[c-nsp] Tag Native VLAN on ASR1000

[Raymond Lucas (AP)]

For the sake of prosperity...

I had a couple of suggestions off-list.  One (thanks Chris) gave me the hint I needed.

It seems that CDP etc actually belong to VLAN 1, not the Native VLAN. So if you define the Native VLAN as something other than 1, those VLAN 1 things end up tagged.

This was easily done on the ASR (encapsulation dot1Q [x] native).

Regards,
Ray

-----Original Message-----
From: cisco-nsp [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Raymond Lucas (AP)
Sent: Monday, 25 January 2016 3:31 p.m.
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] Tag Native VLAN on ASR1000

Hi all,

I am in the unenviable position of having a combination of Nexus linecards (F3) and features (SGTs) which mean that:

a) Where we want to carry SGTs natively, the links must be dot1q trunks.
b) For those trunks, all traffic must be tagged.

So to keep LACP, STP, UDLD, CDP packets happy, I'm trying to get my native VLAN traffic tagged.

Support to do this across Cisco equipment seems mixed.  So far I've found:

- Good support on NX-OS with the interface command "switchport trunk native vlan tag".
- Support on some IOS-XE and IOS gear (5760 WLC, 2911 ISR, Cat6500) with the global command "vlan dot1q tag native".  Although from reading it seems only the 6500 will let you selectively disable this on an individual port with "no switchport trunk native vlan tag".

I have had no luck finding the equivalent for the ASR1000 series (specifically 1001X, 1002X).

Has anyone else found a way to achieve this?

At least with the ASR, if I can't find an appropriate work around it's only CDP and UDLD that I would lose, and they're not required in this situation.  So it's not the end of the world, just inconvenient.

Thanks,
Ray