The Contention Resolution in OBS Network

Abstract

Burst contention occurs when attempting to transmit several optical bursts at the time into the same core router output port. This is a shortcoming of the Optical Burst Switching (OBS) networks and for this reason it has been challenging to implement the OBS mode into the transport networks so far. This problem can be solved applying various contention resolution strategies at core nodes (fiber delay lines, wavelength conversion or deflection routing). The following question arises: how does data transmission through the OBS network quality depend on using such strategy combination in the core node? For these reasons an analytical model has been created to find out what impact a joint application of various contention resolution strategies has on the data transmission quality. An algorithm has been proposed for the burst service in the OBS core router when a contention arises. The authors suggest applying burst segmentation only for the lower priority bursts, reducing the lower priority data losses in the case of mixed priority burst incoming flow. Every additional burst collision resolution strategy increases the time spent at the node however, so it is highly important to determine by means of simulations the optimal amount of resources needed at the core node.

[Retracted] Dynamic Wavelength Scheduling by Multiobjectives in OBS Networks

“…Numerous studies in the current literature focus on burst-based models and the switching framework associated with them. Another intriguing area of study in the context of OBS is data contention [13]. Environmental factors can complicate multiplexing and switching.…”

Performance Evaluation of Optical Burst in High Speed Backbone Networks

“…OBS is a combination of OPS and optical circuit switching (OCS).For the purpose of identifying the path in which data is transferred, connection-oriented circuits are developed in OCS.This is the reason why in OBS, dynamic provisioning using wavelength-based switching is used [2].A control packet is generated and sent prior by using a different reserved channel,and as soon as an adequate amount of data has been received at the sender's input lines, the data burst is released.An electronic controller is responsible for the electronic routing of control and data bursts. This electronic controller also decides the outgoing link and wavelength of the data burst [3].There will be a requirement for a wavelengthrouted network for supporting OBS. This network permits a one-way virtual circuit architecture for processing a large quantity of data transmission over the optical switch with extremely low latency [4].…”