Research And Implementation Of VoIP Gateway Based On SIP And Its Security

As far as we know,VoIP is the future of voice communication.Voice communica-tion based on Next Generation Network will replace the circuit switch network.DespiteVoIP has provided many advantages, replacing all the circuit-switched telephone withVoIP is not practical,traditional circuit-switched network (PSTN) and packet switchingnetwork will also coexist for a long time.In addition, VoIP also has a number of poten-tial security issues,and domestic companies lack of knowledge of information securityin deployment of VoIP equipments.So,it is very important to develop a device withsecurity to achieve a seamless connectivity between PSTN network and IP network.This thesis introduces the design and implementation of a VoIP Gateway based onSIP protocol(The SIP has been defined by IETF) in detail.The implementation involvesa new method of encrypting SIP signaling.The gateway is capable of supplying safecommunication between SIP phone and telephone.Firstly,the thesis introduces the signal principle within PSTN,the principle of NGNand Soft Switch,and then,focus on the principle of SIP and its process.The designscheme of VoIP Gateway based on SIP is also presented by analyzing principle of callprocess both in IP and PSTN.Thirdly,tailored hardware implementation and interfaceis laid out based on the functionality requirements of VoIP gateway.The thesis focuseson the implement of the Gateway software and SIP signaling encryption,covers theconversion between SIP signaling and PSTN signaling code during the realization ofSIP and RTP stack.Finally,the thesis concludes the process of test and test results ofVoIP Gateway,which shows its good performance.