An analytical framework for performance comparison of bandwidth reservation schemes in WDM ring

A number of bandwidth reservation schemes have been proposed for multi-channel rings, generally classified as centralized and distributed. Besides simulation results, the existing analytical models address only the blocking probability and achievable throughput of such schemes. However, in determining the properties and advantages of each reservation scheme (especially the LightRing, a scheme previously proposed by the authors) the above performance figures are not sufficient, as network latency plays a determinant role when fast bandwidth provisioning is of the essence. This paper presents an analytical framework that allows one to derive the response time and throughput of such schemes under the assumption that a single request for bandwidth can be stored and processed by the source at a time. Numerical results obtained using the proposed model reveal a number of interesting properties of the existing bandwidth reservation schemes.