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show chassis environment cb



Display environmental information about the Control Boards (CBs) installed on SRX Series Firewalls.



(Optional) Display environmental information about the specified CB.

Required Privilege Level


Output Fields

Table 1 lists the output fields for the show chassis environment cb command. Output fields are listed in the approximate order in which they appear.

Table 1: show chassis environment cb Output Fields

Field Name

Field Description


Status of the CB. If two CBs are installed and online, one is functioning as the primary, and the other is the standby.

  • Online—CB is online and running.

  • Offline— CB is powered down.


Temperature in Celsius (C) and Fahrenheit (F) of the air flowing past the CB.

  • Temperature Intake—Measures the temperature of the air intake to cool the power supplies.

  • Temperature Exhaust—Measures the temperature of the hot air exhaust.


Power required and measured on the CB. The left column displays the required power, in volts. The right column displays the measured power, in millivolts.

BUS Revision

Revision level of the generic bus device.

FPGA Revision

Revision level of the field-programmable gate array (FPGA).

PMBus device

Enhanced SCB on SRX Series Firewalls allows the system to save power by supplying only the amount of voltage that is required. Configurable PMBus devices are used to provide the voltage for each individual device. There is one PMBus device for each XF ASIC so that the output can be customized to each device. The following PMBus device information is displayed for devices with Enhanced MX SCB:

  • Expected voltage

  • Measured voltage

  • Measured current

  • Calculated power

Sample Output

show chassis environment cb (SRX5600 devices with SRX5K-SCB3 [SCB3] and Enhanced Midplanes)

show chassis environment cb node 1 (SRX5600 devices with SRX5K-SCB3 [SCB3] and Enhanced Midplanes)

Release Information

Command introduced in Junos OS Release 9.2.

Starting with Junos OS Release 12.1X47-D15, the SRX5K-SCBE (SCB2) is introduced and starting with Junos OS Release 15.1X49-D10, the SRX5K-SCB3 (SCB3) with enhanced midplane is introduced.