The Lazy Networker

To test network latency using Wireshark, follow these steps to effectively capture and analyze packet data:Setting Up Wireshark

Install Wireshark: Download and install the latest version of Wireshark from the official website.
Select the Network Interface: Open Wireshark and choose the appropriate network interface to capture packets. This is typically your Ethernet or Wi-Fi connection.

Capturing Packets
Start Packet Capture:Click on the “Capture” menu and select “Start” or simply click the shark fin icon.
Allow Wireshark to run for a sufficient duration to capture relevant traffic.
Stop Packet Capture:Click on the red square button to stop capturing once you have enough data.

Analyzing Latency
Use TCP Stream Graphs:Go to “Statistics” in the menu.
Select “TCP Stream Graph” and then choose “Round Trip Time” (RTT) graph.
This graph will display the round-trip time for packets, allowing you to visualize latency over time1.

Inspect Individual Packets: Click on a specific packet in the capture window.
In the packet details pane, look for timestamps which indicate when packets were sent and received. You can calculate latency by subtracting these timestamps4.

Filter for Specific Protocols: Use display filters (e.g., tcp, icmp) to isolate specific types of traffic that may be contributing to latency issues.

Calculate Latency Using Timestamps: If you have access to both client and server captures, you can compare timestamps from both ends to measure latency more accurately by subtracting the client’s send time from the server’s receive time4.

Additional Analysis
Identify Potential Issues: Look for signs of congestion, such as packet loss or retransmissions, which can contribute to increased latency.
Use other statistics tools within Wireshark, such as “IO Graphs,” to visualize overall network performance.
By following these steps, you can effectively use Wireshark to measure and analyze network latency, helping you identify bottlenecks and optimize your network performance