QinQ and native vlan

[katerina.dardoufa]

Hi all,

we will implement the following scenario:

Hub connected to providers' MetroEthernet Switch (site A) (ME-A)

Switch connected to providers' MetroEthernet Switch (site B) - servers on switch assigned to vlan X.

QinQ should be used by the provider, so as to achieve layer2 communication between sites, meaning that all PC/servers on sites A & B will be on the same subnet.

How will PC/servers on site A be able to communicate with servers on site B? I mean the frames going from the hub to ME-A will be untagged. The provider will tag them with S-VLAN, so as to send them to ME-B. ME-B offloads them to the switch which is configured with trunk port. Should the port be configured with "native vlan X" in order for the communication between the end devices to work or doesn't it make any difference?

Could the switch port on site A connecting to ME-A simply be an access port?

I read that when implementing QinQ the customer port connecting to the metro ethernet switch should be trunk, but maybe I misinterpreted it.

(http://www.cisco.com/c/en/us/td/docs/switches/metro/me3400e/software/release/12-2_44_ey/configuration/guide/3400escg/swtunnel.html#wp1052756)

Thank you all in advance,

Katerina

[Ken.KavanaghJ.R.]

Hello Katerina,

If you make the ports connected to the Providers Metro switches access ports on VLAN-X your switches are actually going to remove the VLAN-X Q tag as the packet leaves your switch.  It would still work as the switch on the other side would add the Q tag back on ingress.  If you make the ports trunk ports your switches maintain the original Q tags from your network and just encapsulate them with S-VLAN Q tags as they traverse the providers network.  It would be best to keep the ports trunk ports in case you wish to extend other vlans across in the future.

Hope this Helps

[katerina.dardoufa]

Hi Ken,

my concern is that on site A there is a hub. We have no access to that, so I suppose that the port on the hub side is by default access. If all else fails, we will have to change the hub on site A and configure the port as trunk.

[Ken.KavanaghJ.R.]

If site A is a hub, with no knowledge of VLANs, the access port option on site B should still give you site to site communications.