Performance of a dynamically wavelength-routed, optical burst switched network

Abstract

The concept of optical burst switching (OBS) aims to allow access to optical bandwidth in dense wavelength division multiplexed (DWDM) networks at fractions of the optical line rate to improve bandwidth utilization efficiency. This paper studies a novel approach to combine OBS with dynamic wavelength allocation to provide a scalable optical architecture with a guaranteed QoS. In the proposed architecture all processing and buffering are concentrated at the network edge and bursts are assigned to fast tuneable lasers an routed over a bufferless optical transport core using dynamic wavelength assignment and no wavelength conversion. This guarantees forwarding with pre-defined delay at the edge, and latency due only to propagation time in the core. The edge burst aggregation mechanisms are evaluated for a range of traffic statistics to identify their impact on the allowable burst lengths, required buffer size and achievable edge delays. Bandwidth utilization and wavelength re-use are introduced and upper bounds for these parameters are derived to quantify the advantages of dynamic wavelength allocation, including the influence of the signaling round-trip time-required for lightpath reservation. The results allow evaluation of the operational gain achievable with dynamic wavelength assignment compared to quasi-static wavelength-routed optical networks.