Description

IFL.16836 associated with an interface gets deleted if any configuration is added to the interface.

This article explains the behavior when logical interface ifl.16386 is deleted on all Junos devices. The article is applicable for all Junos EX/QFX/MX/PTX.

Symptoms

The LLDP information is not showing on the interfaces.

The reason is that the logical interface gets deleted as soon as description or any other config is committed on the interface. And because of this, no logical interface is created, and nothing is seen on <monitor traffic interface interface_id> output.

Solution

The default IFL (.16386) is present only when there is no other configuration (Not even description or any inherited configuration) on the interface.
The default IFL on the interfaces is to support VC auto-provisioning on (et-/xe-) interfaces.

 

Example output:

Without any configuration under xe-0/0/30:

qfx@lab> show configuration | display set | grep xe-0/0/30
>>>> No configuration under the interface
{master:0}
qfx@lab> show interfaces terse xe-0/0/30
Interface               Admin Link Proto    Local                 Remote
xe-0/0/30               up    up
xe-0/0/30.16386         up    up        <<<<<

With configuration under xe-0/0/30

qfx@lab> show configuration | display set | grep xe-0/0/30
set interfaces xe-0/0/30 description "test"
{master:0}
qfx@lab> show interfaces terse xe-0/0/30
Interface               Admin Link Proto    Local                 Remote
xe-0/0/30               up    up


This is an expected behavior. DCD process (Also called device control daemon) will add the default IFL (16386) when there is no config on the IFD. If anything is configured (including the description - which means it is used by the customer), DCD will remove the default IFL.

As this is an expected behavior, manually create an IFL interface when any configuration is added under an interface.

Modification History

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