Research And Implement Of SIP Registrar Server In C Environment

Next Generation Network (NGN), in which various services, such as voice, video and data are provided, is the aim of today's telecommunication network. In the system of softswitch which is the key technique in NGN, the signaling protocols that can be utilized to establish and control a session play an important role and determine whether the ability of providing of services is strong or not. SIP constituted by IETF to initiate and control a session has great advantages in simpleness, opening and expansibility, so it has become the critical protocol of softswith. Research of registrar server that is one of the most important logical elements in SIP system is very necessary.SIP registrar is designed and implemented in C developing environment in this thesis. Firstly, on top of introducing the knowledge of softswith and SIP, the construction scheme of SIP registrar is fixed by technical requirements. Secondly, two kinds of registration flow are designed. Thirdly, according as the function of SIP registrar, the overall program of the stack of SIP registrar is designed and each layer of the stack is implemented in detail; an improved strategy of distribution is raised; the resources of data areas and buffer pools are designed; in order to optimize the system, HASH technique is applied; DIGEST authentication is applied to figure out the risk faced by SIP registrar; the performance of SIP registrar is enhanced largely by the application of the improved strategy of distribution and HASH technique.Passing the test both in function and in performance, the SIP registrar has been put into use.