Heuristic and Optimal Techniques for Light-trail Assignment in Optical Ring WDM Networks

摘要

In this paper we propose a set of heuristicrnalgorithms for assigning light-trails [1-4, 10] to WDMrnring networks so as to facilitate IP centric dynamicrncommunication at the optical layer. A light-trail is arngeneralization of a lightpath such that multiple nodesrncan take part in communication along the path withoutrnthe need for optical switching. Hence, a light-trailrnrepresents an opportunistic medium in which multiplernsub-lambda flows can be accommodated despiterndiversity in source-destination pairs and without thernneed for optical switching. A light-trail is analogous tornan optical bus such that multiple connections betweenrnsource-destination pairs can be provisioned under thernconstraint that the source destination pairs are part ofrnthe light-trail, and no two connections are overlappingrnin time. This enables traffic grooming at the opticalrnlayer. In this paper we will show five heuristic solutionsrnthat solve the light-trail assignment problem inrnpolynomial time. We will also show an LP formulationrnthat assigns light-trails for ring networks in the mostrnoptimal way. A simulation study will comparernperformance of LP evaluation and heuristic algorithms.