How to Calculate Network Packet drop Percentage in NS2

To calculate Packet Drop Percentage in ns2 has a series of steps to follow and it is key parameters that assess the ratio of packets that were dropped that is not successfully delivered to the total number of packets sent. This parameter is helpful in measuring network performance and reliability, specific in wireless and mobile networks in which the packet loss can happen because of congestion, poor signal quality, or mobility.

The given below are the procedures to calculate the Packet Drop Percentage in ns2:

Formula for Packet Drop Percentage:

The Packet Drop Percentage is calculated as:

Packet Drop Percentage=Number of Packets DroppedNumber of Packets Sent×100\text{Packet Drop Percentage} = \frac{\text{Number of Packets Dropped}}{\text{Number of Packets Sent}} \times 100Packet Drop Percentage=Number of Packets SentNumber of Packets Dropped×100

Where:

Packets Dropped: The number of packets that were sent nevertheless not received at the destination.
Packets Sent: The total number of packets transmitted by the sender.

Steps to Calculate Packet Drop Percentage in NS2:

Set Up the Network Simulation: Describe the network topology and mimic traffic among the source and destination nodes.
Generate and Capture Traffic: Use agents such as UDP or TCP to create traffic among nodes, and log events such as packet transmission, reception, and drop in the trace file.
Analyze the Trace File: The trace file has includes the detailed data about all events in the simulation, that has contains when packets are sent, received, or dropped. We can utilize this trace file to extract the essential information about packet drops and transmissions.
Calculate Packet Drop Percentage: summing up the number of packets sent, received, and dropped from the trace file, and then use the formula to estimate the packet drop percentage.

Example Tcl Script to Simulate Packet Drops in NS2:

Here’s a simple NS2 Tcl script that configure a simple network in which UDP traffic is created among two nodes, and packet drops are logged.

# Create a new simulator instance

set ns [new Simulator]

# Define two nodes

set node0 [$ns node]

set node1 [$ns node]

# Create a link between the nodes

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

# Attach UDP agents to both nodes

set udp0 [new Agent/UDP]

set null0 [new Agent/Null]

$ns attach-agent $node0 $udp0

$ns attach-agent $node1 $null0

$ns connect $udp0 $null0

# Create a CBR traffic source

set cbr0 [new Application/Traffic/CBR]

$cbr0 attach-agent $udp0

$cbr0 set packetSize_ 512

$cbr0 set rate_ 1Mb

# Start and stop traffic

$ns at 1.0 “$cbr0 start”

$ns at 5.0 “$cbr0 stop”

# Open a trace file to log events

set tracefile [open trace.tr w]

$ns trace-all $tracefile

# Define a finish procedure to close the trace file and stop the simulation

proc finish {} {

global ns tracefile

$ns flush-trace

close $tracefile

exit 0

}

# End the simulation at 6.0 seconds

$ns at 6.0 “finish”

$ns run

Explanation of the Script:

Network Topology: Two nodes, node0 and node1, are generated, and a link is introduced among them with a bandwidth of 1 Mbps and a delay of 10 ms.
Traffic Generation: A UDP agent and a CBR traffic source are attached to node0, and the traffic is sent to node1. The traffic executes from time 1.0 seconds to 5.0 seconds.
Trace File: The trace file logs all events, has contained packet transmissions, receptions, and drops. This file will be utilized to estimate the packet drop percentage.

Trace File Analysis:

In the NS2 trace file, different events are logged, have contained when packets are sent (s), received (r), and dropped (d). To estimate the packet drop percentage, we can extract the number of packets sent and dropped.

Example Trace File Output:

s 1.0 _0_ AGT — 512 [0 0 0 0] ——- [0:0 1:0 32 0]

r 1.2 _1_ AGT — 512 [0 0 0 0] ——- [0:0 1:0 32 0]

d 2.0 _0_ RTR — 512 [0 0 0 0] ——- [0:0 1:0 32 0]

In the trace file:

s signifies a packet being sent.
r denotes a packet being received.
d symbolizes a packet being dropped.

Bash Script to Calculate Packet Drop Percentage:

We utilize a bash script to measure the trace file and estimates the packet drop percentage in terms of the number of packets sent and dropped.

# Count the total number of packets sent

sent_packets=$(grep “^s” trace.tr | wc -l)

# Count the total number of packets dropped

dropped_packets=$(grep “^d” trace.tr | wc -l)

# Calculate the packet drop percentage

if [ $sent_packets -gt 0 ]; then

drop_percentage=$(echo “scale=2; $dropped_packets / $sent_packets * 100” | bc)

echo “Packet Drop Percentage: $drop_percentage%”

else

echo “No packets were sent.”

Explanation of the Bash Script:

Sent Packets: The script counts the number of lines in the trace file that starts with s, that denoted the packets sent by the sender.
Dropped Packets: It also counts the number of lines that begin with d, denoted the packets dropped by the network.
Packet Drop Percentage: The script estimates the packet drop percentage using the formula:

Post-Simulation Analysis:

Once the simulation is done, we can execute the bash script to measure the trace file and estimate the packet drop percentage. This delivers an important measure of the network’s performance and reliability.

Summary of Steps:

Set Up the Network Simulation: Use NS2 to generate a network topology and mimic traffic among nodes.
Log Events in the Trace File: Use the trace file to record packet transmissions, receptions, and drops.
Analyse the Trace File: Utilize a bash script (or any other method) to count the number of packets sent and dropped.
Calculate Packet Drop Percentage: Estimate the packet drop percentage using the formula:

By following these steps, we can estimate the Packet Drop Percentage in an NS2 simulation and assess the network’s performance. Let me know if you need further clarification or assistance!

Finally, we understand calculation procedures on Packet Drop Percentage that has includes to setting up the emulation scenarios then generate the traffic after that estimate the outcomes using the ns2 tool. We further provide the in-depth information about the Packet Drop Percentage.

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