Performance analysis of Optical Packet Switches enhanced with electronic buffering

Abstract

Optical networks with Wavelength Division Multiplexing (WDM), especially Optical Packet Switching (OPS) networks, have attracted much attention in recent years. However, OPS is still not yet ready for deployment, which is mainly because of its high packet loss ratio at the switching nodes. Since it is very difficult to reduce the loss ratio to an acceptable level by only using all-optical methods, in this paper, we propose a new type of optical switching scheme for OPS which combines optical switching with electronic buffering. In the proposed scheme, the arrived packets that do not cause contentions are switched to the output fibers directly; other packets are switched to shared receivers and converted to electronic signals and will be stored in the buffer until being sent out by shared transmitters. We focus on performance analysis of the switch, and with both analytical models and simulations, we show that to dramatically improve the performance of the switch, for example, reducing the packet loss ratio from 10 −2 to close to 10 −6 , very few receivers and transmitters are needed to be added to the switch. Therefore, we believe that the proposed switching scheme can greatly improve the practicability of OPS networks.

High-Speed Multicast Scheduling in Hybrid Optical Packet Switches with Guaranteed Latency

“…Such an optical switching fabric is nonblocking and has intrinsic multicast capability, i.e., the ability to transmit packets from one input port to multiple output ports simultaneously. For the detailed implementation of the OpCut switch, readers may refer to [21].…”

“…Note that, different from the general OpCut switch proposed in [21], where electronic buffers are shared by all the packets, due to the special feature of the proposed GLMS, we can adopt a simpler buffer structure that assigns a dedicated buffer to each input as shown in Fig. 1.…”

“…In this paper, we study multicast scheduling based on the OpCut switch [21], a recently proposed hybrid optical/ electronic packet switch that combines optical switching and electronic buffering [22], [23]. We first propose a multicast scheduling algorithm called Guaranteed Latency Multicast Scheduling (GLMS), which provides a latency upper bound for all transmitted packets, while keeping the packet loss at minimum level.…”

Performance modeling of hybrid optical packet switches with shared buffer

“…However, since mature optical buffer technology is not readily available and most of the current optical packet switch architectures still rely on fiber delay lines (FDL), none of those schemes is able to reduce packet loss to a reasonable level under heavy traffic load. To address these challenges, a hybrid optical/electronic packet switch architecture [2], [3] combining optical cut-through with shared electronic buffer was proposed as a promising candidate for practical deployment. It utilizes the large capacity of electronic buffer to resolve contention while letting packets cut through the switch optically as much as possible.…”

“…In [2], the performance of the OpCut switch with an infinite buffer was analyzed under Bernoulli traffic. Although the model can give some quantitative characteristics of the OpCut switch, the infinite buffer is not realistic, and some important properties, such as cut-through ratio and packet loss caused by buffer overflow, are not considered.…”