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

• US 6,466,964 B1
• Filed: 06/15/1999
• Issued: 10/15/2002
• 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:
  US09/333,831
• Time in Patent Office: 1,218 Days
• Field of Search: 709/203, 709/202, 709/225, 709/250, 709/229, 709/223, 370/432, 370/401
• US Class Current: 709/202
• 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. A server configured to store and provide authentication keys upon request, the server comprising:

a memory; and

a processor coupled to the memory,

wherein the memory and the processor are adapted to provide a plurality of authentication keys, the plurality of authentication keys being associated with a plurality of nodes, wherein the server is adapted for providing one of the plurality of authentication keys associated with one of the plurality of nodes to a Foreign Agent that supports Mobile IP in response to a request received from the Foreign Agent, the request identifying a node that does not support Mobile IP, thereby enabling the Foreign Agent to generate an authentication extension.

2. The server as recited in claim 1, wherein the authentication extension is a Mobile Node to Home Agent Authentication Extension.

3. The server as recited in claim 1, wherein the server is further adapted to provide one of the plurality of authentication keys associated with one of the plurality of nodes in response to a request received from a Home Agent that supports Mobile IP to enable the Home Agent to authenticate the one of the plurality of nodes.

4. The server as recited in claim 1, wherein the server is a TACACS+ or RADIUS server.

5. 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:

receiving a packet; and

ascertaining from the packet whether a node has been detected in a vicinity of the Foreign Agent;

wherein when a node has been detected, composing a registration request on behalf of the node; and

sending the registration request to the Home Agent.

6. The method as recited in claim 5, further comprising:

receiving a registration reply from the Home Agent; and

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

7. The method as recited in claim 5, wherein receiving a packet comprises at least one of receiving an ARP request, receiving a data packet, and receiving an access point control packet.

8. The method as recited in claim 5, further including:

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

9. The method as recited in claim 8, 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.

10. The method as recited in claim 5, further comprising:

associating a MAC address with an interface of the Foreign Agent; and

associating a dummy interface IP address with the interface of the Foreign Agent, wherein the dummy interface IP address is associated with the interface of each one of a plurality of Foreign Agents, thereby facilitating communication between a node that does not support Mobile IP with one of the plurality of Foreign Agents via the dummy interface IP address.

11. The method as recited in claim 5, wherein ascertaining whether the node has been detected includes at least one of receiving an ARP request, receiving a data packet, and receiving an access point control packet.

12. The method as recited in claim 5, further including:

checking if the node needs to be registered with the Home Agent;

wherein generating a registration request is performed if the node needs to be registered.

13. The method as recited in claim 12, wherein the node needs to be registered when the node is permitted to roam in a network associated with the Foreign Agent.

14. The method as recited in claim 12, wherein the node needs to be registered if a node ID associated with the node is in an access list of the Foreign Agent.

15. The method as recited in claim 8, wherein composing a registration request includes:

composing an authentication extension using an authentication key for the node; and

appending the authentication extension to the registration request.

16. The method as recited in claim 15, wherein the authentication extension is a Mobile-Home Authentication Extension.

17. The method as recited in claim 15, further including:

determining whether the Foreign Agent has the authentication key for the node; and

if it is determined that the Foreign Agent does not have an authentication key for the node, obtaining the authentication key for the node.

18. The method as recited in claim 17, wherein obtaining the authentication key for the node includes:

obtaining the authentication key from a TACACS+ server or a RADIUS server.

19. The method as recited in claim 5, further comprising:

determining whether the Foreign Agent has an authentication key for the node;

wherein when it is determined that the Foreign Agent does not have the authentication key for the node, obtaining the authentication key for the node, generating an authentication extension from the authentication key for the node, and appending the authentication extension to the registration request.

20. The method as recited in claim 19, wherein the authentication extension is a Mobile-Home Authentication extension.

21. The method as recited in claim 5, further comprising:

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

22. The method as recited in claim 5, wherein the node is configured to have a default gateway, wherein the default gateway specifies a virtual agent IP address, the virtual agent IP address being an IP address that is associated with a plurality of Foreign Agents including the Foreign Agent, thereby enabling the node to roam to each one of the plurality of Foreign Agents and send packets via the default gateway.

23. The method as recited in claim 22, wherein each one of the plurality of Foreign Agents are further configured to have a common MAC address.

24. The method as recited in claim 5, 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 a plurality of foreign agents; and

updating an ARP table with a mapping of the IP address to the MAC address associated with the Foreign Agent.

