Methods and apparatus for providing mobility of a node that does not support mobility

• US 6,795,857 B1
• Filed: 09/09/2002
• Issued: 09/21/2004
• Est. Priority Date: 06/15/1999
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Leung, Kent K., Dommety, Gopal K.
• Primary Examiner(s): Lim, Krisna
• Application Number:
  US10/241,286
• Time in Patent Office: 743 Days
• Field of Search: 709/224, 709/229, 709/250, 709/242, 709/223, 711/117, 370/401, 370/432, 370/389
• US Class Current: 709/224
• CPC Class Codes: H04L 63/08 for authentication of entities cryptographic mechanisms or cryptographic arrangements for entity authentication H04L9/32
• CPC Class Codes: H04L 63/0892 by using authentication-authorization-accounting [AAA] servers or protocols
• CPC Class Codes: H04W 12/0431 Key distribution or pre-distribution; Key agreement
• CPC Class Codes: H04W 12/0433 Key management protocols
• CPC Class Codes: H04W 12/06 Authentication
• CPC Class Codes: H04W 8/02 Processing of mobility data, e.g. registration information at HLR [Home Location Register] or VLR [Visitor Location Register]; Transfer of mobility data, e.g. between HLR, VLR or external networks
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 88/182 Network node acting on behalf of an other network entity, e.g. proxy

Abstract

Methods and apparatus for enabling a node that does not support Mobile IP to roam from a first Foreign Agent to a second Foreign Agent are disclosed. In a Foreign Agent that supports Mobile IP, a method of registering a node that does not support Mobile IP with a Home Agent that supports Mobile IP includes detecting a node in a vicinity of the Foreign Agent, composing a registration request specifying a node ID associated with the node, and sending the registration request to the Home Agent. When the Home Agent receives the registration request from a first Foreign Agent, the Home Agent updates a mobility binding table to associate the first Foreign Agent with the node. In addition, the Home Agent notifies a second Foreign Agent to update its visitor table to reflect roaming of the node from the second Foreign Agent to the first Foreign Agent.

Claims

1. In a Foreign Agent that supports Mobile IP, a method of registering a node that does not support Mobile IP with a Home Agent that supports Mobile IP, the method comprising:

detecting a node in a vicinity of the Foreign Agent;

composing a registration request specifying a node ID associated with the node; and

sending the registration request to the Home Agent.

2. The method as recited in claim 1, further including:

receiving a registration reply from the Home Agent; and

examining the registration reply to determine success or failure of the registration.

3. The method as recited in claim 1, wherein detecting includes at least one of receiving an ARP request, receiving a data packet, and receiving an access point control packet.

4. The method as recited in claim 1, further including:

indicating in the registration request that the node has registered with its Home Agent via the Foreign Agent.

5. The method as recited in claim 4, wherein the registration request includes a Time to Live field and wherein indicating in the registration request includes decrementing the Time to Live field upon completion of registration of the node with the Home Agent.

6. The method as recited in claim 1, wherein the Foreign Agent is associated with a virtual agent IP address.

7. The data structure as recited in claim 6, wherein the virtual agent IP address is a single IP address that is associated with an interface of a plurality of Foreign Agents.

8. The method as recited in claim 1,

wherein upon receiving the registration request from the Foreign Agent, the Home Agent performs de-registration of the node to update a mobility binding table such that movement of the node from the Home Agent to the Foreign Agent is recorded, wherein performing de-registration is performed without a de-registration message from the node indicating that the node requests de-registration.

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

assigning an IP address to an interface of the Foreign Agent, the interface of the Foreign Agent being associated with a MAC address, wherein the IP address is assigned to an interface of one or more additional Foreign Agents having a corresponding MAC address,

thereby enabling the node to roam to the additional Foreign Agents by accessing an ARP table in which the IP address is mapped to the MAC address of the interface of each of the one or more additional Foreign Agents.

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

receiving a notification from the Home Agent at the Foreign Agent indicating that the mode has moved to another Foreign Agent; and

updating a visitor table to reflect roaming of the node from the Foreign Agent to another Foreign Agent.

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

wherein the registration request is denied by the Home Agent for a specified period of time when a second registration request is subsequently received by the Home Agent from another Foreign Agent on behalf of the node.

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

detecting a node in a vicinity of the Foreign Agent, wherein detecting the node includes at least one of receiving an ARP request, receiving a data packet, and receiving an access point control packet; and

notifying the node that its ARP table needs to be modified to reflect a mapping of the MAC address to a virtual Foreign Agent IP address associated with the Foreign Agent.

13. The method as recited in claim 12, further including:

determining that the node has not registered with its Home Agent via the Foreign Agent.

14. The method as recited in claim 13, wherein determining that the node has not registered with its Home Agent via the Foreign Agent includes comparing a node ID identifying the node with one or more entries in a visitor table associated with the Foreign Agent.

15. The method as recited in claim 12, wherein notifying includes performing a gratuitous ARP in response to detecting the node such that the MAC address is mapped to the virtual Foreign Agent IP address in the ARP table.

