摘要： 在多进程的VoIP 网关中，需要识别不同的SIP 包，判断是否需要穿越NAT，该文参考SIP 的ALG 草案，将下层的SIP 消息发送到应用层来进行识别区分，将需要穿越NAT 的SIP 消息修改后转发出去，而不需要穿越NAT 的SIP 消息就不作处理，直接转发。该方案无须扩展SIP 协议，就实现了在多进程的VoIP 网关这样的应用场景下的多路SIP 会话。
关键词:
oIP；SIP；NAT；ALG
Abstract: It needs to judge whether needs to through NAT in multi-process VoIP gateway. This paper refers to the SIP ALG draft which describer an application level gateway (ALG) for the SIP. It parses the SIP message in application-layer, and modifies SIP messages which need to through NAT. This scheme implements multi-session in multi-process VoIP gateway, no extension of the SIP.
Key words:
VoIP; Session initiation protocol (SIP); Network address translate (NAT); Application level gateway (ALG
徐静华，左冬红，潘 鹏，叶 婷. 多进程 VoIP 网关中SIP 穿越NAT 的实现[J]. 计算机工程, 2006, 32(1): 145-147.
XU Jinghua, ZUO Donghong, PAN Peng, YE Ting. Implementation of SIP Through NAT in Multi-process VoIP Gateway[J]. Computer Engineering, 2006, 32(1): 145-147.