SIP协议是NGN中的重要协议，越来越得到业界的重视。本文通过SIP协议的背景、功能、网络元素、实现机制、以及SIP消



息的组成等几个方面对SIP协议做了全方位的概要性介绍，以使读者对SIP有初步的概念和认识。

-NGN in the SIP protocol is an important agreement has been more industry attention. In this paper, the background of SIP protocol, function, network elements, implementation mechanism, as well as the composition of the SIP message to the SIP protocol, and several other areas have done a comprehensive summary of introduction to make the reader there is a preliminary concept of SIP and awareness.