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

receiving a data packet identifying the node; and

examining the data packet to ascertain whether the node has previously registered with its Home Agent via another Foreign Agent.

17. The method as recited in claim 16, wherein the data packet includes a Time to Live field and examining the data packet includes determining whether the Time to Live field has previously been decremented to indicate that registration has been completed.

18. The method as recited in claim 16, wherein the data packet includes a header identifying a source MAC address and examining the data packet to ascertain whether the node has previously registered with its Home Agent via another Foreign Agent includes ascertaining whether the source MAC address identifies a router.

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

examining a pending registrations list to determine whether a plurality of registration requests have been sent on behalf of the node within a first specified period of time;

wherein when it is determined that a plurality of registration requests have been sent on behalf of the node within the first specified period of time, the Foreign Agent forwards traffic generated by the node and avoids registration on behalf of the node for a second specified period of time.

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

receiving a message from the node indicating that the node is in a vicinity of the Foreign Agent such that the Foreign Agent is made aware of movement of the node to the second Foreign Agent.

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

receiving a message indicating that the node is in a vicinity of the Foreign Agent; and

modifying a default gateway associated with the node, the default gateway associating a virtual IP address with a MAC address of the Foreign Agent, the virtual IP address being associated with an interface of the Foreign Agent.

22. The method as recited in claim 1 further comprising:

receiving a notification at the Foreign Agent from the Home Agent to update its visitor table to reflect roaming of the node from the Foreign Agent to the Home Agent.

23. A Foreign Agent that supports Mobile IP and adapted for registering a node that does not support Mobile IP with a Home Agent that supports Mobile IP, comprising:

a processor; and

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

detecting a node in a vicinity of the Foreign Agent;

composing a registration request specifying a node ID associated with the node; and

sending the registration request to the Home Agent.

24. A Foreign Agent that supports Mobile IP and adapted for registering a node that does not support Mobile IP with a Home Agent that supports Mobile IP, comprising:

means for detecting a node in a vicinity of the Foreign Agent;

means for composing a registration request specifying a node ID associated with the node; and

means for sending the registration request to the Home Agent.

25. A computer-readable medium storing thereon computer-readable instructions for registering a node that does not support Mobile IP with a Home Agent that supports Mobile IP in a Foreign Agent that supports Mobile IP, comprising:

instructions for detecting a node in a vicinity of the Foreign Agent;

instructions for composing a registration request specifying a node ID associated with the node; and

instructions for sending the registration request to the Home Agent.

26. A Home Agent supporting Mobile IP and adapted for registering a node that does not implement Mobile IP, 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, the registration request specifying a node ID of the node; and

performing de-registration of the node to update a mobility binding table such that movement of the node from the Home Agent to the Foreign Agent is recorded, wherein performing de-registration is performed without a de-registration message from the node indicating that the node requests de-registration.

27. A Home Agent supporting Mobile IP and adapted for registering a node that does not implement Mobile IP, comprising:

means for receiving a registration request from a Foreign Agent, the registration request specifying a node HD of the node; and

means for performing de-registration of the node to update a mobility binding table such that movement of the node from the Home Agent to the Foreign Agent is recorded, wherein performing de-registration is performed without a de-registration message from the node indicating that the node requests de-registration.

28. A computer-readable medium storing thereon computer-readable instructions for registering a node that does not implement Mobile IP in a Home Agent supporting Mobile IP, comprising:

instructions for receiving a registration request from a Foreign Agent, the registration request specifying a node ID of the node; and

instructions for performing de-registration of the node to update a mobility binding table such that movement of the node from the Home Agent to the Foreign Agent is recorded, wherein performing de-registration is performed without a de-registration message from the node indicating that the node requests de-registration.

29. A method of enabling a node that does not support Mobile IP to send a packet from a Foreign Agent that supports Mobile IP, the method comprising:

roaming to a Foreign Agent;

registering with the Home Agent through a registration request composed by the Foreign Agent on behalf of the node; and

sending a packet via a default gateway associated with the node, the default gateway associating a virtual IP address with a MAC address of the Foreign Agent, the virtual IP address being associated with a plurality of Foreign Agents including the Foreign Agent to which the node has roamed.

30. A computer-readable medium for enabling a node that does not support Mobile IP to send a packet from a Foreign Agent that supports Mobile IP, comprising:

instructions for roaming to a Foreign Agent;

instructions for registering with the Home Agent through a registration request composed by the Foreign Agent on behalf of the node; and

instructions for sending a packet via a default gateway associated with the node, the default gateway associating a virtual IP address with a MAC address of the Foreign Agent, the virtual IP address being associated with a plurality of Foreign Agents including the Foreign Agent to which the node has roamed.

