Description

This article explains the behavior differences of VME (Virtual Management Interface) between the ELS (Enhanced Layer 2 Software) EX series such as EX4300/QFX switches and the Legacy EX-series switches such as EX4200 when disabling VME interface from the command line.

Check the Feature Explorer to see whether your switch supports ELS.

Solution

The behavior difference between ELS and non-ELS:

  • “ set interfaces vme disable ” cannot effectively disable IP communication over the VME on ELS while it can disable on non-ELS.
  • “ set interfaces vme unit 0 disable ” can effectively disable IP communication over the VME on both ELS and non-ELS.

Examples:

EX4300VC

root@ex4300# run show interfaces terse | match vme
vme                     up    up
vme.0                   up    up   inet     10.219.41.218/26

{master:0}[edit]
root@ex4300# set interfaces vme disable

{master:0}[edit]
root@ex4300# commit
fpc0:
configuration check succeeds
fpc1:
commit complete
fpc0:
commit complete

{master:0}[edit]
root@ex4300# show interfaces vme
disable ;
unit 0 {
    family inet {
        address 10.219.41.218/26;
    }
}

You cannot effectively disable the IP communication via VME interface by adding "disable" to the VME interface configuration as shown above.

root@ex4300# run show interfaces terse | match vme
vme                      up     up                    <--- vme is still Admin UP
vme.0                    up     up   inet     10.219.41.218/26

 


Instead, you can disable vme.0 as follows, which will effectively disable the IP communication via the VME interface:

root@ex4300# set interfaces vme unit 0 disable

{master:0}[edit]
root@ex4300# commit
fpc0:
configuration check succeeds
fpc1:
commit complete
fpc0:
commit complete

{master:0}[edit]
root@ex4300# show interfaces vme
disable;
unit 0 {
    disable;
    family inet {
        address 10.219.41.218/26;
    }
}

{master:0}[edit]
root@ex4300# run show interfaces terse | match vme
vme                     up    up
vme.0                    down   up   inet     10.219.41.218/26      <--- vme.0 is Admin down

{master:0}[edit]
root@ex4300#


EX4200VC

root@EX4200# run show interfaces terse | match vme
vme                     up    up
vme.0                   up    up   inet     10.85.240.152/25

{master:0}[edit]
root@EX4200# set interfaces vme disable

{master:0}[edit]
root@EX4200-r028# commit
configuration check succeeds
fpc1:
commit complete
commit complete

{master:0}[edit]
root@EX4200# show interfaces vme
disable ;
unit 0 {
    family inet {
        address 10.85.240.152/25;
    }
}


VME can be disabled using this approach on EX4200 and it will effectively disable the IP communication via vme interface:

root@EX4200# run show interfaces terse | match vme
vme                      down   up                   <--- vme is Admin Down
vme.0                   up    down inet     10.85.240.152/25

{master:0}[edit]
root@EX4200#
 

You can disable vme.0 as well. Also disable the IP communication via VME interface.

root@EX4200# set interfaces vme unit 0 disable

{master:0}[edit]
root@EX4200# commit
configuration check succeeds
fpc1:
commit complete
commit complete

{master:0}[edit]
root@EX4200# show interfaces vme
disable;
unit 0 {
    disable;
    family inet {
        address 10.85.240.152/25;
    }
}

{master:0}[edit]
root@EX4200# run show interfaces terse | match vme
vme                     down  up                                     
vme.0                    down   down inet     10.85.240.152/25     <--- vme.0 is Admin down

Modification History

2021-10-04: Added a brief overview of solution prior to presenting CLI commands.