How to Start Wired LANs Projects Using NS2

To start Wired LANs (Local Area Networks) using NS2 (Network Simulator 2) that encompass to set up and design the networks including Ethernet and TCP/IP protocols. A Wired LAN has devices that are associated via cables like Ethernet, and NS2 is a robust simulator that permits for designing network topologies, replicating traffic, and then estimating the performance parameters such as bandwidth, latency, packet loss, and so on.

Below is a simplified approach to get started Wired LANs projects using NS2:

Steps to Start Wired LANs Projects in NS2

Step 1: Install NS2

Make sure that NS2 is installed correctly on the system before starting the projects. We will need to verify if NS2 is installed by running:

ns

If % occurs then installation is effectively functioned.

If it operates and provides NS2 prompt then the installation was effectively set up. Unless, we should install NS2 using offered installation instructions on the NS2 installation page.

Step 2: Define the Problem or Scenario for Wired LANs

In NS2, wired LANs are normally replicated by Ethernet links and TCP/IP protocols. We can make network topology with:

• Volume of nodes (devices or computers within the LAN).
• Router and switch configurations (if designing a more complex network configuration).
• Traffic types such as FTP, HTTP, voice, or video traffic.
• Utilise TCP, UDP, or Ethernet protocols.

Following is a few instance applications of Wired LANs:

1. Basic LAN Simulation: Replicate a small LAN including some machines and a switch.
2. TCP Throughput: Estimate the TCP traffic throughput through the wired LAN.
3. Congestion Control: We need to replicate the congestion control and then in a wired LAN calculate how various protocols manage the packet loss.

Step 3: Create and Configure Network Topology

We describe the nodes, links, and routers in the LAN topology within NS2. We will need to associate the nodes using Ethernet links and set up them by IP addresses for a simple wired LAN.

Example: Simple Wired LAN with Three Nodes

In this case, we can make a simple wired LAN including three nodes that are associated to a switch (or hub) and then execute TCP traffic among them.

# Create simulator object

set ns [new Simulator]

# Create nodes (devices in the LAN)

set node1 [$ns node]

set node2 [$ns node]

set node3 [$ns node]

# Create a switch (Ethernet switch in LAN)

set switch [$ns node]

# Define the network links (Ethernet links)

$ns duplex-link $node1 $switch 10Mb 10ms DropTail

$ns duplex-link $node2 $switch 10Mb 10ms DropTail

$ns duplex-link $node3 $switch 10Mb 10ms DropTail

# Set IP addresses for the nodes

$node1 set ip_ 10.0.0.1

$node2 set ip_ 10.0.0.2

$node3 set ip_ 10.0.0.3

# Create a TCP connection between two nodes (node1 and node2)

set tcp [new Agent/TCP]

$ns attach-agent $node1 $tcp

set sink [new Agent/TCPSink]

$ns attach-agent $node2 $sink

$ns connect $tcp $sink

# Create a UDP connection between node2 and node3 for a different type of traffic

set udp [new Agent/UDP]

$ns attach-agent $node2 $udp

set sink_udp [new Agent/TCPSink]

$ns attach-agent $node3 $sink_udp

$ns connect $udp $sink_udp

# Define applications for traffic generation (FTP or CBR)

set ftp [new Application/FTP]

$ftp attach $tcp

$ns at 0.5 “$ftp start”

$ns at 4.5 “$ftp stop”

set cbr [new Application/Traffic/CBR]

$cbr attach $udp

$cbr set packetSize_ 1000

$cbr set interval_ 0.1

$ns at 1.0 “$cbr start”

$ns at 4.0 “$cbr stop”

# Set up a trace file for logging the simulation

set tracefile “wired_lan.tr”

$ns trace-all $tracefile

# Run the simulation for 5 seconds

$ns at 5.0 “finish”

# Finish procedure to stop the simulation

proc finish {} {

global ns

$ns flush-trace

exit 0

}

# Run the simulation

$ns run

Explanation of Key Components:

