How to Calculate Network Cost in NS2
To calculate the network cost in ns2 indicates the different metric, relaying on the context of your simulation. For instance, network cost can be computed depends on:
- Energy consumption in energy-constrained networks (like wireless sensor networks).
- Transmission cost in terms of the total of data delivered or the number of hops.
- Link cost depends on latency, bandwidth, or reliability.
- Overall network performance factors like delay, throughput, or packet loss rate.
According to your simulation goals, the definition of “cost” will vary. Below are some general approaches to estimating network cost in NS2.
Steps to Calculate the Network Cost in NS2:
- Energy Consumption Cost
If you are working on energy-constrained networks (like wireless sensor networks), network cost is commonly assessed based on energy consumption. Here’s how to calculate it in NS2:
Steps:
- Enable the Energy Model: Make sure that your NS2 script contains an energy model to record the energy consumption of each node:
# Set up the energy model
for {set i 0} {$i < 10} {incr i} {
set node($i) [$ns node]
$node($i) add-energy-model 100.0 0.5 0.3 0.01 # Initial energy, Tx Power, Rx Power, Idle Power
}
- Track Energy Consumption: You can track the left over energy of each node during the simulation by using the energy method:
$node($i) energy
- Calculate Total Network Energy Consumption: To measure the total energy used during the simulation, subtract the final energy of each node from its initial energy:
set initialEnergy 100.0
set totalConsumed 0
for {set i 0} {$i < 10} {incr i} {
set consumed [expr $initialEnergy – [$node($i) energy]]
set totalConsumed [expr $totalConsumed + $consumed]
}
puts “Total Network Energy Consumption: $totalConsumed Joules”
This will give you the total energy utilization in the network, which can be considered as the network cost in energy-constrained systems.
- Transmission Cost
Transmission cost is another form of network cost, frequently measured based on the total data transmitted or the amount of hops amongst nodes. Here’s how to compute transmission cost in NS2:
Steps:
- Enable Tracing: First, make certain that you are creating a trace file:
set tracefile [open out.tr w]
$ns trace-all $tracefile
- Parse the Trace File: Each time a packet is delivered or obtained, an event will be logged in the trace file. Transmission cost can be computed depend on the sum of hops or the amount of data sent.
For instance, if a trace line looks like this:
+ 0.123456 0 1 cbr 1040 ——- [0 0 1 0] ——- [1:0 0:0 32 0] [0] 0 0
-
- The first column (+) represents a packet sent event.
- The 5th column (cbr) refers to the packet type.
- The number 1040 signifies the packet size in bytes.
- Calculate Total Data Sent: You can estimate the total data sent by using AWK script:
awk ‘{
if ($1 == “+” && $4 == “cbr”) {
total_data += $6;
}
} END {
print “Total Data Sent: ” total_data ” bytes”;
}’ out.tr
This script will count all the cbr packet sizes that were sent during the simulation.
- Calculate Transmission Cost Based on Hops: If you want to quantify the hop count cost, you can keep track of how many hops each packet takes. Each packet is sent several times as it travels from node to node.
Alter the AWK script to sum up the number of transmissions for each packet:
awk ‘{
if ($1 == “+” && $4 == “cbr”) {
packet_count++;
}
} END {
print “Total Transmission Cost (in hops): ” packet_count;
}’ out.tr
This will give you the amount of hops or transmissions for all packets.
- Latency-Based Cost
You can also measure the cost based on latency by stating how long it takes for packets to dispatch from source to destination.
Steps:
- Extract Latency from Trace File: In the trace file, each packet has a send (+) and receive (r) event. You can measure the latency for each packet and use it as the basis for the network cost.
Example AWK script to calculate average latency:
awk ‘{
if ($1 == “+” && $4 == “tcp”) {
send_time[$6] = $2;
}
if ($1 == “r” && $4 == “tcp”) {
if (send_time[$6] != “”) {
latency = $2 – send_time[$6];
total_latency += latency;
packet_count++;
delete send_time[$6];
}
}
} END {
if (packet_count > 0) {
print “Average Latency: ” total_latency / packet_count ” seconds”;
}
}’ out.tr
This calculates the average latency for all packets, which could be a measure of network cost.
- Link Cost Based on Bandwidth or Loss
You may want to compute link costs in terms of bandwidth usage, packet loss, or other link-level metrics.
Steps:
- Calculate Bandwidth Usage: Use the entire count of bytes sent and the duration of the simulation to estimate bandwidth consumption:
awk ‘{
if ($1 == “+” && $4 == “tcp”) {
total_bytes += $6;
}
} END {
simulation_time = 10; # Duration of the simulation in seconds
bandwidth = total_bytes / simulation_time;
print “Total Bandwidth Usage: ” bandwidth ” bytes/second”;
}’ out.tr
- Packet Loss Cost: You can quantify packet loss by relating the number of sent and acquired packets:
awk ‘{
if ($1 == “+” && $4 == “tcp”) {
sent_packets++;
}
if ($1 == “r” && $4 == “tcp”) {
received_packets++;
}
} END {
packet_loss = sent_packets – received_packets;
print “Packet Loss: ” packet_loss;
}’ out.tr
This gives you the count of packets that were lost during the simulation, which could be used to compute network cost.
- Overall Network Performance Cost
Network cost can also be assessed according to its whole performance metrics includes throughput, delay, packet loss, and jitter. These metrics can be extracted from the trace file, as displayed above, and integrated to form a holistic network cost function.
Steps:
- Throughput: Total bytes received / simulation time.
- Delay: Time difference amongst sent and received events.
- Packet loss: Difference between the numbers of packets sent and received.
These metrics can be integrated into a cost function relaying on your application.
We have elaborately provided the computational process of the required parameters like energy consumption, transmission cost, link cost and so on for the calculation of network cost using the ns2 simulator tool. You can understand how the network performs the data transmission and how to analyse their overall performance.
To determine the network cost using the NS2 tool, you may visit ns2project.com, where we offer a variety of excellent research ideas and topics.