Patent ID: 7110393

Claim:
A method for providing user mobility handling in a network telephony system, comprising in combination: receiving a register request from a network entity on a first domain, wherein the register request includes a user identifier, and wherein the user identifier is associated with a second domain; modifying the register request to form a modified register request, wherein the modified register request includes a modified user identifier, and wherein the modified user identifier is associated with the first domain; updating a registration database associated with the first domain to include the modified user identifier; transmitting the modified register request via a network to a network telephony server on the second domain; receiving a register response via the network from the network telephony server on the second domain, wherein the register response includes a challenge; transmitting the register response to the network entity on the first domain; receiving a challenge response from the network entity on the first domain; transmitting the challenge response via the network to the network telephony server on the second domain; and determining whether a confirmation is received from the network telephony server on the second domain.