Peer-to-Peer Session Initiation Protocol in Highly Volatile Environments

The session initiation protocol (SIP) is an IETF standardised protocol for multimedia signalling and communication over the internet. SIP has been used in many deployments in client-server architecture. However, this configuration potentially possesses various scalability and redundancy limitations because its architecture relies on various centralised components. To overcome some of these limitations, there has been various proposed architectures for using SIP in a fully decentralised manner with minimal or no centralised authorities. One of these proposed architectures is known as peer-to-peer SIP (P2P-SIP), which uses structured p2p overlay networks to lookup and locate SIP resources over the Internet. In this paper we investigate P2P-SIP in a broader perspective beyond the Internet, focusing on the effects of mobility on this approach especially in highly volatile environments in which the underlying p2p overlay never fully converges or stabilises. Our experimental results shows that P2P-SIP systems using CHORD deployed in these environments are highly scalable. But more interestingly, we also show that as the number of peers in the system increases, the signalling overheads per peer in the overlay tends to decrease.