Configuring Ambient Temperature
Understanding How Configuring Ambient Temperature Helps Optimize Power Utilization
The key to managing power in network infrastructure is the efficient utilization of provisioned power. Provisioned power is the minimum power that is required to bring a router or a switch online. Junos OS determines the minimum required power by considering the worst-case power requirement for all the FRUs installed in the device. One of the methods to optimize the provisioned power on MX Series routers or EX9200 switches is to configure the device to operate at a cooler temperature. You can enable a device to operate at a lower operating temperature by configuring a lower ambient temperature.
Ambient temperature is the maximum operating temperature for a device. By configuring an ambient temperature, you can optimize power provisioned for the cooling system and the line cards. The maximum speed at which fans operate depends on the configured ambient temperature. As the fan speed increases, the power consumed by the fans increases. As a result, the device consumes more power when the temperature is high because the fans run faster to maintain the operating temperature of the chassis within the configured limits.
When a router or a switch restarts, the system adjusts the power allocation or the provisioned power for the line cards on the basis of the configured ambient temperature. If enough power is not available, a minor chassis alarm is raised. However, the chassis continues to run with the configured ambient temperature. You can configure a new higher ambient temperature only after you make more power available by adding new power supply modules or by taking a few line cards offline. By using the provisioned power that is saved by configuring a lower ambient temperature, you can bring more hardware components online.
A specific ambient temperature value might not be applicable to a different geographical location, for example, in a colder region. For devices operating in colder regions, you can configure a lower ambient temperature, which helps reduce provisioned power significantly. However, in a region of higher temperature, you might need to configure a higher ambient temperature to ensure smooth functioning of the device. For example, if the router or switch operates in a colder region, you can set the ambient temperature to 25°C, which reduces the maximum fan speed, thereby reducing the maximum power consumption. Thus, by configuring an appropriate ambient temperature, you can reduce the provisioned power and save cost on network power infrastructure.
You can configure ambient temperature by using the set
chassis ambient-temperature (25C|40C|55C) statement at the [edit chassis] hierarchy level. The default ambient temperature
for MX Series routers and EX9200 switches is 40°C.
The set chassis ambient-temperature temperature
and show chassis ambient-temperature commands are not supported on
PTX10004, PTX10008, and PTX10016 routers because their power allocation is based on
the default ambient temperature.
Monitoring the Power Consumption of PTX5000 FPCs by Configuring the Ambient Temperature
You can configure the ambient temperature of the PTX5000 chassis to manage power allocated to the FPCs. You can set the ambient temperature of the chassis at 25° C, or 40° C. On system initialization, the power manager reads the ambient temperature and allocates power to the FPCs according to the power budget policy at that temperature.
To verify the power consumption of the FPCs, use the following statements:
Use the
show chassis power detail | grep "FPC"statement at the[edit]hierarchy level to view the power consumption of the FPCs.user@host> show chassis power detail | grep "FPC" FPC 0 448 FPC 1 419 FPC 2 373 FPC 3 0 FPC 4 0 FPC 5 0 FPC 6 0 FPC 7 0
Alternatively use the SNMP MIB command,
show snmp mib walk jnxOperatingFRUPower | grep "\.7\."to view the power consumption of each FPC:user@host> show snmp mib walk jnxOperatingFRUPower | grep "\.7\." jnxOperatingFRUPower.4.1.7.0 = 0 jnxOperatingFRUPower.7.1.0.0 = 457 < ------ For FPC 0 jnxOperatingFRUPower.7.2.0.0 = 428 < ------ For FPC 1 jnxOperatingFRUPower.7.3.0.0 = 381 < ------ For FPC 2 jnxOperatingFRUPower.15.7.0.0 = 0
Use the
show chassis alarmsstatement to view the alarms generated for any of the FPCs:user@host> show chassis alarms Alarm time Class Description 2007-04-08 05:51:12 UTC Minor FPC 1, Consumption > 90percent of allocated Budget 2007-04-08 05:51:12 UTC Minor FPC 0, Consumption > 90percent of allocated Budget 2007-04-08 05:50:26 UTC Minor FPC 0 SIB Link Error 2007-04-08 05:49:34 UTC Minor SIB 0 FPC Link Error 2007-04-08 05:48:02 UTC Minor No Redundant Power for FPC 0-7 2007-04-08 05:48:01 UTC Minor No Redundant Power for Rear Chassis 2007-04-08 05:48:01 UTC Minor No Redundant Power for Fan 0-2
If an FPC consumes more than 90% of the allocated power budget, the
Consumption > 90percent of allocated Budgetalarm is raised. FPC power consumption is measured at intervals of 65 seconds.Note:Starting in Junos OS Release 18.4R1, the PTX5000 routers do not raise a chassis alarm in the following events:
Power consumption by an FPC exceeds 90% of the allocated power budget.
Power consumption by an FPC exceeds 100% of the allocated power budget (in this case, a system log is registered).
