Reference Guide

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Virtual LANs (VLANs)

Virtual LANs (VLANs) are supported on the S4820T platform.

VLANs are a logical broadcast domain or logical grouping of interfaces in a local area network (LAN) in which all data

received is kept locally and broadcast to all members of the group. When in Layer 2 mode, VLANs move traffic at wire

speed and can span multiple devices. The Dell Networking operating system (FTOS) supports up to 4093 port-based

VLANs and one default VLAN, as specified in IEEE 802.1Q.

VLANs benefits include:

• Improved security because you can isolate groups of users into different VLANs

• Ability to create one VLAN across multiple devices

For more information about VLANs, refer to the

IEEE Standard 802.1Q Virtual Bridged Local Area Networks

. In this guide,

also refer to:

• Bulk Configuration in the Interfaces chapter.

• VLAN Stacking in the Service Provider Bridging chapter.

For a complete listing of all commands related to FTOS VLANs, refer to these

FTOS Command Reference Guide

chapters:

• Interfaces

• 802.1X

• GARP VLAN Registration Protocol (GVRP)

• Service Provider Bridging

• Per-VLAN Spanning Tree Plus (PVST+)

The following table lists the defaults for VLANs in FTOS.

Feature

Default

Spanning Tree group

All VLANs are part of Spanning Tree group 0.

Mode Layer 2 (no IP address is assigned).

Default VLAN ID VLAN 1

Default VLAN

When you configure interfaces for Layer 2 mode, they are automatically placed in the Default VLAN as untagged

interfaces. Only untagged interfaces can belong to the Default VLAN.

The following example displays the outcome of placing an interface in Layer 2 mode. To configure an interface for Layer

2 mode, use the switchport command. As shown in bold, the switchport command places the interface in Layer

2 mode and the show vlan command in EXEC privilege mode indicates that the interface is now part of the Default

VLAN (VLAN 1).

By default, VLAN 1 is the Default VLAN. To change that designation, use the default vlan-id command in

CONFIGURATION mode. You cannot delete the Default VLAN.

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