SIPCache: A Distributed SIP Location Service for Mobile Ad-Hoc Networks

Internet-based communication is currently in a hype. People utilize Internet services more and more to communicate with each other, e.g., via VoIP or chat. The next step would be to reutilize the same applications to achieve ubiquitous communication, anytime and anywhere, also where network support is not available, such as in ad-hoc networks. Existing Internet protocols must be modified for working in the ad-hoc server-less environment. The session initiation protocol (SIP) is a fundamental element in the Internet for establishing multimedia communication sessions. However, SIP cannot be used in ad-hoc networks, as it relies on the support of SIP servers in the network; e.g, in ad-hoc networks it is not possible to locate SIP users since the assistance of a dedicated SIP server is missing. A solution for this problem is presented in this paper which describes and evaluates a fully decentralized mechanism for locating SIP users in ad-hoc networks