On the Blocking Time Distribution of Core OBS Switches

Given the bufferless nature of Optical Burst-Switched networks, data bursts are either transmitted or dropped; the latter typically occurs when all the wavelengthsof a given output port are occupied. Clearly, the amount of time during which a given output port is blocked and cannot schedule incoming data bursts is a key performance measure of OBS networks. This work shows that, under Poissonianburst arrivals, the blocking time distribution of a given output port in an OBS node approaches the exponential distribution as the number of wavelengths increases. It is further shown that this behavior remains regardless of the size distributionof incoming bursts, and therefore, regardless of the burstassembly algorithms employed at the border nodes. Finally, this result is also applied to the characterization of the amount of overspill traffic, that is, the number of bursts that arrive within a blocked period, and thereforemust be either dropped or diverted over alternative routes.

On the Blocking Time Distribution of Core OBS Switches Articles