Advances in parallel computing area have made Multistage Interconnection Networks (MINs) a promising networking choice to meet the increasing demands of high performance computing. MINs are known as cost efficient means to offer programmable data paths among functional modules in multiprocessor systems. MINs with the Omega property are proposed to connect a large number of processors to establish a multiprocessor system. By adding Shuffle-Exchange Networks (SENs) in Omega network it has been commonly consider as convenient interconnection systems due to their size of its switching elements (SEs) and uncomplicated configuration. SEN is a unique path it has only a single path between a particular input and output. These networks are frequently applied with simple modular switches, make use of two input and two output switching elements. It can be implementing in Multistage Interconnection Network (MINs) and Optical Multistage Interconnection Network (OMINs). A major problem in SEN is path complexity occur when the routing procedure have been apply. SEN provide more redundant paths, by adding stage to the SEN is to allow two paths for communication between each source and destination. SENs in addition designed to provide inter process communication and developed fault tolerant architecture and reduce the cost and latency in the interconnection process.
The interconnection among switches, number of switches and types of switches normally determine the system performance. Reliability and performance of interconnection network system significantly depends on the interconnection of its components. In general, multiple path MINs have higher network reliability compared to the single path MINs. Shuffle-exchange networks (SENs) have been widely considered as practical interconnection systems due to their size of its switching elements (SEs) and uncomplicated configuration. By adding shuffle exchange network in this multistage interconnection network it can helps in fault tolerance and reduce the latency of the MINs network. Currently execution, most of the SEN technology was implement in 8x8 network sizes.
Figure 1 : 8x8 Shuffle Exchange Network
3. Problem Overview
Multistage Interconnection Networks (MINs) are design to provide an effective communication in switching. By using Shuffle Exchange Network (SEN) in MINs the stages can route the switching element through the path. Shuffle-exchange networks (SENs) with additional stages have been widely considered as practical interconnection systems due to their size of its switching elements (SEs) and uncomplicated configuration. In this types of network the major problem occur when the switching element failed to route in the stage. If these situations occur the switching element need to be route to an alternative path to avoid from system failure. By adding a stages in the SEN and with the permutation mapping the switch can be route to an alternative path and at the same time can improve the network performance. Beside that SEN can helped to provide inter process communication and developed and developed fault tolerant architecture. This network can provides permutation to route source to destination when both switches in a loop are simultaneously faulty at any stages.
4. Shuffle Exchange Network Category
The following subsections are organized as follows. Sub-sections review the Shuffle Exchange Network from previous works according to SEN with additional stages, Improved Irregular Augmented Shuffle Multistage Interconnection Network (IIASN), Irregular Modified Alpha Network (ALN), Irregular Augmented Shuffle Network (IASN), and Irregular Augmented Shuffle Exchange Network (IASEN).
4.1 SEN with additional stages.
There are three types of Shuffle Exchange Networks (SEN) from the previous work, which is SEN, SEN with additional stage (SEN+) and SEN with two additional stages (SEN+2). SEN is a unique path it has only a single path between a particular input and output. SEN+ provide two paths between each source and destination and it has N input and N output. SEN+2 consist of four paths between any pair of input and output. It can be observed from the result that by adding one additional stage it is efficient and give a better performance rather than adding with a two stages.
4.2 Improved Irregular Augmented Shuffle Multistage Interconnection Network (IIASN)
An Improved Irregular Augmented Shuffle Multistage Interconnection Network (IIASN) is design to provide inter process communication and developed and developed fault tolerant architecture. This network provides permutation to route source to destination when both switches in a loop are simultaneously faulty at any stages. IIASN has improved path length and cost effectiveness analysis. From the result it can be observe the permutation passable of IIASN is much better than existing networks such as IASN, FT and MFT.
4.3 Irregular Modified Alpha Network (ALN)
The Irregular Modified Alpha Network (Modified ALN) has proposed to reduce the cost and latency in the interconnection process. The number of stages in this network is lesser compared to Alpha Network but it can maintain the full access capability at the same time. This network is more reliable because it has auxiliary link to route source to destination when SE in the next stage faulty or busy. This network attains higher values of other important parameters.
