High-level Fault Isolation Tips


Effective troubleshooting depends in part on measures that you take before you experience trouble in your network. Cambium recommends the following measures for each site:



Identify troubleshooting tools that are available at your site (such as a protocol analyzer).


Identify commands and other sources that can capture baseline data for the site. These may include:

·         Ping

·         tracert or traceroute

·         Throughput Test results

·         Throughput data

·         Configure GUI page captures

·         Monitor GUI page captures

·         Session logs


Start a log for the site, including:

·         Operating procedures

·         Site-specific configuration records

·         Network topology

·         Software releases

·         Types of hardware deployed

·         Site-specific troubleshooting process

·         Escalation procedures

·         GPS latitude/longitude of each network element


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
    • AP to SM
    • AP to CMM
    • AP to GPS
    • CMM to GPS
    • power
  • Researching System Logs of the involved equipment.
  • 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?

·         Have we changed something recently?

·         Have we seen other symptoms before this?


How wide-spread is the symptom?

·         Is the problem on only a single SM? (If so, focus on that SM.)

·         Is the problem on multiple SMs? If so:

o    is the problem on one AP in the cluster? (If so, focus on that AP)

o    is the problem on multiple, but not all, APs in the cluster? (If so, focus on those APs)

o    is the problem on all APs in the cluster? (If so, focus on the CMM and the GPS signal.)


Based on data in the System Log

·         Is intermittent connectivity indicated? (If so, verify your configuration, power level, SNR, cables and connections, and the speed duplex of both ends of the link).

·         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?

For more information on troubleshooting SM registration, see: How to Troubleshoot STA Registration

For guidelines on testing radio links with Communication or Reliability Challenges, see: Guidelines for Testing Radio Links with Communication or Reliability Challenges