7-9
QinQ (Provider Bridging)
Introduction
■ 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 
svlan 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, HP recommends that you configure all port-based 
S-VLANs to accept jumbo frames. See the section on “Jumbo Frames” in 
the Management and Configuration Guide for details.
■ 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 only be 
classified 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 recreated 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 svlan mode:
• Only S-VLANs are supported—the keyword on all vlan-related com-
mand syntax changes from vlan to svlan.
• Routing related features such as ip-routing, RIP, OSPF, PIM, and VRRP 
are NOT supported in svlan 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 (see page 7-13 for 
details).