System and method for active geographic redundancy

• US 20070253328A1
• Filed: 04/02/2007
• Published: 11/01/2007
• 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: Ramankutty, Rajesh, Harper, Matthew, Cheever, Greg, Puthiyandyil, Sanil
• Granted Patent: US 8,565,070 B2
• Time in Patent Office: Days
• US Class Current: 370/219
• CPC Class Codes: H04L 41/06 Management of faults, events, alarms or notifications
• CPC Class Codes: H04L 41/0869 Validating the configuration within one network element
• CPC Class Codes: H04L 43/00 Arrangements for monitoring or testing data switching networks
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00

Abstract

Systems and methods are provided that allow voice and data traffic to be shifted from one chassis to other chassis without interrupting service. Geographic Redundancy (GR) is an inter-chassis redundancy, where the chassis may be a home agent, a packet data serving node, or any combination of wireless networking devices. Additionally, each chassis can have one or more partitions that handle subscriber session traffic and a corresponding redundant partition on a different chassis. The redundant chassis partition can take over all or a portion of the functionality of the active chassis partition if the active chassis or any critical peer servers/gateways communicating with the active chassis should fail. This provides users with uninterrupted service in the case of some failures.

Claims

1. A system comprising:

a first chassis including a first partition and a second partition;

a second chassis in operable communication with the first chassis and including a first partition and a second partition;

the first partition of the first chassis accepting subscriber session traffic and sending at least one update to the first partition of the second chassis; and

the first partition of the second chassis maintaining subscriber session information corresponding to subscriber session information on the first partition of the first chassis.

2. The system of claim 1, wherein the first chassis is implementing a home agent.

3. The system of claim 1, further comprising the first chassis communicating with the second chassis using a service redundancy protocol (SRP), which is based on a transfer control protocol (TCP).

4. The system of claim 1, wherein the first partition includes an ingress context and an egress context, wherein the ingress context and the egress context each include an interface.

5. The system of claim 1, wherein the first chassis includes an authentication, authorization, and accounting (AAA) context and a service redundancy protocol (SRP) context.

6. The system of claim 1, wherein the first chassis includes a session controller to monitor the first partition of the first chassis and a session manager instance to handle subscriber session tasks.

7. The system of claim 1, wherein the second partition of the first chassis is in a standby mode.

8. The system of claim 1, wherein the first partition of the first chassis uses a loopback address that is common to both partitions.

9. A method comprising:

receiving subscriber session traffic at a first partition in a first chassis;

sending a checkpoint message to update a first partition in a second chassis with information from the first partition in the first chassis;

initiating a switchover event where the first partition in the second chassis advertises a common loopback address that is shared with the first partition in the first chassis; and

processing subscriber session traffic received at the first partition in the second chassis using information received in the checkpoint message.

10. The method of claim 9, further comprising determining which partition will transition to active by exchanging hello messages with attributes.

11. The method of claim 9, further comprising providing an ingress context and an egress context in the first chassis.

12. The method of claim 9, further comprising communicating between the first chassis and the second chassis using a service redundancy protocol (SRP), which is based on a transfer control protocol (TCP).

13. The method of claim 9, further comprising providing a session controller to monitor the first partition and a session manager instance to handle subscriber session tasks.

14. The method of claim 13, further comprising providing a suspend state for the session manage instance in a standby partition.

15. The method of claim 9, further comprising providing a virtual media access control (MAC) address for operation over a common IP subnet.

16. The method of claim 15, further comprising holding an IP address for a user who disconnected for an amount of time determined by an IP hold timer.

17. A system comprising:

means for receiving subscriber session traffic;

means for sending a checkpoint message to update a first partition in a second chassis with information from the means for receiving;

means for initiating a switchover event where the first partition in the second chassis advertises a common loopback address that is shared with the means for receiving; and

means for processing subscriber session traffic received at the first partition in the second chassis using information received in the checkpoint message.