A general resource assignment scheme for successful transmission in optical burst switched networks

This work proposes a general resource assignment strategy for Optical Burst Switched networks to avoid burst losses. Given a set of communications and the associated paths defined by a routing, we propose a wavelength assignment scheme in which contentions can always be solved or avoided by delaying properly the transmission of some (perhaps all) data bursts. Two mechanisms are defined for this purpose. One is based on adding a suitable extra-offset time to each burst transmission (static approach). The other consists of adding the additional delay, only when contention occurs in an intermediate node of the network, by using a single fiber delay line (dynamic approach). In both cases, the additional delay is independent of the link lengths. Moreover, we resort to Linear Programming (LP) methods to compute the number of wavelengths needed to serve a given traffic matrix. Some examples show that the proposed method gives optimal or near-optimal solutions. This strategy works in either synchronous or asynchronous transmission environments. Moreover, the burst arriving and length distributions can be of general type.