Blocking in all-optical networks

Abstract

Abstract-We present an analytical technique of very low complexity, using the inclusion-exclusion principle of combinatorics, for the performance evaluation of all-optical, wavelength-division multiplexed networks with no wavelength conversion. The technique is a generalized reduced-load approximation scheme which is applicable to arbitrary topologies and traffic patterns. One of the main issues in computing blocking probabilities in all-optical networks is the significant link load correlation introduced by the wavelength continuity constraint. One of the models we propose takes this into account and gives good results even under conditions with high link load correlation. Through numerous experiments we show that our models can be used to obtain fast and accurate estimates of blocking probabilities in all-optical networks and scale well with the path length and capacity of the network. We also extend one of our models to take into account alternate routing, in the form of Fixed Alternate Routing and Least Loaded Routing.

Blocking Evaluation and Wavelength Dimensioning of Dynamic WDM Networks Without Wavelength Conversion

“…Many works assume that the traffic load offered by each connection to the network is statistically the same [8]- [15]. This hypothesis strongly simplifies the modeling, but it does not adequately represent the operation of optical networks (or computer networks in general), because the offered traffic is usually very heterogeneous.…”

“…Another commonly used hypothesis is the Poisson traffic assumption, shared by the majority of papers published so far [8]- [15], [17]- [19], which greatly simplifies the mathematical evaluation. However, a Poisson process is not representative of the real traffic in optical networks, for several reasons.…”

Analysis of Blocking Probability for First-Fit Wavelength Assignment in Transmission-Impaired Optical Networks

“…Several analytical models for random-pick (RP) WA with no QoT constraint have been proposed in the literature [11][12][13]. For example, in [12], a path decomposition technique is proposed, in which a long path is divided into small segments (of two or three links).…”

“…However, BPs in WRONs for FF WA are harder to analyze [12,13]. The utilization of a layered graph approach, or "wavelength decomposition," is proposed in several papers [14][15][16][17].…”

Traffic grooming and wavelength conversion in optical networks

“…Their analytical model takes into account both wavelength correlation and the dynamic nature of the traffic. Sridharan and Sivarajan [47] presented a new analytical tech nique based on the inclusion-exclusion principle for networks with no wavelength conversion and random wavelength assignment. Their model improves on Birman's model in that it is independent of hop-length and scales only with the capacity of the link.…”