I knew QinQ was not working with Titanium (see features below) but I was working on a lab where I needed to do some VLAN translation. The commands are available on Titanium (NX-OS) so I gave it a try. TL;DR: It doesn’t work. Scenario I tried to test a migration scenario, where the same VLAN ID was used for different subnets in two data centers. The plan was that a Nexus switch provided mapping between the existing VLAN in the source DC and a new destination VLAN in the target DC; hosts could keep their IP settings this way. This is how it looked like:

Note: The GNS3 generic switches required only to make traffic capturing available. Configuration Very straightforward, a trunk is configured between NX-3 and the remote Nexus switch, and VLAN 2 is translated to VLAN 103.

interface Ethernet2/11
  description NX-1_Eth2/11
  switchport
  switchport mode trunk
  switchport vlan mapping 2 103
  switchport vlan mapping enable
  no shutdown

Packet capture The capture reveals that the mapping is like NAC, Netflow, and PBR: only useful for CLI verification but you can’t build a lab on it. The capture file can be downloaded from here.