Research And Implementation Of High Availability SoftSwitch

The telecom system always pays much attention on High availability. The Class 4 and 5 switch in traditional telecom system has already achieve High Availability.As the core equipment of NGN,the Softswitch must run with High Availability. However,because of the complication of HA technology and the lack of open description, the methods to implement a HA system in Softswitch equipment becomes our research focus.Through the study of HA technology,we can master the basic conception and implementation of HA system.So that we can design and research the implementation of a HA system and conclude a set of solutions.The overall system framework which is built on the open architecture HA solution provided by HA forum is discussed,and also the HA implementation of application layer,OS layer,hardware layer and most important,the HA manage middleware.In the course of design, characteristic of the universal hardware platform have been completely analyzed from the point of view of high availability, such as the ability in hot swapping, inter-communicating, fault detection and control. With the fact that high availability is composed by hardware and software reliability and maintainability, one way to realize high availability is to improve software reliability and combine hardware redundancy and software maintenance, so as to get the ability to deal with hardware fault and improve the availability of application layer. And the design of the HA manage middleware and Fault detect mechanism are discussed detailedly.And some critical technology,including heartbeat,watchdog,and redundancy of N+1module is deeply researched. Finally, the result of the analysis of high availability in logic and performance shows that the whole solution has been proven to be able to achieve the goal of high availability.