25. The method as recited in claim 24, wherein updating an ARP table is performed on a periodic basis.

26. The method as recited in claim 5, 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; and

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

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

updating the ARP table with a mapping of the IP address to the MAC address associated with the Foreign Agent.

28. The method as recited in claim 27, wherein updating is performed by the Foreign Agent such that the MAC address is being mapped to the IP address in the ARP table.

29. The method as recited in claim 28, wherein updating includes:

sending a gratuitous ARP to update the ARP table.

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

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

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

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

32. The method as recited in claim 31, wherein determining that the node has not registered with its Home Agent via the Foreign Agent comprises comparing a node ID identifying the node with one or more entries in a visitor table associated with the Foreign Agent.

33. The method as recited in claim 30, wherein notifying comprises performing a gratuitous ARP in response to detecting the node such that the MAC address is mapped to the virtual IP address in the ARP table.

34. The method as recited in claim 21, 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.

35. The method as recited in claim 5, wherein the packet is a data packet, the method further comprising:

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

36. The method as recited in claim 35, wherein the data packet includes a Time to Live field and examining the data packet comprises determining whether the Time to Live field has previously been decremented to indicate that registration has been completed.

37. The method as recited in claim 35, 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 comprises ascertaining whether the source MAC address identifies a router.

38. The method as recited in claim 5, 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.

39. The method as recited in claim 5, wherein the packet is sent in response to a signal received from an access point associated with the Foreign Agent, the signal indicating that the node is in a vicinity of the Foreign Agent.

40. The method as recited in claim 5, wherein the packet is sent to the Foreign Agent when it is detected that the signal from an access point associated with the Foreign Agent is greater than a signal from another access point associated with another Foreign Agent.

41. The method as recited in claim 5, wherein the node is associated with a default gateway, 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 a plurality of Foreign Agents including the Foreign Agent, thereby enabling the node to roam to each one of the plurality of Foreign Agents.

42. In a Home Agent supporting Mobile IP, a method of registering a node that does not support Mobile IP, the method comprising:

receiving a registration request from a first Foreign Agent, the registration request being composed by the first Foreign Agent on behalf of the node and identifying the node;

updating a mobility binding table to associate the first Foreign Agent with the node;

updating the mobility binding table to perform de-registration of the node such that movement of the node from a second Foreign Agent to the first 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; and

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

43. The method as recited in claim 42, wherein notifying comprises sending a message to the second Foreign Agent such that an entry associated with the node is removed from a visitor table associated with the second Foreign Agent.

44. The method as recited in claim 42, wherein notifying is performed without a message from the node indicating that the node requests de-registration.

45. The method as recited in claim 42, further comprising:

updating the mobility binding table to remove the 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.

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

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;

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;

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

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.

47. The method as recited in claim 46, further including:

forwarding a data packet through at least one of the first and second tunnels specified in the mobility binding table.

48. The method as recited in claim 46, further including:

forwarding a data packet through the first and the second tunnels specified in the mobility binding table.

49. The method as recited in claim 46, further including:

forwarding a data packet through only one of the first and the second tunnels specified in the mobility binding table.

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

receiving a first registration request from a first Foreign Agent, the first registration request being composed by the first Foreign Agent on behalf of the node and including a node ID of the node;

receiving a second registration request from a second Foreign Agent, the second registration request being composed by the second Foreign Agent on behalf of the node and including the node ID of the node; and

denying registration from the first Foreign Agent for a specified period of time.

51. The method as recited in claim 50, wherein denying registration comprises:

composing a registration reply including an indication that registration of the node is denied.

52. A computer-readable medium for registering a node that does not support mobile IP with a Home Agent that supports Mobile IP, comprising:

instructions for receiving a packet;

instructions for ascertaining from the packet whether a node has been detected in a vicinity of a Foreign Agent that supports Mobile IP;

instructions for composing a registration request on behalf of the node when the node has been detected; and

instructions for sending the registration request to the Home Agent.

53. The computer-readable medium as recited in claim 52, further comprising:

instructions for determining whether a Foreign Agent that supports Mobile IP has an authentication key for the node;

instructions for obtaining the authentication key for the node when it is determined that the Foreign Agent does not have the authentication key for the node;

instructions for generating an authentication extension from the authentication key for the node; and

instructions for appending the authentication extension to the registration request.

54. The computer-readable medium as recited in claim 52, further comprising:

instructions for associating a MAC address with an interface of the Foreign Agent; and

instructions for associating a dummy interface IP address with the interface of the Foreign Agent, wherein the dummy interface IP address is associated with the interface of each one of a plurality of Foreign Agents thereby facilitating communication between a node that does not support Mobile IP with one of the plurality of Foreign Agents via the dummy interface IP address.

