About the G/D/C/B/A-Series Overtemp Threshold feature

[FAQ_User]

Article ID: 11747

Products
G-Series, firmware 1.02.00.0043 and higher
D-Series, firmware 6.03.01.0008 and higher
C5-Series, all firmware
C3-Series, firmware 1.02.01.0004 and higher
C2-Series, firmware 5.02.01.0006 and higher
B5-Series, all firmware
B3-Series, firmware 1.02.01.0004 and higher
B2-Series, firmware 4.02.01.0006 and higher
A4-Series, firmware 6.61.02.0007 and higher

Changes
Configured the "Temp alarm max threshold" ('set system temperature...') to a lower value.
Loss of Air Conditioning (AC) in network closet, creating over-temp/over-thermal condition.

Symptoms
Unit has a blinking red CPU LED.
Unit sent a Temp Alarm trap.
Unit sent a Temp Alarm syslog item.
Unit is otherwise functional, passing traffic, with full management access.

Cause
The (standard) LED, (optional) trap, and (optional) syslog symptoms are occurring because, as visible in the output of a 'show system' command, the "Thermal Threshold" value has reached or exceeded the "Temp alarm max threshold" value.

These are elements of a new feature announced in release notes; which state, in the 'Firmware Changes and Enhancements' section:
(G/C3/C2/B3/B2-Series)Added support for protecting the health of the switch based on predetermined safe
operating temperature limits. The administrator can change the maximum thermal
threshold where a trap and syslog message is generated warning them of
high-temperature conditions before service is affected.(D-Series)High-Temperature Alerts allows the network administrator to change the maximum
temperature threshold where a trap and syslog message is generated warning them of
high-temperature conditions before service is affected.
The controlling command set uses the format:
set system temperature {[syslog enable | disable] [trap enable | disable]
[overtemp-threshold ]}
The default condition, visible in the output of a 'show config all system' command, is:
set system temperature syslog disable trap disable overtemp-threshold 100
The readout for this functionality, slightly different for the G, D, and C/B/A-Series, is located in the output of a 'show system' command:
C2(su)->show system
. . .
Temp-Alarm
-----------
off <-- Supported, Not overtemp [off | on | NA]
Thermal Threshold: 58% <-- What the measurement is now
Temp alarm max threshold: 100% <-- Per 'overtemp-threshold'
Temp alarm trap: disabled <-- Per 'trap disable'
Temp alarm syslog: disabled <-- Per 'syslog disable'
. . .
C2(su)->
The B2G124-24, C2G124-24, C2G134-24P, and C2G170-24 have no onboard temperature sensor, and thus do not support the feature discussed in this document. A designation of "NA" indicates this non-support.
G3(su)->show system
. . .
Temp-Alarm
-----------
off <-- Not overtemp [off | on]
Temp alarm max threshold: 100% <-- Per 'overtemp-threshold'
Temp alarm trap: disabled <-- Per 'trap disable'
Temp alarm syslog: disabled <-- Per 'syslog disable'
Thermal Sensor Thermal Threshold
-------------- -----------------
Fixed Slot 68% <-- What the measurement is now
Power Supply 2 62% <-- What the measurement is now
. . .
G3(su)->
Notes:

• The "Thermal Threshold" value is not an actual temperature reading, but a percentage of the maximum thermal capacity of the switch.
• The "Temp alarm max threshold" value is the high-water mark that, when reached, triggers the set of user alerts described above.
• When a high temperature alert condition occurs, the CPU LED on the front panel of the switch will flash red. In addition, if enabled, a syslog message will be logged and/or an SNMP trap will be sent. This occurs on an over-temp condition regardless of whether the user has chosen to configure the system temperature parameters. However, an over-temp condition is more likely when the user has reduced the "Temp alarm max threshold" from its default value.
• Any resulting traps are of the following types, as defined in the cabletron-traps.txt MIB file:
  • chHotTemp, OID 1.3.6.1.4.1.52.0.11004
  • chTempOK, OID 1.3.6.1.4.1.52.0.11008

Solution
Functions as Designed (FAD)

For further information about this feature, please refer to the Configuration Guide for your product and firmware version.
See also: 11520.