This KB explains how native VLAN behaves on switches with Enhanced Layer 2 Software (ELS) Junos version enabled.

Consult the following for a list of switches that support ELS Junos OS: Software Feature: Uniform Enhanced Layer 2 Software (ELS) CLI configuration statements and operational commands

On switches with non-ELS Junos OS, the native VLAN will NOT tag traffic if native VLAN ID is not mapped in "VLAN Member" configuration.

Example output: (Non-ELS Junos OS)

ge-0/0/23 {
    unit 0 {
        family ethernet-switching {
            port-mode trunk;
            vlan {
                members [ Cust_150 Cust_151 ];
            }
            native-vlan-id 1; <--- Native VLAN traffic will be sent as untagged.
        }
    }
}

However, output of " show vlans " indicates that the physical port is already active and mapped into native VLAN.

{master:0}[edit]
root@EX3300-1# run show vlans

Name           Tag     Interfaces
NATIVE         1       ge-0/0/23.0*

<Output Truncated>

{master:0}[edit]
root@EX3300-1# show vlans

NATIVE {
    vlan-id 1;
}

On the other hand, Junos ELS version will NOT recognize the same physical port active into native VLAN even when "native VLAN" is enabled on the specific interface. Communication will fail though using Native VLAN if it isn't mapped into "vlan members" on the specific interface.

Example output: (ELS Junos OS)

{master:0}[edit]
root@EX2300-1# run show vlans

Routing instance        VLAN name             Tag          Interfaces
default-switch          NATIVE                100          ge-0/0/0.0     <--- There are no active interfaces mapped into native VLAN.
default-switch          v1                    1            ge-0/0/2.0*

 

{master:0}[edit]
root@EX2300-1# show interfaces ge-0/0/2

native-vlan-id 100;                          <--- Native VLAN has already been enabled under interface ge-0/0/2.
unit 0 {
    family ethernet-switching {
        interface-mode trunk;
        vlan {
            members v1;                      <--- Native VLAN is not mapping in "vlan members" for interface ge-0/0/2, which will make communication via native VLAN fail.
        }
        storm-control default;
    }
}

{master:0}[edit]
root@EX2300-1# show vlans

NATIVE {
    vlan-id 100;
}

Note: On non-MP EX4300 platforms, the correct hierarchy level to configure "native-vlan-id" is [edit interfaces <interface-name>]. Although the statement native-vlan-id is accepted when typed under [edit interfaces <interface-name> unit 0 family ethernet-switching], the same is not listed in the valid completions there. You should configure native-vlan-id with the command "set interfaces <interface-name> native-vlan-id".

Communication via Native VLAN will not work well until the Native VLAN is mapped into "vlan members".

{master:0}[edit]

root@EX2300-1# show interfaces ge-0/0/2

native-vlan-id 100;              
unit 0 {
    family ethernet-switching {
        interface-mode trunk;
        vlan {
            members [ v1 NATIVE ] ;  <--- Native VLAN mapped under "vlan members"

        }
        storm-control default;
    }
}

09/03/2025: Adding EX4300 config note.

• KB17419 [juniper.net]
• Feature Explorer for ELS JUNOS OS