تجزیه و تحلیل عملکرد از شنارژآماده چندمسیری کارآمد

This paper presents a comprehensive analysis of high-performance crossbars where crossbars can be asymmetrical in size, buffered at all crosspoints, and capable of multipath routing. A crossbar, as a building block of switching networks, with the mentioned features in its structure can demonstrate fault-tolerant property. This property is a major factor for crossbars to play the role of high-performance entity in modern computer and communication systems. A generic condition of n×k crossbar with n inputs (rows), k columns, and n outputs (rows) under which a crossbar becomes multipath is examined. In a multipath crossbar a packet can be routed through k different paths to an output. The multipath feature ensures the property of fault-tolerance and provides a faster congestion resolution especially under the multicast traffic. This paper describes a two-dimensional Markov chain associated with the queueing model, and presents the performance evaluation of crossbars.

As the high-speed networks are destined to play an increasingly important role in the new communication networking, there is a growing concern in identifying suitable switching architectures capable of handling high-rate traffic. The capability of multicasting traffic [9] is a fundamental factor for example. Switching systems must be able to multicast a message to many users and even route many messages to one user. In the multimedia environment, traditional networks are subject to severe blocking since they are not typically designed for high bandwidth communications. Under this condition, the performance of switching networks closely relies on the network architecture. The efficiency also depends on how fast networks can transfer the traffic. The inclusion of all of the new features into modern switching systems requires considerable sophistication in the architecture. Simplistic approaches can fail to meet required performance or cost objectives. Crossbars are the building blocks of switching systems[2], [6] and [3]. Conventional unipath and symmetrical crossbars are vulnerable to faults. There have been a number of papers in the literature [1], [9] and [13] analyzing modern networks taking into account the efficiency of crossbar switches. There are also several papers [7] that compare the switching systems from different perspectives, providing a comprehensive survey of different systems. A number of different factors can be used to characterize switching systems, including buffering, capability of multipoint connections, speed, performance, cost, reliability, fault-tolerance, and scalability. The growing demand for large-scale switching networks and the increase of traffic volume call for reliable, high-speed, and low-cost fabrics. The performance of switching networks closely relies on the crossbar efficiency and fault-tolerance. This paper evaluates the performance of crossbar switches when they are multipath, fault-tolerance, non-symmetrical in dimension, multicast, and buffered. This paper is organized as follows. In Section 2, the crossbar structure and routing and multicast techniques are introduced. Section 3 presents an analytical queueing model and uses it to evaluate the performance of the network. In this section, the results of performance evaluation are also presented and discussed.