How to Start Network on Chip Topology Projects Using NS2

To create a Network-on-Chip (NoC) topology in NS2 (Network Simulator 2) has includes their design a communication for a chip structure in which several cores or processing elements (PEs) communicate via an interconnection network. NoC topologies are typically meshed, torus, or custom pattern has enhance for the on-chip communication.

Here’s a step-by-step guide to start your Network-on-Chip Topology project in NS2:

Steps to Simulate NoC Topology in NS2

  1. Understand Network-on-Chip (NoC)
  • Structure:
    • Nodes are signifying the processing elements (PEs).
    • Links connect the nodes for a detailed in topology for sample 2D Mesh, Torus, Star, Tree.
    • Packet-based is communication, by routing protocols are maintaining the congestion.
  • Applications:
    • Calculating for the high-performance.
    • System-on-Chip (SoC) designs.
    • Embedded systems by multi-core processors.
  1. Set Up NS2
  1. Install NS2:

sudo apt-get install ns2

  1. Verify Installation: Validate by a simple replication of  script:

ns example.tcl

  1. Define NoC Topology
  • Select the topology for instance 2D Mesh, Torus.
  • Describe the nodes for processing elements (PEs).
  • Link the nodes using connection based on the topology.
  1. TCL Script for NoC Topology

Below is a sample TCL script for replicate the 2D Mesh Topology for NoC:

TCL Script Example (2D Mesh)

# Initialize NS2 Simulator

set ns [new Simulator]

set tracefile [open noc_topology.tr w]

$ns trace-all $tracefile

# Define grid dimensions for 2D Mesh

set rows 3

set cols 3

set num_nodes [expr $rows * $cols]

# Create nodes for the NoC

for {set i 0} {$i < $num_nodes} {incr i} {

set n($i) [$ns node]

}

# Create links to form the 2D Mesh

for {set i 0} {$i < $rows} {incr i} {

for {set j 0} {$j < $cols} {incr j} {

set index [expr $i * $cols + $j]

 

# Connect to right neighbor

if {$j < [expr $cols – 1]} {

set right [expr $index + 1]

$ns duplex-link $n($index) $n($right) 1Gb 1ms DropTail

}

 

# Connect to bottom neighbor

if {$i < [expr $rows – 1]} {

set bottom [expr $index + $cols]

$ns duplex-link $n($index) $n($bottom) 1Gb 1ms DropTail

}

}

}

 

# Attach agents for traffic simulation

# Example: Traffic from Node 0 to Node 8

set tcp0 [new Agent/TCP]

$ns attach-agent $n(0) $tcp0

set sink0 [new Agent/TCPSink]

$ns attach-agent $n(8) $sink0

$ns connect $tcp0 $sink0

# Add a traffic generator

set ftp [new Application/FTP]

$ftp attach-agent $tcp0

# Start traffic

$ns at 1.0 “$ftp start”

# End simulation

$ns at 5.0 “finish”

proc finish {} {

global ns tracefile

$ns flush-trace

close $tracefile

exit 0

}

$ns run

  1. Key Features to Simulate
  1. Traffic Flow:
    • It replicates the communication among change the processing fundamentals.
    • Validate the mesh topology for multi-hop communication paths.
  2. Performance Metrics:
    • Throughput: Calculate the data delivery with the NoC.
    • Latency: Study the delays among source and destination nodes.
    • Congestion: Estimate the traffic congestion in the network.
  1. Analyze the Trace File
  • Build the use of trace file (noc_topology.tr) for examine the network performance.
  • Excerpt the detailed the parameter metrics:
    • Throughput:

grep “tcp” noc_topology.tr > throughput.log

    • Dropped Packets:

grep “drop” noc_topology.tr > dropped_packets.log

  1. Visualize Results

It use the outcomes for Gnuplot or other envision tool:

  1. Throughput Graph:

set title “NoC Throughput”

plot “throughput.log” using 1:2 with lines title “Throughput”

  1. Latency Graph:
    • Associate the delays for congestion with many nodes.
  1. Extend the Simulation
  2. Implement Advanced Routing
  • Research by changed routing procedures for instance XY Routing, Adaptive Routing.

proc xy_routing {src dst packet} {

# Example: Route through X-dimension first, then Y-dimension

# Add routing logic based on node coordinates

}

  1. Dynamic Traffic Patterns
  • Improve the several concurrent congestion flows:

set tcp1 [new Agent/TCP]

$ns attach-agent $n(2) $tcp1

set sink1 [new Agent/TCPSink]

$ns attach-agent $n(6) $sink1

$ns connect $tcp1 $sink1

  1. Simulate Node or Link Failures
  • Validate the  NoC resilience through replicate a node or connection failures:

$ns at 3.0 “$ns reset-links $n(1) $n(2)”

  1. Simulate Traffic Congestion
  • Establish the congestion increase the loads for validate the congestion management.
  1. Modify NS2 Core for Advanced Features
  1. Custom Routing Algorithms:
    • Execute the advanced routing protocols in the C++ main of NS2.
  2. Traffic Shaping:
    • Alter the packet behavior for replicate the real-world application workloads.

Tools and Resources

  • Wireshark: Examine the congestion flows in the NoC.
  • Gnuplot: Envision for the performance of parameter metrics such as throughput and latency.
  • NS2 Documentation: Reference for encompassing the operation and enhance the custom structures.

Enhancements

  • Simulate Torus Topology:
    • Encompass the 2D mesh for involves the wraparound connection for improve the connectivity.

# Add wraparound links for torus topology

$ns duplex-link $n(0) $n(2) 1Gb 1ms DropTail

  • Add Energy Models:
    • It replicates the power usage for various congestion designs.
  • Compare NoC Topologies:
    • Estimate the performance of mesh, torus, and custom topologies.

In this manual, we gathered the essential details which will help you to implement the Network on chip topology in ns2 with sample snippets. For further clarification, please check the additional manual to be provided.