3Com 3C15500 - Network Director - PC, User Manual

Page: 396 / 924

392 C
HAPTER
9: P
ERFORMANCE
R
EPORTING
These database files are never automatically removed by 3Com Network
Director, though the file size is allocated on initial creation and will not
increase over time. For more on file sizes and managing the database
size, see
“Database management” on page 398 .
Examples
Determining the
cause of high errors
on a link
An event has just been logged due to a link having a high number of
errors. To determine the cause of high errors on the link:
1 Launch the event browser.
2 Select the event.
3 Launch the More Detail dialog box. This gives an explanation of the
event.
4 Navigate to the Graph tab to see the monitor history for immediately
before and after the time the event was generated.
5 To launch the historical report for this link, click the hotlink below the
graph.
6 Scroll down to the Errors graph at the daily resolution.
7 Click the hyperlink to view the breakdown of errors.
This report breaks down error types into under- and oversized packets,
fragments, CRC errors and jabbers. This will enable you to determine the
cause of the high number of errors. For example, a high volume of
fragments indicates a high utilization on the link. To verify this check the
utilization graph in the same report.
Predicting demand
for bandwidth
requirements
You have been asked to provide estimates for required network upgrades
over the coming months. To do this:
1 Select one of your core links.
2 Launch the historical report for the link by selecting the Monitoring >
Historical Report menu option.
3 Click the Yearly Graphs (1 day average) hot-link at the top of the report to
navigate to the yearly resolution graphs.
4 Scroll down to the Utilization graph and examine it to determine its trend.