Operating notes and restrictions

Cannot run concurrently with RPVST+

QinQ cannot run concurrently with RPVST+

Changing bridge modes requires a reboot

When changing the operating mode (to/from: QinQ S-VLAN mode, QinQ mixed VLAN mode, or QinQ disabled), you will prompted to restart the system before the changes can take effect. Upon reboot, all configuration information for the prior QinQ mode will be lost. Any configurations created will be erased, and the device will boot up with a default configuration for the new QinQ mode.

Provider edge devices at Layer 2 only

QinQ does not provide Layer 3 capabilities of complete network isolation between customers. In a mixed VLAN configuration, there is no switching/routing between C-VLANs and S-VLANs. S-VLANs are essentially Layer 2 VLANs that switch packets based on S-VIDs.

IP support

Regular VLANs support IP and can be routing enabled. S-VLANs of mixed VLAN mode devices cannot be ip enabled. S-VLANs of S-VLAN mode devices can be ip-enabled, though routing related features (such as ip routing) are not supported.

Double-tagging causes frame size increases

Since there is both a provider VLAN tag and customer VLAN tag in each QinQ frame, the size of each double-tagged frame increases by 4 bytes. To accommodate the frame size increase, HPE recommends that you configure all port-based S-VLANs to accept jumbo frames.

S-VLAN configuration restrictions

S-VLAN commands are not available when QinQ is disabled on the switch.

VLAN configuration restrictions in mixed VLAN mode
  • Both C-VLANs and S-VLANs can be configured on the switch. In a mixed mode device, the default VLAN is always a C-VLAN.

  • VLAN types cannot be updated dynamically. A VLAN can be classified only as an S-VLAN or a C-VLAN at the time its created. Once created, the VLAN cannot be moved between being a C-VLAN and an S-VLAN. If a VID that was initially created as a regular VLAN needs to be used for an S-VLAN, the VID must be deleted and re-created as an S-VLAN.

  • If a VLAN being configured as an S-VLAN already exists as a GVRP C-VLAN or a static C-VLAN on the switch, the S-VLAN creation is blocked. Similarly, a C-VLAN creation is blocked if the same VID exists as a static S-VLAN on the device.

  • S-VLANs in a mixed vlan device cannot be configured as a voice-VLAN, primary-VLAN, or management-VLAN.

  • S-VLANs cannot be configured with ip-layer functionality, except for ip-acls.

VLAN configuration restrictions in S-VLAN mode
  • Only S-VLANs are supported—the keyword on all vlan-related command syntax changes from vlan to svlan.

  • Routing related features such as ip-routing, RIP, OSPF, PIM, and VRRP are not supported in S-VLAN mode.

Port-based restrictions
  • In QinQ mixed VLAN mode, a port must be explicitly GVRP-disabled before it can be assigned to the S-VLAN space.

  • In QinQ mixed VLAN mode, only ports that are members of S-VLANs can be configured as customer network or provider network ports; ports that are members of C-VLANs cannot be configured to any port-type.

  • QinQ mixed VLAN mode devices cannot be connected in an S-VLAN mesh topology. This is because STP cannot be run in the S-VLAN space, and so amesh topology (or the presence of any redundant links) would result in loops.

  • A port can either be a member of S-VLANs or C-VLANs only, but not a combination of both.

  • A port cannot be configured as a Customer-Edge as specified in Section 12.13.3 of the IEEE 802.1ad specification. In the current software release, such C-tagged interfaces are not supported—only port-based/S-tagged interfaces are supported.

  • Moving ports between C-VLANs and S-VLANs may cause conflicts. For example, if a port has any mirroring/monitoring sessions set up, they will not be allowed to change VLAN domains until these sessions are re-configured.

Interoperating with other vendor devices
When enabling QinQ, you can configure a unique tpid value, such as 0x8100, to allow the device to interoperate with devices that require this value for the inner and outer VLAN-tag. If the provider tag-type is configured as 0x8100, then:
  • Customer-network ports cannot be configured as tagged-S-VLAN members

  • Tagged-S-VLAN members cannot be configured as customer-network ports.

Configuring QinQ with other network protocols

The networks for both the customer and provider can be complex. For information on how QinQ may impact other network protocols (such as spanning tree, LLDP, and GVRP), see the figure in QinQ mixed VLAN mode.