【摘要】 SIP协议作为NGN的重要协议,广泛地应用于视频会议和IP电话中,但是由于SIP本身不支持穿越防火墙和地址翻译,大大限制了SIP的进一步发展。参照当前的SIP穿越技术,结合对SIP协议本身的分析,提出了一种采用应用层网关配合MidCom协议,能够透明地支持SIP穿越带防火墙的NAT和NAT_PT的方案。方案能够简单而有效地控制防火墙,透明地支持NAT和NAT-PT两边的互相呼叫,并拥有部署的灵活性。更多还原

【Abstract】 SIP is the important protocol of NGN, which is used in the net meeting and VoIP widely. But the limitation of SIP cannot traverse Firewall/NAT blocks the development of SIP. With the state-of-the-art techniques and the SIP protocol, a schema is proposed to support SIP traversing Firewall/NAT (-PT) transparently with the cooperation of SIP ALG and MidCom protocol. The schema can simply, effectively control firewall, and support bi-directional call traversing NAT (-PT) transparently. The schema also has the ability of deploy agility.更多还原