Finisar Surveyor - Manual (Page 304)

10-100
Surveyor
User’s Guide
Unstable MST
Counter
The Unstable MST counter increments when a change in the number of MST
topology changes per second exceeds a threshold. The default threshold is a delta of
5 topology changes per second; however, this value can be changed from the Expert
Thresholds tab in the
Configuration
→
Module
→
Settings... menu. A count of all
Unstable MST events displays in the Overview counters of Expert View. A
threshold for this counter can be set in Expert Alarms.
MST topology changes are topology changes required to support IEEE 802.1d
(Minimum Spanning Tree). Excessive topology changes infer that the Minimum
Spanning Tree (MST) is unstable.
Expert Symptom
Unstable MST events are automatically logged as expert symptoms. The Symptom
Summary field provides information about the rate of change for the MST topology.
For example:
Rate of change of Topology=10
Diagnostic Details
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Problem Description:
The threshold for the number of IEEE 802.1D packets with topology change bit has
been exceeded for this segment. The Spanning tree may be unstable.
__________________________________________________________________
Probable Cause(s):
1. There may be too many configuration changes for the bridge/switch.
2. There may be a temporary loss of connectivity.
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Recommended Action(s):
1. Identify the device causing this message and fix it.