Using the 'sc_tracediff' Command (with examples)

The sc_tracediff command is a tool from the cooperative association for internet data analysis (CAIDA). It allows users to detect and display changes in traceroute paths, making it a powerful utility for network troubleshooting and analysis. The sc_tracediff command operates on files created by the scamper tool and provides a comparison of traceroute paths to identify any variations between datasets. This can be crucial for understanding network behavior, diagnosing issues, or managing network adjustments.

Use case 1: Show the difference between traceroutes in two warts files

Code:

sc_tracediff path/to/file1.warts path/to/file2.warts

Motivation:

When managing large networks, it’s essential to maintain reliable connectivity. This example is motivated by the need to identify any alterations in network routes that may affect performance or connectivity. By employing sc_tracediff, network administrators can quickly pinpoint differences between two sets of traceroute data, thus enabling them to understand which paths have changed and potentially trace the cause of disruptions.

Explanation:

• path/to/file1.warts: This argument represents the path to the first warts file containing a set of traceroute paths. It serves as the baseline for comparison.

• path/to/file2.warts: This argument represents the path to the second warts file. It is compared against the first file to detect any variations in traceroute paths.

Example Output:

Tracepath changes between file1.warts and file2.warts:
Route changed:
From: 192.168.1.1 -> 192.168.1.5 -> 10.0.0.1
To: 192.168.1.1 -> 192.168.1.9 -> 10.0.0.1

Use case 2: Show the difference between the traceroutes in two warts files, including those that have not changed

Code:

sc_tracediff -a path/to/file1.warts path/to/file2.warts

Motivation:

Sometimes, understanding both changes and consistencies in network paths can offer a comprehensive view of the network’s stability. This example highlights how you can use sc_tracediff not just to focus on changes, but also to confirm parts of the network that remain stable over time, offering a more thorough analysis.

Explanation:

• -a: This option enables the display of all traceroute paths, listing even those that have not changed. This perspective is beneficial for verifying overall network integrity.

• path/to/file1.warts and path/to/file2.warts: As previously mentioned, these are the data files being compared.

Example Output:

Tracepath results including unchanged paths:
No change: 192.168.2.1 -> 192.168.2.9 -> 10.0.0.5
Route changed:
From: 10.0.0.2 -> 10.0.0.5
To: 10.0.0.2 -> 10.0.0.6

Use case 3: Show the difference between the traceroutes in two warts files and try to show DNS names and not IP addresses if possible

Code:

sc_tracediff -n path/to/file1.warts path/to/file2.warts

Motivation:

Understanding network paths using domain names rather than IP addresses can simplify the analysis for individuals who are more familiar with hostnames. This use case demonstrates how converting IP addresses to DNS names can enhance readability and understanding of network topology.

Explanation:

• -n: This option attempts to translate the IP addresses into DNS names where feasible. It provides a user-friendly output that is aligned with human-readable domain names.

• path/to/file1.warts and path/to/file2.warts: These are the standard files being compared to reveal differences.

Example Output:

Tracepath changes with DNS names:
From: host1.example.com -> host2.example.com
To: host1.example.com -> newhost.example.com

Conclusion:

The sc_tracediff command is an invaluable tool for understanding and managing network paths. Its ability to contrast traceroute data helps network administrators maintain the reliability and efficiency of their systems. By leveraging options such as displaying all paths or converting IPs to DNS names, users can tailor the tool’s functionality to meet specific needs, enhancing clarity and depth in network analysis. Whether you’re ensuring connectivity, verifying stability, or simplifying path representations, sc_tracediff equips you with powerful insights.