[c-nsp] N7k sending LACP PDUs tagged w/ "vlan dot1q tag native"?

Phil Mayers p.mayers at imperial.ac.uk
Thu Jul 25 12:31:31 EDT 2013

(Apologies to people who've seen the other half of this on j-nsp)

Has anyone seen an N7k sending LACP PDUs tagged with the following config:

vlan dot1Q tag native
int eth3/1
   channel-group 20 mode active
int po20
   switchport mode trunk
   switchport trunk native vlan 111
   switchport trunk allowed vlan 999

In this situation, the LACP PDUs are coming out tagged with vlan 111, 
and are being ignored by the neighbouring device (a Juniper SRX).

AFAIK, IOS doesn't do this, even with "vlan dot1q tag native" set 
globally (which we set for avoidance of "half-directional" tagged links).

We are able to work around with this config:

int eth3/1
   channel-group 20 mode active
int po20
   no shut
int po20.999
   encapsulation dot1q 999

...but I'd prefer to avoid that.

Also unlike IOS, there doesn't seem to be a per-interface "[no] 
switchport trunk native vlan tag" to override it :o(

This is on NX-OS 5.2(4), with M-series linecards.


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