Routing multiservice traffic in ATM networks

A routing algorithm is proposed for multiservice ATM networks. It is based on a previously proposed algorithm to which significant modifications have been made. The routing algorithm is currently being verified by simulation, but some preliminary comments are made in this paper. Effective bandwidth calculations are assumed to be performed by the network and the routing algorithm must balance the load against a background of long and short-term call-level traffic fluctuations. The previously proposed algorithm, minimum loaded path (MLP), computes routes for new calls based on average bit-rates of calls and global knowledge of the network status. The adapted algorithm uses effective bandwidths as the basis for routing decisions, and uses flooding to provide each node with knowledge of the network status. The algorithm requires that updates are flooded frequently for effective performance, particularly if the traffic is dominated by short-duration calls. The algorithm performs well at moderate loads but poorly at heavy loads due to the unrestricted use of long, alternative paths. Several different techniques have been proposed to avoid this problem in other network environments, and one or more of these could be adapted for use with the new algorithm. (7 pages)