Controlling hand-off in a mobile node with two mobile IP clients

1. A method of operating a mobile node, the method comprising:

storing a first access node address corresponding to a first access node and a first roaming node address corresponding a first roaming node in a memory; and

comparing a received access node address and a received roaming node address to the first access node address and the first roaming node address, respectively, to detect: a local handoff between the first access node and a second access node in an access network in which said mobile node is located without a handoff between roaming nodes or a remote handoff including a handoff between the first roaming node and a second roaming node in said access network, said access network being coupled to a home network which includes a home agent corresponding to said mobile node.

2. The method of claim 1 , further comprising:

in response to detecting a local handoff, updating address information corresponding to the mobile node stored in the first roaming node; and

in response to detecting a remote handoff, updating a roaming address corresponding to the mobile node, stored in the home agent, with a new roaming address corresponding to the second roaming node.

3. The method of claim 2 , wherein updating address information corresponding to the mobile node stored in the first roaming node in response to detecting a local handoff includes:

sending a message to update a foreign agent care of address which is stored in the first roaming node, and associated with the mobile node, with an address of the second access node.

4. The method of claim 3 , wherein updating a roaming address corresponding to the mobile node in response to detecting a remote handoff includes:

sending a message used to register the new roaming address corresponding to the second roaming node with the home agent.

5. The method of claim 4 , further comprising:

following detecting a remote handoff and prior to updating a roaming address corresponding to the mobile node,

requesting assignment of said new roaming address from said second roaming node.

6. The method of claim 2 ,

wherein said updating address information corresponding to the mobile node stored in the first roaming node in response to detecting a local handoff is performed by a local mobility agent module in said, mobile node; and

wherein said updating a roaming address corresponding to the mobile node in response to detecting a remote handoff is performed by a remote mobility agent module in said mobile node.

7. The method of claim 1 , wherein said first and second roaming nodes are included in a local network, said first and second roaming nodes being in the same local network.

8. The method of claim 1 , wherein said access network is a local network, said home network being coupled to said local network by a communications link.

9. The method of claim 8 , wherein said first and second access nodes arc located in first and second cells, respectively, of said local network.

10. The method of claim 9 , wherein said first roaming node and said second roaming node are located external to said first and second cells.

11. The method of claim 1 , wherein said first roaming node is coupled to said second roaming node by a network node which is coupled to at least one of said first and second access nodes.

12. A mobile node, comprising:

means for storing a first access node address corresponding to a first access node and a first roaming node address corresponding a first roaming node; and

means for comparing a received access node address and a received roaming node address to the first access node address and the first roaming node address, respectively, to detect: a local handoff between the first access node and a second access node in an access network in which said mobile node is located without a handoff between roaming nodes or a remote handoff including a handoff between the first roaming node and a second roaming node in said access network, said access network being coupled to a home network which includes a home agent corresponding to said mobile node.

13. The mobile node of claim 12 , further comprising:

means for updating address information corresponding to the mobile node stored in the first roaming node in response to detecting a local handoff; and

means for updating a roaming address corresponding to the mobile node, stored in the home agent, with a new roaming address corresponding to the second roaming node, in response to detecting a remote handoff.

14. The mobile node of claim 13 , wherein said means for updating address information corresponding to the mobile node stored in the first roaming node in response to detecting a local handoff includes:

means for sending a message to update a foreign agent care of address which is stored in the first roaming node, and associated with the mobile node, with an address of the second access node.

15. The mobile node of claim 14 , wherein said means for updating a roaming address corresponding to the mobile node in response to detecting a remote handoff includes:

means for sending a message used to register the new roaming address corresponding to the second roaming node with the home agent.

16. The mobile node of claim 15 , further comprising:

means for requesting assignment of said new roaming address from said second roaming node following detecting a remote handoff and prior to said updating a roaming address corresponding to the mobile node.

17. The mobile node of claim 13 ,

wherein said means for updating address information corresponding to the mobile node stored in the first roaming node in response to detecting a local handoff is part of a local mobility agent module in said mobile node; and

wherein said means for updating a roaming address corresponding to the mobile node in response to detecting a remote handoff is part of a remote mobility agent module in said mobile node.

