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Tip of the Month

January 2001

Enhancing Workstation Analysis

When using a protocol analyzer to investigate performance issues specific to a particular workstation, capture packets from the workstation's segment (either via a hub or a mirror/span port off a switch) AND take a snapshot of the workstation's configuration parameters. Sometimes it also pays to capture all traffic on the user's segment during a problem trace, because the background traffic can provide additional clues related to the problem (for example, maybe those spanning tree Bridge Protocol Data Unit (BPDU) packets aren't broadcasting at fixed intervals). These days, with fewer users per hub and in some cases one user per switch port, you won't capture as much traffic as the shared media of old. Later, you can always filter out the workstation traffic.

Taking a snapshot of a workstation's IP and MAC parameters along with system information will help you to remember how the workstation was configured (including CPU speed, physical and virtual memory, running processes, etc.) when you obtained your trace.

For Windows platforms, use the command prompt "ipconfig /all >ipsetupl.txt" to save IP information to a text file, then transfer the file to your analyzer (via floppy disk if you are using a portable analyzer) and store it in the same directory as your trace files. In a similar fashion, use the GUI "winmsd" command to display and save comprehensive system information.

By making this a habit, you will always have comprehensive information about the platform along with your trace when comparing different workstations (or servers for that matter) for performance-related issues.