The Analysis of Mesh-Connected Networks

By Fatima Radi

Kufa University

College of Computer Science and mathematics

Computer

Architecture

Introduction

• Multiprocessor mesh interconnection networks are 2-dimensional networks,with the processors arranged at the nodes of a grid, and point-to-point linksconnecting each node to its neighbors.

• Networking strategy was originally employed in the 1950's by the telephoneindustry as a means of reducing the time required for a call to go through.Similarly, the computer industry employs networking strategy to provide fastcommunication between computer subparts, particularly with regard toparallel machines.

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Introduction

• A Mesh Network is a network topology in which each node relaysdata for the network. All nodes cooperate in the distribution ofdata in the network. Every node in a mesh network is called amesh node.

• Mesh networking is a type of network topology in which a device(node) transmits its own data as well as serves as a relay forother nodes

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• The performance requirements of many applications, such asweather prediction, signal processing, radar tracking, and imageprocessing, far exceed the capabilities of single-processorarchitectures. Parallel machines break a single problem down intoparallel tasks that are performed concurrently, reducingsignificantly the application processing time.

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Mesh Node

A mesh node is a node on a mesh network. This node can beanything with a network transceiver. Mesh nodes communicate witheach other and use some sort of ad hoc networking protocol toroute messages amongst themselves without the need for atraditional, hierarchical routing model. This also allows for nodes tojoin, move among, and drop out of the network without having tomake administrative changes.

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Mesh Network Topologies

The connection between each pair ofadjacent nodes may be

unidirectional

bidirectional

with the latter usually being implementedas two unidirectional links.

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Cont.

A node in a unidirectional network

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Organization of a Node

• A node in the system typically consists of one or more processors,some associated local memory, and a hardware switch thatcontrols the routing of messages through the node .

• When the node needs to send a message to another node, itqueues the message in a local buffer . The message waits untilthe node-to-switch link (connecting the processor and memory tothe local switch) becomes free

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Example

example of a 16 -node mesh.Note that the last element inone row is connected to the firstelement in the next .If the lastelement in each row wereconnected to the first elementin the same row, we would havea torus instead

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cont.

each processor i was connected to processors:

{i+1, i–1, i+8, and i–8} (mod 64).

Here are the routing functions:

R+1(i) =(i + 1) mod N

R–1(i) =(i – 1) mod N

R+r (i) = (i + r) mod N

R–r (i) = (i – r) mod N where r = 𝑁

The diameter of an llliac IV mesh is 𝑁 – 1.

For example, in a 16-

node mesh structure, it takes a maximum of 3 steps. To see that, let

us look at the mesh interconnection network shown in the form of a

chordal ring:

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Cont.

In a 64-element mesh, any node can be reached from any other in no

more than 7 of these shifts.

Without the end-around connections (a “pure” 2D mesh), the

diameter is 2( 𝑁 –1(

It is also possible to have a multidimensional mesh. The diameter of

a d-dimensional mesh is d(N1/d )–1 and its bisection width is N(d–1)/d

The average distance is d × 2(N1/d )/3 (without end-around

connections).

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Advantage and disadvantage of mesh Network

Advantage

• Traffic Abundance : Data can be transmitted from differentdevices simultaneously. This topology can withstand hightraffic.

• Reliability : Even if one of the components fails there isalways an alternative present. So data transfer doesn’t getaffected.

• Ever growing Expansion and modification in topology can bedone without disrupting other nodes.

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disadvantage

• Highly expensive: Overall cost of this network is way too highas compared to other network topologies

• High maintenance: Set-up and maintenance of this topology isvery difficult. Even administration of the network is tough.

• There are high chances of redundancy in many of the networkconnections.

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References

• [1] Vikram S. Adve &Mary K. Vernon " Performance Analysis ofMesh Interconnection Networks with Deterministic Routing "Computer Sciences Technical Report #1001b † July 1993

• [2]http://networkwire.org/what-is-mesh-topology.html

• [3] http://en.wikipedia.org/

• [4] http://www.ianswer4u.com/2011/05/mesh-topology-advantages-and.html

• [5]http://people.engr.ncsu.edu/efg/506/s03/lectures/notes/lec25.html

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