实现非对称型NAT穿越的VoIP系统设计方案  

VoIP system design for non-symmetric NAT traversal

作　　者：孙昆[1] 孙斌[1] 赵振民[2] 

机构地区：[1]北京邮电大学计算机科学与技术学院,北京100876 [2]北京邮电大学信息与通信工程学院,北京100876

出　　处：《计算机应用》2009年第B06期13-14,29,共3页journal of Computer Applications

摘　　要：基于SIP的VoIP系统在Internet上已经取得广泛应用,但在企业网环境中,由于大量NAT设备的存在,端到端的SIP呼叫难以实现。分析了四类NAT的映射规则及其对SIP消息造成的影响,介绍了现有的NAT穿越方法,最后在STUN方式基础上提出了一种实现非对称型NAT穿越的VoIP系统设计方案。该方案在用户认证服务器和VoIP软终端上各开设一个端口侦听穿越请求,并对收到的包进行相应处理。经过校园网到企业网环境的测试证明该方案能达到很好的接通率。Session Initailization Protocol （SIP） -based VoIP systems have been broadly applied over Internet. However, as the board use of Network Address Translation （NAT） facilities, end-to-end SIP call becomes hard to realize in Intranet. This paper introduced the mapping rules of four types of NAT; then it analyzed NAT＇ s influence on SIP messages. After introducing the existing travcrsal methods, the author proposed a VoIP system design with the function of non-symmetric NAT travcrsal. This solution opened one UDP port on user authentication server and another on VoIP client respectively to listen traversal requirements, and dealed with received packages accordingly. Tests on campus and corporation environments show that this solution can achieve high performance.

关 键 词：网络地址转换 会话初始化协议 STUN 

分 类 号：TP393.09[自动化与计算机技术—计算机应用技术]