A P2PSIP event notification architecture

Abstract—This paper presents a P2PSIP notification architec-ture, where a traditional SIP notification server is replaced by a P2P overlay network for enhanced scalability, redundancy, as well as failure and recovery features. At the same time non-overlay SIP user agents continue to transparently access the overlay as they would in a centralized SIP notification architecture. The proposed mechanism is implemented with a structured P2P overlay network, an application level multicast protocol, and an accompanying modified SIP stack that allows the invocation of the P2P functionality. Not all the overlay peers need to have a SIP stack; only the ones acting as gateways to out of overlay SIP requests. Internally the application level multicast protocol distributes and decentralizes the entire notification process in terms of publications, subscriptions, and notifications. Finally, our proof of concept implementation is presented. I