Dynamic multicast routing for mobile networks

Multicast is a mechanism widely used in the Internet to disseminate information. Multicast delivery paths may need to be frequently restructured along with host migrations. But all existing multicast routing proposals implicitly assume static hosts when configuring the multicast delivery tree. The delivery trees established for static multicast cannot be changed easily or efficiently in all cases due to the propagation of these trees to many routers, and the potentially large cost associated with making changes to the trees' structure. This paper presents a dynamic multicast routing for mobile hosts. We first construct the multicast tree for static group members using the strategy based on shortest-path trees and minimal spanning trees but biases routes through group members. When establishing the tree for static members we adopt a specific cost function that combines link cost and nodes degrees, so that a maximum set of mobile receivers could join the tree later on with a minimum cost. The experimental results show that the algorithm proposed could find the multicasting tree with lower cost than the SPT does. Its performance also compares well other known heuristics.