Question

The Unix utility traceroute, or its Windows equivalent tracert, can be used to find the sequence of routers through which a message is routed. Use this to find the path from your site to some others. How well does the number of hops correlate with the RTT times from ping? How well does the number of hops correlate with geographical distance?

Short answer

Use traceroute/tracert to record the number of hops and RTT to your destination. Compare the number of hops with RTT from ping and estimate geographical distance to analyze correlations.

Step-by-step solution

- Use traceroute or tracert

Open a command line interface on your computer. For Unix-based systems, use the command `traceroute `, and for Windows, use `tracert `, where '' is the address of the site you want to trace.

- Record the sequence of routers

Observe the output which lists each router (hop) your packet passes through along with the time taken for each hop. Record the number of hops and the RTT (Round Trip Time) for each hop.

- Use ping to find RTT

Next, use the `ping ` command to find the average RTT time for the same destination. Record this information.

- Compare hops with RTT

Analyze the data to see how the number of hops correlates with the RTT times from the ping command. Generally, more hops can indicate a higher RTT, but this is not always the case as RTT is affected by other factors such as the speed and performance of each router.

- Correlate hops with geographical distance

Estimate the geographical distance to the destination site. You may use map services or online tools for this. Compare this distance with the number of hops recorded. Note that while closer geographical locations often correlate with fewer hops, this is not always accurate due to network architecture and routing policies.

Key concepts

traceroute usage

The 'traceroute' utility is a powerful tool to understand how packets travel across a network. This command traces the path your data takes from your computer to a specified destination. By running `traceroute ` on Unix-based systems or `tracert ` on Windows, you can observe each router or node that your data flows through. This helps diagnose network problems and understand the route taken.

router hops

Router hops are essentially the stops your data packet makes as it travels across the network to its destination. Each hop represents a router that forwards the packet to the next point. By using traceroute, the sequence of these routers, including the time taken for each hop, is displayed. Counting the number of hops helps you see how many intermediary devices are involved.

Round Trip Time (RTT)

Round Trip Time (RTT) measures the time it takes for a packet to travel to the destination and back to the source. With traceroute, the RTT for each hop is displayed, providing insights into which hops might be slowing down the packet. Higher RTT values can indicate network congestion or longer distances. RTT is crucial for assessing network performance.

ping command

The 'ping' command is a simpler yet equally important tool used to measure the RTT of packets to a destination. By running `ping `, you continuously send packets to the target and receive echo responses. The result shows the average RTT, helping diagnose connectivity issues and assessing the performance.

geographical distance and network routing

Geographical distance plays a role in network routing but isn't the only factor. While shorter distances often mean fewer hops and lower RTTs, other elements like network policies and infrastructure impact routing. More hops don't always equal higher RTT, which can be influenced by router performance and congestion. Comparing traceroute hops with physical distance helps comprehend this complexity.