How to Calculate Network NTP Management in NS2
To calculate the Network Time Protocol (NTP) management within NS2, which encompasses replicating the performance of the NTP that is responsible for synchronizing the clocks of various network devices to a usual reference time. Network NTP management using NS2 can be mimicked the exchange of time synchronization messages among the clients and an NTP server, compute the clock offsets, and analyse the synchronization accuracy over time.
Although NS2 does not directly support NTP, we can be replicated the NTP-like behaviour by describing an NTP server node and client nodes, then swapping synchronization messages, and tracing the accuracy of time synchronization over the network. Given below is a simple guide for simulating and computing the NTP management in NS2:
Steps to Simulate and Calculate NTP Management in NS2
- Set Up NS2 Simulation with NTP-Like Behavior
To replicate the NTP, describe one node as the NTP server (reference time) and other nodes as NTP clients, which request time synchronization. The clients are receive time updates from the server, then compute the clock offset, and alter their clocks consequently.
Example NS2 Script for Simulating NTP Management
# Create NS2 simulator instance
set ns [new Simulator]
# Open trace file for logging NTP events
set tracefile [open ntp_management_trace.tr w]
$ns trace-all $tracefile
# Define network nodes
set ntp_server [$ns node] ;# Node simulating the NTP server (reference clock)
set client1 [$ns node] ;# NTP client node 1 requesting time sync
set client2 [$ns node] ;# NTP client node 2 requesting time sync
# Create duplex links between nodes
$ns duplex-link $ntp_server $client1 1Mb 10ms DropTail
$ns duplex-link $ntp_server $client2 1Mb 10ms DropTail
# Set up UDP agents to simulate NTP synchronization messages
set udp_server [new Agent/UDP]
$ns attach-agent $ntp_server $udp_server
set udp_client1 [new Agent/UDP]
$ns attach-agent $client1 $udp_client1
$ns connect $udp_client1 $udp_server
set udp_client2 [new Agent/UDP]
$ns attach-agent $client2 $udp_client2
$ns connect $udp_client2 $udp_server
# Set up CBR traffic to simulate NTP synchronization messages from clients to server
set ntp_sync1 [new Application/Traffic/CBR]
$ntp_sync1 set packetSize_ 500
$ntp_sync1 set interval_ 1.0 ;# Sync interval from client1 (every 1 second)
$ntp_sync1 attach-agent $udp_client1
set ntp_sync2 [new Application/Traffic/CBR]
$ntp_sync2 set packetSize_ 500
$ntp_sync2 set interval_ 1.5 ;# Sync interval from client2 (every 1.5 seconds)
$ntp_sync2 attach-agent $udp_client2
# Start NTP synchronization process
$ns at 0.5 “$ntp_sync1 start”
$ns at 1.0 “$ntp_sync2 start”
# Stop synchronization after some time
$ns at 4.0 “$ntp_sync1 stop”
$ns at 4.5 “$ntp_sync2 stop”
# End simulation at 5 seconds
$ns at 5.0 “finish”
proc finish {} {
global ns tracefile
$ns flush-trace
close $tracefile
exit 0
}
# Run the simulation
$ns run
Explanation:
- NTP Server: The node ntp_server mimics the reference clock (NTP server).
- Clients: client1 and client2 are performs as NTP clients, which request time synchronization from the server.
- Traffic: CBR traffic replicates the exchange of time synchronization messages (e.g., NTP requests from the client and NTP responses from the server).
- Sync Interval: Various intervals for harmonisation messages are used to mimic differing the client sync periods.
- Simulating NTP Synchronization Process
- NTP Request: Clients delivers the synchronization requests to the NTP server at normal intervals.
- NTP Response: The NTP server reacts with the reference time, and the clients are modifies their clocks rely on the received time.
- Clock Offset: The clients are compute the clock offset (difference between their clock and the server’s reference clock) and try to reduce this offset over time.
- Monitor NTP Synchronization Events
The trace file will be recorded the time synchronization messages transmitted from clients to the server and the server’s responses. We can be examined the trace file to estimate the clock offset, round-trip time, and other metrics are related to time synchronization.
- Calculate Key NTP Management Metrics
Clock Offset
The clock offset is the variance among the time reported by the NTP server and the time at the client when the synchronization message is received. The aim is to reduce this offset via periodic synchronization.
