초록 ▼

Methods and apparatus for improving tunneling techniques and reducing packet loss in mobile communications systems are described. The methods and apparatus are well suited for use with Mobile IP and can facilitate handoff operations. A mobile node establishes multiple tunnels, representing downlinks

Methods and apparatus for improving tunneling techniques and reducing packet loss in mobile communications systems are described. The methods and apparatus are well suited for use with Mobile IP and can facilitate handoff operations. A mobile node establishes multiple tunnels, representing downlinks, from the mobile node perspective. The different downlink tunnels are through different access nodes but terminate at the same home agent. The mobile node maintains, at most, a single uplink tunnel at any given time with the home agent. Tunnels representing uplinks and downlinks are managed independently. Thus, each of the uplink and downlink tunnels can have different lifetimes and can be created/removed independently allowing for flexibility in handoff operations.

대표청구항 ▼

What is claimed is: 1. A communications method, for use with a first mobile node, the method comprising: operating a mobility management node to receive mobility management signals relating to said first mobile node; storing, in response to the received mobility management signals, tunnel informati

What is claimed is: 1. A communications method, for use with a first mobile node, the method comprising: operating a mobility management node to receive mobility management signals relating to said first mobile node; storing, in response to the received mobility management signals, tunnel information defining first and second incoming tunnels and an outgoing tunnel, said tunnels being associated with said first mobile node, said incoming and outgoing being relative to said mobility agent node; said stored tunnel information including an IP address of said first mobile node which is associated with said first and second incoming tunnels and said outgoing tunnel; said stored tunnel information, defining said first incoming tunnel and said outgoing tunnel, including first and second tunnel end node addresses corresponding to first and second tunnel end nodes, respectively, the end nodes of said first incoming tunnel and said outgoing tunnel being the same, the first tunnel end node address being an address corresponding to said mobility management node, the second tunnel end node address being a destination address of the outgoing tunnel and a source address of said first incoming tunnel; and said stored tunnel information, defining said second incoming tunnel, including third and fourth tunnel end node addresses corresponding to third and fourth tunnel end nodes, respectively, the third tunnel end node address being the destination address of the second incoming tunnel and corresponding to said nobility management node, said fourth tunnel end node address being different from said first, second and third tunnel end node addresses and being the source address of the second incoming tunnel. 2. The method of claim 1, further comprising: operating the mobility management node to receive another mobility management signal; and in response to said another mobility management signal, updating the stored tunnel information to change the destination address of the outgoing tunnel from said second tunnel end node address to another tunnel end node address. 3. The method of claim 2, wherein updating the stored tunnel information to change the destination address of the outgoing tunnel does not affect the stored first incoming tunnel address information. 4. The method of claim 3, wherein said another tunnel end node address is said fourth tunnel end node address. 5. The method of claim 2, further comprising: removing said first incoming tunnel, said step of removing the first incoming tunnel including deleting at least some of the address information corresponding to the first incoming tunnel. 6. The method of claim 5 wherein said deletion is in response to yet another mobility management signal received by said mobility management node. 7. The method of claim 5, wherein said deletion is performed without affecting the information corresponding to said outgoing tunnel. 8. The method of claim 2, further comprising: in response to receiving an additional mobility management signal, deleting from the stored tunnel information the information defining said second incoming tunnel without altering information defining said first incoming tunnel and said outgoing tunnel. 9. The method of claim 2, further comprising: storing independent tunnel life time information for each of the first and second incoming tunnels and said outgoing tunnel. 10. The method of claim 1, wherein the source addresses of the first and second incoming tunnels correspond to different access nodes. 11. The method of claim 1, wherein the source addresses of the first and second incoming tunnels are different IP addresses corresponding to said mobile node. 12. The method of claim 1, further comprising: operating said mobility management node to perform mobility management tunnel operations corresponding to a plurality of mobile nodes, said mobility management operations including storing information used to maintain multiple incoming tunnels and at least one outgoing tunnel for each of a plurality of mobile nodes at the same time, the incoming tunnels corresponding to individual ones of said mobile nodes having different tunnel source node addresses. 