On Delay Performance of Throughput Optimal Back-Pressure Routing: Testbed Results
Maximizing network throughput via back-pressure routing is the subject of a considerable body of literature. It is well known that back-pressure routing induces long delays and this has motivated a number of proposals for improving the delay performance. However, to their knowledge, no useful results are available in the literature that characterizes the delays induced by packet re-ordering which is due not only to the nature of back-pressure routing but also to the ubiquity of routing loops. Therefore, in this paper the authors provide a systematic evaluation of basic back-pressure routing algorithm and two of its recently proposed variants on an experimental testbed. This provides the first direct comparison of delay performance.