Telecommunications Network. Softswitch Megaco Protocol Fault Tolerance And High Availability In The Design And Realization

The Soft Switch network architecture, which is based on IP/ATM technology, can satisfy the requirement that multiple services including voice, data, multimedia, etc; and can be easy to provide the powerful capability to support various new value-adding service. So Soft Switch technology is becoming the main choice of NGN (Next Generation Networks).Any critical telecom system would give a highest requirement to the FT/HA (Fault Tolerance/High Availability). It means so much to the FT/HA implementation of the hardware/software components --especially to the latter ~ in the Soft Switch network architecture, which consists of lot of protocols and is implemented mainly by software.In this dissertation, the details about Soft Switch network architecture are introduced, and the decomposition of gateway in the Soft Switch network is described in further. Then we demonstrate MEGACO protocol, which is a Soft Switch core protocol running on WACOS access gateway and need a FT/HA implementation, in details.Based on the detailed analysis on the current main HA technologies and the HA architecture in WACOS gateway, which is a typical Soft Switch network device, and considered the characteristics of Trillium's implementation of HA and protocols, the dissertation presents a warm-standby HA design based on PSF (Protocol-Specific-Function) information update mechanism.In this HA design, the PSF module is divided into three sub-modules including the core control sub-module, the state update sub-module and the system agent sub-module. Then all the interface functions are well defined and the critical data structure is given. Finally the flow of related state information update procedure is designed and all the function primitives are defined and implemented.At the end of this dissertation, a general HA test platform used for PSF mechanism and a cluster of considerate test cases, which are specific to MEGACO FTHA, are given and executed in a simulation environment. The test result is fairly successful.The major meaning provided in this thesis is that it provides a HA design and implementation based on PSF information update mechanism, and implement the fault tolerance function of MEGACO protocol stack, complete the integration of Trillium's MEGACO product, which is a typical distributed telecom software, and WACOS HA manager. The HA design has a general framework that is independent from the actual protocol stack or other telecom application software module, and can give a reference to the HA design of related protocol and telecom software product as well.