Groupe d’études et de recherche en analyse des décisions

G-2009-29

Core OBS Traffic Properties and Behavior

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Today, OCS (Optical Circuit Switching) is still the only mature technology for optical transfer, even if it suffers from its coarse granularity under dynamic and bursty scenarios. It remains the case in spite of the grooming technologies, together with the VCAT (Virtual conCATenation) and LCAS (Link Capacity Adjustment Scheme) enhancements. OBS (Optical Burst Switching) has been proposed to improve the resource usage efficiency in unfavorable scenarios to OCS, e.g., bursty traffic.

Yet far from being mature, OBS is a bufferless packet oriented switching paradigm. Such a bufferless paradigm is still unusual. We show in this paper that the traffic in the core network conforms to the yet unrevealed OBS transparency property: Switching operations do not modify the OBS traffic profile. This entails that the emission process completely defines the traffic profile in OBS core networks.

Following the disclosure of the OBS transparency property, we investigate the resulting OBS traffic in core networks and propose an accurate traffic model. Empirical observations of various configurations have highlighted some impacting factors and favorable configurations for reducing burst losses and, therefore, maximizing the throughput. Based on the conclusions of the analysis, we elaborate new recommendations for burst traffic aggregation design so that friendly aware traffic is emitted.

, 16 pages