Communications system, mobile node apparatus, and method of performing a handover

摘要

A communications system comprises a first network node (102) and a second network node (110). A mobile node (108) attached to the first network node (102) hands over from communicating with the first network node (102) at a link layer (208) of a protocol stack to communicating with the second network node (110) by performing a link layer handover procedure. Thereafter, the link layer (208) of the mobile node (108) interrogates incoming packets to identify a router advertisement packet (300) broadcast by the second network node (110). Upon receipt of the packet (300), the link layer (208) modifies the packet (300) to include trigger information (518) in an IPv6 Destination Options Extension Header (508). The packet (300) is then passed up the protocol stack to a network layer (210) thereof, where the modified packet (300) is recognised as containing the trigger information (518) and a network layer handover procedure is initiated in response to receipt of the modified packet (300).