Switching

Hi all, 

I want to clarify something on native VLAN on Juniper vendor. 
First of all, I know that by default Juniper do not have specific VLAN number for native VLAN. 
In my circumstance,
I create two VLAN are VLAN_100 and VLAN_200 with VLAN number 100 and 200 respectively. Then, I define the interface ge-0/0/0 assigned trunk mode member all,

set interfaces ge-0/0/0 unit 0 family ethernet-switching port-mode trunk
set interfaces ge-0/0/0 unit 0 family ethernet-switching vlan members all

The member all is mean that the interface ge-0/0/0 is assigned to VLAN_100 and VLAN_200 which have tag id, and the interface ge-0/0/0 leave VLAN default because at moment the interface ge-0/0/0 set trunk needs tag id (by default, the VLAN default do not have tag id). 
After that, What happens when I set native VLAN id is 100 mapping VLAN_100? As I show VLAN on CLI device will see only the interface ge-0/0/0 assigned VLAN_200?

The next circumstance, as I define native VLAN id is 100 mapping VLAN_100 and the interface ge-0/0/0 assigned trunk mode member [VLAN_100 VLAN_200]. Does CLI command work? And what behavior of VLAN_100 when transmit and receive? The interface ge-0/0/0 connect with VLAN number 100 must be tagged id when transmitting/receiving traffic or not?

Please correct and clarify this to me. 

Thanks a lot. 

set vlans VLAN_100 vlan-id 100
set vlans VLAN_200 vlan-id 200

== CASE 1

set interfaces ge-0/0/0 unit 0 family ethernet-switching port-mode trunk
set interfaces ge-0/0/0 unit 0 family ethernet-switching vlan members all

OR

set interfaces ge-0/0/0 unit 0 family ethernet-switching port-mode trunk
set interfaces ge-0/0/0 unit 0 family ethernet-switching vlan members VLAN_100
set interfaces ge-0/0/0 unit 0 family ethernet-switching vlan members VLAN_200

lab@switch# run show vlans
Name           Tag     Interfaces
VLAN_100       100
                       ge-0/0/0.0*
VLAN_200       200
                       ge-0/0/0.0*

Traffic from/to VLAN_100 sent/received on ge-0/0/0 is tagged.

== CASE 2

set interfaces ge-0/0/0 unit 0 family ethernet-switching port-mode trunk
set interfaces ge-0/0/0 unit 0 family ethernet-switching vlan members all
set interfaces ge-0/0/0 unit 0 family ethernet-switching native-vlan-id VLAN_100

OR

set interfaces ge-0/0/0 unit 0 family ethernet-switching port-mode trunk
set interfaces ge-0/0/0 unit 0 family ethernet-switching vlan members VLAN_100
set interfaces ge-0/0/0 unit 0 family ethernet-switching vlan members VLAN_200
set interfaces ge-0/0/0 unit 0 family ethernet-switching native-vlan-id VLAN_100

lab@switch# run show vlans
Name           Tag     Interfaces
VLAN_100       100
                       ge-0/0/0.0*
VLAN_200       200
                       ge-0/0/0.0*

Traffic from VLAN_100 sent over ge-0/0/0 is tagged. Received traffic can be tagged with ID 100 or not tagged.
Either way it will be classified as traffic destined to VLAN_100.

=== CASE 3

set interfaces ge-0/0/0 unit 0 family ethernet-switching port-mode trunk
set interfaces ge-0/0/0 unit 0 family ethernet-switching vlan members VLAN_200
set interfaces ge-0/0/0 unit 0 family ethernet-switching native-vlan-id VLAN_100

lab@switch# run show vlans
Name           Tag     Interfaces
VLAN_100       100
                       ge-0/0/0.0*
VLAN_200       200
                       ge-0/0/0.0*

Traffic from/to VLAN_100 sent/received on ge-0/0/0 is not tagged.

== CASE 4

set interfaces ge-0/0/0 unit 0 family ethernet-switching port-mode trunk
set interfaces ge-0/0/0 unit 0 family ethernet-switching vlan members VLAN_100
set interfaces ge-0/0/0 unit 0 family ethernet-switching vlan members VLAN_200
set interfaces ge-0/0/0 unit 0 family ethernet-switching vlan members default

COMMIT ERROR

set interfaces ge-0/0/0 unit 0 family ethernet-switching port-mode trunk
set interfaces ge-0/0/0 unit 0 family ethernet-switching vlan members VLAN_100
set interfaces ge-0/0/0 unit 0 family ethernet-switching vlan members VLAN_200
set interfaces ge-0/0/0 unit 0 family ethernet-switching native-vlan-id default

Traffic from/to default vlan sent/received on ge-0/0/0 is not tagged.

== CASE 5

set vlans default vlan-id 300

Behavior of default vlan is the same as any other user configured vlan (CASE 1-3).

Regards, Wojtek

Hi wdudys, 

Thank you for your clarification. 🙂 

Regards,

FYI...the native vlan behavior changes on QFX or ELS junos OS versions - 

https://kb.juniper.net/InfoCenter/index?page=content&id=KB32289&pmv=print&actp=RSS&searchid=&type=currentpaging