18. The mobile node of claim 12 , wherein said first and second roaming nodes are included in a local network, said first and second roaming nodes being in the same local network.

19. The mobile node, of claim 12 , wherein said access network is a local network, said home network being coupled to said local network by a communications link.

20. The mobile node of claim 19 , wherein said first and second access nodes are located in first and second cells, respectively, of said local network.

21. The mobile node of claim 20 , wherein said first roaming node and said second roaming node are located external to said first and second cells.

22. The mobile node of claim 12 , wherein said first roaming node is coupled to said second roaming node by a network node which is coupled to at least one of said first and second access nodes.

23. A mobile node, comprising:

memory for storing a first access node address corresponding to a first access node and a first roaming node address corresponding a first roaming node; and

a module for comparing a received access node address and a received roaming node address to the first access node address and the first roaming node address, respectively, to detect: a local handoff between the first access node and a second access node in an access network in which said mobile node is located without a handoff between roaming nodes or a remote handoff including a handoff between the first roaming node and a second roaming node in said access network, said access network being coupled to a home network which includes a home agent corresponding to said mobile node.

24. The mobile node of claim 23 , further comprising:

a local mobility agent module for updating address information corresponding to the mobile node stored in the first roaming node in response to detecting a local handoff; and

a remote mobility agent module for updating a roaming address corresponding to the mobile node, stored in the home agent, with a new roaming address corresponding to the second roaming node, in response to detecting a remote handoff.

25. The mobile node of claim 24 , wherein said local mobility agent module is configured to send a message to update a foreign agent care of address which is stored in the first roaming node, and associated with the mobile node, with an address of the second access node, in response to detecting a local handoff.

26. The mobile node of claim 25 , wherein said remote mobility agent module is configured to send a message used to register the new roaming address corresponding to the second roaming node with the home agent in response to detecting a remote handoff.

27. The mobile node of claim 26 , wherein said remote mobility agent module is further configured to request assignment of said new roaming address from said second roaming node following detecting a remote handoff.

28. The mobile node of claim 23 , wherein said first and second roaming nodes are included in a local network, said first and second roaming nodes being in the same local network.

29. The mobile node of claim 23 , wherein said access network is a local network, said home network being coupled to said local network by a communications link.

30. The mobile node of claim 29 , wherein said first and second access nodes are located in first and second cells, respectively, of said local network.

31. The mobile node of claim 30 , wherein said first roaming node and said second roaming node are located external to said first and second cells.

32. A device comprising circuitry configured to:

compare a received access node address and a received roaming node address to a first access node address and a first roaming node address, respectively, to detect: a local handoff between the first access node and a second access node in an access network in which said device is located without a handoff between roaming nodes or a remote handoff including a handoff between the first roaming node and a second roaming node in said access network, said access network being coupled to a home network which includes a home agent corresponding to said mobile node.

33. The device of claim 32 ,

wherein the circuitry is further configured to generate a message used to update address information corresponding to the device stored in the first roaming node in response to detecting said local handoff.

34. The device of claim 33 ,

wherein the circuitry is further configured to generate a message used to update a roaming address corresponding to the mobile node, stored in the home agent, with a new roaming address corresponding to the second roaming node, in response to detecting a remote handoff.

35. The mobile, node of claim 32 , wherein said first roaming node is coupled to said second roaming node by a network node which is coupled to at least one of said first and second access nodes.

36. The device of claim 32 , wherein said first and second roaming nodes are included in a local network, said first and second roaming nodes being in the same local network.

37. The device of claim 36 , wherein said access network is a local network, said home network being coupled to said local network by a communications link.

38. The device of claim 37 , wherein said first and second access nodes are located in first and second cells, respectively, of said local network.

39. The device of claim 38 , wherein said first roaming node and said second roaming node are located external to said first and second cells.

40. The device of claim 32 , wherein said first roaming node is coupled to said second roaming node by a network node which is coupled to at least one of said first and second access nodes.

41. The device of claim 32 ,

wherein said device is a mobile node.