Notifying a mobile terminal device of a change in point of attachment to an IP internetwork to facilitate mobility

摘要

A mobile packet network call is established over a transmission link, extending between a mobile terminal device and a given interworking function. The transmission link connects the mobile terminal device to a wireless communication device over a first interface and further connects the wireless communication device to the given interworking function over a second interface via a wireless link to a base station. The transmission link further comprises a packet mode in which the traffic channel is up and a dormant mode in which the traffic channel is down while the data link layer link and the network layer link are maintained. Network region identifier information is provided to the wireless communication device. The wireless communication device determines when the given interworking function has changed from a first interworking function to a second interworking function by determining when there is a corresponding change in the network region identifier information. The wireless communication device initiates a link control protocol renegotiation with the mobile terminal device when the corresponding change in the network region identifier information has been determined. The mobile terminal device responds to the initiation of the link control protocol, and causes the transmission link to enter the packet mode, and to bring up the traffic channel. The data link layer link is then established with the second interworking function. The mobile terminal device and the second interworking function then negotiate network control protocol options and establish a network layer link. If the second interworking function corresponds to a new foreign agent, the mobile terminal device will then update its IP mobility registration.