Specifications

December 2008 Page 5–13
Chapter 5. Alternate Path Mode (APM)
5
tions and chassis ID numbers are identifi-
able.
Figure 5-10 shows a sketch of a sample loop.
Figure 5–10. Sample APM Loop Sketch.
3. Write the information
you gathered in Step 1
on the map you drew
in Step 2.
This should give you a
good overview of the
failure scenario. Figure
5-11 shows a sample
scenario of one type of
failure.
4. Analyze the failure
using the information
you gathered and the
possible scenarios.
By comparing the map
you completed in Step 3
with the possible
scenarios in Table 5-4,
you should be able to
complete your analysis and determine both
the location and the probable cause of the
failure.
5.1.5.3 Determining the Reason for
Failure
After determining the location and probable cause
of failure, your next step is to perform a further
analysis to determine the exact cause of failure. To
do this, you will need the following:
• The FOCUS event data (target buffer) you
saved or printed out earlier
• The FOCUS error count data (see below)
•Table 5-5
We recommend that you save or print regular
updates on the event data (target buffers) from the
chassis adjacent to the failure. If RNC is not
working, due to excessive data errors, you must do
this locally.
To get the FOCUS error count data, use the
FCS “Get Error Counts” command. This displays
Figure 5–11. Sample APM Failure Scenario.