A METHOD FOR NOTIFYING A MOBILE TERMINAL DEVICE WHEN AN INTERWORKING FUNCTION TO WHICH IT IS CONNECTED BY A WIRELESS LINK CHANGES TO A NEW INTERWORKING FUNCTION

摘要

A mobile packet network call is established over a transmission link, extending between a mobile terminal device (12) and a given interworking function (18). The transmission link comprises a packet mode in which the traffic channel (32) is up and a dormant mode in which the traffic channel is down while the data link layer (26) link and the network layer (24) link are maintained. Network region identifier information is provided to the wireless communication device (14). The wireless communication device (14) determines when the given interworking function (18) 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 data link layer (26) link is then established with the second interworking function. The mobile terminal device (12) and the second interworking function then negotiate network control protocol options and establish a network layer (24) link. If the second interworking function corresponds to a new foreign agent, the mobile terminal device will then update its IP mobility registration.