Performance Evaluation Of The Multicast In All Optical Networks

In all optical networks, the optical signal is all-optically transmitted from the source to the destination. Compared with the traditional opaque optical network, the all optical network is more flexible, transparent and is sure to be the one of the best solutions for the next generation broadband (or ultra-broadband) network. At the same time, as the emergence of new application such as IPTV, how to support multicasting services in all optical networks becomes an important and challenging topic.According to the switching granularity, the all optical network can be divided into three types:optical circuit switching(OCS), optical burst switching(OBS) and optical packet switching(OPS).Among them, the OPS is still immature and unfeasible to be commercially deployed due to the limitation of optical processing and buffering technologies. So this paper will mainly investigate the multicasting under the other two switching schemes. In order to construct an all optical multicasting tree in the all optical network, wavelength continuity constraint and node splitting capability need to be considered during the RWA. Moreover, in the OBS, burst aggregation is performed and accordingly two different multicasting schemes are proposed, namely separate multicasting and tree-shared multicasting. Separate multicasting is a straightforward scheme, in which each multicasting session constructs its own multicasting tree along which the assembled multicasting data bursts consisting of the traffic only for that session are delivered. On the contrary, in the tree-shared multicasting, all multicasting sessions are mixed together to form a burst that is then delivered by a shared multicasting tree due to a certain overlap degree. These multicasting sessions share a common BHP and GBs, which can reduce the waste on bandwidth and improve the bandwidth usage.In order to evaluate the performance of various multicasting schemes in above, an all-optical network simulation platform enhanced with optical multicasting was implemented based on NS2 tool. During the simulation, we design some simulation platforms to support the multicasting in OCS and OBS which includes separate multicasting and tree-shared multicasting schemes. After the simulation, we obtain some results on the network resource usage, transmission latency and packet lossrate/blocking rate. Finally, we analyse and compare the simulation results, and also make a summary from these results, then some proposals for further research are presented.