[f-nsp] Preserving double-tagged traffic on ICX6100

[Igor Ybema]

> My testing used 0x8100 for both inner and outer and no aggregated-VLAN.
> Nothing special about configuration --
> vlan 1048
>  tagged ethe 1/3/1 ethe 2/3/1
>
> Traffic goes in and out 1/3/1 and out 2/3/1.  VLAN tag 235 is the inner tag.
> Nothing about VLAN 235 is configured on the ICX6100 -- it doesn't need to
> be.  Yet VLAN tag 235 is stripped out.


Ok I haven't tested this yet. Clearly you are using the ICX as a
provider core switch, not a prodider edge switch which I tested.
Will test this monday if I have some spare time.

Two questions though:
- Why aren't you using the aggregated-vlan feature? To my knowledge
this is needed to support q-in-q. Stripping unknown vlan's from
etherframes could be a 'normal' thing if this feature is disabled.
- Could you try and use another tag-type for the outer tag? Using
0x8100 for both outer and inner should work but it is used less and
less lately. Using 0x9100 or even better the standard for provider
bridging 0x88a8 will keep you and maybe your equipment from getting
headaches.

regards, Igor