13. The method of claim 1, wherein said stored tunnel information defining said first incoming tunnel and said outgoing tunnel include a tunnel type indicator flag associated with said first and second tunnel end node addresses, said indicator flag indicating that said first and second tunnel end node addresses correspond to a bi-directional tunnel, said outgoing tunnel and said first incoming tunnel being included in said bi-directional tunnel. 14. The method cit claim 13, further comprising: operating the mobility management node to receive another mobility management signal; and in response to said another mobility management signal, updating the stored tunnel information to remove said outgoing tunnel by changing said bi-direction tunnel flag to an incoming tunnel flag. 15. The method of claim 14, further comprising: establishing a new outgoing tunnel between said mobility management node and the tunnel end node which serves as the source tunnel end node of said second incoming tunnel. 16. The method of claim 15, wherein establishing said new outgoing tunnel includes changing a tunnel type identifier flag associated with said second incoming tunnel to indicate that said second incoming tunnel is a bidirectional tunnel. 17. A communications system, for use with a first mobile node, the system comprising: a mobility management node including: means for receiving mobility management signals relating to said first mobile node; means for storing, in response to the received mobility management signals, tunnel information defining first and second incoming tunnels and an outgoing tunnel, said tunnels being associated with said first mobile node, said incoming and outgoing being relative to said mobility management node; said stored tunnel information including an IP address of said first mobile node which is associated with said first and second incoming tunnels and said outgoing tunnel; said stored tunnel information, defining said first incoming tunnel and said outgoing tunnel, including first and second tunnel end node addresses corresponding to first and second tunnel end nodes, respectively, the end nodes of said first incoming tunnel and said outgoing tunnel being the same, the first tunnel end node address being an address corresponding to said mobility management node, the second tunnel end node address being a destination address of the outgoing tunnel and a source address of said first incoming tunnel; and said stored tunnel information further defining said second incoming tunnel, including third and fourth tunnel end node addresses corresponding to third and fourth tunnel end nodes, respectively, the third tunnel end node address being the destination address of the second incoming tunnel and corresponding to said mobility management node, said fourth tunnel end node address being different from said first, second and third tunnel end node addresses and being the source address of the second incoming tunnel. 18. The system of claim 17, wherein said mobility management node further includes: means for updating the stored tunnel information to change the destination address of the outgoing tunnel from said second tunnel end node address to another tunnel end node address, in response to another mobility management signal. 19. The system of claim 18, wherein updating the stored tunnel information to change the destination address of the outgoing tunnel does not affect the stored first incoming tunnel address information. 20. The system of claim 19, wherein said another tunnel end node address is said fourth tunnel end node address. 21. A mobile communications method for use with a mobile node having a mobile node IP address, comprising: receiving mobility management signals at a mobility agent node; in response to said received signals independently establishing first and second incoming tunnels and at most one outgoing tunnel, said first and second incoming tunnels and said at most one outgoing tunnel corresponding to said mobile node and being associated with said mobile node IP address, said incoming and outgoing being relative to said mobility agent node; said first and second incoming tunnels having a mobility agent node address as a destination tunnel end node address and said at most one outgoing tunnel having said mobility agent node address as a source tunnel end node address; and said first and second incoming tunnels having different source tunnel end node addresses. 22. The mobile communications method of claim 21, wherein the source tunnel end node address of one of said first and second incoming tunnels is the same as the destination tunnel end node address of said at most one outgoing tunnel. 23. The method of claim 22, wherein said first incoming tunnel and said at most one outgoing tunnel exist between said mobility agent node and a first network node; and wherein said second incoming tunnel exists between said mobility agent node and a second network node, said second network node being different from said first network node. 24. The mobile communications method of claim 23, further comprising: moving the at most one outgoing tunnel without moving said incoming tunnel. 25. The mobile communications method of claim 24, where moving the at most one outgoing tunnel includes; changing the destination address of said at most one outgoing tunnel by modifying stored tunnel destination address information. 26. The mobile communications method of claim 23, further comprising: removing one of the established incoming tunnels in response to receiving another mobility management signal. 