This experimental procedure outlines how to use the provided simulation to understand Network Time Protocol (NTP) concepts. In the simulation, we explore the effects on time synchronization between a client and a server in a number of scenarios. These include:

• Local Area Network (LAN)
• Local Area Network (noisy)
• Local Area Network (asymmetric)
• Metropolitan Area Network (noisy)
• Metropolitan Area Network (asymmetric)
• Wide Area Network (noisy)
• Wide Area Network (asymmetric)
• Globally Distributed Network (noisy)
• Globally Distributed Network (asymmetric)
• Custom

Each scenario can be customized by adjusting various parameters. The goal is to observe how different factors influence the accuracy and reliability of time synchronization in a networked environment. A figure plotting the actual round-trip time versus the time synchronization error is displayed to visualize the synchronization process.

Simulation Controls

Buttons

• Start Simulation: Begin the simulation with the selected parameters.
• Stop Simulation: Halt the simulation in progress.
• Synchronize Now: Force an immediate synchronization between the client and server (multiple packets may be exchanged to achieve synchronization).
• Send Packet: Add a packet to the current synchronization process manually. This may help improve the synchronization accuracy.
• Adjust Parameters: Modify the network and client parameters to observe their effects on synchronization.
• Clear Plot: Reset the current plot of round-trip time versus synchronization error.

Network and Simulation Parameters

• Round trip time (ms): The time taken for a packet to travel from the client to the server and back, in milliseconds.
• Round trip time variation (ms): The variation in the round trip time, simulating network jitter, in milliseconds.
• Round trip time asymmetry variation (ms): The variation in difference of forward and return trip times, simulating network asymmetry, in milliseconds.
• Simulation speed (ms/s): The speed at which the simulation progresses, in milliseconds per second.

NTP Client Parameters

• Initial time offset of the client (ms): The initial offset of the client's clock relative to the server's clock, in milliseconds.
• Drift rate of the client (ppm): The rate at which the client's clock drifts from the server's clock, in parts per million.
• Synchronization interval (ms): The time interval between synchronization attempts by the client, in milliseconds.
• Synchronization period (ms): The duration for which the client synchronizes with the server, in milliseconds.
• Synchronization packet interval (ms): The time interval between packets sent during synchronization, in milliseconds.

NTP Server Parameters

• Time error of the server (ms): The error in the server's clock relative to the actual time, in milliseconds.
• Delay at server before responding to a request (ms): The delay introduced by the server before responding to a client request, in milliseconds.

Experimental Steps

1. Load the Simulation Page

   • Open the Simulation tab in your browser to access the simulation interface.

2. Select a Scenario

   • Choose a scenario from the dropdown menu to simulate different network configurations.
   • The scenarios range from local networks to globally distributed networks with varying levels of noise and asymmetry.

3. Adjust Parameters and Observe Effects Use the control form to modify the following parameters individually and observe their effects on synchronization. The provided figure will help visualize the changes.

   Network Trip Time

   • Increase/decrease "Round trip time" to simulate longer or shorter network trip times.
   • Observation: Longer trip times may result in greater uncertainty in the time synchronization process.

   Network Asymmetry

   • Adjust "Round trip time asymmetry variation" to introduce unequal delays in the forward and return paths.
   • Observation: Higher asymmetry may result in greater discrepancies in calculated offsets.

   Network Trip Variation

   • Change "Round trip time variation" to simulate varying network jitter.
   • Observation: Greater variation can make synchronization less predictable and accurate.

   Client Offset

   • Set different values for "Initial time offset of the client" to observe the impact of initial clock differences.
   • Observation: Initial offsets should be corrected over multiple synchronization attempts.

   Client Drift Rate

   • Modify "Drift rate of the client" to simulate clock drift in the client.
   • Observation: Higher drift rates necessitate more frequent synchronization to maintain accuracy.

   Client Sync Interval and Period

   • Adjust "Synchronization interval" and "Synchronization period" to control the synchronization frequency and duration.
   • Observation: More frequent synchronization can mitigate the effects of clock drift but may increase network load.

   Server Response Delay

   • Change "Delay at server before responding to a request" to simulate server response delays.
   • Observation: Higher response delays can increase the uncertainty in synchronization.