Ž . Computer Networks 31 1999 2391–2410 www.elsevier.comrlocatercomnet Design, performance and wavelength assignment of a wavelength division multiaccess protocol for optical fibre ring networks 1 A.E. Kamal a, ) , G.K. Janssens b,2 a Department of Electrical & Computer Engineering, Kuwait UniÕersity, P.O. Box 5969, 13060 Safat, Kuwait b Business Information Systems, Operations and Logistics Management, UniÕersity of Antwerp, Middelheimlaan 1, 2020 Antwerp, Belgium Abstract This paper presents a multiaccess strategy for use over optical fibre ring networks employing two counter rotating rings, and using wavelength division multiplexing. Transmitters employ tunable lasers, while receivers employ one or more fixed wavelength filters. The paper introduces an algorithm for the optimal assignment of the receivers to the channels, such that the possibility of finding an unused channel leading to a certain receiver is maximized. The paper contains a performance study of the network protocol. q 1999 Elsevier Science B.V. All rights reserved. Ž . Keywords: Ring networks; Wavelength division multiplexing WDM ; Medium access control protocols; Wavelength assignment; Optimization; Performance 1. Introduction The continuous advances in computing equip- ment, and the prevalent trend in their interconnection through networks compounded with the introduction w x of bandwidth-hungry applications 6,7,14,32–34,38 , have contributed to the increasing need for high-speed network operation. In such networks, the optical fibre is the natural transmission medium. Networks based on fibres can be configured according to a number of topologies, e.g., the bus, the star, and the w x ring topology 22 . In all such topologies, nodes ) Corresponding author. E-mail: kamal@eng.kuniv.edu.kw 1 This research was supported by a grant from the Government of Alberta, Canada and the Flanders Government, Belgium, under the the AlbertarFlanders agreement, and grant no. EE-084 from Kuwait University Research Administration. 2 E-mail: gerritj@ruca.ua.ac.be transmit and receive through optical taps, which are either of the passive or active type. Because of the disparity between the speed of the electronics and the fibre’s bandwidth, it is practically impossible for a single transmitter to fully utilize the bandwidth of the fibre. This is referred to as the electronic bottle- w x neck 22 . The most practical approach to circumvent the electronic bottleneck problem is to use dense Wave- Ž . w x length Division Multiplexing WDM 4,19 . In this approach, the fiber bandwidth is accessed in the wavelength domain by using several wavelengths, where the spacing between the distinct wavelengths is on the order of 1 nm. Multiple transmissions and receptions may proceed simultaneously and indepen- dently using this approach. Even after circumventing the electronic bottleneck problem, there still remains two intertwined issues. The first is the medium access protocol, which can be a very important factor in determining the net- 1389-1286r99r$ - see front matter q 1999 Elsevier Science B.V. All rights reserved. Ž . PII: S1389-1286 99 00092-4