Dell C9000 series, Reference Manual

Page: 2278 / 2286

VLAN Stacking
With the virtual local area network (VLAN)-stacking feature (also called stackable VLANs and QinQ), you can
“stack” VLANs into one tunnel and switch them through the network transparently.
For more information about basic VLAN commands, see the
Virtual LAN (VLAN) Commands section in the
Layer 2 chapter.
Important Points to Remember
• If you do not enable the spanning tree protocol (STP) across the stackable VLAN network, STP bridge
protocol data units (BPDUs) from the customer’s networks are tunneled across the stackable VLAN
network.
• If you do enable STP across the stackable VLAN network, STP BPDUs from the customer’s networks are
consumed and not tunneled across the stackable VLAN network unless you enable protocol tunneling.
NOTE: For more information about protocol tunneling on the E-Series, see
Service Provider Bridging .
• Layer 3 protocols are not supported on a stackable VLAN network.
• Assigning an IP address to a stackable VLAN is supported when all the members are only stackable VLAN
trunk ports. IP addresses on a stackable VLAN-enabled VLAN are not supported if the VLAN contains
stackable VLAN access ports. This facility is provided for the simple network management protocol
(SNMP) management over a stackable VLAN-enabled VLAN containing only stackable VLAN trunk
interfaces. Layer 3 routing protocols on such a VLAN are not supported.
• Dell Networking recommends that you do not use the same MAC address, on different customer VLANs,
on the same stackable VLAN.
• Interfaces configured using stackable VLAN access or stackable VLAN trunk commands do not switch
traffic for the default VLAN. These interfaces are switch traffic only when they are added to a non-
default VLAN.
• Starting with the Dell Networking OS version 7.8.1 for C-Series and S-Series (Dell Networking OS version
7.7.1 for E-Series, 8.2.1.0 for E-Series ExaScale), a vlan-stack trunk port is also allowed to be configured
as a tagged port and as an untagged port for single-tagged VLANs. When the vlan-stack trunk port is
also a member of an untagged vlan, the port must be in Hybrid mode. See portmode hybrid .
• VLAN stacking is not supported on Port Extender (PE) ports and on LAGs with port extender ports.
• VLAN stacking interface commands are blocked (hidden) on PE ports.
• VLAN stacking interface commands will fail on the VP-LAG (LAG with PE ports).
Topics:
• member
• vlan-stack access
• vlan-stack compatible
• vlan-stack dot1p-mapping
65
VLAN Stacking 2278