Method and program recording media for controlling seamless vertical roaming between a wireless local area network and a wireless wide area network in a personal communication unit

摘要

The present invention relates to a method for controlling a seamless vertical roaming personal information device with a wireless modem and the wireless LAN device is mounted. Roaming control method according to the present invention includes receiving the IP address allocated by the external agent (FA) in a connectable wireless LAN using the DHCP client, the method comprising: transmitting a mobile IP (MIP) request message to the FA, MIP notification message from the FA the method comprising: receiving, sending a MIP registration request message to the FA - to claim 1 MIP address from, FA - where, FA forwards the MIP registration request message to the home agent (HA) and a first 1 MIP address from the HA receiving receiving, - wherein the first MIP address is stored in the filter, FA is the first registering the MIP address to the HA-, determining deviated an area of ​​the WLAN (Hot spot), it is determined that, the radio the method comprising if nateu off the WLAN area, and connected to the PDSN PPP session in the radio network at the same time to shut down the drive by using a dial-up networking, a wireless modem of the wireless LAN device, and receiving a claim 2 MIP address from the PDSN - include - Here, the MIP address 2 is assigned by the HA corresponding to claim 1 MIP address, stored in the filter, the PDSN registers the MIP address to the HA claim 2.