VoIP信令协议SIP和H.323的比较

VoIP系统凭借其低廉的话费和较好的语音质量,已经成为重要的电信业务,并有取代传统长途业务的趋势.许多组织研究并制定了IP网络上呼叫的协议标准,但有两种IP电话信令和控制标准最具有影响力.一种是ITU推荐的H.323协议,另一种是IETF的SIP.这两种协议代表了解决同一问题的两种不同的方法:H.323是信令基于ISDN Q.931和早期推荐的H系列协议的传统的电路交换的方法,而SIP是一种支持基于HTTP的IP网络的超轻量协议标准.本文,我们主要针对SIP和H.323的体系结构,可靠性,复杂性,可扩展性,可伸缩性以及支持业务类型方面进行比较.

Comparing SIP and H.323

VoIP system by virtue of its low tariffs and better voice quality, has become an important telecommunica- tions business, and there is a trend to replace the traditional long-distance business. Many organizations have studied and instituted the IP network protocol standards to the call, but there are two IP telephony signaling and control protocols of the most influential standards. One is ITU recommendation H.323, and the other is the IETF SIP. These two protocols represent very different approaches to the same problem: H.323 embraces the more traditional circuit-switched approach to signaling based on the ISDN Q.931 protocol and earlier H-series recommendations, and SIP favors the more lightweight Internet approach based on HTTP. In this paper, we compare SIP and H.323 on system construction, dependability, complexity, extensibility, scalability and supported services.