Evaluation of transport protocols for SIP signaling over IPv6 DVB-RCS satellite networks

With the proliferation of the Internet, voice over IP and multimedia communication become more and more important. One of the protocol that facilitated this development is Session Initiation Protocol (SIP). SIP is a signaling protocol which manages the session establishment and termination. It can be based on UDP or TCP at the transport layer. In this paper, the strengths and weaknesses of SIP over UDP and TCP are analyzed in satellite environment. The performance issues of SIP related to transport layer over the next generation protocol, IPv6, are studied. The experimentation is carried out on the satellite network testbed at Centre for Communication Systems Research (CCSR), University of Surrey. The results show that SIP performance on UDP is better than on TCP. SIP over TCP, requires more retransmissions due to the congestion control and flow control mechanisms of TCP, resulting in larger call setup time and bandwidth consumption.