The Research And Design Of S-CSCF In IMS

To solve the problem how to provide IP multimedia service to mobile subscriber, As a result, IP Multimedia Subsystem occurs. Standard organizations like ETSI and ITU-T have already decided to use IMS architecture as next generation network's solution. The most important function entity is CSCF, which is responsible for handling multimedia session including session control, address translation and service negotiation. And S-CSCF is the core controller of IMS and the execution node for IMS session management, so the design of S-CSCF decides the performance of the whole IMS.Currently some famous telecommunication manufacturers have provided IMS solutions to customers, but because IMS related standards are in progress, so there is no mass business deployment worldwide now. The deployed IMS systems are all metropolitan applications according to collected technical solutions and documents. One of the important reasons is design defects of overload protection and redundancy mechanism in S-CSCF cause the whole IMS occur bottleneck.After researching IMS system architecture related technology and SIP&DIAMETER protocols, I have deeply grasp function of S-CSCF, based on which i designed S-CSCF system including hardware&software platform, software layer and module function and message defination. According to the defects and flaws mentioned above, i raised the concept of monitor point and control point for overload protection. For redundancy mechanism problem, ip redundancy, context sharing and serialized data communication and master/slave control function are the three related methods described in the contents to optimize the system.Through the test data of our system, we can conclude that the capability of overload protection and redundancy mechanism of S-CSCF is improved largely,and this kind of architecture can make message handling capability of IMS more stable and provide technical warranty for mass business IMS deployment.