Offset-time compensation algorithm - QoS provisioning for the control channel of the optical burst switching network

Abstract

Optical Burst Switching (OBS) has intrinsically time-sensitive nature with the separation of the header and the payload. Thus, minute care for offset-time is definitely required, which has not been a highlighted issue in an existing OBS research. In this paper, we focus on the relatively early arrival of the data burst due to the excessive queueing delay of the burst control packet (BCP) under a heavily loaded network. We propose a new scheduling algorithm for the OBS control channel, the Offset-Time Compensation (OTC) algorithm to solve the early arrival problem incurring the data burst drop. In the OTC algorithm, the offset-time is determined by the existing static offset-time scheme and the proposed dynamic offset-time reflecting the offered load of the OBS network. scheme varying with the network condition. By scheduling the BCP, the OTC can reduce the data burst loss rate due to early arrival. With the dynamic offset-time scheme, the data burst loss rate decreases significantly and maintains regular rate regardless of the offered load. We also expend the OTC, QoS-Aware (QA) OTC to provides controllable QoS differentiation in terms of data burst loss rate due to early arrival. The service objective of higher class is satisfied even in a heavily loaded situation.