Deploy NGN VoIP Over A Data IP Network With Firewall

VoIP' s realtime transmission requirement to IP network conflicts with almost all current IT' s data network secruity policies, which requests the network being accessed by authorised sources and under control. At the same time, lots of data network are using NAT/PAT equipment to overcome the IP address limition. This also blocks direct implemenation of a VoIP system over existing IP network. This paper will lead you close to the NAT traversal solutions and approaches to ensure VoIP' s deploying effectively and safely, in the following aspects.Analyze IP telephony technologies, and understand the requirment to a VoIP system, highlight the issues need be resolved for a VoIP system.Introduce the common VoIP singling protocol and its carrier protocal with call flow, conclude those factors may influence system safety.Disscus some common data security technologies, such as traditional firewall system, NAT equipment, IP Sec VPN and VLAN, to analyze their features and utilization & possibilities to be used to protect VoIP system.Research NAT/PAT traversal solutions and their env & charcateristics, like ALG, STUN, MidCom, fullproxy and so on, propose some blended traversal solution for specific VoIP network environment.Treat VoIP as a kind of application running over IP network, its safety is hard to be archived by anyone simplex data security methods. While a VoIP project deploying, a whole view, systemic seurity structure & policies is the base, a security plan should be highlighted as well.Summarize the chief principles to be followed for VoIP structuring, look forward to an unified convergence IP core network in the future.