Patent ID: 7177646

Claim:
A method of controlling packet routing in a single routing domain including an infrastructure of packet switching nodes using the same routing protocol and interconnected by packet transport links, and a plurality of access nodes to which a routing path, defined by 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: routing packets along a first routing path for a first network address in said single routing domain, which routing path is directed to a first access node serving a mobile node using said first network address via a communications link; handing over the communications link of the mobile node, such that a second access node serves said mobile node; altering said first routing path using a first type of routing update to create a second routing path for said first network address in said single routing domain, directed to said second access node; routing packets to said second access node via said second routing path; handing over the communications link of the mobile node, such that a third access node serves said mobile node; altering routing in said infrastructure using a second type of routing update, different to said first type of update, to create a third routing path for said network address in said single routing domain, directed to said third access node; routing packets to said third access node via said third routing path; altering said second routing path using said first type of routing update to create a fourth routing path for said first network address in said single routing domain, directed to said third access node; and subsequently removing said fourth routing path, while maintaining said third routing path.