Influence of Chord Length on the Blocking Performance of Wavelength Routed Chordal Ring Networks

Abstract

In this paper, we present an assessment of the blocking performance of wavelength routed optical networks with chordal ring topology. The performance is focused on chord lengths of 3, N/4, and \(\sqrt N + 3\), being N the number of nodes. It is shown that, in a 100-node chordal ring network, the use of the chord length of N/4 instead of 3 clearly reduces the blocking probability. A reduction of the blocking probability is also observed when the chord length of \(\sqrt N + 3\) is used, instead of N/4 or w=3. The increase of the node degree from 3 (chordal ring with 100 nodes and a chord length of \(\sqrt N + 3\)) to 4 (mesh torus with 100 nodes) has also revealed an important feature: very small blocking gains were observed due to the increase of the node degree from 3 to 4. Thus, the choice of a chordal ring with a chord length of \(\sqrt N + 3\), instead of a mesh-torus, leads to a reduction in the number of network links, and hence in the total cable length, since the number of links in a N-node chordal ring is 3N, and the number of links in a N-node mesh-torus is 4N.