Efficient On-Line Call Control Algorithms
In this paper we study the problem of on-linecall controlin a communication network, namely, the problem of accepting or rejecting an incoming call (a request for a connection between two points in a network) without having the knowledge of future calls. The problem is a part of the more general problem of bandwidth allocation and management. Intuition suggests that knowledge of future call arrivals can be crucial to the performance of the system. In this paper, however, we present preemptive deterministic on-line call control algorithms. We use competitive analysis to measure their performance?i.e., we compare our algorithms to their off-line, clairvoyant counterparts?and prove optimality for some of them. We consider two specific networks, a line of nodes and a single edge, and investigate a variety of cases concerning thevalueof the calls. The value is accrued only if the call terminates successfully; otherwise?if the call is rejected, or prematurely terminated?no value is gained. The performance of the algorithm is then measured by the cumulative value achieved, when given a sequence of calls. The variety of call value criteria that we study?constant; proportional to the length of the call's route; proportional to its holding time?captures many of the natural cost assignments to network services.