Feature Issue on Photonics in Switching
Optical burst switching (OBS) is a collision-based scheme in nature. It is a challenge to provide absolute quality of service (QoS), such as a guaranteed loss rate, for critical applications. Existing research often focuses on modifying the parameters or operations of the whole network, but there is hardly any work on controlling the loss rate based on operations at edge nodes only. We design an edge-based controlling scheme to achieve a guaranteed loss performance for an optical burst flow. Starting with the analysis of traffic characteristics of burst flows that are assembled by different algorithms, we investigate the relationship of major assembly parameters and the loss performances of different flows. Several loss predictors and assembly adjusters are designed in order to achieve a desired loss rate for a burst flow. Our control system does not affect the packet transmission load, which is especially useful for some critical applications such as multimedia streams. Our design can be applied to various networks using different assembly algorithms, signaling protocols, contention resolution methods, or varying network inputs. Compared with existing control schemes for OBS networks, our method is simple, efficient, and distributed for easy implementation using the information at edge nodes. The simulation results demonstrate that our system has an accurate and stable operation.
© 2007 Optical Society of America