Softswitch A Number Of Key Issues In Technology Research

With the rapid development of communication network technology,the convergence of conventional PSTN/ISDN and IP network has becomean inexorable trend. And the softswitch technology, which is based onnext generation network (NGN), can seamlessly implement thisconvergence, which has also become the focus in industry study. Withsoftswitch technology, the maximum protection will be given to theexisting investment of telecommunication network and the smoothtransition from the existing telecommunication network to NGN will beaccelerated. That is, we can easily achieve the inter working ofconventional PSTN/ISDN and with no impact on the services of theexisting network.The softswitch is the core technique of NGN. This paper emphasizeson security of softswitch technology communications protocol, NATtraversal based on SIP protocol, Media Gateway based on softswitch. Inthis paper, the status and problems of the softswitch technique areintroduced, the softswitch network of softswitch technology is alsoanalyzed, and key points of softswitch technique are proposed, such assecurity, traversal of NAT and Media Gateway.For the security of softswitch technology communications protocol, anew method to enhance the security of SIP is proposed based on theanalysis of secure problems and countermeasures, and the LAX protocolof open source Asterisk is also improved. For NAT traversal based on SIPprotocol, a strategy of SIP traversing the double symmetrical NAT ispresented by researching signal stream and the process of SIP. For MediaGateway, a new one is designed, which is based on the function of MediaGateway and the theory of adaptive variable-rate coding. It can adjust ratecoding by network condition and satisfy the requirement of VoIP.At last, three key questions of the softswitch technology have beensummed up and the futures are prospected.