Below is an AWK script to assess clock offset for client1:
awk ‘
{
if ($1 == “+”) { # Message sent from ntp_server
if ($3 == “ntp_server”) {
server_time[$7] = $2; # Record the server timestamp
}
}
if ($1 == “r” && $3 == “client1”) { # Message received at client1
if (server_time[$7] != “”) {
clock_offset = $2 – server_time[$7]; # Calculate the clock offset
print “Clock Offset between ntp_server and client1:”, clock_offset, “seconds”;
}
}
}’ ntp_management_trace.tr
When the message is received, this script computes the clock offset by comparing the server’s time with the client’s local time.
Round-Trip Time (RTT)
The round-trip time (RTT) is the time it takes for a harmonisation message to travel from the client to the server and back. It supports in estimating the network delays and modifying the synchronization process consequently.
The following is an AWK script to estimate RTT for client1:
awk ‘
{
if ($1 == “+”) { # Message sent from client1
if ($3 == “client1”) {
send_time[$7] = $2; # Record the time the request was sent
}
}
if ($1 == “r” && $3 == “client1”) { # Message received at client1
if (send_time[$7] != “”) {
rtt = $2 – send_time[$7]; # Calculate the round-trip time
print “Round-Trip Time for client1:”, rtt, “seconds”;
}
}
}’ ntp_management_trace.tr
This script computes the RTT by determining the time from when the message is transmitted until the response is received.
Synchronization Accuracy
Synchronization accuracy estimates how closely the clients’ clocks are synchronized with the NTP server’s reference clock. We can be computed it by observing how the clock offset alters over time.
Here’s an AWK script to estimate the synchronization accuracy for client1:
awk ‘
{
if ($1 == “r” && $3 == “client1”) {
if (sync_accuracy_start == 0) {
sync_accuracy_start = $2; # Start tracking synchronization time
}
sync_accuracy_end = $2; # Continuously update the end time of synchronization
}
}
END {
print “Synchronization Duration for client1:”, sync_accuracy_end – sync_accuracy_start, “seconds”;
}’ ntp_management_trace.tr
This script traces the whole synchronization duration for client1 then indicating how long the client has been harmonised with the NTP server.
- Evaluate Synchronization Quality
When we have evaluated the key metrics such as clock offset, RTT, and synchronization accuracy then we can be computed the quality of the synchronization. For sample:
- Lower clock offset: Shows that the client is closely synchronized including the NTP server.
- Lower RTT: Indicates lower network delays that leads to more accurate time synchronization.
- Stable synchronization accuracy: Means which the client is reliably synchronized with minimal fluctuations.
- Visualize NTP Synchronization Metrics
We can be used the tool Python (matplotlib) to envision the NTP synchronization metrics, like clock offset, RTT, and synchronization accuracy, to know better the performance of NTP in the simulation.
Example Python Plot for Clock Offset:
import matplotlib.pyplot as plt
# Example data for clock offset over time
time = [0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5]
clock_offset = [0.02, 0.015, 0.01, 0.005, 0.003, 0.002, 0.0015, 0.001, 0.0008] # Example clock offset data
plt.plot(time, clock_offset, marker=’o’)
plt.title(‘Clock Offset Over Time’)
plt.xlabel(‘Time (seconds)’)
plt.ylabel(‘Clock Offset (seconds)’)
plt.grid(True)
plt.show()
Summary
To assess the network NTP management in NS2:
- Set up the simulation: Describe an NTP server and clients and replicating time synchronization using UDP traffic.
- Monitor synchronization events: Trace the exchange of time synchronization messages in the trace file.
- Calculate key metrics: We can use the AWK scripts to estimate the clock offset, round-trip time, and synchronization accuracy.
- Evaluate synchronization quality: Measure how successfully the clients are synchronized with the NTP server rely on the computed metrics.
- Visualize results: We can be used the tools such as Python to plot synchronization metrics like clock offset and RTT.
To conclude, we comprehensively implicit and learn the concepts and stepwise approach on how to calculate and simulate the Network NTP management through the NS2 simulation tool. Furthermore, we will be presented more details regarding this topic in another manual. We’re here to help you with your performance analysis! Just send us the details about your parameters. If you need info about your Network NTP Management in the NS2 tool, reach out to us. We can also help you brainstorm cool project ideas and topics. Our work includes NTP server nodes, client nodes, and a lot more to support your project.