1. Creating Nodes:
   • $ns node makes nodes that contain devices within the LAN.
2. Ethernet Link Configuration:
   • $ns duplex-link generates the bi-directional links among the nodes and the switch. The metrics has bandwidth (10Mb), delay (10ms), and queue type (DropTail) for Ethernet link set up.
3. TCP and UDP Agents:
   • For reliable interaction, we need to utilise TCP and UDP agents for connectionless traffic.
4. Traffic Generation:
   • FTP is applied for making TCP traffic among the nodes like node1 and node2.
   • Make UDP traffic among the node2 and node3 with the support of CBR (Constant Bit Rate).

Step 4: Run the Simulation and Monitor Results

When we configure the network and traffic generation then we will need to execute the simulation and examine these outcomes.

• NS2 Trace Files: Collect data on the simulation with trace files. The trace file want to include packet-level data (arrival, loss, etc.), which may examine to utilise post-processing tools such as AWK or Perl scripts.

awk ‘{print $1, $2, $3, $4, $5}’ wired_lan.tr > output_data.txt

We will need to examine the performance indicators like TCP throughput, packet loss, delay, end-to-end delay, and so on.

Step 5: Analyze and Extend the Simulation

• Measure TCP Performance:
  • In the network, mimic and estimate the throughput of TCP to apply NS2’s TCP agent and FTP application. We will explore TCP congestion control and packet loss to utilise Trace files.
• Evaluate Link Performance:
  • Test with various link performance like bandwidths and delays on the connections. For instance, to modify the link delay or bandwidth for replicating congestion and network performance in diverse situations.
• Add More Complex Network Elements:
  • Integrate the components such as routers, firewalls, or firewall strategies for mimicking more complex network topologies. In this example, we may design complete network including several subnets and then replicate the effect of network traffic.
• Congestion Control:
  • Combine traffic, which makes congestion and experiment the capability of network for retrieving with TCP congestion control approaches. We will need to launch the queue management mechanisms or focus on TCP variants such as TCP Reno or TCP Vegas.

Step 6: Extend and Experiment with More Complex Scenarios

After functioning the simulation then we need to prolong it:

1. Adding Routers/Switches:
   • Design a more complex LAN by means of integrating the routers or layer 2 switches.
   • Launch VLANs, Quality of Service (QoS) strategies, and network security approaches such as firewalls or intrusion detection systems (IDS).
2. Varying Traffic Loads:
   • Replicate various network loads by way of modifying the traffic generation rate or packet sizes.
   • Mimic real-world traffic to apply traffic patterns such as CBR (Constant Bit Rate) or Poisson.
3. Evaluate QoS:
   • Test with Quality of Service (QoS) policies like Differentiated Services (DiffServ) or IEEE 802.1p prioritization, making sure that managing traffic effectively.

Step 7: Analyze the Results

Examine the trace files and also estimate the performance of network using AWK, Perl, or Python. We need to analyse the simulation performance metrics such as:

• Throughput
• Packet loss
• Jitter
• End-to-end delay

For example, below is a basic AWK script for estimating packet delay from the trace file:

awk ‘{if ($1==”r”) print $2, $3, $4, $5, $6, $7, $8}’ wired_lan.tr > packet_delay.txt

Conclusion

To start a Wired LANs project using NS2 that contains:

1. Creating a Network Topology: We specify the nodes, switches, and links in network topology.
2. Configuring Traffic: Configure the TCP and UDP traffic for data transfer.
3. Simulating Traffic: Make traffic with the support of FTP and CBR applications.
4. Running Simulations: Monitor and examine the simulation performance indicators to apply trace files.
5. Extending the Simulation: Integrate complexity by means of incorporating more network devices, modifying traffic models, and estimating Quality of Service (QoS).

These projects provide various kinds of Wired LANs to design and simulate then estimate its behaviour in diverse scenarios by leveraging NS2 environment. If you want additional insights on this topic, we will provide it to you.