Study Of Communication Based On H.323

Technical development of network and computers, make the long range video meeting system that negotiates according to the TCP/ IP get the extensive universality in the application in the business enterprise of the distribute type management. For the sake of the business enterprise safety of the internal network of IP, the NAT will be installed at the exit of the network. And the NAT makes it inconvenience to communication over several video terminals in several LANs. The terminal behind the NAT can communicate any another terminal of the LAN to start the call sign, but can't receive the signal of the terminal (or is another behind the NAT) outside the LAN. There has been some articles talk about the tunnel technique that based on the HTTP to resolve this problem. This thesis emphasizes the solution of description as a kind of in general tunnel technique. This thesis does not limit at a certain protocol, but design a tunnel based on the whole H. 323, which aims at making the video correspondence more convenience.The tunnel solution is made of two modules, software of Server and software of Client. The Client put in the firewall of private net; the Server puts in public space out of the firewall. The communication between Server and Clients mainly pass two ports (can install according to the concrete circumstance of the network) for fixes to deliver the data, making the customer of the inner part carry to carry to build up an appropriation passage with the server in the DMZ area of the firewall exterior. The tunnel for the firewall is completely transparent. This thesis introduces the background knowledge of the firewalls concerning the H. 323 first. Introduced in chapter 2 currently several kinds solve the ways. It is emphasized to introduce the tunnel solution in chapter 3. Chapter 4 give the originally medium solution is in the coal business enterprise video meeting system of a physically applied and various test data. Chapter 5 discusses the safety of tunnel solution, and the direction of the further development...