27. A mobile communications method for use with a mobile node having a mobile node IP address, comprising: receiving mobility management signals at a mobility agent node; in response to said received signals independently establishing first and second incoming tunnels and at most one outgoing tunnel, said first and second incoming tunnels and said at most one outgoing tunnel corresponding to said mobile node and being associated with said mobile node IP address, said incoming and outgoing being relative to said mobility agent node; said first and second incoming tunnels having a mobility agent node address as a destination tunnel end node address and said at most one outgoing tunnel having said mobility agent node address as a source tunnel end node address; said first and second incoming tunnels having different source tunnel end node addresses; wherein the source tunnel end node address of one of said first and second incoming tunnels is the same as the destination tunnel end node address of said at most one outgoing tunnel; wherein said first incoming tunnel and said at most one outgoing tunnel exist between said mobility agent node and a first network node; wherein said second incoming tunnel exists between said mobility agent node and a second network node, said second network node being different from said first network node; removing one of the established incoming tunnels in response to receiving another mobility management signal; and wherein the removed incoming tunnel is the first incoming tunnel, the method further comprising: generating, prior to said removing step, said another mobility management signal in response to a first handoff operation involving a handoff of said mobile node from said first network node to said second network node. 28. The method of claim 27, further comprising: receiving an additional mobility management signal as part of a handoff of said mobile node from said second network node to a third network node; and in response to receiving said additional mobility management signal adding an additional incoming tunnel corresponding to said mobile node, said additional incoming tunnel being between said third network node and said mobility agent node. 29. The method of claim 28, further comprising: prior to establishing said additional incoming tunnel, establishing a forwarding tunnel between said third network node and said second network node. 30. The method of claim 29, further comprising: operating the third network node to receive IP packets from said mobile node; and operating the third network node to forward the received IP packets to said second network node through said forwarding tunnel. 31. The method of claim 30, further comprising: operating the second network node to transmit IP packets received from said forwarding tunnel to said mobility agent node through said second incoming tunnel. 32. The method of claim 31, further comprising: terminating said forwarding tunnel following establishment of said additional incoming tunnel; and using said additional incoming tunnel to transmit packets received by said third network node from said mobile node to said mobility agent node. 33. The method of claim 32, further comprising: moving said at most one outgoing tunnel so that said at most one outgoing tunnel is between said mobility agent node and said third node; and terminating said second incoming tunnel. 34. A communications method, for use with a first mobile node and a mobility management node, the method comprising; operating the mobility management node to encapsulate and forward inner packets that arrive at the mobility management node with a destination address equal to the home address of the first mobile node, into a first tunnel that at least supports outgoing tunneling; operating the mobility management node to additionally decapsulate and forward inner packets, that have a source address equal to the home address of the first mobile node, and that arrive at the mobility management node in a second incoming only tunnel; said incoming and outgoing being relative to said mobility management node; said first and second tunnels being described by stored tunnel information in the mobility management node; said stored tunnel information including the home address of said first mobile node which is associated with said second incoming only tunnel and said first tunnel; said stored tunnel information, defining said first tunnel including first and second tunnel end node addresses corresponding to first and second tunnel end nodes, respectively, the first tunnel end node address being an address corresponding to said mobility management node, the second tunnel end node address being at least the destination address of the first tunnel for outgoing packets; and said stored tunnel information defining said second incoming only tunnel, including third and fourth tunnel end node addresses corresponding to third and fourth tunnel end nodes, respectively, the third tunnel end node address being only the destination address of the second incoming tunnel and corresponding to said mobility management node, said fourth tunnel end node address being different from said first, second and third tunnel end node addresses, and being the source address of the second incoming only tunnel. 