How to Implement Network Traffic Differentiation in NS2

To implement Network traffic differentiation in NS2 has needs to follow numerous steps and usually it denoted to the capability to detect and manage the different types of traffic with changing priorities or Quality of Service (QoS) requirements. Traffic differentiation is vital in modern networks, specifically for applications such as video streaming, voice over IP (VoIP), and web browsing, in which each application is needs a different handling based on its bandwidth, latency, or packet loss tolerance. Please contact us to get  the implementation of Network Traffic Differentiation in NS2 tool tailored to your needs..

In NS2, we can execute traffic differentiation by setting up different traffic types, allocating priorities, and handling queues at routers or nodes. Here’s a guide to implementing network traffic differentiation in NS2:

Steps to Implement Network Traffic Differentiation in NS2

  1. Set Up NS2 Environment

Make sure NS2 is installed and functioning properly. If NS2 is not installed, we need to follow these steps to install it:

wget https://sourceforge.net/projects/nsnam/files/latest/download -O ns-allinone-2.35.tar.gz

tar -xzvf ns-allinone-2.35.tar.gz

cd ns-allinone-2.35

./install

  1. Understanding Traffic Differentiation in NS2

Traffic differentiation is achieved by:

  • Classifying Traffic Types: Describing different types of traffic like TCP, UDP, CBR (Constant Bit Rate), and allocating numerous QoS requirements such as delay, throughput, or packet loss tolerance.
  • Priority-Based Queuing: Executing different queuing mechanisms such as DropTail, RED, and Priority Queue at routers or switches to manage the traffic based on priority.
  • Handling QoS: Implementing different traffic policies to make sure that high-priority traffic (like VoIP) gets preferred treatment compared to low-priority traffic (like bulk file transfers).
  1. Define Network Topology

Initially, we need to generate a network topology that consists of routers, nodes (end hosts), and links. In this instance, we will configure a simple topology with one router and several end hosts.

3.1 Create Nodes and Links

# Create a simulator object

set ns [new Simulator]

# Open trace file for visualization

set nf [open out.nam w]

$ns namtrace-all $nf

# Create Nodes

set node1 [$ns node]    ;# End host 1

set node2 [$ns node]    ;# End host 2

set node3 [$ns node]    ;# End host 3

set router [$ns node]   ;# Router

# Define Links

$ns duplex-link $node1 $router 100Mb 10ms DropTail

$ns duplex-link $node2 $router 100Mb 10ms DropTail

$ns duplex-link $node3 $router 100Mb 10ms DropTail

This generates a basic network with three nodes (node1, node2, and node3) associated to a router. Traffic will be differentiated as it flows via the router.

  1. Configure Traffic Differentiation

To execute traffic differentiation, we can describe various traffic types like TCP, UDP and allots different priorities. We will simulate three different types of traffic:

  • High-priority VoIP traffic using UDP.
  • Medium-priority video streaming traffic using UDP.
  • Low-priority file transfer traffic using TCP.

4.1 Create Traffic Agents

Describe traffic agents (TCP and UDP) for each type of traffic.

# High-Priority Traffic (VoIP)

set udp1 [new Agent/UDP]         ;# UDP for VoIP

$ns attach-agent $node1 $udp1

set null1 [new Agent/Null]       ;# Null agent as the sink

$ns attach-agent $router $null1

$ns connect $udp1 $null1

# Create a CBR application for constant VoIP traffic

set cbr1 [new Application/Traffic/CBR]

$cbr1 attach-agent $udp1

$cbr1 set packetSize_ 200        ;# Smaller packet size for VoIP

$cbr1 set rate_ 512Kb            ;# Data rate for VoIP

$ns at 1.0 “$cbr1 start”         ;# Start VoIP traffic at time 1.0

# Medium-Priority Traffic (Video Streaming)

set udp2 [new Agent/UDP]         ;# UDP for video streaming

$ns attach-agent $node2 $udp2

set null2 [new Agent/Null]       ;# Null agent as the sink

$ns attach-agent $router $null2

$ns connect $udp2 $null2

# Create a CBR application for video traffic

set cbr2 [new Application/Traffic/CBR]

