针对SIP的STUN解决方案的设计与实现

Implementation the Traversing of NAT in SIP-based VoIP System

SIP是一个基于文本的应用层协议,但SIP协议本身无法实现让SIP消息安全地穿过NAT和防火墙。从SIP消息的特点出发,提出一种无需扩展SIP协议的应用层解决方案,引入STUN协议,取得IP地址和端口的映射关系,修改SIP和SDP消息的内容来保证通信连接,从而实现对NAT的穿越。

SIP is a text-based application-layer protocol. It can/t be used in NAT or firewall environment. According to the specialties of entities of SIP messages, an application layer solution without expanding SIP, by achieving the mapped relation of IP address and Ports with STUN and overwriting the SIP messages and SDP messages to assure the communication connection are presented. In this way the system can implement the traversing of the NAT.