While performing a downgrade on the QFX5100 device, if force-host is not added in the request system software add command and if the host OS is on a version later than the base OS, the FPC slot shows empty in the output for show chassis fpc .

This article provides more details.

The OS versions for the Base OS and Host OS will vary. Ideally, we would see a later version on the host. This will show FPC slots offline even though there is hardware availability.

root@:RE:0% cli
{master:0}
root> show version
fpc0:
--------------------------------------------------------------------------
Model: qfx5100-96s-8q
Junos: 14.1X53-D28.17
JUNOS Base OS Software Suite [14.1X53-D28.17]
JUNOS Base OS boot [14.1X53-D28.17]
JUNOS Crypto Software Suite [14.1X53-D28.17]
JUNOS Online Documentation [14.1X53-D28.17]
JUNOS Kernel Software Suite [14.1X53-D28.17]
JUNOS Packet Forwarding Engine Support (qfx-ex-x86-32) [14.1X53-D28.17]
JUNOS Routing Software Suite [14.1X53-D28.17]
JUNOS Enterprise Software Suite [14.1X53-D28.17]
JUNOS Web Management Platform Package [14.1X53-D28.17]
JUNOS py-base-i386 [14.1X53-D28.17]
JUNOS Host Software [14.1X53-D47.3]

[master:0]
root> show chassis fpc
                     Temp  CPU Utilization (%)   Memory    Utilization (%)
Slot State            (C)  Total  Interrupt      DRAM (MB) Heap     Buffer
  0  Empty          
  1  Empty          
  2  Empty          
  3  Empty          
  4  Empty          
  5  Empty          
  6  Empty          
  7  Empty          
  8  Empty          
  9  Empty       

While performing a downgrade on QFX5100, always perform a request system software add with a force-host added along with the file path. This prevents unavailability of FPC slots for PFE functionality.

[master:0]

USER@SWITCH> show version
fpc0:
--------------------------------------------------------------------------
Hostname: CFTS-QFX-2018
Model: qfx5100-96s-8q
Junos: 14.1X53-D28.17
JUNOS Base OS Software Suite [14.1X53-D28.17]
JUNOS Base OS boot [14.1X53-D28.17]
JUNOS Crypto Software Suite [14.1X53-D28.17]
JUNOS Online Documentation [14.1X53-D28.17]
JUNOS Kernel Software Suite [14.1X53-D28.17]
JUNOS Packet Forwarding Engine Support (qfx-ex-x86-32) [14.1X53-D28.17]
JUNOS Routing Software Suite [14.1X53-D28.17]
JUNOS Enterprise Software Suite [14.1X53-D28.17]
JUNOS Web Management Platform Package [14.1X53-D28.17]
JUNOS py-base-i386 [14.1X53-D28.17]
JUNOS Host Software [14.1X53-D28.17]
 
[master:0]
USER@SWITCH> show chassis fpc
                     Temp  CPU Utilization (%)   Memory    Utilization (%)
Slot State            (C)  Total  Interrupt      DRAM (MB) Heap     Buffer
  0  Online            39      6          0       1953        0         44
  1  Empty          
  2  Empty          
  3  Empty          
  4  Empty          
  5  Empty          
  6  Empty          
  7  Empty          
  8  Empty           
  9  Empty        

2021-02-19: Article reviewed for accuracy, no changes required; article accurate and valid

• QFX Series Host Upgrade