Reference Guide

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.

This feature is supported by the Dell Networking OS on the S5000.

For more information about basic VLAN commands, refer to 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.

• 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 is 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 are not switch

traffic for the default VLAN. These interfaces are switch traffic only when they are added to a non-

default VLAN.

• 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. Refer to portmode hybrid.

dei enable

Make packets eligible for dropping based on their DEI value.

S5000

Syntax

dei enable

Defaults Packets are colored green; no packets are dropped.

VLAN Stacking

1359