This article is intended to explain why the 1G ports are not usable as virtual chassis port (vc-port) on the platforms EX4600.

The customer wants to convert a 1G port into a virtual chassis port, but the same stays in "Absent" state after conversion with the command "> request virtual-chassis vc-port set pic-slot 0 port 0".

SWITCH 1

{master:0}
user@switch1> show virtual-chassis vc-port
fpc0:
--------------------------------------------------------------------------
Interface  Type       Trunk Status    Speed    Neighbor
or               ID         (mbps)    ID Interface
PIC / Port
0/0     Configured        Absent

SWITCH 2

{master:0}
user@switch2> show virtual-chassis vc-port
fpc0:
--------------------------------------------------------------------------
Interface  Type       Trunk Status    Speed    Neighbor
or               ID         (mbps)    ID Interface
PIC / Port
0/0     Configured        Absent

Actually, once converted into vc-port and reverted, the port may no longer appear in interfaces terse output.

SWITCH 1

{master:0}
user@switch1> show interfaces terse | match 0/0/0
gr-0/0/0        up  up
ip-0/0/0        up  up
pfe-0/0/0        up  up
pfe-0/0/0.16383     up  up  inet
pfh-0/0/0        up  up
pfh-0/0/0.16383     up  up  inet
pfh-0/0/0.16384     up  up  inet

SWITCH 2

{master:0}
user@switch2> show interfaces terse | match 0/0/0
ge-0/0/0        up  up
ge-0/0/0.16386     up  up
gr-0/0/0        up  up-10-05 22:45:09 UTC
ip-0/0/0        up  up
pfe-0/0/0        up  up
pfe-0/0/0.16383     up  up  inet
pfh-0/0/0        up  up
pfh-0/0/0.16383     up  up  inet
pfh-0/0/0.16384     up  up  inet

The 1G ports are not supposed to be used as vc-ports for best practices, since the vc-ports are intended to handle a large a mount of traffic through the virtual chassis stack. The EX4600 ETHERNET SWITCH DATASHEET also indicates that this platform can use the 10G ports as vc-port, but it does not include 1G ports for this purpose.

If the interface does not appear on the output of "> show interfaces terse", proceed to bounce the interface, and if the issue persists, proceed to reboot the switches presenting this behavior. Note that reboot should be performed during scheduled maintenance window time out of business hours.

https://www.juniper.net/content/dam/www/assets/datasheets/us/en/switches/ex4600-ethernet-switch-datasheet.pdf