Extending domain name service to support Internet telephony personal mobility

We propose a new approach that realizes the inter-operability between Domain Name System (DNS) and Internet Telephony Signaling System (ITSS) to support personal mobility of telephone subscribers. In traditional ITSS, when a user wants to initiate a call to a mobile user, DNS enquiries must be performed many times during call signaling. The time to locate a user might be long, resulting in high call setup delay. Thus, we propose to extend the domain name services to support personal mobility. This design allows telephone users to roam without modifying their identifiers and can reduce call setup delay. Our approach does not change the syntax or semantics of the DNS and ITSS messages, so it can be implemented incrementally, allowing for a graceful evolution from the current system to the new design.