Dynamic Discovery of Home Agent With Specific Binding

• US 20080291867A1
• Filed: 10/10/2006
• Published: 11/27/2008
• Est. Priority Date: 10/21/2005
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Weniger, Kilian, Bachmann, Jens
• Granted Patent: US 8,345,593 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• 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 8/04 Registration at HLR or HSS [Home Subscriber Server]
• CPC Class Codes: H04W 8/082 for traffic bypassing of mobility servers, e.g. location registers, home PLMNs or home agents
• CPC Class Codes: H04W 8/12 between location registers or mobility servers
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]

Abstract

The invention relates to a method for obtaining a home node address in a packet switched network comprising nodes. The method comprises the steps of a first node sending to a first home node of a home network a request containing information about a home address of a mobile node to determine whether a binding with said home address indicating a registration of said mobile node at the first home node exists; the first home node receiving the request, said first home node comprising a stored binding table; determining whether the binding with said home address exists in any home node of the home network; and if the home address of the mobile node is in the binding table of any of the home nodes in the home network, the first node receiving a reply comprising the address of the home node with said binding.

Claims

1-40. -40. (canceled)

41. A method for obtaining a home node address in a packet switched network comprising nodes, the method comprising the steps of:

a) sending by a first node to a first home node of a home network a request containing information about a home address of a mobile node to determine whether a binding with said home address indicating a registration of said mobile node at the first home node exists;

b) receiving the request by the first home node, said first home node comprising a stored binding table;

c) determining whether the binding with said home address exists in any home node of the home network; and

d) receiving by the first node a reply comprising the address of the home node with said binding, if the home address of the mobile node is in the binding table of any of the home nodes in the home network.

42. The method according to claim 41, wherein the registration is a Mobile IP, SIP, HIP, or mobile registration, and

wherein the first home node is a Mobile IP home agent or a SIP server or a HIP rendezvous server or a mobile server or a mobility anchor point or an access router, and

wherein the first node is a mobile node or a Mobile IP home agent or a SIP server or a HIP rendezvous server or a mobile server or a mobility anchor point or an access router.

43. The method according to claim 41 wherein step c) comprises searching the binding table of the first home node for the home address of the mobile node.

44. The method according to claim 41, wherein step a) uses an unicast address as destination address.

45. The method according to claim 41 wherein multiple requests are sent to different home nodes using different unicast addresses and multiple replies are sent by different home nodes.

46. The method according to claim 44, wherein said unicast addresses are determined by a prior request and reply exchange or by a DNS request and reply exchange.

47. The method of claim 44, wherein the unicast address of the first home node is determined by a mapping function between the home address of the mobile node and the first home node address.

48. The method of claim 41, wherein step a) uses an anycast address as destination address;

all home nodes being configured with the anycast address, or

wherein step a) uses a multicast address as destination address;

all home nodes are configured with the multicast address.

49. The method according to claim 41 further comprising the steps of:

e) searching by the first home node in its binding table and in an additional pre-established backup binding table for the home address of the mobile node, with the backup binding table containing bindings stored in other home nodes belonging to the same home network as the first home node; and

f) sending by the first home node to the first node a reply comprising the address of a second home node with the specific binding.

50. The method according to claim 41 further comprising the step of

g) forwarding the first node'"'"'s request to other home nodes in the home network if the home address of the mobile node has not been found in the binding table of the first home node.

51. The method according to claim 50, wherein step g) uses broadcast, unicast or multicast.

52. The method according to claim 48 further comprising the steps of:

h) receiving by a second home node the forwarded request;

i) searching by the second home node in its binding table for the home address of the mobile node; and

j) sending by the second home node a reply directly to the first node.

53. The method according to claim 50 further comprising the steps of:

h) receiving by a second home node the forwarded request;

i) searching by the second home node in its stored binding table for the home address of the mobile node; and

k) sending by the second home node a reply to the first home node.

54. The method according to claim 53 further comprising the steps of

l) receiving by the first home node the reply from the second home node;

m) sending by the first home node to the first node a reply comprising an indication that the specific binding exists in the binding table of the second home node.

55. The method according to claim 41, wherein the request and/or reply messages are Mobile IP Home Agent Address Discovery requests and/or reply messages.

56. The method according to claim 55, wherein the address of the home node storing the specific binding is communicated to the first node by a source address field in an IP header of the Home Agent Address Discovery reply, if the sender of the reply is storing the specific binding, and a new flag in a reserved field of the Home Agent Address Discovery reply message is added for indication thereof, or

wherein the address of the home node storing the specific binding is communicated to the mobile node by adding it to the binding list in the Home Agent Address Discovery reply message and adding a new flag to a reserved field in the Home Agent Address Discovery reply message for indication thereof.

57. The method according to claim 41, wherein the request of step a) contains the home address or a compressed value of the home address.

58. The method according to claim 57, wherein the home address of the mobile node is compressed by applying a hash function.

59. The method according to claim 58, wherein the compressed home address is transported in the identifier field of the Home Agent Address Discovery request message.

61. The method according to claim 58, wherein the first home node searches the binding table for the specific binding by, for each binding table entry, applying the hash function to the home address in the entry or to the concatenation of the home address in the entry and the source address of the request message and comparing the resulting hash value with the identifier field in the request message.

62. The method according to claim 61, wherein the first node concludes that a hash collision exists if multiple replies indicating different home node addresses or one reply containing multiple different home node addresses are received.

63. The method according to claim 62, wherein the first node and first home node have a pre-configured ordered list of hash functions which are used to compress the home address of the mobile node in subsequent request/reply messages in order to resolve the hash collision, or wherein the hash collision is resolved by including the home address of the binding found in the binding table in the reply message.

64. The method according to claims 62, wherein the hash function is a keyed hash function and the ordered list contains different keys, and

wherein a hash function index field or hash key index field in the reserved field of the Home Agent Address Discovery request header indicates a specific hash function or hash key used.

65. A system for obtaining a home node address in a packet switched network comprising nodes, the system comprising:

a first node adapted to send to a first home node of a home network a request containing information about a home address of a mobile node to determine whether a binding with said home address indicating a registration of said mobile node at the first home node exists;

the first home node being adapted to receive the request and comprising a stored binding table;

the first home node further being adapted to search in the binding table for a home address of the mobile node; and

the first node further being adapted to receive a reply comprising the home node address with said binding, if the home address of the mobile node is in the binding table of any of the home nodes in the home network.