Benefits of TLS for SIP

Session Initiation Protocol (SIP) signaling can be used over 3 transport protocols to include UDP, TCP, and TLS. UDP can be used because it is lightweight and quick nature of “fire and forget” packets. On the other hand, it is susceptible to spoofing. TCP requires a three-way handshake that prevents this issue along with adding benefits of an open connection that is used in almost every major protocol. The issues with signaling over TCP however, is that it’s slightly slower than UDP and foremost the information is presented in clear text. TLS (successor to SSL) takes the benefits of TCP and then adds encryption to provide security. SIP is normally used on port 5060, but secure SIP is used on port 5061 to identify its use of TLS.