A low-latency and bandwidth-efficient distributed optical burst switching architecture for metro ring

Abstract

Optical Burst Switching (OBS) provides statistical multiplexing capabilities at the optical layer with relaxed hardware requirements when compared to optical packet switching.One of the open challenges of OBS is to assemble as many packets as possible in the same burst, while at the same time ensuring low latency of the transmitted packets.The authors propose the use of OBS to realize a geographically distributed packet switch for metro rings. High efficiency of the ring bandwidth and low packet latency are obtained at the ring node by combining a multi-token based protocol for contentionless and loss-free transmission of bursts, known as the LightRing protocol, with the creation of bursts that contain packets belonging to multiple traffic flows (classified by priority and destination).As illustrated in the paper, the proposed solution yields throughput that is significantly higher than that one offered by a centralized packet switch connected to the ring nodes via dedicated optical circuits. Latency of real time packets is kept at few dozens of milliseconds under a variety of network scenarios. The solution scales well geographically for metro applications.

Distributed contention avoidance in Optical Burst-Switched ring networks

“…A token approach was introduced in [4]. The approach was a distributed OBS metro ring architecture referred to as LightRing.…”

Access Protocols to Support Different Service Classes in an Optical Burst Switching Ring

“…The work done so far on OBS rings considered traffic tobe best effort except in Fumagalli and Krishnamoorthy [3], where real-time and best-effort were considered. The aim of this paper is to investigate how an OBS ring can support different dasses of traffic.…”

“…Jong [4] proposed several access protocols for multicasting in such an environment. A new architecture called the Light Ring has been proposed by Fumagalli and Krishnamoorthy [3] with multi-token protocol to prevent contention among bursts. Bouabdallah et al [2] proposed a collision avoidance MAC protocol for a metropolitan bus-based optical access network.…”

Benefits of static WDM add/drop multiplexers in optical burst switching networks of ring configuration

“…Unlike packet switches, PBSs have little (or sometimes no) queueing space, so that providing PBSs in every node will lead to increased burst loss and latency. Recently, various design alternatives to OBS networks cooperating with OXCs of first circuit switching capability and OADMs of dynamic drop/insertion capability have emerged for decreasing burst loss rate and latency [4,5]. For example, the optical burst add/drop multiplexing (OB-ADM) technique provides low latency as well as bandwidth efficiency [5].…”

“…Recently, various design alternatives to OBS networks cooperating with OXCs of first circuit switching capability and OADMs of dynamic drop/insertion capability have emerged for decreasing burst loss rate and latency [4,5]. For example, the optical burst add/drop multiplexing (OB-ADM) technique provides low latency as well as bandwidth efficiency [5]. However, the OB-ADM node is composed of a conventional PBS and a dynamic ADM, both with a full access to all the wavelengths multiplexed, and thus its complexity becomes formidable.…”