User's Manual

Table Of Contents
General fault isolation process
Troubleshooting
7-2
pmp-0049 (September 2012)
General fault isolation process
Effective troubleshooting also requires an effective fault isolation methodology that includes
attempting to isolate the problem to the level of a system, subsystem, or link, such as
o AP to SM
o AP to CMM
o AP to GPS
o CMM to GPS
o BHM to BHS
o BHM to CMM
o power
researching Event Logs of the involved equipment
interpreting messages in the Event Log
answering the questions listed in the following section.
reversing the last previous corrective attempt before proceeding to the next.
performing only one corrective attempt at a time.
Questions to help isolate the problem
When a problem occurs, attempt to answer the following questions:
What is the history of the problem?
o Have we changed something recently?
o Have we seen other symptoms before this?
How wide-spread is the symptom?
o Is the problem on only a single SM? (If so, focus on that SM.)
o Is the problem on multiple SMs? If so
is the problem on one AP in the cluster? (If so, focus on that AP)
is the problem on multiple, but not all, APs in the cluster? (If so, focus on those APs)
is the problem on all APs in the cluster? (If so, focus on the CMM and the GPS signal.)
Based on data in the Event Log
o does the problem correlate to External Hard Resets with no WatchDog timers? (If so, this
indicates a loss of power. Correct your power problem.)
o is intermittent connectivity indicated? (If so, verify your configuration, power level, jitter,
cables and connections, and the speed duplex of both ends of the link).
o does the problem correlate to loss-of-sync events?
Are connections made via shielded cables?
Does the GPS antenna have an unobstructed view of the entire horizon?
Has the site grounding been verified?