A new approach for delay-constrained routing

Delay-constrained routing protocols are used to find paths subject to a delay constraint while efficiently using network resources. Many of the delay-constrained routing protocols that have been proposed in the literature give priority to cost minimization during the path computing process. With this approach, paths with end-to-end delays too close to the delay constraint are obtained. We believe that such paths are prone to delay constraint violations during load variations in the network. The root of such violations can be found in the imprecision of delay information during the routing process. In this paper, we propose a new approach for delay-constrained routing which captures the tradeoff between cost minimization and the risk level regarding to the delay constraint. We propose a protocol called Parameterized DelayConstrained Routing protocol that implements our approach using a simple and efficient parameterized selection function. We expand this work to multicasting by proposing three new delay-constrained multicast routing protocols based on the source (Naı̈ve), destination (Greedy) and mixed multicast routing techniques. Our simulations show that our protocols produce paths and trees which are stable, less risky and suitable for various network conditions. q 2002 Elsevier Science B.V. All rights reserved.