computer network, the apparatus comprising:

a route processor of one of the neighboring routers, the route processor programmed to generate a transmission control protocol (TCP) segment and an open message for exchange with a processor of its neighboring router to establish a peer connection between the neighboring routers; and

a memory device operably connected to the processor for storing the TCP segment and open message, the open message having an optional parameters field for storing a capability optional parameter,

the processor further programmed to generate a dynamic capability parameter for storage within the optional parameters field, the dynamic capability parameter announcing an ability of the one neighboring peer router to receive and properly handle a capability message after the peer connection is established.

16. A computer readable medium containing executable program instructions for dynamically exchanging or updating routing capabilities between neighboring peer routers in a computer network, the executable instructions comprising program instructions for:

establishing a peer connection between the neighboring routers;

announcing the ability to support a new capability, or revise or remove a previously announced capability, from one of the neighboring routers to the other of the neighboring routers while the peer connection is established; and

exchanging a capability message between the neighboring routers to thereby facilitate graceful capability changes between the routers without terminating the peer connection.

17. The computer readable medium of claim 16 wherein the peer connection is a border gateway protocol (BGP) peer connection and wherein the program instructions for establishing comprises program instructions for:

exchanging transmission control protocol (TCP) segments between the neighboring routers; and

identifying the neighboring routers through the exchange of a BGP open message.

18. The computer readable medium of claim 17 wherein the program instructions for announcing comprises program instructions for providing a dynamic capability parameter stored within an optional parameters field of the open message.

19. The computer readable medium of claim 18 wherein the program instructions for providing a dynamic capability parameter comprises the step of embodying the dynamic capability parameter as a BGP capability parameter having a code and length that conforms to a format of a capabilities optional parameter.

20. The computer readable medium of claim 19 wherein the program instructions for announcing further comprises program instructions for announcing an ability to receive and properly handle the capability message after the BGP peer connection is established.

21. A router comprising:

means for establishing a peer connection between said router and a neighboring router in a computer network, said connection having a first capability;

means for announcing an ability to support a new capability, or revise or remove said first capability, from said router to said neighboring router while said peer connection is established; and

means for exchanging a capability message between said router and said neighboring router to thereby facilitate capability changes between said router and said neighboring router without terminating said peer connection.

22. The router of claim 21 further comprising:

means for receiving a received capability message, and in response, changing said first capability.

23. A method for operating a router comprising the steps of:

establishing a peer connection between said router and a neighboring router in a computer network, said connection having a first capability;

announcing an ability to support a new capability, or revise or remove said first capability while said peer connection is established; and

exchanging a capability message between said router and said neighboring router to thereby facilitate capability changes between said router and said neighboring router without terminating said peer connection.

24. The router of claim 23 further comprising the step of:

receiving a received capability message, and in response, changing said first capability.

25. A router comprising:

a route processor to establish a peer connection between said router and a neighboring router in a computer network, said connection having a first capability;

a processor to select a new capability, or revise or remove said first capability while said peer connection is established; and

a network interface to exchange a capability message, said capability message generated by said processor, between said router and said neighboring router to thereby facilitate capability changes between said router and said neighboring router without terminating said peer connection.

26. The router of claim 25 further comprising:

said network interface receiving a received capability message, and in response, said processor changing said first capability.