Date Added: Dec 2011
Securing VoIP is a crucial requirement for its successful adoption. A key component of this is securing the signaling path, which is performed by SIP. Securing SIP is accomplished by using TLS instead of UDP as the transport protocol. However, using TLS for SIP is not yet widespread, perhaps due to concerns about the performance overhead. This paper studies the performance impact of using TLS as a transport protocol for SIP servers. The authors evaluate the cost of TLS experimentally using a testbed with OpenSIPS, OpenSSL, and Linux running on an Intel-based server.