A Geometric Approach to Capacity Provisioning inWDM Networks with Dynamic Traffic

摘要

In this paper, we use an asymptotic analysis similarrnto the sphere-packing argument in the proof of Shannon's channelrncapacity theorem to derive optimal provisioning requirements forrnnetworks with both static and dynamic provisioning. We considerrnan N -user shared-link model where W s wavelengths are staticallyrnassigned to each user, and a common pool of W d wavelengths arernavailable to all users. We derive the minimum values of W s andrnW d required to achieve asymptotically non-blocking performancernas the number of users N becomes large. We show that it is al-waysrnoptimal to statically provision at least enough wavelengthsrnto support the mean of the traffic. We then consider allowing thernshared wavelengths W d to be switched in groups (or wavebands)rnrather than on an individual basis, and show that by employingrnwaveband switching, a link with only a few switches per user canrnachieve the same performance as a link provisioned with unlim-itedrnswitches per user using only marginally more wavelengths.rnWe also derive the optimal band size and wavelengths required.rnFinally, we discuss adaptation of these results to the case of a finiternand small number of users.