Configuring port types

The IEEE 802.1ad standard requires that every S-VLAN member port be configured as either a provider-network or as a customer-network port. In a typical deployment scenario, customer-network ports will be configured as untagged members of S-VLANs while provider-network ports will be configured as tagged members of S-VLANs. Note the following configuration rules and guidelines:

All ports of a device that is QinQ enabled (in S-VLAN mode or mixed VLAN mode) are provider-network ports by default—if there are any ports that connect to a customer device, they must be manually configured as customer-network ports.
Configuring a port-type is applicable only if the device is QinQ enabled and the port is a member of an S-VLAN. In QinQ mixed mode, ports that are members of C-VLANs cannot be configured to any port-type.

NOTE:

If a device running in QinQ S-VLAN mode has one or more customer-network ports, it is considered to be a provider edge and not a provider core bridge. This may affect certain operations, such as meshing, UDLD, and stacking. This is because at the edge of the provider network such proprietary protocol are filtered out at customer network ports. This prevents the intermix of stacking meshing/UDLD protocols in the customer and provider domains (since they use the same dst-mac address in either domain).