Research On Availability Model Of Control Element In The Forces Router

ForCES is one of the hottest architectures in routing area of next generation Internet. From the views of future popularization and industrialization, availability and stability of ForCES router should be paid more attention. As the core of ForCES router, CE抯 availability largely determines the whole availability of ForCES router. This thesis studies the availability modeling of CE.Firstly, this thesis introduces basic concepts of High Availability (HA) and CE HA requirements defined by ForCES relevant protocols. Then, this thesis proposes and analyzes various schemes of CE HA.Secondly, an instantaneous availability model is proposed, and the model is for the single master CE. The model extends 1+1 backup to 1+N backup system, but doesn抰 consider switching time. So this thesis modifies the model, and adds switching time into 1+1 backup system. Moreover, the simulation results show that switching time has greater impact on system availability in the early time.Finally, the thesis presents a model of steady-state availability for multiple master CEs. The model takes into account:the hardware/software failure model and the request loss model due to buffer overflow. However, the model is merely applied to load balancing. Therefore, this thesis amends the model, and makes the multiple CEs cluster divide into two different sub-clusters. And then two sub-clusters are synthesized by means of series to a multiple CEs cluster which achieves the distributed control function. According to the simulation results, a conclusion can be obtained which availability of the multiple CEs cluster of load balancing is greater than the cluster of distributed control. And availability of the cluster is closely related to the load types and division of sub-cluster.