SIP, which stands for Session Initiation Protocol, is a communication protocol for signalling and controlling multimedia communication sessions.
It falls under the bracket of being an Internet Engineering Task force standard that is used to create, modify, and terminate sessions with one or more users.
SIP is most commonly used in Internet telephony for voice and video calls, in addition to instant messaging over IP networks.
The protocol works by defining the messages that are sent between endpoints, these govern establishment, termination, and other elements of a call.
