Contour-Based Priority Scheduling in Optical Burst Switched Networks

Abstract

Abstract-Optical burst switching (OBS) is an emerging technology that allows variable size data bursts to be transported directly over dense wavelength division multiplexing links. Although several quality-of-service (QoS) schemes have been proposed for OBS networks, how to provide QoS at the high speed required by the OBS network is still an open question. In this paper, we propose a novel O(1) runtime contour-based priority algorithm that provides complete priority isolation among different priorities. This is the first practical O(1) runtime priority algorithm proposed for OBS, and it is well suited to high-speed hardware implementation.Index Terms-Algorithm, optical burst switching (OBS), optical packet switching, scheduling, wavelength division multiplexing (WDM).

Deduction of TWCs and Internal Wavelengths Needed for a Design of Asynchronous OPS System with Shared or Output FDL Buffer

“…scheduling algorithms without void filling [15][16][17]20] and scheduling algorithms with void filling [16][17][18][19][20] .…”

“…For this reason, efforts are required to increase buffer capacity in an optical packet switch with a limited number of FDLs [7][8][9][10][11][12][13][14] . For asynchronous and variable-length packets, scheduling algorithms without void filling as well as those with void filling can be used to allocate incoming packets in each output channel using an FDL buffer [15][16][17][18][19][20] .…”

“…Most studies on contention resolution of asynchronous and variable-length packets have fully assumed the use of switch resources such as TWCs and internal wavelengths, while a number of OPS architectures to share FDLs and wavelength converters have been addressed for synchronous and fixed length packets [16][17][18][19][20] . However, the number of TWCs in an asynchronous optical packet or burst switch is a factor in the system cost, and the number of internal wavelengths is related to the conversion range of the TWC and is also a factor in the system cost [8,[21][22][23] .…”

The use of a triangular estimator to improve scheduling in optical burst switched networks

“…Consider, for example, a system with 16 inputs and 64 wavelengths per fiber, each operating at 10 Gb/s. In order to support an average burst length of 100 kBytes the system would have to be able to process a control packet every 78 ns [15].…”

“…where m is the total number of voids for all wavelengths. Efficient implementations of the LAUC-VF algorithm [14,16] report a complexity equal to O(log m) but require 10 log m memory accesses per burst scheduling request, which means that they can take up to a few microseconds to schedule a single burst [15].…”