METHOD AND APPARATUS FOR MAINTAINING SIP CONTACT ADDRESSES USING EVENT SUBSCRIPTION

摘要

The present application describes various embodiments that address the need in wireless environments and within the SIP framework to efficiently maintain SIP contact addresses. It introduces the concept of a SIP proxy user agent (UA) (e.g., 123 or 124) to serve as a gateway between a SIP core network and a SIP-unaware mobile(101). A new message is described, a combined registration and event subscription message, which is used by SIP proxy UAs to both register a new contact address for a mobile and to subscribe to the mobile's contact information. By updating and subscribing to the contact information, a SIP proxy UA is notified of subsequent changes to a mobile's contact information. Registration and deregistration of contact addresses can thus be effected in a manner that allows SIP contact addresses to be more efficiently maintained.