55. The computer-readable medium as recited in claim 52, further comprising:

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

56. The computer-readable medium as recited in claim 52, wherein the packet is an ARP request, a data packet, or an access point control packet.

57. The computer-readable medium as recited in claim 52, further comprising:

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

58. The computer-readable medium as recited in claim 52, further 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; and

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.

59. The computer-readable medium as recited in claim 52, wherein the packet is sent in response to detection of a signal from an access point, the packet indicating that the node is in a vicinity of the Foreign Agent.

60. The computer-readable medium as recited in claim 52, wherein a default gateway is 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 a plurality of Foreign Agents including the Foreign Agent.

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

instructions for receiving a registration request from a first Foreign Agent, the registration request being composed on behalf of the node by the first Foreign Agent and identifying the node;

instructions for updating a mobility binding table to associate the first Foreign Agent with the node;

instructions for performing de-registration of the node to update the mobility binding table such that movement of the node from a second Foreign Agent to the first 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; and

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

62. The computer-readable medium as recited in claim 61, further comprising:

instructions for updating the mobility binding table to remove the assocation 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.

63. A computer-readable medium for registering a node that does not support Mobile IP by a Home Agent that supports Mobile IP, comprising:

instructions for receiving a first registration request identifying the node from a first Foreign Agent, the first registration request being composed on behalf of the node by the first Foreign Agent;

instructions for receiving a second registration request identifying the node from a second Foreign Agent, the second registration request being composed on behalf of the node by the second Foreign Agent;

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

instructions 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.

64. A computer-readable medium for registering a node that does not support Mobile IP in a Home Agent that supports Mobile IP, comprising:

instructions for receiving a first registration request from a first Foreign Agent, the first registration request being composed on behalf of the node by the first Foreign Agent and including a node ID of the node;

instructions for receiving a second registration request from a second Foreign Agent, the second registration request being composed on behalf of the node by the second Foreign Agent and including the node ID of the node; and

instructions for denying registration from the first Foreign Agent for a specified period of time.

65. A Foreign Agent that supports Mobile IP, the Foreign Agent being 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;

receiving a packet;

ascertaining from the packet whether a node has been detected in a vicinity of the Foreign Agent;

composing a registration request on behalf of the node when the node has been detected; and

sending the registration request to the Home Agent.

68. The Foreign Agent as recited in claim 65, the Foreign Agent having a virtual Foreign Agent IP address and a MAC address, the virtual Foreign Agent IP address being associated with a plurality of foreign agents, wherein at least one of the processor and the memory are further adapted for:

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

69. The Foreign Agent as recited in claim 65, wherein the packet is an ARP request, a data packet, or an access point control packet.

70. Foreign Agent as recited in claim 65, wherein at least one of the processor and the memory are further adapted for:

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

71. The Foreign Agent as recited in claim 65, wherein at least one of the processor and the memory are further 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; and

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.

66. A Foreign Agent that supports Mobile IP, the Foreign Agent being adapted for generating a registration request for a node that does not support Mobile IP, comprising:

a processor; and

a memory, the memory storing therein;

instructions for determining whether the Foreign Agent has an authentication key for the node;

instructions for obtaining the authentication key for the node when it is determined that the Foreign Agent does not have the authentication key for the node;

instructions for composing a registration request identifying the node;

instructions for generating an authentication extension from the authentication key for the node; and

instructions for appending the authentication extension to the registration request.

67. A Foreign Agent supporting Mobile IP, the Foreign Agent being adapted for implementing a virtual Foreign Agent in a network having a plurality of Foreign Agents, comprising:

a processor; and

a memory, the memory storing therein;

instructions for associating a MAC address with an interface of the Foreign Agent such that an interface of each one of the plurality of Foreign Agents is associated with a different MAC address; and

instructions for associating a dummy interface IP address with the interface of the Foreign Agent, wherein the dummy interface IP address is associated with the interface of each one of the plurality of Foreign Agents thereby facilitating communication between a node that does not support Mobile IP with one of the plurality of Foreign Agents via the dummy interface IP address.

72. A Foreign Agent that supports Mobile IP, the Foreign Agent being adapted for registering a node that does not support mobile IP with a Home Agent that supports Mobile IP, comprising:

means for receiving a packet;

means for ascertaining from the packet whether a node has been detected in a vicinity of the Foreign Agent;

means for composing a registration request on behalf of the node when the node has been detected; and

means for sending the registration request to the Home Agent.