The Obs Network Multicast Mechanisms And Algorithms

Due to optical network switching technology which isn't suitable for burst traffic in existence. Therefore, it proposes Optical Burst Switching (OBS)technology in order to solve burst problem. Optical burst switching has received a lot of attentions because it combines the benefits of optical circuit switching and optical packet switching and overcomes their shortcomings, is more efficient in the bandwidth statistical multiplexing and the reservation scheme. Meanwhile, IP multicast application becoming increasingly popular and meeting growing demands on bandwidth with the applications such as video-on-demand services and video-conferencing. Recently, it is more eminent to implement efficient multicast in WDM optical networks. Optical layer multicast is more efficient because first of all it can avoid"electronic bottle-neck"and take full advantage of WDM bandwidth, and can also make optical network to support more multicast application. According to the research status of optical layer multicast, one is based on wavelength routing, the other is based on OBS. The former specially suits traffic that go on so long, doesn't suit traffic that go on so short. However, the latter makes up the disadvantage of the former. The main motivation for considering optical burst switching(OBS) is that some traffic in broadband multimedia services is inherently bursty. Therefore, the research of optical multicast in OBS network has been a hotspot.In the paper, we mainly research multicast implement mechanism and algorithm for OBS networks, and propose a multicast algorithm which is called least redundant packets multicast tree sharing (LRP-MCAST-TS) algorithm. Whereafter, we make simulation of link utilization. Main contents of this paper is listed as follows:1. By analyzing deeply the switching machanism and network performance of OBS. In order to reduce redundant packets due to the TS-MCAST algorithm and effectively utilize link bandwidth, we propose a multicast algorithm for OBS networks by introducing tree patition mechanism, called least redundant packets multicast tree sharing (LRP-MCAST-TS) algorithm.2. In order to optimize the link of sharing tree. we simultaneously reseach multicast tree constructing protocol of multicast tree-sharing mechanism, so that it saves further link resource.3. Based on the proposed LRP-MCAST-TS algorithm , we make the simulation of link utilization in OPNET Modeler. Simulation results show that LRP-MCAST-TS algorithm can reduce the bandwidth consumption.4. In order to realize a reliable multicast, we research local retransmission mechanism by improving traditional retransmission of multicast.On the whole, there are the following contributions in the dissertation:1. We propose a multicast algorithm for OBS networks,called least redundant packets multicast tree sharing (LRP-MCAST-TS) algorithm.2. In order to solve packet loss and retramission problem, we research local retransmission mechanism in detail.