$cbr2 attach-agent $udp2

$cbr2 set packetSize_ 1000       ;# Larger packet size for video

$cbr2 set rate_ 2Mb              ;# Data rate for video

$ns at 1.5 “$cbr2 start”         ;# Start video traffic at time 1.5

# Low-Priority Traffic (File Transfer)

set tcp3 [new Agent/TCP]         ;# TCP for file transfer

$ns attach-agent $node3 $tcp3

set sink3 [new Agent/TCPSink]    ;# TCP sink at the router

$ns attach-agent $router $sink3

$ns connect $tcp3 $sink3

# Create FTP traffic for file transfer

set ftp [new Application/FTP]

$ftp attach-agent $tcp3

$ns at 2.0 “$ftp start”          ;# Start file transfer at time 2.0

In this setup:

  • High-priority traffic (VoIP) uses UDP with a small packet size and a low data rate, starting at time 1.0 second.
  • Medium-priority traffic (video streaming) uses UDP with a larger packet size and a higher data rate, starting at time 1.5 seconds.
  • Low-priority traffic (file transfer) uses TCP with FTP starting at time 2.0 seconds.
  1. Implement Queuing Discipline for Traffic Differentiation

Now that the traffic types are defined, we can execute a queuing discipline to differentiate among the types of traffic. We can use a Priority Queue or other mechanisms such as RED (Random Early Detection) to handle traffic flow based on priority.

5.1 Priority Queue Setup

NS2 supports priority queues that permit to allocate different priorities to different traffic flows.

# Create a priority queue at the router

set pq [new Queue/DropTail/PriQueue]

$pq set numQueues_ 3  ;# Define three priority levels

# Assign priority to each traffic flow

$ns queue-limit $router $pq

In this case, a Priority Queue is configures with three levels of priority at the router. Traffic will be allocated to different queues according to its significance.

5.2 Assign Traffic to Queues

We can map various types of traffic to different queues based on their priority.

# Map traffic flows to priority queues

$udp1 set prio_ 0      ;# VoIP traffic (highest priority)

$udp2 set prio_ 1      ;# Video streaming (medium priority)

$tcp3 set prio_ 2      ;# File transfer (lowest priority)

In this configuration:

  • VoIP traffic is mapped to the highest priority queue (prio_ 0).
  • Video traffic is mapped to the medium priority queue (prio_ 1).
  • File transfer traffic is mapped to the lowest priority queue (prio_ 2).
  1. Enable Trace Files and Visualize with NAM

We can enable trace files to capture the simulation behaviour and envision it with NAM (Network Animator).

6.1 Enable Trace Files

# Enable tracing

set tracefile [open “out.tr” w]

$ns trace-all $tracefile

6.2 Run and Visualize Simulation

Execute the simulation and envision the traffic differentiation in NAM.

ns your_script.tcl

nam out.nam

In NAM, we will be able to monitor on how traffic flows are selected at the router according to their assigned priority levels.

  1. End the Simulation

Describe when to terminate the simulation.

# End the simulation after 10 seconds

$ns at 10.0 “finish”

proc finish {} {

global ns nf

$ns flush-trace

close $nf

exit 0

}

$ns run

  1. Analyse the Results

Once the simulation is complete, we can evaluate the outcomes by inspecting the trace file. We can collect information such as:

  • Packet delivery: How many packets from each traffic flow were successfully delivered?
  • End-to-end delay: How long it took for packets to reach their destination.
  • Queuing behaviour: How each priority queue handles traffic?

Use tools such as AWK, Python scripts, or NS2 trace analysers to parse the trace file and extract relevant parameters.

Finally, we understand implementation procedures on network traffic differentiation that has includes to setting up the emulation scenarios then implement Queuing Discipline mechanisms and finally analyse the outcomes using the ns2 tool. We further provide the in-depth information about the network traffic differentiation.