Methods and apparatus for mobile IP dynamic home agent allocation

• US 7,587,498 B2
• Filed: 05/06/2002
• Issued: 09/08/2009
• Est. Priority Date: 05/06/2002
• Status: Expired due to Fees

• 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
• Primary Examiner(s): Winder; Patrice
• Assistant Examiner(s): BILGRAMI, ASGHAR H
• Application Number:
  US10/139,941
• Publication Number:
  US 20040202126A1
• Time in Patent Office: 2,682 Days
• Field of Search: 709/228, 709/226, 709/238, 709/243, 709/219, 709/227, 455/439, 455/437, 455/435.1, 455/435, 370/228, 370/229, 370/338, 370/251, 370/329
• US Class Current: 709/228
• 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. A network device adapted 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 or the memory being adapted for;

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

determining whether a binding for the Mobile Node exists in a list of temporary bindings;

if a binding for the Mobile Node is determined to exist in the list of temporary bindings, forwarding the registration request to the one of the plurality of Home Agents identified in the binding;

if it is determined that a binding for the Mobile Node does not exist in the list of temporary bindings,

selecting one of the plurality of Home Agents to be an active Home Agent to which the registration request is to be forwarded, wherein an IP address associated with the selected one of the plurality of Home Agents has not previously been configured on the Mobile Node as a Home Agent of the Mobile Node, wherein the registration request that has been received does not identify the selected one of the plurality of Home Agents;

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, wherein the network device is not one of the plurality of Home Agents; and

creating a binding associated with the Mobile Node in the list of temporary bindings, wherein the binding associated with the Mobile Node in the list of temporary bindings indicates that a registration request has been sent to the one of the plurality of Home Agents.

2. The network device 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 network device 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 network device as recited in claim 1, wherein the network device does not store a registration lifetime associated with the registration request.

6. The network device as recited in claim 1, at least one of the processor or the memory being further adapted for:

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 network device.

7. The network device as recited in claim 6, at least one of the processor or the memory being further adapted for:

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

9. The network device as recited in claim 1, at least one of the processor or the memory being further adapted for:

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

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

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

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

15. The network device 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 network device 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 network device as recited in claim 16, wherein the routing redundancy protocol is HSRP or VRRP.

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

19. The network device as recited in claim 1, at least one of the processor or the memory being further adapted for:

obtaining an IP address of the plurality of Home Agents.

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

21. The network device 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, or availability of the plurality of Home Agents.

22. The network device as recited in claim 21, at least one of the processor or the memory being further adapted for:

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

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

24. The network device as recited in claim 1, wherein the binding includes a Mobile Node identifier, address of the selected Home Agent, and time during which the-binding will be maintained.

25. The network device as recited in claim 24, at least one of the processor or the memory being further adapted for:

deleting the binding when the time has expired.

26. The network device as recited in claim 24 at least one of the processor or the memory being further adapted for:

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

27. The network device as recited in claim 1, at least one of the processor or the memory being further adapted for;

sending the binding for one or more Mobile Nodes identified in the list of temporary bindings to one or more backup network devices, wherein the one or more backup network devices are not Home Agents, wherein each binding is not a mobility binding table entry.

28. The network device as recited in claim 24, at least one of the processor or the memory being further adapted for:

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 binding.

29. The network device as recited in claim 1, at least one of the processor or the memory being further adapted for:

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. The method as recited in claim 1, wherein the selected Home Agent is not identified in the registration request.

33. The method as recited in claim 1, wherein the registration request that has been received does not identify the plurality of Home Agents.

34. The network device as recited in claim 1, wherein the network device is not a Home Agent.

35. The network device as recited in claim 1, further comprising:

resetting a timer associated with the binding if a binding for the Mobile Node is determined to exist in the list of temporary bindings, thereby increasing a time during which the binding is maintained in the list of temporary bindings.

36. The network device as recited in claim 24, at least one of the processor or the memory being further adapted for:

maintaining the temporary binding until the Mobile Node is registered with the one of the plurality of Home Agents.

37. The network device as recited in claim 1, wherein the network device does not intercept registration replies sent from the one of the plurality of Home Agents.

38. The network device as recited in claim 1, wherein the network device is not a Foreign Agent.

39. The network device as recited in claim 1, wherein the registration request identifies a care-of address of the Mobile Node and wherein the binding does not include the care-of address of the Mobile Node.

40. The network device as recited in claim 24, wherein the time during which the binding will be maintained is not a registration lifetime indicating a lifetime during which the Mobile Node is registered with the selected Home Agent.

41. The network device as recited in claim 24, wherein the time during which the binding will be maintained is a time during which an initial registration request from the Mobile Node is considered to be pending.

45. The network device as recited in claim 24, wherein forwarding the registration request to the one of the plurality of Home Agents identified in the binding is performed if the registration request is received from the Mobile Node during the time specified in the binding.

30. 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 determining whether a binding for the Mobile Node exists in a list of temporary bindings;

means for forwarding the registration request to the one of the plurality of Home Agents identified in the binding if a binding for the Mobile Node is determined to exist in the list of temporary bindings;

means for selecting one of the plurality of Home Agents to be an active Home Agent to which the registration request is to be forwarded, sending the registration request to the selected one of the plurality of Home Agents, and creating a temporary binding associated with the Mobile Node in the list of temporary bindings if it is determined that a binding for the Mobile Node does not exist in the list of temporary bindings, wherein an IP address associated with the selected one of the plurality of Home Agents has not previously been configured on the Mobile Node as a Home Agent of the Mobile Node, wherein the registration request that has been received does not identify 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, wherein the network device is not one of the plurality of Home Agents.

42. The network device as recited in claim 30, wherein the binding associated with the Mobile Node in the list of temporary bindings indicates a time during which the binding will be maintained, wherein the time during which the binding will be maintained is a time during which an initial registration request from the Mobile Node is considered to be pending.

32. 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;

determining whether a binding for the Mobile Node exists in a list of temporary bindings;

if a binding for the Mobile Node is determined to exist in the list of temporary bindings, forwarding the registration request to the one of the plurality of Home Agents identified in the binding;

if it is determined that a binding for the Mobile Node does not exist in the list of temporary bindings,

selecting one of the plurality of Home Agents to be an active Home Agent to which the registration request is to be forwarded, wherein an IP address associated with the selected one of the plurality of Home Agents has not previously been configured on the Mobile Node as a Home Agent of the Mobile Node, wherein the registration request that has been received does not identify the selected one of the plurality of Home Agents;

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, wherein the network device is not one of the plurality of Home Agents; and

creating a binding associated with the Mobile Node in the list of temporary bindings.

43. The method as recited in claim 32, wherein the binding associated with the Mobile Node in the list of temporary bindings does not include a registration lifetime associated with a binding between the Mobile Node and the one of the plurality of Home Agents to which the registration request has been forwarded

44. The method as recited in claim 32, wherein the binding associated with the Mobile Node in the list of temporary bindings indicates a time during which the binding will be maintained, wherein the time during which the binding will be maintained is a time during which an initial registration request from the Mobile Node is considered to be pending.