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Troubleshooting Protocol Analysers

What kind of information will a Protocol Analyser provide to help troubleshoot or maintain the overall health of my LAN or Switch ?

Protocol Analysers should provide three main sources of information about your LAN traffic.

1. Network Statistics about traffic flow, station health and network or station line errors. This information helps identify trends and general conditions that may signal an unexpected network problem condition, or a load issue that is causing slowdowns. Additionally if you are considering adding a switch, the statistical traffic breakdown can show how best to implement the new switch. If you currently have a switch installed, statistical analysis can show if your switch is configured correctly and your ports are supporting a balanced load of LAN traffic.

2. Packet Capture and Decode displays LAN traffic (packets) decoded into specific function and sub-function for LAN or protocol problem isolation. Being able to view the specific packet-by-packet conversion can show exactly what is happening during a system-to-system communication, both when things are functioning correctly and when things are not.

3. Trending Information displays historical usage data over days, weeks, months or even years. This information provides a historical perspective on any new problem, and can show trends that may indicate a potential problem before it happens.

Examples of  Network Statistics troubleshooting applications:

Viewing frame errors can show if a LAN slowdown is because of excess CRC or alignment errors. Once the error rate is determined to be above normal, viewing errors by station will show which stations are sending the error packets, and let you focus your attention to the source of the problem.

Protocol Analyser Statistics displays the percentage of your LAN bandwidth that a particular protocol is using. This helps determine efficient segmentation, and allows for problem isolation based on application or server type.

Station Statistics shows the traffic generation by each station, server, bridge, router and the percent of the total bandwidth each station is using. With this information, you can determine who is using your bandwidth and what stations or devices are using more bandwidth than expected. For example, if one station is sending 40% of the total data sent this could indicate either a faulty network adapter (multiple retries) or simply a device that consumes more network bandwidth than expected. In either case, having a Protocol Analyser allows you to take the appropriate action based on facts, not guesswork.

Packet Capture and Decode allows you to capture traffic in real time and record and view the decoded information. Packet decodes show you conversations between workstation and host, between workstations or between hosts. This information helps in any problem situation by showing you exactly what is happening and when, and exactly which device is doing what.

Some example problem situations where a Protocol Analyser's information is indispensable:

Host sessions are "hanging" - packet capture and decode will show which system sent the last packet and which system failed to respond. This helps pinpoint which device - host or workstation - is causing the problem.

Problematic network printing - an analyser answers the question: "Did the station send the job or does it just look as though it was sent?

Can't log in - Packet Capture can display login negotiations, retransmits and response times to determine where the problem is, and where to focus your attention.