KB.15.15

Figure 83 HP Switch in mixed-VLAN mode

Configuring VLANs

• A VLAN created on a QinQ mixed VLAN mode device can be either a regular VLAN (C-VLAN)

or a tunnel VLAN (S-VLAN). C-VLANs have no mapping/relation whatsoever to the S-VLANs

on the device.

• VLANs created on a QinQ S-VLAN mode device can be S-VLANs only. S-VLANs provide

QinQ tunneling of customer frames and behave like a port-based/s-tagged interface.

QinQ and duplicate VIDs

Duplicate VID's for c-tagged and s-tagged VLANs (for example, C-VID=100; S-VID=100) are

allowed in certain cases and disallowed in others. Customer-network ports are essentially S-VLAN

ports: they simply read the C-tags in the customer frame to insert them into the appropriate untagged

S-VLAN for that port. Once this double-tagging occurs, frames are forwarded based on the S-VLAN

tag only, while the C-VLAN tag remains shielded during data transmission.

Figure 84 QinQ and duplicate VIDs: examples of allowed configurations

Assigning ports to VLANs

In mixed VLAN mode, a port can be a member of a C-VLAN or of an S-VLAN but not both.

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

334 QinQ (Provider bridging)