Distributed applications such as video conferencing require data to be transmitted to a group of destinations from a single source. Such applications can be implemented using multicasting. However in multicasting, if any one of the fixed members in the group can not satisfy the service requirement of the application, the multicast request is said to be blocked. This drawback of multicasting has paved way for the communication paradigm called manycasting, where in, the destination can join or leave the group dynamically, depending on whether it satisfies the service requirement or not. Manycasting over Optical Burst Switched (OBS) networks is Quality of Service (QoS) constraints based. These multiple constraints are in the form of noise factor, propagation delay and reliability of the link. Due to the consideration of multiple QoS constraints, there is a possibility of the request to get blocked. The algorithms for reducing the request blocking are called MulticonstrainedManycast (MCM) algorithms. In MCM-Nearest Destinations(MCM-ND), the burst data is transmitted from the source to the minimum nearest destinationsrequired for the manycast request. The destinations are selected among the candidate destinations on the basis of their shortest paths from the source,provided they satisfy the QoS constraints. However, if any of these primary destinations fail to satisfy the QoS constraints, the request gets blocked. On the other hand, in improved-MCM (I-MCM),all the candidate destinations thatsatisfy the QoS constraintsare available, out of which the minimum required destinations are chosen using genetic algorithm. Our simulation results show that, in most scenarios I-MCM performs better than MCM-NDin terms oflower average request blocking, thus making it useful for data as well as real time service applications.
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