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RouteExplorer™ Tutorial – Troubleshooting and Diagnostics

What exactly went wrong?

In previous section we showed how Route Explorer couldisolate a routing failure to the prefix and router. In this section we show how to drill-down even further todetermine the nature of the failure.

Figure 1shows a list of all events that were related to the prefix in question. This list can be displayed from RouteExplorer’s history navigator using the Events button. Selecting a time period just before the outage will displayall events from all sources during that time. This list may then be filtered to show only the eventsconcerning the failing prefix. The filter specification appears at the top ofthe events window.

Figure 1

Having thus narrowed to all events concerning failing prefixwe note that both routers to which the server network is connected to --10.1.251.6 and 10.1.251.7 are reporting the prefix flapping. The flap frequency ranges from 5minutes to 35 minutes. There is astrong indication that this is a switch in the server LAN or a load balancerthat is rebooting.

With this detailed knowledge, the routing engineer candiscuss the problem with the server maintenance engineers and problem can befixed without further delay.

HOW TO:

Open an X Windows or VNC session to the Route Explorer.
Open topology and open History Navigator (see above)
Show Events List:

Click on Event button.
Select begin and end times for the event list. The event list will be displayed with the first 1000 events in the selected period.
To see the router or link affected by any particular event, simply click on it in the list. The event will be highlighted in blue/cyan background and the router or link involved will be highlighted in the topology map.

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