Chapter 4. SIP Overview
In this chapter, we will introduce SIP. First of all, we will define some key concepts in the SIP framework, such as sessions and addressing. Then the main functions of the protocol will be presented. After that, we will describe the different SIP entities in the SIP architecture. We will also show a first example of how the SIP entities are involved in a basic SIP call.
What is SIP?
The Session Initiation Protocol is an application-level signaling protocol defined by the IETF in [RFC 3261] for the creation and management of sessions over an IP network. The term “session” refers to the media plane aspect of the communication—that is, to the exchange of media (e.g., voice, video, and so on) among an association of participants. ...