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Configuring Ambient Temperature on SRX5800 Services Gateway

 

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 device 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 a device 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 line cards.

When a device 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 device operates in a colder region, you can set the ambient temperature to 25°C, which reduces the power consumption of line cards, 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 SRX5800 Services Gateways is 55°C.

When the ambient temperature is set and if the temperature exceeds the ambient temperature, the power requirement of the services gateway may exceed its actual capacity. If this condition persists for 30 seconds:

  1. All the line cards will be reset.

  2. The system will power off one Services Processing Card (SPC) to save power.

  3. A major alarm is raised.

Monitoring the Power Consumption of SRX5800 Services Gateways Cards by Configuring the Ambient Temperature

You can configure the ambient temperature of the SRX5800 chassis to manage power allocated to the cards. You can set the ambient temperature of the chassis at 25° C, 40° C, or 55° C. On system initialization, the power manager reads the ambient temperature and allocates power to the cards according to the power budget policy at that temperature.

  1. To configure the ambient temperature, include the set chassis ambient-temperature 25|40|55 statement at the [edit] hierarchy level in the configuration mode:
  2. To verify the ambient temperature of the chassis, use the show chassis ambient-temperature command at the [edit] hierarchy level in the operational mode:

To verify the power consumption of the cards, use the following statements:

  1. 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"

    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\."
  2. Use the show chassis alarms statement to view the alarms generated for any of the cards:
    user@host> show chassis alarms
    Note

    If the SRX5800 chassis has redundant power supply modules, and if one PSM fails, the card can still be online. Only the No redundant power supply alarm is raised.

    If the SRX5800 chassis does not have redundant power supply modules, failure of one PSM can cause the cards to go offline, depending on the total chassis power available at that time.

  3. When the power consumption of a card is more than the allocated budget for 60 seconds, PWR Range Overshoot alarm is raised for that particular card.
    user@host> show chassis alarms

Calculating Power Requirements to Support Eight SRX5K-SPC3s with Three IOC3s or Three IOC4s on an SRX5800 Services Gateway

Ambient temperature is the maximum operating temperature for a device. By configuring an ambient temperature on SRX5800 Services Gateway, you can optimize power provisioned for SPC3, IOC3 and IOC4 on SRX5800.

After you set the ambient temperature of SRX5800 to 25° C, SRX5800 can support eight SRX5K-SPC3s with three IOC3s or three IOC4s.

The SRX5800 Services Gateway chassis with normal-capacity AC power supplies has one overall zone. The SRX5800 Services Gateway Chassis with high-capacity AC power supplies or either standard- or high-capacity DC power supplies is zoned. Zoning means that certain components are powered by specific power supplies (see Table 1 and Figure 1 for information on zoning). When calculating power requirements, be sure that there is adequate power for each zone.

Three AC power supplies are mandatory for a SRX5800 Services Gateway chassis with normal-capacity AC power supplies.

Table 1: SRX5800 Services Gateway Zoning

Zone

Power Supply (PEM)

Components Receiving Power

Zone 0

PEM 0 or 2

  • Lower fan tray

  • IOC/SPC slots 6 through 11

  • SCB slots 1 through 2

Zone 1

PEM 1 or 3

  • Upper fan tray

  • IOC/SPC slots 0 through 5

  • SCB slot 0

Figure 1: Power Distribution from DC and High-Capacity AC Power Supplies in the SRX5800 Services Gateway Chassis
Power Distribution from
DC and High-Capacity AC Power Supplies in the SRX5800 Services Gateway
Chassis

After setting the ambient temperature of SRX5800 to 25° C, you can have two different configurations:

  1. SRX5800 with eight SRX5K-SPC3s and three IOC3s, See Table 2Note
    • You must install four high-capacity PEMs with two inputs for each PEM.

    • You must install atleast one IOC3 and four SPC3s in each power zone.

    • You must have the third SCB in Slot 6.

