[j-nsp] JunOS 18, ELS vs non-ELS QinQ native vlan handling.

[Karsten Thomann]

Hi,

I haven't tested the behvaior, but to avoid the big surprises you should at least check the tables in 
the kb:
https://kb.juniper.net/InfoCenter/index?page=content&id=KB35261&actp=RSS

As you're not writing the exact release, there was a change if you upgraded from R1 or R2.

Kind regards
Karsten

Am Freitag, 9. April 2021, 10:02:21 schrieb Antti Ristimäki:
> Hi list,
> 
> Returning to this old thread. It seems that the behaviour has again changed,
> because after upgrading QFX5110 to 18.4R3-S7 the switch does not add the
> native-vlan tag when forwarding the frame to QinQ uplink. Previously with
> version 17.3 the switch did add the native-vlan tag along with the S-tag.
> It seems that "input-native-vlan-push <enable|disable>" is available as a
> hidden command in 18.4R3-S7, but it doesn't seem to have any impact on the
> behaviour.
> 
> Any experience from others?
> 
> Antti
> 
> ----- On 22 Mar, 2019, at 19:03, Alexandre Snarskii snar at snar.spb.ru wrote:
> > Hi!
> > 
> > Looks like JunOS 18.something introduced an incompatibility of native
> > vlan handling in QinQ scenario between ELS (qfx, ex2300) and non-ELS
> > switches: when ELS switch forwards untagged frame to QinQ, it now adds
> > two vlan tags (one specified as native for interface and S-vlan) instead
> > of just S-vlan as it is done by both non-ELS and 'older versions'.
> > 
> > As a result, if the other end of tunnel is non-ELS (or third-party)
> > switch, it strips only S-vlan and originally untagged frame is passed
> > with vlan tag :(
> > 
> > Are there any way to disable this additional tag insertion ?
> > 
> > PS: when frames sent in reverse direction, non-ELS switch adds only
> > S-vlan and this frame correctly decapsulated and sent untagged.
> > 
> > ELS-side configuration (ex2300, 18.3R1-S1.4. also tested with
> > qfx5100/5110):
> > 
> > [edit interfaces ge-0/0/0]
> > flexible-vlan-tagging;
> > native-vlan-id 1;
> > mtu 9216;
> > encapsulation extended-vlan-bridge;
> > unit 0 {
> > 
> >    vlan-id-list 1-4094;
> >    input-vlan-map push;
> >    output-vlan-map pop;
> > 
> > }
> > 
> > (when native-vlan-id is not configured, untagged frames are not
> > accepted at all).
> > 
> > _______________________________________________
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> > 
> > 
> > --
> 
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