How to Implement Network Management in NS2

To implement the Network Management in NS2, we have to develop some feature for monitoring, controlling and upholding a network. It includes tasks like performance observing, fault detection, traffic control and configuration of devices to make sure that the network performs efficiently.

Follow the given step-by-step guide on how to implement Network Management in NS2:

Step-by-Step Guide to Implement Network Management in NS2

Set Up a Basic Network Topology:

First, set up the network topology that you will handle. This could be a wired, wireless, or hybrid network. You need to build nodes, state links, and decide on the protocols for communication.

Example OTcl script for a simple network topology:

set ns [new Simulator]

set nf [open out.tr w]

$ns trace-all $nf

set namfile [open out.nam w]

$ns namtrace-all $namfile

# Create nodes

set node0 [$ns node]

set node1 [$ns node]

set node2 [$ns node]

# Create duplex links between nodes

$ns duplex-link $node0 $node1 1Mb 10ms DropTail

$ns duplex-link $node1 $node2 1Mb 10ms DropTail

# Create TCP communication between node0 and node2

set tcp [new Agent/TCP]

set sink [new Agent/TCPSink]

$ns attach-agent $node0 $tcp

$ns attach-agent $node2 $sink

$ns connect $tcp $sink

set ftp [new Application/FTP]

$ftp attach-agent $tcp

# Start the FTP traffic at 1 second

$ns at 1.0 “$ftp start”

$ns at 5.0 “$ftp stop”

# Run the simulation

$ns at 10.0 “finish”

proc finish {} {

global ns nf namfile

$ns flush-trace

close $nf

close $namfile

exec nam out.nam &

exit 0

}

$ns run

In this simplified topology, we define three nodes linked by duplex links, where TCP communication happens amongst node0 (source) and node2 (sink).

Monitor Network Performance (Data Collection):

Manage the network by observing performance metrics includes packet transmission, delay, and throughput. NS2 offers trace files where you can log events like packet sends, receives, and drops.

Example OTcl script to log packets sent and received:

# Log the number of packets sent and received at a node

proc monitor_traffic {node} {

global ns

set sent_packets 0

set received_packets 0

# Monitor traffic at the node

$ns at 1.0 “puts \”Monitoring node $node…\””

trace_event $node “s” “Packet Sent” sent_packets

trace_event $node “r” “Packet Received” received_packets

}

# Helper function to trace events at a node

proc trace_event {node event action var} {

puts “Node $node event $event: $action”

incr $var

}

# Start monitoring traffic at node1

$ns at 1.0 “monitor_traffic $node1”

This script monitors the counts of packets sent and received at node1, permitting you to track network performance over time.

Traffic Management and Control:

You can control the traffic flow by executing traffic shaping or policing mechanisms like rate limiting or fine-tuning the packet queue size. This helps handle congestion and enhance network performance.

Example OTcl script to implement traffic shaping (rate limiting):

# Limit the bandwidth of the link between node0 and node1

$ns duplex-link $node0 $node1 512Kb 10ms DropTail

# Set a queue size limit to control packet flow (traffic shaping)

$ns queue-limit $node0 $node1 50

In this sample, the bandwidth amongst node0 and node1 is limited to 512 Kb/s, and the queue size is set to 50 packets to handle congestion.

Fault Detection and Recovery:

Network management has identifying faults (e.g., link failure) and recovering from them. You can replicate a link failure and execute logic to redirect traffic or take other corrective actions.

Example OTcl script to simulate link failure and recovery:

# Simulate a link failure between node0 and node1 at 3.0 seconds

$ns at 3.0 “$ns link $node0 $node1 down”

# Simulate link recovery at 4.0 seconds

$ns at 4.0 “$ns link $node0 $node1 up”

# Detect link failure and take corrective action (rerouting or notifying)

proc handle_link_failure {node0 node1} {

puts “Link between $node0 and $node1 has failed. Taking corrective action…”

# Rerouting traffic or taking other measures could go here

}

# Call link failure detection

$ns at 3.1 “handle_link_failure $node0 $node1”

This script mimics a link failure amongst node0 and node1 at 3.0 seconds and then recovers the link at 4.0 seconds. A function is also called to manage the failure and initiate corrective actions.

Dynamic Configuration of Network Devices:

Network management commonly requires dynamically fine-tuning network configurations like altering bandwidth, queue size, or traffic routes during runtime according to the network conditions.

Example OTcl script to dynamically change bandwidth:

# Dynamically change the bandwidth between node0 and node1 at runtime

proc adjust_bandwidth {node0 node1 new_bw} {

global ns

puts “Adjusting bandwidth between $node0 and $node1 to $new_bw”

$ns duplex-link-op $node0 $node1 bw $new_bw

}

# Change bandwidth to 1Mb at 4.5 seconds

$ns at 4.5 “adjust_bandwidth $node0 $node1 1Mb”

In this sample, the bandwidth amongst node0 and node1 is dynamically altered to 1Mb at 4.5 seconds into the simulation.

Monitor and Log Events for Analysis:

Network management requires logging key events like traffic anomalies, packet drops, and configuration variations for analysis. You can use the trace file to log and later analyze these events.

Example AWK script to log packet drops:

awk ‘{if ($1 == “d” && $4 == “TCP”) drop_count++;}

END { print “Total dropped TCP packets:”, drop_count }’ out.tr

This script counts the amount of dropped TCP packets from the trace file and logs them for analysis.

Run the Simulation and Analyze Results:

After designing the network management mechanisms, execute the simulation to monitor how traffic is handled, how faults are identified and corrected, and how the network performance is influenced.

To execute the simulation:

ns your_script.tcl

The trace file (out.tr) will contain details about packet transmission, packet drops, link failures, and other events. You can assess this file to analyze the effectiveness of your network management techniques.

Visualize Network Management in NAM:

Visualize the network topology, traffic flow, and management events (like link failures or dynamic bandwidth adjustments) in real-time by using NAM (Network Animator).

nam out.nam

In NAM, you can monitor how the network operates, how traffic flows are controlled, and how the network responds to failures or bandwidth modifications.

The above manual will walk you through the implementation and evaluation process of Network Management by offering the detailed structure of steps that will assist you with the execution and visualization. You can be able to acquire many information like how to work with the ns2 simulator tool.

For effective Network Management using the NS2 tool, connect with us for top-notch guidance. Our team is fully equipped with the necessary resources to ensure you receive excellent support and timely delivery.