Methods and apparatus for mobile IP dynamic home agent allocation

• US 20040202126A1
• Filed: 05/06/2002
• Published: 10/14/2004
• Est. Priority Date: 05/06/2002
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Raab, Stefan B., Leung, Kent K., Patel, Alpesh
• Granted Patent: US 7,587,498 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1008 based on parameters of servers, e.g. available memory or workload monitoring of computer activity G06F11/30
• CPC Class Codes: H04L 67/1036 Load balancing of requests to servers for services different from user content provisioning, e.g. load balancing across domain name servers
• 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

In accordance with one aspect of the invention, methods and apparatus for distributing a Mobile IP registration request to one of a plurality of Home Agents are disclosed. A registration request is received from a Foreign Agent to which the Mobile Node has roamed. One of the plurality of Home Agents is selected. The registration request is then forwarded to the selected one of the plurality of Home Agents. The source IP address of the registration request is an IP address of the Foreign Agent to which the Mobile Node has roamed, thereby enabling the selected one of the plurality of Home Agents to send a Mobile IP registration reply directly to the Foreign Agent without interception by the network device.

Claims

1. In a network device, a method of distributing a Mobile IP registration request to one of a plurality of Home Agents, the method comprising:

receiving a registration request from a Foreign Agent to which the Mobile Node has roamed;

selecting one of the plurality of Home Agents; and

sending the registration request to the selected one of the plurality of Home Agents, the source IP address of the registration request being an IP address of the Foreign Agent to which the Mobile Node has roamed, thereby enabling the selected one of the plurality of Home Agents to send a Mobile IP registration reply directly to the Foreign Agent without interception by the network device.

2. The method as recited in claim 1, wherein the network device does not intercept data packets sent by the Mobile Node or sent to the Mobile Node.

3. The method as recited in claim 1, wherein a subsequent registration request sent by the Mobile Node to the selected Home Agent is not intercepted by the network device.

4. The method as recited in claim 1, wherein the network device is a switch or router.

5. The method as recited in claim 1, wherein the network device does not store binding information associated with the registration request.

6. The method as recited in claim 1, further comprising:

wherein a destination IP address of the registration request is an IP address of the network device;

wherein the plurality of Home Agents are configured with the IP address of the nework device.

7. The method as recited in claim 6, further comprising:

modifying a destination MAC address of the registration request such that the destination MAC address is a MAC address associated with the selected Home Agent;

wherein the plurality of Home Agents and the network device are layer 2 adjacent.

8. The method as recited in claim 7, wherein the method is performed using Server Load Balancing Protocol in dispatched mode.

9. The method as recited in claim 1, further comprising:

modifying the destination IP address of the registration request such that the destination IP address is an IP address of the selected one of the plurality of Home Agents.

10. The method as recited in claim 9, wherein the destination MAC address of the registration request is not modified by the network device.

11. The method as recited in claim 10, wherein the method is performed using Server Load Balancing Protocol in directed mode.

12. The method as recited in claim 1, wherein the Home Agent address of the registration request indicates that a Home Agent is to be assigned by the network device.

13. The method as recited in claim 12, wherein the Home Agent address of the registration request is zero.

14. The method as recited in claim 1, wherein the destination IP address of the registration request is a virtual IP address.

15. The method as recited in claim 14, wherein the virtual IP address is associated with the network device and one or more additional network devices adapted for performing the method of claim 1.

16. The method as recited in claim 15, wherein the network device and the one or more additional network devices are each configured with a routing redundancy protocol.

17. The method as recited in claim 16, wherein the routing redundancy protocol is HSRP or VRRP.

18. The method as recited in claim 1, wherein the network device is configured with an IP address of the plurality of Home Agents.

19. The method as recited in claim 1, further comprising:

obtaining an IP address of the plurality of Home Agents.

20. The method as recited in claim 19, wherein obtaining an IP address of the plurality of Home Agents is performed using a Discovery Protocol.

21. The method as recited in claim 1, wherein selecting one of the plurality of Home Agents comprises:

selecting one of the plurality of Home Agents according to information indicating at least one of health, load conditions, and availability of the plurality of Home Agents.

22. The method as recited in claim 21, further comprising:

monitoring at least one of health, load conditions, and availability of the plurality of Home Agents.

23. The method as recited in claim 22, wherein monitoring is performed using Cisco Discovery Protocol or Dynamic Feedback Protocol.

24. The method as recited in claim 1, further comprising:

storing a temporary binding associated with the Mobile Node, the temporary binding including a Mobile Node identifier, address of the selected Home Agent, and time during which the temporary binding will be maintained.

25. The method as recited in claim 24, further comprising:

deleting the temporary binding when the time has expired.

26. The method as recited in claim 24, further comprising:

if a re-registration request is received before the time has expired, renewing the time in the temporary binding.

27. The method as recited in claim 24, further comprising;

sending the temporary binding for one or more Mobile Nodes to one or more backup network devices.

28. The method as recited in claim 24, further comprising:

sending a subsequent registration request received from the Mobile Node to the address of the selected Home Agent if the subsequent registration request is received during the time specified in the temporary binding.

29. The method as recited in claim 1, further comprising:

determining whether a registration request from the Mobile Node is pending for the selected Home Agent; and

and when it is determined that a registration request from the Mobile Node is not pending for the selected Home Agent, sending the registration request to the selected Home Agent.

30. The method as recited in claim 29, further comprising:

retaining the source IP address of the registration request as the source IP address of the Foreign Agent, thereby enabling the selected Home Agent that receives the registration request to send a registration reply to the Foreign Agent.

31. A network device for distributing a Mobile IP registration request to one of a plurality of Home Agents, comprising:

means for receiving a registration request from a Foreign Agent to which the Mobile Node has roamed;

means for selecting one of the plurality of Home Agents; and

means for sending the registration request to the selected one of the plurality of Home Agents, the source IP address of the registration request being an IP address of the Foreign Agent to which the Mobile Node has roamed, thereby enabling the selected one of the plurality of Home Agents to send a Mobile IP registration reply directly to the Foreign Agent without interception by the network device.

32. A network device for distributing a Mobile IP registration request to one of a plurality of Home Agents, comprising:

a processor; and

a memory, at least one of the processor and the memory being adapted for;

receiving a registration request from a Foreign Agent to which the Mobile Node has roamed;

selecting one of the plurality of Home Agents; and

sending the registration request to the selected one of the plurality of Home Agents, the source IP address of the registration request being an IP address of the Foreign Agent to which the Mobile Node has roamed, thereby enabling the selected one of the plurality of Home Agents to send a Mobile IP registration reply directly to the Foreign Agent without interception by the network device.

33. A computer-readable medium storing thereon computer-readable instructions for distributing a Mobile IP registration request by a network device to one of a plurality of Home Agents, comprising:

instructions for receiving a registration request from a Foreign Agent to which the Mobile Node has roamed;

instructions for selecting one of the plurality of Home Agents; and

instructions for sending the registration request to the selected one of the plurality of Home Agents, the source IP address of the registration request being an IP address of the Foreign Agent to which the Mobile Node has roamed, thereby enabling the selected one of the plurality of Home Agents to send a Mobile IP registration reply directly to the Foreign Agent without interception by the network device.