Support mobile device in asymmetric link environment

• US 20070104170A1
• Filed: 12/27/2006
• Published: 05/10/2007
• Est. Priority Date: 12/28/2000
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Leung, Kent, Patel, Alpesh
• Granted Patent: US 7,630,352 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

Methods and apparatus for registering a mobile device such as a mobile node or mobile router with a Home Agent in an asymmetric link environment. A Foreign Agent associates each of one or more interfaces of the Foreign Agent with a different care-of address. An agent advertisement including the care-of address for the one or more interfaces of the Foreign Agent is then sent via one or more uplinks. A registration request is received via a downlink router. The registration request identifies a care-of address associated with one of the one or more interfaces of the Foreign Agent. One of the interfaces identified by the care-of address is ascertained, thereby identifying the interface to which the mobile device has roamed. The registration request is forwarded to the Home Agent. A registration reply is received from the Home Agent. The registration reply is then forwarded to the mobile device via the ascertained interface.

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25. A Foreign Agent that supports Mobile IP, the Foreign Agent being capable of registering a mobile device with a Home Agent in an asymmetric link environment, the Foreign Agent comprising:

a processor; and

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

associating each one of a plurality of interfaces of the Foreign Agent with a different care-of address such that each of the plurality of interfaces is mapped to a different care-of address;

sending at least one agent advertisement including the care-of address for each of the plurality of interfaces of the Foreign Agent via one or more uplinks;

receiving a registration request forwarded via a downlink router, the registration request identifying a care-of address associated with only one of the plurality of interfaces of the Foreign Agent;

ascertaining the one of the plurality of interfaces identified by the care-of address in the registration request, thereby identifying the interface to which the mobile device has roamed;

forwarding the registration request to the Home Agent;

receiving a registration reply from the Home Agent; and

forwarding the registration reply to the mobile device via the ascertained interface.

26. The Foreign Agent as recited in claim 25, wherein the registration request further includes an extension including a source MAC address of the mobile device.

27. The Foreign Agent as recited in claim 26, wherein the registration reply includes a destination MAC address that is the source MAC address of the mobile device.

28. The Foreign Agent as recited in claim 25, wherein the registration request includes a destination IP address field having a value of the care-of address from the agent advertisement.

29. The Foreign Agent as recited in claim 25, at least one of the processor or the memory being further adapted for:

entering the registration request in a pending registration request list; and

updating the pending registration request list when the registration reply is received from the Home Agent.

30. The Foreign Agent as recited in claim 25, at least one of the processor or the memory being further adapted for:

marking the registration request as having been received on the interface advertising the care-of address.

31. The Foreign Agent as recited in claim 30, wherein marking the registration request as having been received on the interface advertising the care-of address comprises:

updating a pending registration request list to indicate that the registration request has been received on the interface advertising the care-of address.

32. The Foreign Agent as recited in claim 25, wherein the registration reply includes a destination MAC address that is a broadcast address.

33. The Foreign Agent as recited in claim 25, wherein the registration reply includes a destination MAC address that is a multicast address.

34. The Foreign Agent as recited in claim 25, wherein each of the plurality of interfaces has been assigned a different care-of address.

35. A downlink router adapted for forwarding a Mobile IP registration request in an asymmetric link environment, comprising:

a processor; and

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

receiving a registration request composed and sent by a mobile device, the registration request identifying a care-of address associated with only one of a plurality of interfaces of a Foreign Agent, wherein each of the plurality of interfaces of the Foreign Agent has a different care-of address; and

forwarding the registration request to the Foreign Agent, thereby enabling the Foreign Agent to process the registration request and forward a registration reply to the mobile device via the interface.

36. The downlink router as recited in claim 35, wherein the mobile device includes a router.

37. The downlink router as recited in claim 35, wherein the mobile device is a mobile node supporting Mobile IP.

38. The downlink router as recited in claim 35, wherein the registration request includes a time to live field having a value that is greater than one.

39. The downlink router as recited in claim 35, wherein the downlink router is a Foreign Agent.

40. The downlink router as recited in claim 35, wherein the asymmetric link environment includes one or more satellites.

41. The downlink router as recited in claim 35, wherein the registration request further includes an extension including a source MAC address of the mobile device.

42. The downlink router as recited in claim 35, wherein the registration request includes a destination IP address field having a value of the care-of address.

43. The downlink router as recited in claim 35, wherein the registration request is sent using a destination MAC address that is a broadcast or multicast MAC address.

44. The downlink router as recited in claim 35, wherein each of the plurality of interfaces has been assigned a different care-of address.

45. A downlink router adapted for forwarding a Mobile IP registration request in an asymmetric link environment, comprising:

means for receiving a registration request composed and sent by a mobile device, the registration request identifying a care-of address associated with only one of a plurality of interfaces of a Foreign Agent, wherein each of the plurality of interfaces of the Foreign Agent has a different care-of address; and

means for forwarding the registration request to the Foreign Agent, thereby enabling the Foreign Agent to process the registration request and forward a registration reply to the mobile device via the interface.