A challenge for routing algorithms in optical multistage interconnection networks

Problem statement: A class of dynamic interconnection networks is Multistage Interconnection Networks (MINs) that connects input devices to output devices through a number of switch stages. MINs have assumed importance in recent years; because of their cost-effectiveness. Optical MINs are one type of MINs that have large transmission capacity in the communication networks. There is a major problem in Optical MIN that is crosstalk, which is caused by coupling two signals within a switching element. Approach: To avoid crosstalk in Optical MINs many algorithms have been proposed by many researchers that we review applying five routing algorithms and scheduling them in the Optical MINs. Results: The comparative results of routing algorithms show affective of avoiding crosstalk in number of passes and execution time for different algorithm. Conclusion: The challenge between these routing algorithms is thoroughly investigated, by applying them on Optical MIN and showing which algorithm has better performance to avoid crosstalk

On the relation between network throughput and delay curves

The theoretical background of network throughput and delay has been widely used in the previous studies to efficiently study the behaviour of different interconnection networks. In this paper, we derive a new relationship between the network throughput and delay curves. Specifically, we prove that this relation on the average delay and throughput in x-Folded TM topology by considering the tangent line of each curve. Based on the achievements, we introduce the reflection relation between these two performance metrics, while considering the gradient of the metric curves. Moreover, we show the superiority of x-Folded TM topology, previously introduced with same authors, is obvious with this relation in interconnection networks. Consequently, the obtained results have been verified with simulation results to signify how to relate the performance metrics for various topologies in interconnection networks

Mathematical modelling for TM topology under uniform and hotspot traffic patterns

Interconnection networks are introduced when dealing with the connection of a significant number of processors in massively parallel systems. TM topology is one of the latest interconnection networks to solve the deadlock problem and achieve high performance in massively parallel systems. This topology is derived from a Torus topology with removing cyclic channel dependencies. In this paper, we derive a mathematical model for TM topology under uniform and hotspot traffic patterns to compute the average delay. The average delay is formulated from the sum of the average delay of network, the average waiting time of the source node and the average degree of virtual channels. The results obtained from the mathematical model exhibit a close agreement with those predicted by simulation. In addition, sufficient simulation results are presented to revisit the TM topology performance under various traffic patterns

Analyzing the performance of low stage interconnection network

In order to avoid crosstalk, a new architecture is proposed for Optical Multistage Interconnection Networks (OMINs). In the new architecture, two switches are replaced by one switch in each row. Reduction in the number of switches makes the considerable reduction in the execution time. To study the performance of the new architecture, analytical techniques also can be used effectively. The theory of probability is used to derive mathematical equation for network bandwidth allocation of a unit load. The obtained results show the improvement in the network performance. By increasing load, the bandwidth is reduced. In addition the simulation is applied to validate the new architecture and show improvement in the performance by approximately 30 % reduction in the execution time

A cost-effective architecture for optical multistage interconnection network.

In this paper a new architecture for Optical Multistage Interconnection Networks (OMINs) has been proposed to avoid crosstalk problem. At the same time, the probablity of losing pass through an optical long connection path is reduced in this architecture. The new architecture is inherent form the standard OMIN by converting two switches of the network to one switch in each row. By reducing the number of switches in new architecture, the reduction in the execution time is considered. The modifying in the number of passes via the same low stage transformation is negligible. The ability of the new architecture to decrease cost and avoid crosstalk has been validated through simulations that show improvement in the network performance in terms of approximately 30% reduction in the execution time

Adaptive routing algorithm in x-Folded TM topology

In recent days, more complicated interconnection topologies have been replaced with previously simple topologies that also exhibit high performance. x-Folded TM network is a TM network that is folded according to the imaginary x-Axis in interconnection networks. For a x-Folded TM network, there is a reduction in the average distance and diameter which corroborates the efficient performance. Also many routing algorithms can be applied to interconnection network for the efficient use of network resources. This paper presents the effectiveness of the x-Folded TM network with the average latency and network throughput under the adaptive routing algorithm to improve dynamic communication performance. We evaluate the communication performance with simulating the topology under the adaptive routing algorithm. It is found from the result that the performance of a x-Folded TM network has been improved compared with other topologies

A GreedyZero algorithm to minimise the conflicts in an Optical Multistage Interconnection Network

An Optical Multistage Interconnection Network (OMIN) is an important class of Interconnection Network that has large transmission capacity in the communication networks. One of the severe problems is the conflict which is caused through coupling two signals within switching elements. In this paper, we have proposed a new algorithm to minimise the number of conflicts of OMINs using the greedy graph colouring and Zero algorithm. The greedy graph colouring approach employed the Zero algorithm to categorise inputs of the OMINs without conflict. The results showed that the number of passes reduced by approximately 30%. In addition, the average execution time of our proposed algorithm was less than the average execution time of the Zero algorithm

Greedyzero-based scheduling algorithm to route in optical low stage interconnection networks

A class of dynamic interconnection networks is Multistage Interconnection Networks (MINs) that is popular in switching and communication applications. In recent years, MINs have assumed important because of their cost- effectiveness. The advances in electro-optic technologies have made significant improvement in the optical technology. The idea of optical implementation of MINs meet the ever increasing demands of high performance computing communication applications for high channel bandwidth, low communication latency and parallel processing. Optical Multistage Interconnection Network (OMIN) is very popular in switching, large transmission capacity, and communication among other types of interconnection networks. OMINs present crosstalk that related with optical switches, as a result of undesired coupling two signals within each switching element. Therefore, it is not possible to route more than one message at the same time, without any crosstalk, over a switching element in an OMIN. This thesis is focused on an efficient solution to avoid crosstalk, which is routing traffic through an optical network to avoid coupling two signals within each switching element. Under the constraint of avoiding crosstalk, what we have been interested is how to realize a permutation that will use the minimum number of passes, the minimum execution time and the maximum bandwidth to route the input request to output without crosstalk. Many algorithms have been designed to perform the routing better. This research contains two approaches to improve the performance of networks to solve the problem. First, the new architecture of Interconnection Network (Low Stage reduce number of switches and decrease execution time considerably while modifying bandwidth and number of passes via the same low stage transformation is negligible. Then the GreedyZero algorithm is developed to minimize the number of passes approximately 30% in compare with Zero algorithm to route all the inputs to outputs without any crosstalk. The GreedyZero algorithm has been presented in the Low Stage Interconnection Network. This algorithm has been developed to achieve performance goals in terms of 50% reduction in the number of passes

GreedyZero algorithms for conflict-free scheduling in low stage interconnection network

Low Stage Interconnection Networks are a class of Interconnection Networks. They have been generated from Multistage Interconnection Networks (MINs). Although the conflict in the optical switches, there is the considerable interest to use the optical technology in interconnection networks implementation. To avoid this problem, GreedyZero algorithms has been assigned to the Low Stage Interconnection Networks for improving the network performance by reducing the number of passes. The results marked nearly 50% reduction in the number of passes and proved improvement of scheduling in the Low Stage Interconnection Networks by GreedyZero algorithms