On Mon, 18 Feb 2019 at 18:14, <sth...@nethelp.no> wrote: > > > Cat6K and 6880 support QinQ. > > We use it to connect some L3 vlans between our DC. > > I’m not at my desk, but from memory, .. > > 1) on the access port facing the ‘client’ …. > > Switchport mode dot1q-tunnel > > switchport access vlan xxx. Where xxx is the transport/service provider > > side vlan assigned to this client. > > 2) add the above ‘xxx’ transport vlan to any dot1q trunks used between > > client sites. > > Note well the difference between > > - QinQ: An extra (outer) VLAN tag is added to ingress Ethernet frames > which already contain one or more VLAN tags. Example configuration is > "switchport mode dot1q-tunnel" + "switchport access vlan X". > > - Double VLAN tag termination: An Ethernet service (e.g. IP based) is > terminated on the Catalyst switch based on both outer (SVLAN) and inner > (CVLAN) tags. Example config is "encapsulation dot1Q X second-dot1q Y". > > As far as I know, Cat 6500 supports the former but not the latter. I > have no experience with the 6880.
^ This. 6500s can't terminate double tagged frames at layer 3. They can perform dot1q "tunnelling" only. I looked at 6880 a few years ago, I'm pretty sure this was one of the reasons we doing for it it, too similar to the 6500 (including this limitation). Cheers, James. _______________________________________________ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
