Disruption tolerance for SIP

The wireless networks have been built with versatile wireless network technology, including both wide area wireless networks and local area wireless networks. In such heterogeneous network environment, mobile users may experience either short or long interruption for different reasons while having a multimedia conversation. A lot of emphasis is concentrated on improving radio signal and enhancing seamless handover. However, recovery and backup multimedia conversation from a temporary network failure is also an interesting topic to be discussed. In this thesis, a SIP-based communication with enabling of disruption tolerance mechanism is introduced. We present the idea of media stream and SIP signaling based detection and recovery mechanisms, and come with an implementation of the prototype. The disruption tolerance functions include the ways of detecting network failure, storing the conversation during the meanwhile of the network disconnection, recover the previous broken multimedia session and replay the unheard voice. A brief experimental SIP network is built to evaluate the disruption tolerance functions of the software prototype. The result of the experimentation shows that the multimedia session can be recovered from the broken session in a short time, and the important conversation will not be lost during the short network disconnection. The replayed voice brings a delay to the recovered conversation which is not good experience for the users. However, the delayed conversation is much better than losing the conversation