Improving network performance with prioritized dispersal

Redundant traffic dispersal exploits the topological redundancy of networks and improves load balancing by replicating each message or partitioning it into several “data” packets and generating several “redundant” ones; all are then sent over different paths to the destination. The redundancy overcomes the “weakest link” problem, but increases the load. This paper introduces “prioritized dispersal”, whereby “redundant” packets receive lower priority than the “data” ones. Moreover, the use of non-FCFS queuing policies for the redundant packets leads to the timely arrival of at least a fraction of them even under heavy load. Queuing-theoretic analysis shows the new schemes to substantially outperform non-prioritized ones in terms of both the blocking probability and that of delay exceeding a specified limit. One possible use of prioritized dispersal, which is discussed in this paper, is to improve the quality of service for best-effort traffic in ATM networks with multiple paths between nodes. Another is in conjunction with ad hoc path trunking. Additional likely uses include parallel access to mirrored data sites and reliable multicast