Many applications of ATM networks require the multicast function, whic
h sends the same packet to a group of destinations. This paper propose
s an algorithm for multicast routing in ATM networks. We define the ne
twork cost of a routing as the combination of the cost of establishing
connections, the cost of overall bandwidth and the cost of overall sw
itchings. Our routing algorithm works on the original topology of ATM
networks with physical switches and physical links, and considers the
different switching functionalities of VP (virtual path) switches and
VC (virtual channel) switches in the networks. It generates an optimal
multicast routing with the minimal overall network cost. Simulations
have been done to compare the quality of the routing generated by our
algorithm with those of other major algorithms.