Reducing delays related to NAT traversal in P2PSIP session establishments

This paper focuses on reducing the Network Address Translator (NAT) traversal-related components of the session establishment delay in peer-to-peer Session Initiation Protocol (P2PSIP) overlays. To reduce the delay, we propose to group the management of different connections so that the (time-consuming) NAT traversal procedures performed for one connection can be reused when establishing other connections. To do this, we propose to use the Host Identity Protocol (HIP) to perform connection management in P2PSIP overlays. In order to evaluate the performance gains resulting from this approach, we have implemented a P2PSIP system whose modular design allows us to build overlay networks with and without HIP and measure their differences in performance. Our experiments show that grouping the management of different connections results in a significant reduction in the session establishment delay in the presence of NATs.