Abstract
The shared tree established by the Core Based Trees (CBT) multicast routing algorithm is rooted at a center node called core. The core plays an important rote in the CBT. In this paper, the problem of selecting the location of the core for delay sensitive multimedia services is studied. Mean and maximum delays for the CBT using several core placement methods are compared by extensive simulations. Our results show that a good core placement method may significantly reduce the mean and maximum delay for the CBT. For some application services, nodes may be allowed to join or leave the multicast group dynamically. Our study shows that the method that produces the lowest maximum delay for the case where the multi-cast group members are static does not necessary produce the lowest maximum delay for the case where the multi-cast group members are dynamic. To accommodate the dynamic group membership, one may consider to periodically relocate the core according to the new group membership. We found that migrating the location of the core does not always produce better performance than keeping the location of the core fixed