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[Junos] Major Alarm 'CB x SG2P Revision unsupported'



Article ID: KB36110 KB Last Updated: 29 Mar 2021Version: 3.0

This article explains the meaning of 'CB x SG2P Revision unsupported' alarm and the steps to resolve it.


Active Alarm:

user@host> show chassis alarms
1 alarms currently active
Alarm time               Class  Description
2020-01-06 19:18:10 PST  Major  CB 0 SG2P Revision unsupported

Syslog Message:

alarmd[1530]: Alarm set: CB color=RED, class=CHASSIS, reason=CB 1 SG2P Revision unsupported

The following chassisd message may also appear in logs:

chassisd[1378]: acb_sglink_init: Oceanus SG2P FPGA rev(20) < minimum rev(26)

  1. CB SGLS version does not match with the other CB.
  2. Very old Firmware on the CB.

Check the CB Environment:

user@host> show chassis environment cb
CB 0 status:
State                      Online Master
Temperature                37 degrees C / 98 degrees F
Power 1
1.0 V                        999 mV
1.2 V                       1214 mV
1.5 V                       1475 mV
1.8 V                       1804 mV
2.5 V                       2513 mV
3.3 V                       3338 mV
5.0 V                       5040 mV
5.0 V RE                    4962 mV
12.0 V                     11968 mV
12.0 V RE                  11968 mV
Power 2
4.6 V bias MidPlane         4866 mV
11.3 V bias PEM            11253 mV
11.3 V bias FPD            11292 mV
11.3 V bias POE 0          11311 mV
11.3 V bias POE 1          11292 mV
Bus Revision               64
FPGA Revision              0    <-- Here is the issue. The FPGA revision is too old.
PMBus                          Expected   Measured   Measured Calculated
device                         voltage    voltage    current   power
XF ASIC A                     1000 mV     999 mV   11093 mA   11081 mW
XF ASIC B                     1000 mV     999 mV   11234 mA   11222 mW

This alarm indicates that an older FPGA version exists or there is an issue reading this value from the SG2P chipset. It also indicates that the FPGA version that is active is not the latest.

Check SGLS Version:

On dual RE devices, the issue may be seen due to multiple CBs on different SGLS versions. Please verify the SGLS versions as below:

Login to shell as root user on Primary RE:

>start shell user root
root@host% sglsc 0
Register offset Value
SGLS Version 0x160 0x0000001a  <-- 1A (HEX) = 26 (DEC)

root@host% sglsc 1
Register offset Value
SGLS Version 0x160 0x00000014  <-- 14 (HEX) = 20 (DEC)

root@host% sglsc 2
Register offset Value
SGLS Version 0x160 0x0000001a   <-- 1A (HEX) = 26 (DEC)

Here, the CB 1 value is different from CB 0 and CB 2. This could be another reason for exhibiting this error on CB1. In both the above described cases, the CB needs to be replaced. Since there is no way to upgrade SGLS version / SG2P revision manually through software, it is best to replace the hardware.

Please contact Support for replacement of the faulty part if there is no stock available in your spares.

Collect the logs below for JTAC Analysis:

user@host> show chassis hardware
user@host> show log chasssid
user@host> show log messages

Modification History:
2021-03-24: Updated the article terminology to align with Juniper's Inclusion & Diversity initiatives
2020-08-25: Added chassisd log message, 'SG2P FPGA rev(20) < minimum rev(26)' under symptoms.
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