Reliable and Scalable DHT-Based SIP Server Farm

Session initiation protocol has been widely deployed to enable multimedia communication. To guarantee service reliability and scalability, service providers usually deploy SIP server farms. In this paper, we present a reliable and scalable DHT-based SIP server farm. In the proposed server farm, one-hop DHT is adopted and a new SIP event package called SIEP (server information event package) is designed. In addition, a novel load sharing and failover scheme is designed based on one-hop DHT and SIEP. Compared with multi-hop DHT, one-hop DHT produces less overhead in DHT-based SIP server farm. Using SIEP, DHT routing hop number can be further reduced to zero in registration and intra-domain call setup process. Performance analysis shows the whole message overhead (overhead caused by SIP and DHT messages) can further reduce about 25% by applying SIEP. It´s proven that the proposed load sharing and failover scheme is effective, scalable and reliable even in dynamic environments. What´s more, it doesn´t increase the deployment and maintenance cost.