A Geometric Approach to Capacity Provisioning in WDM Networks with Dynamic Traffic

In this paper, we use an asymptotic analysis similar to the sphere-packing argument in the proof of Shannon´s channel capacity theorem to derive optimal provisioning requirements for networks with both static and dynamic provisioning. We consider an TV-user shared-link model where W_s wavelengths are statically assigned to each user, and a common pool of W_d wavelengths are available to all users. We derive the minimum values of W_s and W_d required to achieve asymptotically non-blocking performance as the number of users N becomes large. We show that it is always optimal to statically provision at least enough wavelengths to support the mean of the traffic. We then consider allowing the shared wavelengths W_d to be switched in groups (or wavebands) rather than on an individual basis, and show that by employing waveband switching, a link with only a few switches per user can achieve the same performance as a link provisioned with unlimited switches per user using only marginally more wavelengths. We also derive the optimal band size and wavelengths required. Finally, we discuss adaptation of these results to the case of a finite and small number of users.