    • SCB4 is not supported.

    • You can install IOC3 in slot 11 only when the ambient temperature is configured to 25° C.

    • Dual Routing Engines is optional.

    • You cannot install SPC3 in slot 11.

    • In chassis cluster if you configured dual control links, then each power zone must have one control link.

    • You must power-cycle the SRX5800 Services Gateway after the configuration.

    Table 2: SRX5800 Services Gateway Power Requirement with 8xSPC3 and 3xIOC3

    Zone

    Chassis Component

    Part Number

    Power Budget (default)

    Power budget (with 25° C config)

    Power Budget at Ambient Temperature (25° C)

    Zone 1

    High-capacity cooling system (Upper Fan Tray)

    SRX5800-HC-FAN

    320 W

    320 W

    320 W

    SPC - slots 0 through 3

    SPC3

    650 W * 4 =2600 W

    615 W * 4 =2460 W

    614.5 W * 4 =2458 W

    IOC - slots 4 and 5

    IOC3

    607 W * 2 =1214 W

    511 W * 2 =1022 W

    511 W * 2 =1022 W

    SCB 0

    SCB3 with RE2

    275 W

    275 W

    245 W

    Zone 0

    SCB 1

    SCB3 with RE2

    275 W

    275 W

    245 W

    SCB 2/Slot 6

    SCB3

    185 W

    185 W

    155 W

    SPC - slots 7 through 10

    SPC3

    650 W * 4 =2600 W

    615 W * 4 =2460 W

    614.5 W * 4 =2458 W

    IOC - slot 11

    IOC3

    607 W

    511 W

    511 W

    High-capacity cooling system (Lower Fan Tray)

    SRX5800-HC-FAN

    320 W

    320 W

    320 W

    Total power allocation

    8396 W

    7828 W

    7734 W

  2. SRX5800 with eight SRX5K-SPC3s and three IOC4s. See Table 3Note
    • You must install four high-capacity PEMs with two inputs for each PEM.

    • You must install atleast one IOC4 and four SPC3s in each power zone.

    • You must have the third SCB in Slot 6.

    • SCB4 is not supported.

    • You can install IOC4 in slot 11 only when the ambient temperature is configured to 25° C.

    • Dual Routing Engines is optional.

    • You cannot install SPC3 in slot 11.

    • In chassis cluster if you configured dual control links, then each power zone must have one control link.

    • You must power-cycle the SRX5800 Services Gateway after the configuration.

    Table 3: SRX5800 Services Gateway Power Requirement with 8xSPC3 and 3xIOC4

    Zone

    Chassis Component

    Part Number

    Power Budget (default)

    Power budget (with 25° C config)

    Power Budget at Ambient Temperature (25° C)

    Zone 1

    High-capacity cooling system (Upper Fan Tray)

    SRX5800-HC-FAN

    320 W

    320 W

    320 W

    SPC - slots 0 through 3

    SPC3

    650 W * 4 =2600 W

    615 W * 4 =2460 W

    614.5 W * 4 =2458 W

    IOC - slots 4 and 5

    IOC4

    545 W * 2 =1090 W

    440 W * 2 =880 W

    440 W * 2 =880 W

    SCB 0

    SCB3 with RE2

    275 W

    275 W

    245 W

    Zone 0

    SCB 1

    SCB3 with RE2

    275 W

    275 W

    245 W

    SCB 2/Slot 6

    SCB3

    185 W

    185 W

    155 W

    SPC - slots 7 through 10

    SPC3

    650 W * 4 =2600 W

    615 W * 4 =2460 W

    614.5 W * 4 =2458 W

    IOC - slot 11

    IOC4

    545 W

    440 W

    440 W

    High-capacity cooling system (Lower Fan Tray)

    SRX5800-HC-FAN

    320 W

    320 W

    320 W

    Total power allocation

    8210 W

    7615 W

    7521 W