Session Initiation Protocol (SIP)

Session Initiation Protocol or SIP for short is used for controlling voice and video calls over Internet Protocol (IP) networks. As a signaling communications protocol, a SIP identifies messages that are sent between peers – these peers govern establishment, terminations and various other aspects of a call broadcast.

In addition to voice broadcasts, a SIP can be utilized in video conferencing, online stream distribution, instant messaging, fax over IP, online video games, and much more. Since its inception in 1996, SIP (Session Initiation Protocol) has been developed and standardized by the Internet Engineering Task Force (IETF).

SIP works in conjunction with the following protocols:

Session Description Protocol (SDP) – Media ID and negotiation
Real-time Transport Protocol (RTP) – Transmissions of voice and video media streams
Transport Layer Security (TLS) – Encryption to secure SIP messages