Managing the NetIron MLX Series Chassis and Modules
December 2008
© 2008 Foundry Networks, Inc.
5-7
Figure 5.1 Fan Speeds and Temperature Thresholds
The low and high temperature thresholds enable the NetIron MLX Series system to determine at which speed the
fans should operate. In general, the fans operate as follows:
•
If the temperature of all modules falls between the low and high thresholds for a fan speed, the fan continues
to operate at that fan speed.
•
If the temperature of a management module or the switch fabric module or two interface modules exceeds the
high threshold specified for a fan speed, the fan increases its speed to the next higher speed. If the
temperature of any of these modules exceeds the high threshold for the high speed for three minutes (the
actual number of polls is determined by the setting of the
temp-poll-period
command), the system shuts
down the modules to prevent damage. (For information about
temp-poll-period
command, see “Changing
the Temperature Polling Interval” on page 5-11.)
•
If the temperature of a management module, the switch fabric module, and all interface modules falls below
the low threshold for a fan speed, the fan decreases its speed to the next lower speed. If the temperature of all
modules falls below the high threshold for the low speed, the fan operates at the low speed.
If the temperature of a management module or the switch fabric module or two interface modules exceeds the high
temperature threshold for any of the fan speeds, the system sends a warning message to the system log and an
SNMP trap. For information about viewing the warning messages, see “Displaying Temperature Warnings” on
page 5-12.
Table 5.3 outlines the default low and high temperature thresholds for each module and fan speed.
Operating
Temperature
Medium
Speed
Low Speed
Med-High
Speed
High
Speed
50 55 60 65 70 75 80 85 90 95
High, 60 deg.
Low 57, deg.
High, 70 deg.
Low, 67 deg.
High, 80 deg.
Low, 77 deg. High, 85 deg.
