Decentralized network connection preemption algorithms

Abstract

Connection preemption provides available and reliable services to high-priority connections when a network is heavily loaded and connection request arrival patterns are unknown, or when the network experiences link or node failures. Coupled with the capability to reroute connections Ž preempted due to failure or preemption., connection preemption allows a high quality of service to be provided to network connections and bandwidth to be used more efficiently. The main contributions of this paper are the following. It presents a comprehensive simulation study of preemption in a general connection-oriented network setting. Our simulation study also provides useful insights into connection preemption and network dimensioning problems in order to achieve a desired level of network availability. Based on the observations made in this study, we designed two connection preemption selection algorithms that operate in a decentralizedrdistributed network where individual link managers run the algorithm for connection preemption selection on their outgoing links. The first algorithm optimizes the criteria of Ž. i the bandwidth to be preempted, Ž ii. the priority of connections to be preempted, and Ž iii. the number of connections to be preempted, in that order, and has exponential complexity. The second algorithm optimizes the criteria of Ž. i the number of connections to be preempted, Ž ii. the bandwidth to be preempted, and Ž iii. the priority of connections to be preempted, in that order, and has polynomial complexity. From a comparison study of these two algorithms we conclude that the polynomial algorithm is almost as good as the exponential algorithm in terms of overal