Method for providing home agent geographic redundancy via a service redundancy protocol

• US 8,223,687 B2
• Filed: 11/23/2005
• Issued: 07/17/2012
• Est. Priority Date: 11/23/2005
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Cheever, Greg, Puthiyandyil, Sanil Kumar, Ramankutty, Rajesh
• Primary Examiner(s): Pérez-Gutiérrez, Rafael
• Assistant Examiner(s): Miah, Liton
• Application Number:
  US11/286,050
• Publication Number:
  US 20070116020A1
• Time in Patent Office: 2,428 Days
• Field of Search: 370/331, 370/338, 370/395.52, 455/435.1
• US Class Current: 370/328
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06
• CPC Class Codes: H04W 8/065 involving selection of the user mobility server
• CPC Class Codes: H04W 8/12 between location registers or mobility servers
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

Methods and systems for providing redundancy in servicing packet data communications within wireless mobile data networks are disclosed. More particularly, the method and system provide a redundant Home Agent with the ability to assume the role of the primary Home Agent in the event of a primary Home Agent network, software, or other failure. The redundancy allows the Home Agent services to remain functional even in the event of a failure of one of the Home Agents in the redundant group, which may be composed of one or more Home Agents. The Home Agents can use a service redundancy protocol which is composed of messages that are sent between the redundant group of Home Agents. The messages allow the Home Agents to, for example, back up call session information, check on the status of one another, and share priority information.

Claims

1. A system for providing redundancy in a communication network comprising:

a first Home Agent acting as a backup Home Agent to a primary Home Agent, wherein the primary Home Agent provides mobility management functions for a plurality of mobile nodes and maintains a subscriber session for each mobile node processed by the primary Home Agent;

the first Home Agent configured to receive a Hello Message from the primary Home Agent that is remotely located from the first Home Agent, wherein the Hello Message includes system attributes and information to determine a remote Home Agent'"'"'s state;

the first Home Agent configured to receive at least one Checkpoint Message from the second Home Agent which provides information for a plurality of subscriber sessions where each subscriber session includes information for a particular mobile node that is used by the primary Home Agent in providing mobility management for that mobile node; and

the first Home Agent being able to transition to become the primary Home Agent to provide mobility management for the plurality of mobile nodes using redundant subscriber session information received from the primary Home Agent and to advertise primary Home Agent identification information into the routing domain using a routing protocol, which prompts network devices to route messages to the first Home Agent instead of the primary Home Agent;

wherein the first Home Agent transitions to the primary Home Agent based on priority and state information in the Hello Message, wherein priority information is used to determine which Home Agent transitions to active.

2. The system of claim 1, further comprising a communication link coupling the first and primary Home Agent as a redundancy link.

3. The system of claim 1, wherein the Hello Message and the Checkpoint Message are formatted in accordance with a Transfer Control Protocol (TCP) based networking protocol.

4. The system of claim 1, wherein the system attributes of the Hello Message include Home Agent state, Priority, and BGP modifier.

5. The system of claim 1, wherein the second Home Agent, after transitioning to the primary Home Agent, advertises IP pool information of the first Home Agent.

6. The system of claim 1, wherein the advertising of information includes the advertising of loopback interface routes, where loopback interface routes are performed using a dynamic routing protocol in an IP routing domain.

7. A method for providing redundancy in a communication network comprising:

receiving a first message containing system attributes from a first Home Agent at a second Home Agent that is remotely located from the first Home Agent;

receiving a second message from the first Home Agent acting as a primary Home Agent at the second Home Agent, wherein the second message provides information for a plurality of subscriber sessions where each subscriber session includes information for a particular mobile node that is used by the primary Home Agent in providing services to that mobile node;

transitioning the second Home Agent to the primary Home Agent;

processing subscriber sessions at the second Home Agent using the subscriber session information received in the second message; and

advertising primary Home Agent identification information from the second Home Agent into the routing domain using a routing protocol, which prompts network devices to route messages to the second Home Agent instead of the first Home Agent;

wherein the transitioning step is based on priority and state information in the first message, and wherein the first message is a Hello Message and the priority information is used to determine which Home Agent transitions to active.

8. The method of claim 7, wherein the communication occurs through a redundancy link.

9. The method of claim 7, further comprising receiving the first message and the second message using a Transfer Control Protocol (TCP) based networking protocol.

10. The method of claim 7, wherein the system attributes of the first message include Home Agent state, Priority, and BGP modifier.

11. The method of claim 7, further comprising advertising loopback interface routes and IP pool information of the first Home Agent after the second Home Agent transitions to the primary Home Agent.

12. The method of claim 7, wherein the advertising of loopback interface routes is performed using a dynamic routing protocol in an IP routing domain.

13. A system for providing redundancy in a communication network comprising:

a first means for providing backup redundancy for a second means for providing mobility management functions for IP communications on behalf of a mobile node that is remotely located from the first means;

a means for communicating between the first means and the second means;

the first means receiving a first message from the second means, the first message containing system attributes; and

the first means receiving a second message from the second means providing information for a plurality of subscriber sessions where each subscriber session includes information for a particular mobile node that is used by the second means in providing mobility management for that mobile node, wherein the first means transitions to become the primary means for providing mobility management and advertises the identification information of the primary means into the routing domain using a routing protocol;

wherein the first means transitions to the primary Home Agent based on priority and state information in the Hello Message, and the priority information is used to determine which Home Agent transitions to active.

14. The system of claim 13, wherein the communication means is a redundancy link.

15. The system of claim 13, wherein the first message is a Hello Message and the second message is a Service Checkpoint Message, which are formatted according to a Transfer Control Protocol (TCP) based networking protocol.

16. The system of claim 13, wherein the system attributes of the Hello Message include Home Agent state, Priority, and BGP modifier.

17. The system of claim 13, wherein the second means after transitioning to the primary Home Agent advertises loopback interface routes and IP pool information of the first means through the communication means.

18. The system of claim 13, wherein the advertising of loopback interface routes is performed using a dynamic routing protocol in an IP routing domain.