Based On The Sip Protocol In Voice Gateways And H.323 Interoperability Study And Realization

With the rapid development of optical communication technology and digital transmission technology, both the bandwidth problem and QoS problem are no more the bottle-neck in data communication network.Consequently, promote the development of various real-time service in Internet. As a typical IP application, VolP gains much attention and development with the trend of broadband and real-time application.As a critical part of VoIP system, VoIP gateway are widely used to supply cheap VoIP application and value-added service based on Voip for various network subscribers.Two major technical standarand exist in the field of Voip at present, one is ITU-T recommendation H.323 and the other is the SIP proposed by IETEH.323 is put forward earlier than SIP and now is used widely. However, due to the merits of SIP such as flexibility, expansibility, the terminal equipments based on SIP have occupied more and more markets. Although H.323 protocol and SIP protocol can both construct IP phone network, the way they used are different and they can not be compatible with each other. So, the interworking between SIP and H.323 is the key factor to keep the VoIP development.The main purpose of the article is to research the communication between the different IP phone networks architecture, then we can design gateway which make communication between the different IP phone networks to solve a series of key problems such as user registration, session description, call sequence and so on.In order to implement the goal, this article does work as follow:1. Analyse the SIP protocol and H.323 protocol, realize their architecture and call flow. This is the basic of the design.2. Based on the call model and combine the characteristic of SIP and H.323,we design the call model which is independent on protocol.3. Research the media capability negotiation between SIP and H.323.4. Research the address translation and mapping between SIP and H.323.5. At last, the entire system is running in the router of Harbour Network Company, then we do the function test and profermence test based on the experiment environment.