4.4 Irregular Augmented Shuffle Network (IASN)
An innovative class of irregular fault tolerant multistage interconnection network called Irregular Augmented Shuffle Network (IASN) has been designed and evaluate. The irregular network IASN helps in dropping the latency or delay. IASN has been considered in a way to develop the performance of the network. The recommended IASN networks assure the fault tolerance criteria it can be operate even in existence of assured faults. The existences of the auxiliary links accessible in the network afford an alternate path used for routing procedure, except at the last stage. It has decreased number of stages thus exhibiting reduced latency and enhanced performance.
4.5 Irregular Augmented Shuffle Exchange Network (IASEN)
IASEN (Irregular augmented shuffle exchange) has been recommend modify presented ASEN-2 network. IASEN improved a better fault-tolerance by afford the additional paths among any pair of source destination as contrast to ASEN-2 at the expanse of small extra cost. IASEN is a dynamically re-routable and provides multiple paths of varying lengths between a given source and destination pair.
5. Comparative Analysis
Table 1 shows the comparison of reviewed schemes. As for comparison, most of the proposed schemes are initially focusing on network performance. SEN with their own scheme has different algorithm to solve the problem in the Multistage Interconnection with their own behavior. This different algorithm helped to provide more redundant path to improve the network performance. Rather than that different algorithm also helped in term of developed the fault tolerant and reduce the latency. SEN scheme has considered as cost effectiveness in Multistage Interconnection Network.
SEN Scheme
Proposed Solution
Comments
SEN with additional stages
SEN with additional stage (SEN+) provide more redundant path for the routing procedure process. It can help to provide a
better performance in term of reliability performance.
It is noted that by adding two additional stages in the SEN+2 do not increase the reliability of the network since the links complexity leads to higher network system failure.
Improved Irregular Augmented Shuffle Multistage Interconnection Network (IIASN)
IIASN is design to provide inter process communication and developed and developed fault tolerant architecture. IIASN has improved path length and cost effectiveness analysis and permutation passable of IIASN is much better than existing networks such as IASN, FT and MFT.
The multiplexer doesn't have the alternative way to provide multiple paths if a fault occur in the first stage.
Irregular Modified Alpha Network (Modified ALN)
Modified ALN has proposed to reduce the cost and latency in the interconnection process. This network is more reliable because it has auxiliary link to route source to destination when SE in the next stage faulty or busy.
Modified ALN provide 2 identical groups of SE which is G0 and G1 when the G0 faulty then it will pass the task to G1 to complete the job. But when all the SEs in the loops in both groups, Modified ALN will fail.
Irregular Augmented Shuffle Network (IASN)
IASN has been designed and evaluate, helps in dropping the latency or delay. IASN networks assure the fault tolerance criteria it can be operate even in existence of assured faults. It has decreased number of stages thus exhibiting reduced latency and enhanced performance.
IASN is a single switch fault tolerance. By adding multiple switches it can provide a better network performance.
Irregular augmented shuffle exchange (IASEN)
IASEN improved a better fault-tolerance by afford the additional paths among any pair of source destination as contrast to ASEN-2 at the expanse of small extra cost. IASEN is a dynamically re-routable and provides multiple paths of varying lengths between a given source and destination pair.
IASEN provide 8 alternate paths for routing procedure. Even though it can help to route the switch when the previous path is failure but with may path available it can give a complexity to switch.
Table 1 : Comparison of SEN scheme
5. Conclusion
From the analysis, we investigated five different scheme of Shuffle Exchange Network in Multistage Interconnection Network; SEN with additional stages, Improved Irregular Augmented Shuffle Multistage Interconnection Network (IIASN), Irregular Modified Alpha Network (ALN), Irregular Augmented Shuffle Network (IASN), and Irregular Augmented Shuffle Exchange Network (IASEN). This paper review the scheme provided from the SEN in MINs infrastructure. The analysis (according to Table 1) has shown that SEN scheme can provide a more redundant path by adding the stages. It also can developed the fault tolerant and reduce the latency of the network. Most of the researchers are considering to using the SEN scheme in MINS architecture since it can help to reduce cost in the MINs architecture.
