| When we study a signaling system,the important aspect is to analyse it' s function,it' s signaling messages.it' s system timer.it' s number plan,and interworking with other signaling networks.Every signaling system has it' s own characteristics due to the signaling classify organization,the date about declaration,the difference of the networks to apply,a protocol family work together to perform the function of the network signaling function. The difference is from the realization,based on different hardware networks.it' s physical layer radically result in the difference of the protocol stacks,for example,a system based on El and a system based on ethernet network.With the needs of application,the inosculation of networks becomes mainstream,especially the inosculation of signaling networks. The inosculation of traditional telephony network based on circuit-switch (SCN) and IP network based on packet-switch (PSN) unfurls a huge developing space to us. The Softswitch is the core technology of the next generation network,for it can be the core to offer calling,control and service for voice service,data service and video service in the next generation network,and it also plays the key role in the evolvement of SCN to the PSN. In our country,the Network and Switch Standard Research Force has finished the technology required frame in the mass of our country' s Softswitch system ,and serviceproviders are experimenting on it actively,the deviceprovides are fetching out devices in succession. The interwoking of ISUP,INAP,wireless access,SIP,H. 323,MGCP,etc,is the foundation for us to realize the core device of the Softswitch. But the NGN can' t replace the former voice network based on circuit-switch,the former telephony network will be existing for a long time. Thus we need technology that can not only construct new packet-based networks ,but can realize the inosculation of the traditional telephony network and the new networks. On one side we want to design a new network,on the other hand we must provide the services that have been provided in the traditional telephony network,and can only do it better. So in final sense,what we want to do is to realize the interworking of different signaling system.In ITU and IETF,there are relevant work force engage in the interworking Specially. In the middle of 1990' s,some international large-scale companies have entered on thinking over how to make use of Internet technology to endue new features for the popular POTS,and have constructed their own prototype systems(for examples,the network call center of Siemens' ,the IN bearing system,and so on. ),and later be called by a joint name Pre -PINT appliance system. In Jul 1997,IETF was initiated by the Bell lab,and erected up the PSTN Interne (PINT) interworking force aimed to make the IP users to use the traditional services of the PSTN by the most popular WWW application and research the network framework and protocols that provide this function. In Sep 1997,ITU- T SG11 erected up the,Signaling Of Internet special topic force.In this paper,we research the interworking of SIP and MGCP in the Softswitch system mostly,the primary working contents and results are as follows: research scope:There are many versions of SIP and MGCP currently,we only work onthe bases,the difference of each version is not discussed in this paper. And aboutthe questions of counting ,QOS,security ,etc,are not discussed in this paper,leftfor further study. Orientation of this paper:The primary protocols using in this paper:RTP,RTCP,SDP,SIP,MGCP.RTP equals the Transport Layer of OSI (RTP usually works over UDP,they work togetherto perform the function of Transport Layer' s).RTCP equals the Session Layer of OSI.SDP equals the Presentation Layer of OSI.SIP and MGCP equals the Application Layer of OSI.So from the point of view of communication,this paper is to realize the interwoking of signaling in the IP side and signaling in the PSTN side;from the point of view of OSI,this paper is to realize the interwo...
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