本文首先介绍了IP电话的定义、业务类型、结构以及语音通信协议ITU - T的H。323系列和IETF的会话初始化协议(SIP)。

This paper firstly introduces the definition, operation type, instruction and voice communication protocol including H. 323 of ITU-T and Session Initiation protocol (SIP) of IETF.

youdao

目前，会话初始协议(SIP)大部分认证机制只提供了服务器到客户端的认证，HTTP摘要认证便是其中的一种。

At present, most of the session initial protocol (SIP) authentication schemes only provide client-to-server authentication. And HTTP digest authentication is one of them.

youdao

会话初始化协议(SIP)是IETF提出的IP电话呼叫信令协议，是一个基于文本的协议，用来创建、修改和终止多媒体呼叫与会话。

SIP is proposed by IETF as IP phone call order protocol which is totally a text modality that to be used to establish, modify and terminate multimedia calls and conversation.

youdao