35. The method of claim 34 further comprising: a first portion of said first tunnel information supporting communication of outgoing tunneled packets from the mobility management node directed to the home address of the first mobile node; a second portion of said first tunnel information supporting communication of incoming tunneled packets to the mobility management node via a second tunnel end node having said second tunnel end node address, said incoming tunneled packets having a source address which is the home address of the mobile node; a third portion of said first tunnel information supporting communication of incoming tunneled packets to the mobility management node via a fourth tunnel end node having said fourth tunnel end node address, said incoming tunneled packets having a source address which is the home address of the mobile node; said first and second portions being selectively enabled at a given point in time to create one of an outgoing only tunnel, an incoming only tunnel, and a bi-directional tunnel. 36. The method of claim 34, wherein the second and fourth tunnel end node addresses correspond to different access nodes or to different IP addresses corresponding to said mobile node. 37. The method of claim 34, further comprising: operating said mobility management node to perform mobility management tunnel operations corresponding to a plurality of mobile nodes, said mobility management operations including storing information used to maintain multiple incoming tunnels and at least one outgoing tunnel for each of a plurality of mobile nodes at the same time, the incoming tunnels corresponding to individual ones of said mobile nodes having different tunnel source node addresses. 38. The method of claim 35, further comprising: selectively enabling the third portion of said first tunnel information to create an incoming only tunnel when at least said first portion of said first tunnel information has been enabled. 39. The method of claim 38, further comprising: in response to receiving an additional mobility management signal, deleting from the stored tunnel information the information defining said second incoming tunnel without altering information defining said first incoming tunnel and said outgoing tunnel. 40. The method of claim 35 further comprising a fourth portion of said first tunnel information, said forth portion supporting communication of outgoing tunneled packets from the mobility management node via a fourth tunnel end node having said fourth tunnel end node address, said outgoing tunneled packet having a destination address equal to the home address of the first mobile node, said third and fourth portions being selectively enabled at a point in time to create one of an outgoing only tunnel, an incoming only tunnel, and a bidirectional tunnel. 41. The method of claim 40, further comprising: operating the mobility management node to receive mobility management signals relating to said first mobile node; said mobility management signals defining the status of the first or second tunnel as to whether it is now outgoing only, incoming only, bi-directional or cancelled; updating in response to the said received mobility management signals, the outgoing and incoming information of the first or second tunnel; and modifying the tunnel information associated with the second or first tunnel respectively as a result of the signaled changes to the first or second tunnel. 42. The method of claim 41, further comprising: the first tunnel supporting the bi-directional tunnel capability; operating the mobility management node to receive another mobility management signal; and in response to said another mobility management signal, updating the stored tunnel information to activate the outgoing tunnel capability of the second tunnel and cancel the outgoing tunnel capability of the first tunnel. 43. The method of claim 41 further comprising; operating the mobility management node to receive another mobility management signal; said signal defining a third incoming only tunnel which is added to the tunnel information in the mobility management node; and said signal not affecting the tunnel information for the first tunnel but deleting the information for the second incoming only tunnel. 44. The method of claim 35, further comprising; storing independent tunnel life time information for each of the first and second incoming tunnels and said outgoing tunnel. 45. A mobility management node including a processor configured to implement a communications method, the communications method comprising: receiving mobility management signals relating to a first mobile node; storing, in response to the received mobility management signals, tunnel information defining first and second incoming tunnels and an outgoing tunnel, said tunnels being associated with said first mobile node, said incoming and outgoing being relative to said mobility agent node; said stored tunnel information including an IP address of said first mobile node which is associated with said first and second incoming tunnels and said outgoing tunnel; said stored tunnel information, defining said first incoming tunnel and said outgoing tunnel, including first and second tunnel end node addresses corresponding to first and second tunnel end nodes, respectively, the end nodes of said first incoming tunnel and said outgoing tunnel being the same, the first tunnel end node address being an address corresponding to said mobility management node, the second tunnel end node address being a destination address of the outgoing tunnel and a source address of said first incoming tunnel; and said stored tunnel information, defining said second incoming tunnel, including third and fourth tunnel end node addresses corresponding to third and fourth tunnel end nodes, respectively, the third tunnel end node address being the destination address of the second incoming tunnel and corresponding to said mobility management node, said fourth tunnel end node address being different from said first, second and third tunnel end node addresses and being the source address of the second incoming tunnel. 