Note:If the PTX5000 chassis has redundant power supply modules, and if one PSM fails, the FPCs can still be online. Only the
No redundant power supplyIf the PTX5000 chassis does not have redundant power supply modules, failure of one PSM can cause the FPCs to go offline, depending on the total chassis power available at that time.
When the power consumption of an FPC is more than the allocated budget for three consecutive intervals, the
Consumption > 90percent of allocated Budgetis cleared andPWR Range Overshootalarms is raised for that particular FPC and the ambient temperature is set to the next higher setting.user@host> show chassis alarms 9 alarms currently active Alarm time Class Description 2007-04-08 05:56:38 UTC Minor FPC 2, Consumption > 90percent of allocated Budget 2007-04-08 05:55:33 UTC Minor FPC 1, PWR Range Overshoot 2007-04-08 05:53:22 UTC Minor FPC 0, PWR Range Overshoot 2007-04-08 05:50:26 UTC Minor FPC 0 SIB Link Error 2007-04-08 05:49:34 UTC Minor SIB 0 FPC Link Error 2007-04-08 05:48:02 UTC Minor No Redundant Power for FPC 0-7 2007-04-08 05:48:01 UTC Minor No Redundant Power for Rear Chassis 2007-04-08 05:48:01 UTC Minor No Redundant Power for Fan 0-2
Note:Consumption > 90percent of allocated Budgetalarms are updated according to the new ambient temperature setting but the chassis ambient temperature is not changed.user@host> show chassis alarms 5 alarms currently active Alarm time Class Description 2007-04-01 04:36:53 UTC Minor No Redundant Power for FPC 0-7 2007-04-01 04:36:52 UTC Minor No Redundant Power for Rear Chassis 2007-04-01 04:36:51 UTC Minor No Redundant Power for Fan 0-2 2007-04-01 04:36:47 UTC Minor PDU 1 Absent
You can verify the temperature by using the
show chassis ambient-temperaturecommand.user@host> show chassis ambient-temperature Ambient Temperature: 25C
Enter the configuration mode and check the configured ambient temperature. Use the
show chassis ambient temperatureoperational mode command.user@host# show chassis ambient temperature Ambient Temperature: 25C
This is set to the last configured value.
To clear the temperature set for the overshooting condition, use the
request chassis power-manager reset ambient-configcommand.user@host> request chassis power-manager reset ambient-config
Verify the ambient temperature after the reset.
show chassis ambient-temperature Ambient Temperature: 25C
Verify the active alarms in the chassis by using the
show chassis alarmscommand.user@host> show chassis alarms 7 alarms currently active Alarm time Class Description 2007-04-01 04:36:53 UTC Minor No Redundant Power for FPC 0-7 2007-04-01 04:36:52 UTC Minor No Redundant Power for Rear Chassis 2007-04-01 04:36:51 UTC Minor No Redundant Power for Fan 0-2 2007-04-01 04:36:47 UTC Minor PDU 1 Absent
Managing Power Allocated to PTX5000 FPCs on the Basis of Chassis Ambient Temperature Configuration
The power management feature of the PTX5000 Packet Transport Router is enhanced to manage the power supplied to the FPCs on the router by configuring the ambient temperature of the chassis. You can set the ambient temperature of the chassis at 25° C, or 40° C. On system initialization, the power manager reads the ambient temperature and allocates power to the FPC according to the power budget policy at that temperature. If the actual power consumption of any FPC exceeds the configured value for more than three minutes, the power manager overrides the configured ambient temperature setting of that FPC, and resets its ambient temperature to the next higher level and reallocates power according to the new temperature setting. All the overshooting FPCs remain in the dynamic ambient temperature mode until the next reboot, or until you override it with a CLI command. The power manager then resets the power budget of the FRUs according to the configured ambient temperature setting.
If the ambient temperature is not set, then, 55° C is considered as the default ambient-temperature and FPCs are assigned power according to the default ambient temperature.
For example, if the chassis ambient temperature is set to 25°
C, the power manager allocates power to the FPCs according to the
power budget policy at 25 ° C. If an FPC consumes more than 90%
of the allocated power, an alarm—Consumption
> 90percent of allocated Budget—is raised. If
the FPC power consumption exceeds the allocated power for more than
three minutes, the PWR Range Overshoot alarm is raised and the power manager reallocates power to that
FPC according to the next higher temperature setting, that is, 40°
C .
During the PWR Range Overshoot alarm condition, you cannot reconfigure or delete the ambient temperature
setting. You can reset the ambient temperature to the earlier setting
after clearing the alarm condition by using the request chassis power-manager reset ambient-config command.
If the PTX5000 chassis has redundant power supply modules,
and if one PSM fails, the FPCs can still be online. Only the No redundant power supply
If the PTX5000 chassis does not have redundant power supply modules, failure of one PSM can cause the FPCs to go offline, depending on the total chassis power available at that time.