How to Implement Network Resource Allocation in NS2

To implement the Network Resource Allocation within NS2 that has encompasses designing a simulation in which the resources such as bandwidth, power, or channel time are assigned well between the network nodes. This allocation can contain various methods, like bandwidth allocation, scheduling algorithms, or power control in wireless networks.Share with us your reseach details we provide you with best simulation results.  We present step-by-step guide to executing simple bandwidth resource allocation in NS2 that can be extended to other resources as required.

Step-by-Step Implementation:

  1. Understand Resource Allocation Basics
  • Bandwidth Allocation: Assign various bandwidths to the network nodes or links.
  • Channel Access Scheduling: Ascertain how nodes are access the wireless channel (e.g., TDMA, CSMA).
  • Power Control: Manage the transmission power to handle interference and resource usage.
  1. Set up the Environment

Make certain that we have NS2 installed and set up for the operating system.

  1. Create a TCL Script for Bandwidth Resource Allocation

The given specimen establishes how to implement bandwidth allocation for various nodes in a network.

Step-by-Step TCL Script for Bandwidth Allocation:

# Create a new NS2 simulator instance

set ns [new Simulator]

# Define the output files for trace and NAM visualization

set tracefile [open resource_allocation.tr w]

$ns trace-all $tracefile

set namfile [open resource_allocation.nam w]

$ns namtrace-all $namfile

# Define the network topology

set num_nodes 4

set bandwidth_high 5Mb    ;# High bandwidth allocation

set bandwidth_low 1Mb     ;# Low bandwidth allocation

set delay 10ms            ;# Link delay

# Create nodes (network devices)

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

set node($i) [$ns node]

}

# Set up the links with different bandwidths

# High bandwidth link between node 0 and node 1

$ns duplex-link $node(0) $node(1) $bandwidth_high $delay DropTail

# Low bandwidth link between node 1 and node 2

$ns duplex-link $node(1) $node(2) $bandwidth_low $delay DropTail

# Low bandwidth link between node 2 and node 3

$ns duplex-link $node(2) $node(3) $bandwidth_low $delay DropTail

# Configure traffic generation (TCP/FTP)

# TCP connection from node 0 to node 3 (passes through the high and low bandwidth links)

set tcp [new Agent/TCP]

set sink [new Agent/TCPSink]

$ns attach-agent $node(0) $tcp

$ns attach-agent $node(3) $sink

$ns connect $tcp $sink

# Start FTP application over TCP to generate traffic

set ftp [new Application/FTP]

$ftp attach-agent $tcp

$ftp start

# Schedule the simulation end

$ns at 20.0 “finish”

# Finish procedure to close trace and nam files

proc finish {} {

global ns tracefile namfile

$ns flush-trace

close $tracefile

close $namfile

exec nam resource_allocation.nam &

exit 0

}

# Run the simulation

$ns run

  1. Explanation of the Script
  • Bandwidth Allocation: The script makes a duplex links with various bandwidths. For specimen, a 5 Mbps link among the nodes are node(0) and node(1) (high bandwidth) and 1 Mbps links among node(1) and node(2) and node(2) and node(3) (low bandwidth).
  • Traffic Generation: TCP traffic is produced among the nodes node(0) and node(3) using an FTP application.
  • Simulation End: The simulation ends after 20 seconds, then the trace and NAM files are produced for examines.
  1. Simulate and Visualize the Bandwidth Allocation

We can save the above script as resource_allocation.tcl then we run the simulation:

ns resource_allocation.tcl

After the simulation is complete, we can open the NAM file for visualization:

nam resource_allocation.nam

  1. Resource Allocation Strategies

We can expand the simple bandwidth allocation scenario by executing more furthered resource allocation approaches:

  1. a) Dynamic Bandwidth Allocation

In dynamic networks, the bandwidth may be reallocated depending on the traffic demands and we can actively modify the bandwidth while the simulation using the rtmodel command in NS2.

For instance, alter the link bandwidth after 10 seconds:

$ns at 10.0 “$ns duplex-link $node(1) $node(2) 2Mb 10ms DropTail”

It will double the bandwidth among node(1) and node(2) after 10 seconds.

  1. b) QoS-based Allocation

We can use the DiffServ (Differentiated Services) or Integrated Services (IntServ) to deliver the QoS-based bandwidth allocation.

In this instance, nodes with higher priority traffic could acquire more bandwidth. For specimen, we can allocate various bandwidths rely on the traffic priority using varius traffic classes (e.g., premium vs. regular traffic).

  1. c) Scheduling Algorithms

For wireless networks, the channel access scheduling algorithms such as TDMA, CSMA, or OFDMA can be executed. The simulation environment NS2 supports these protocols via particular wireless extensions (802.11 MAC, etc.).

  1. d) Power Control

In wireless networks, controlling the power levels of various nodes to minimise interference or conserve energy is another resource allocation strategy. We can change the power levels of nodes actively while the simulation.

For instance, change the transmission power of a wireless node:

$node(0) set TxPower_ 0.5  ;# Set transmission power to 0.5W

  1. Analyzing the Results

We can be examined the result trace file (resource_allocation.tr) to calculate metrics like:

  • Throughput: Calculate the total number of bits transmitted over each link.
  • Packet Loss: Find any dropped packets by reason of the congestion on low-bandwidth links.
  • Delay: Determine the end-to-end delay experienced by packets.

The following is a basic AWK script to compute throughput from the trace file:

awk ‘/tcp/ && /r/ {sum+=$5} END {print “Throughput:”, sum/10, “bits/sec”}’ resource_allocation.tr

This script strains the tcp packets received (r) then it computes throughput over a 10-second interval.

  1. Advanced Resource Allocation Techniques

To execute more furthered network resource allocation schemes, we can test with the following:

  1. a) Fairness Allocation

We can be executed the fairness algorithms such as Weighted Fair Queuing (WFQ) or Round Robin (RR) for packet scheduling over several traffic flows.

  1. b) Cross-Layer Resource Allocation

This approach to deliberate the data from numerous layers (physical, MAC, network, etc.) that to create more effective allocation decisions. For sample, we can allocate resources depending on the link quality or congestion information from lower layers.

  1. c) Centralized Resource Allocation

For more furthered simulations, we can be executed a centralized controller, which observes the comprehensive network and actively reallocates resources rely on the global optimization objectives. For instance, maximizing overall throughput or minimizing delay.

  1. Run the Simulation and Analyse Results

We can learn how various resource allocation strategies effect the performance of the network such as throughput, delay, and fairness, after running the simulation and investigating the trace files.

Within this module, we presented the entire demonstration concerning the Network Resource Allocation that were executed and analysed the outcomes through the executing protocol in NS2. Further specific information about this topic will also be made available