【摘要】 对网络地址转换(NAT)及H.323呼叫过程进行了深入分析,H.323系列协议和应用依赖于端到端的网络,数据包不加修改地从源地址发送到目的地址.在NAT或防火墙的网络中,由于需要对协议的端口和地址进行转换或过滤,经过修改的地址与数据包载荷内容不符,导致H.323呼叫不能正常进行.采用应用层网关模型,对NAT进行应用层扩展,提出了在使用NAT网关情况下H.323的跨网关呼叫的几个有效解决办法.更多还原

【Abstract】 Some efficient solutions for making H.323 call through network address translation(NAT) gateway are proposed in this paper. The H.323 protocol packets are unmodified from the source to the destination in end-to-end network. However, the port and IP address of these packets will be modified when they pass through the NAT gateway. The modified packets address cannot match the calling address in the H.323 protocol packets. This will result the H.323 call abnormal. We present some efficient methods to solve this problem by extending the ALG (application layer gateway) model.更多还原