Patent ID: 7487199

Claim:
A method for maintaining SIP contact addresses, the method comprising: receiving a first registration message for a remote unit from a first SIP proxy user agent (UA); storing, as an additional member of a group of contact addresses for the remote unit, both a first contact address based on the first registration message and a first creation timestamp for the first contact address; receiving a second registration message for the remote unit from a second SIP proxy UA after receiving the first registration message; storing, as an additional member of the group of contact addresses for the remote unit, both a second contact address for the remote unit and a second creation timestamp for the second contact address; receiving a third registration message for the remote unit from the first SIP proxy UA; sending, in response to the third registration message, a response that indicates a contact address more recent than any contact addresses provided by the first SIP proxy UA; receiving a deregistration message for the remote unit from the first SIP proxy UA; and removing, from the group of contact addresses for the remote unit, the first contact address.