The Perfermance Analysis Of A Satellite Onboard Multicast Switch Fabric

With the populuation and development of the broadband networks, Internet must not only support the data, image, voice and video, but also must support the group users' interactive communication, which is referred to distributive video conference, remote internet courses and internet game. It takes more networks bandwidth using unicast to these services, so multicast is just the solution to the problem.Because of its characteristic of broad coverage, the satellite can support the distributive users in different areas to co-share the resource, which make the multicast communication very matchable to the satellite communication. For the GEO satellite network is viewed as a star subnet, the switching node onboard is one of the key to realize the multicast internetworking.Because the onboard equipments must have a small volume, a low power, and big switching capacity, an onboard shared-buffer switch fabric is proposed in this paper. Then a functional analysis of this switching fabric is presented. When utilizing the FIFO scheduling to the unicast and multicast in the same time, it is NP-hard to select an optimal output. So an alternative stragety is proposed to make one input port maintain 12 virtul queues, and multicast copy is non-splitinging. For the maximum capacity of the fabic is so big, the multi-layer fabic is present to solve the problem.At last, the queueing theory is adapted to perfermance analysis of the swiching fabric under unicast and multicast services. In queueing theory, this switching fabric is an input queue model. And the states of the queue in every input port can be modeled by the Markov Chain. Under different service the serving probability of one head of line is different, so a sevice distribution matrix is set up to calculate it. Then the analysis of the average throughput, the average time delay, the average delay jitter, and the cell loss probability is present. Since speedup of the swich schedulling can make an optimal performance of the fabric, so the scheme is analysing.