46. The mobility management node of claim 45, wherein said processor is further configured to: receive another mobility management signal; and in response to said another mobility management signal, update the stored tunnel information to change the destination address of the outgoing tunnel from said second tunnel end node address to another tunnel end node address. 47. The mobility management node of claim 46, wherein updating the stored tunnel information to change the destination address of the outgoing tunnel does not affect the stored first incoming tunnel address information. 48. The mobility management node of claim 46, wherein said another tunnel end node address is said fourth tunnel end node address. 49. A computer readable medium including machine executable instructions for controlling a mobility management node to implement a communications method, the communications method comprising: receiving mobility management signals relating to a first mobile node; storing, in response to the received mobility management signals, tunnel information defining first and second incoming tunnels and an outgoing tunnel, said tunnels being associated with said first mobile node, said incoming and outgoing being relative to said mobility agent node; said stored tunnel information including an IP address of said first mobile node which is associated with said first and second incoming tunnels and said outgoing tunnel; said stored tunnel information, defining said first incoming tunnel and said outgoing tunnel, including first and second tunnel end node addresses corresponding to first and second tunnel end nodes, respectively, the end nodes of said first incoming tunnel and said outgoing tunnel being the same, the first tunnel end node address being an address corresponding to said mobility management node, the second tunnel end node address being a destination address of the outgoing tunnel and a source address of said first incoming tunnel; and said stored tunnel information, defining said second incoming tunnel, including third and fourth tunnel end node addresses corresponding to third and fourth tunnel end nodes, respectively, the third tunnel end node address being the destination address of the second incoming tunnel and corresponding to said mobility management node, said fourth tunnel end node address being different from said first, second and third tunnel end node addresses and being the source address of the second incoming tunnel. 50. The computer readable medium of claim 49, wherein the computer readable medium further includes instruction for controlling the mobility management node to: receive another mobility management signal; and in response to said another mobility management signal, updating the stored tunnel information to change the destination address of the outgoing tunnel from said second tunnel end node address to another tunnel end node address. 51. The computer readable medium of claim 50, wherein updating the stored tunnel information to change the destination address of the outgoing tunnel does not affect the stored first incoming tunnel address information. 52. The computer readable medium of claim 51, wherein said another tunnel end node address is said fourth tunnel end node address. 53. A mobility management node, for use with a first mobile node, the mobility management node comprising: a receiver for receiving mobility management signals relating to said first mobile node; a memory module for storing, in response to the received mobility management signals, tunnel information defining first and second incoming tunnels and an outgoing tunnel, said tunnels being associated with said first mobile node, said incoming and outgoing being relative to said mobility agent node; said stored tunnel information including an IP address of said first mobile node which is associated with said first and second incoming tunnels and said outgoing tunnel; said stored tunnel information defining said first incoming tunnel and said outgoing tunnel, including first and second tunnel end node addresses corresponding to first and second tunnel end nodes, respectively, the end nodes of said first incoming tunnel and said outgoing tunnel being the same, the first tunnel end node address being an address corresponding to said mobility management node, the second tunnel end node address being a destination address of the outgoing tunnel and a source address of said first incoming tunnel; and said stored tunnel information further defining said second incoming tunnel, including third and fourth tunnel end node addresses corresponding to third and fourth tunnel end nodes, respectively, the third tunnel end node address being the destination address of the second incoming tunnel and corresponding to said mobility management node, said fourth tunnel end node address being different from said first, second and third tunnel end node addresses and being the source address of the second incoming tunnel. 54. The mobility management node of claim 53, further includes: an update module for updating the stored tunnel information to change the destination address of the outgoing tunnel from said second tunnel end node address to another tunnel end node address, in response to another mobility management signal. 55. The system of claim 54, wherein updating the stored tunnel information to change the destination address of the outgoing tunnel does not affect the stored first incoming tunnel address information.