A heuristic wavelength assignment algorithm for multihop wdm networks with wavelength routing and wavelength re-use

Abstmct-In this paper, we present a heuristic algorithm for effectively assigning a limited number of Wavelengths among the access stations of a multihop network wherein the physical medium consists of optical fiber segments which interconnect waveleagtbaelective optical switches. Such a physical medium permits the limited number of wavelengths to be re-used among the various fiber links, thereby offeting very high aggregate capacity. Although the optical connectivity among the access station cam be altered by changiqq the stptes of the vmrrbus aptical switches, the resulting optical connectivlty pattern is constrained by the limitation imposed at the physical level. We also study two routing schemes, used to route requestrs fw virtual connections. The heuristic is tested on a realistic traffic model, and the call blocking performance of new requests for virtual connections is studied througih extensive simulations and compared against the Moeking performance @fan /deal ididme capacity centralized switch &west passible call blogking camd exclusively by con-gestion on the finite capacity user ifipuuoutput links, never by the switch fabric itseln. Surpri$ingly, we fiad that, for a wide range of p a r “ , the blocking perfommce af the lightwave network is dm & the same as that d tha ideal centralized switch. Fmm these roslrltg we conclude thqt the heurhtic algorithm is mective and the muting scheme is cfficlent. I