Patent ID: 7039028

Claim:
A method for carrying out soft handoff of a mobile station from a first base station served by a first wireline subnet to a second base station served by a second wireline subnet, wherein each subnet has a link layer different than the link layer of the wireless network serving the mobile station, the mobile station has initially a first IP address compatible with the first wireline subnet, and each base station has a wireline link layer address, and wherein the first base station is served by a nearest router, the method comprising assigning by the first base station a shadow address for the mobile station, the shadow address corresponding to the mobile station, having a format compatible with the link layer of the first wireline subnet, and being distinct from said base station layer addresses and said mobile station first IP address. storing the first IP address and the shadow address in the nearest router, assigning a second IP address in the mobile station compatible with the second wireless subnet, communicating the second IP address from the mobile station to the nearest router via the first base station, and transmitting a frame containing a packet as conveyed by a sending device from the nearest router over the first wireline subnet to the first base station as determined by the shadow address and over the second wireline subnet to the second base station based upon the second IP address.