Session Initiation Protocol (SIP)RFC3261 is one of the popular protocols used for the exchange of text, voice and video on Internet Protocol (IP) or next generation networks which happens in a client-server environment. The servers are used to provide centralised control of the entire network environment. While there are advantages for client-server environment, the servers create a single point of failure. This it not ideal for resource limited settings, such as in environments with limited Internet connectivity and infrastructure.
To avoid the use of centralised servers, the SIP community via the Internet Engineering Task Force (IETF), has been working on decentralising SIP by creating a Peer-to-Peer version of SIP called P2PSIP. In this thesis, we investigated the progress of this work. We also tested some of the implemented P2PSIP systems with the view of comparing how these systems have addressed various issues that need to be resolved before P2PSIP is declared a standard for decentralised SIP communication. We then went further to compare tested implementations using some of the designs decisions made in the P2PSIP working group. These comparisons helped us to choose two implementations, 39 Peers and SIP2P that can be used for research purpose, in particular within the Rhodes University Convergence research group.