HIP Node Reachability

Abstract

A method of configuring a plurality of rendezvous servers to provide a Host Identity Protocol, HIP, based mobility service to HIP nodes, where the servers are arranged in a hierarchical branching structure. For each HIP node, a Host Identity Tag, HIT,-and contact address mapping is registered with a rendezvous server ( 101 ). That server then identifies itself and the HIT to each higher level server within the same branch, without explicitly identifying the contact address to those higher level servers ( 103 ) wherein, in use, when a first rendezvous server receives a HIP contact message addressed to a given HIT ( 201 ), if that first server is unaware of the destination HIT, it forwards the message to a higher level server within the same branch ( 204 ), and if the first server is not the server at which the HIT is registered but is aware of the HIT, it forwards the contact message to the neighbouring rendezvous server corresponding to the HIT ( 203 ).

1 . A method of configuring a plurality of rendezvous servers to provide a Host Identity Protocol, HIP, based mobility service to HIP nodes, the method comprising:
 arranging the servers in a hierarchical branching structure;   for each HIP node, registering a Host Identity Tag, HIT, and contact address mapping with a rendezvous server, and identifying to each higher level server within the same branch the HIT and a neighbouring or other lower level server within the branch, without explicitly identifying the contact address to those higher level servers,   
       wherein in use, when a first rendezvous server receives a HIP contact message addressed to a given HIT, if that first server is unaware of the destination HIT, it forwards the message to a higher level server within the same branch, and if the first server is not the server at which the HIT is registered but is aware of the HIT, it forwards the contact message to the neighbouring or other lower level rendezvous server corresponding to the HIT. 
     
     
         2 . A method according to  claim 1  and comprising, following registration of a HIP node at a registration rendezvous server, sending a notification from that registering server to one or more other servers within the same hierarchical layer to identify to the other server(s) the HIT to contact address mapping for the HIP node. 
     
     
         3 . A method according to  claim 2  and comprising sending said notification to servers within the same geographic region as the registration server. 
     
     
         4 . A method according to any one of the preceding claims, wherein upon registration of a HIP node the registration rendezvous server sends notifications to other servers accompanied with a certificate verifying that the registration server is an approved server. 
     
     
         5 . A method according to any one of  claims 1  to  3 , wherein upon registration of a HIP node the registration rendezvous server sends notifications to other servers with which it has an established trust relationship. 
     
     
         6 . A method according to any one of the preceding claims, wherein said contact address is an IP address. 
     
     
         7 . A method according to any one of the preceding claims, wherein both the destination HIP node and the originating HIP node of said HIP contact message are registered with one of said rendezvous servers. 
     
     
         8 . A method according to any one of the preceding claims, wherein said step of identifying to each higher level server within the same branch the HIT and a neighbouring or other tower level server within the branch, comprises informing, each server above the server at which the HIP node is registered of the HIT and the identity of the registering server. 
     
     
         9 . A method according to any one of  claims 1  to  7 , wherein said step of identifying to each higher level server within the same branch the HIT and a neighbouring or other lower level server within the branch, comprises identifying to each higher level server in the same branch the HIT and an identity of the neighbouring server lower level server. 
     
     
         10 . A method of operating a HIP based network comprising a plurality of rendezvous servers configured according to any one of the preceding claims, the method comprising receiving an I1 HIP contact message at a rendezvous server and, if the rendezvous server is unaware of the destination HIT, forwarding the I1 message to a rendezvous server higher in the hierarchical server structure. 
     
     
         11 . A method of operating a rendezvous server for use in providing a Host Identity Protocol, HIP, based mobility service to HIP nodes, the method comprising:
 receiving a HIP contact message destined for a HIP node and, if the server is aware of the destination HIT, forwarding the contact message to a contact address associated with the HIT or to another rendezvous server associated with the HIT and positioned lower in a hierarchical rendezvous server structure and, if the server is unaware of the destination HIT, forwarding the contact message to another rendezvous server positioned higher in the hierarchical rendezvous server structure.   
     
     
         12 . A rendezvous server for use in a Host Identity Protocol, HIP, based network, the rendezvous server being arranged to register Host Identity Tag, HIT, to contact address mappings for HIP nodes and, upon registration, to inform one or more other rendezvous servers positioned higher in the hierarchical rendezvous server structure that it knows the contact address for the HIP node without explicitly identifying the contact address. 
     
     
         13 . A rendezvous server according to  claim 12  and being arranged at registration of a HIP node to inform one or more other rendezvous server within the same layer of the hierarchical structure of the HIT to contact address mapping. 
     
     
         14 . A rendezvous server according to  claim 13  and being arranged to send said notification to servers within the same geographic region as the registration server. 
     
     
         15 . A rendezvous server according to any one of  claims 12  to  14  and being arranged, upon registration of a HIP node, to send notifications to other servers accompanied with a certificate verifying that the sending server is an approved server. 
     
     
         16 . A rendezvous server according to any one of  claims 12  to  14  and being arranged, upon registration of a HIP node, to send notifications to other servers with which it has an established trust relationship. 
     
     
         17 . A rendezvous server according to any one of  claims 12  to  16 , wherein said contact address is an IP address.