Patent ID: 7085241

Claim:
A method of controlling routing of packets to a mobile node in a packet switching network including an infrastructure of packet switching nodes interconnected by packet transport links, and a plurality of access nodes to which a routing path, defined by routing protocol data held in packet switching nodes located along said routing path, may be directed in said infrastructure for a given network address, said method comprising: generating first routing protocol data for a network address used by said mobile node, said first routing protocol data specifying a characteristic of a first route passing through a first access node, said first access node serving said mobile node via a communications link; and in response to said mobile node receiving service from a second access node, generating second routing protocol data for said network address, by a routing defining process involving transmitting directed routing update messages to a limited number of said packet switching nodes, said second routing protocol data specifying a characteristic of a second route passing through said second access node, such that said first routing protocol data is held in a first set of packet switching nodes, and said second routing protocol data is held in a second set of packet switching nodes, different to said first set of packet switching nodes, so that the first and second routes co-exist in the packet switching network.