31. A Home Agent that supports Mobile IP and adapted for registering a node that does not support Mobile IP, comprising:

means for receiving a first registration request identifying the node from a first Foreign Agent composed by the first Foreign Agent on behalf of the node that does not support Mobile IP;

means for receiving a second registration request identifying the node from a second Foreign Agent composed by the second Foreign Agent on behalf of the node that does not support Mobile IP;

means for updating a mobility binding table to include an entry specifying a first tunnel between the Home Agent and the first Foreign Agent; and

means for updating the mobility binding table to include an entry specifying a second tunnel between the Home Agent and the second Foreign Agent, wherein updating the mobility binding table to include an entry specifying the second tunnel is performed without removing the entry specifying the first tunnel.

32. A Foreign Agent having a virtual Foreign Agent IP address and a MAC address, the Foreign Agent implementing Mobile IP and adapted for updating an ARP table, the comprising:

a processor; and

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

detecting a node in a vicinity of the Foreign Agent, wherein detecting the node includes at least one of receiving an ARP request, receiving a data packet, and receiving an access point control packet; and

notifying the node that the ARP table needs to be modified to reflect a mapping of the MAC address to the virtual Foreign Agent IP address.

33. A computer-readable medium storing thereon computer-readable instructions for updating an ARP table in a Foreign Agent having a virtual Foreign Agent IP address and a MAC address, the Foreign Agent implementing Mobile IP, comprising:

instructions for detecting a node in a vicinity of the Foreign Agent, wherein detecting the node includes at least one of receiving an ARP request, receiving a data packet, and receiving an access point control packet; and

instructions for notifying the node that the ARP table needs to be modified to reflect a mapping of the MAC address to the virtual Foreign Agent IP address.

34. A Home Agent supporting Mobile IP, a method of registering a node that does not support Mobile IP, comprising:

a processor; and

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

updating a mobility binding table to remove an association between the first Foreign Agent and the node when the node roams from the first Foreign Agent to its Home Agent; and

notifying the first Foreign Agent to update its visitor table to reflect roaming of the node from the first Foreign Agent to the Home Agent.

35. A computer-readable medium storing thereon computer-readable instructions for registering a node that does not support Mobile IP in a Home Agent supporting Mobile IP, comprising:

instructions for updating a mobility binding table to remove an association between the first Foreign Agent and the node when the node roams from the first Foreign Agent to its Home Agent; and

instructions for notifying the first Foreign Agent to update its visitor table to reflect roaming of the node from the first Foreign Agent to the Home Agent.

36. A Foreign Agent that supports Mobile IP, the Foreign Agent being adapted for determining whether a node has previously registered with its Home Agent via another Foreign Agent, comprising:

a processor; and

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

receiving a data packet identifying the node; and

examining the data packet to ascertain whether the node has previously registered with its Home Agent via another Foreign Agent.

37. A computer-readable medium storing thereon computer-readable instructions for determining whether a node has previously registered with its Home Agent via another Foreign Agent in a Foreign Agent that supports Mobile IP, comprising:

instructions for receiving a data packet identifying the node; and

instructions for examining the data packet to ascertain whether the node has previously registered with its Home Agent via another Foreign Agent.

38. A Foreign Agent that supports Mobile IP and adapted for registering a node that does not support Mobile IP, comprising:

a processor; and

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

examining a pending registrations list to determine whether a plurality of registration requests have been sent on behalf of the node within a first specified period of time;

wherein when it is determined that a plurality of registration requests have been sent on behalf of the node within the first specified period of time, the Foreign Agent forwards traffic generated by the node and avoids registration on behalf of the node for a second specified period of time.

39. A computer-readable medium storing thereon computer-readable instructions for registering a node that does not support Mobile IP in a Foreign Agent that supports Mobile IP, comprising:

instructions for examining a pending registrations list to determine whether a plurality of registration requests have been sent on behalf of the node within a first specified period of time;

instructions for forwarding traffic generated by the node and avoiding registration on behalf of the node for a second specified period of time when it is determined that a plurality of registration requests have been sent on behalf of the node within the first specified period of time.

40. A Foreign Agent that supports Mobile IP and adapted for registering a node that does not support Mobile IP, comprising:

means for examining a pending registrations list to determine whether a plurality of registration requests have been sent on behalf of the node within a first specified period of time;

means for forwarding traffic generated by the node and avoiding registration on behalf of the node for a second specified period of time when it is determined that a plurality of registration requests have been sent on behalf of the node within the first specified period of time.

41. A node that does not support Mobile IP capable of roaming from a first Foreign Agent to a second Foreign Agent, comprising:

a processor; and

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

detecting a signal from an access point associated with the second Foreign Agent; and

sending a message indicating that the node is in a vicinity of the second Foreign Agent such that the second Foreign Agent is made aware of movement of the node to the second Foreign Agent.

42. A computer-readable medium storing thereon computer-readable instructions for enabling a node that does not support Mobile IP to roam from a first Foreign Agent to a second Foreign Agent, comprising:

instructions for detecting a signal from an access point associated with the second Foreign Agent; and

instructions for sending a message indicating that the node is in a vicinity of the second Foreign Agent such that the second Foreign Agent is made aware of movement of the node to the second Foreign Agent.