On the design of optical buffer for optical input-queued switches with quality of service guarantees

Abstract

This paper presents a quality of service (QoS) enable optical delay line (ODL) architecture to solve the problem of resource contention and support multilevel priority queues in an optical packet switch. ODL has been used in optical packet switches to resolve resource contention; however, the packets travel continuously in ODL limits the management of random access of the packets and increases the packet loss probability. Moreover, multiple ODL sets usually are needed to realize multiple priority queues in order to support QoS. In this paper, a new Unicast Recirculatiion ODL (URODL) architecture is proposed to resolve the output contention problem in an input-queued optical packet switch. To improve relatively poor throughput due to the head of Line (HOL) blocking in the input-queued switch, we modify URODL to support a more efficient window-based lookahead scheduling algorithm. Furthermore, a control strategy is designed to turn a single set of URODL into multiple logical queues to hold different priority packets. The simulation results show our URODL model reduces packet loss effectively with the capability to support QoS. This URODL model can be easily implemented and managed in a fast optical packet switch.

Service differentiating supporting output circuiting shared optical buffer architecture

“…There are mainly three kinds of methods for a buffering architecture based on FDL in time domain: input buffer structure [5], circulated sharing buffer structure [6,7], and output buffer structure [8]. For the case of input buffer structure, the FDL is placed on the input optical fiber.…”

“…With this manner, the fixed and finite packet delay can be provided effectively. As the most similar with the buffering technologies in electronic networks, it has been extensively studied to resolve the contention effectively [5][6][7][8].…”

An effective buffering architecture for optical packet switching networks

“…In the second method, optical packets are transferred to another output port which has an idle channel, but that may result in a chaos in networks. Comparably speaking, optical buffering using fiber delay lines (FDLs) has been proved to be a best choice to handle resource contention by providing fixed length and finite delay [3][4][5]. The length of FDLs is measured in terms of a delay unit, called granularity.…”