Users Guide

Default VLAN
When you congure 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 congure 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.
NOTE: You cannot assign an IP address to the Default VLAN. To assign an IP address to a VLAN that is currently the Default
VLAN, create another VLAN and assign it to be the Default VLAN. For more information about assigning IP addresses, refer to
Assigning an IP Address to a VLAN.
• Untagged interfaces must be part of a VLAN. To remove an untagged interface from the Default VLAN, create another VLAN and place
the interface into that VLAN. Alternatively, use the no switchport command, and Dell Networking OS removes the interface from
the Default VLAN.
• A tagged interface requires an additional step to remove it from Layer 2 mode. Because tagged interfaces can belong to multiple
VLANs, remove the tagged interface from all VLANs using the no tagged interface command. Only after the interface is
untagged and a member of the Default VLAN can you use the no switchport command to remove the interface from Layer 2
mode. For more information, refer to VLANs and Port Tagging.
Example of Conguring an Interface for Layer 2 Belonging to the Default VLAN
Dell(conf)#interface gigabitethernet 1/2
Dell(conf-if)#no shut
Dell(conf-if)#switchport
Dell(conf-if)#show config
!
interface GigabitEthernet 1/2
no ip address
switchport
no shutdown
Dell(conf-if)#end
Dell#show vlan
Codes: * - Default VLAN, G - GVRP VLANs
NUM Status Q Ports
* 1 Active U Gi 1/2
T Gi 1/1
Port-Based VLANs
Port-based VLANs are a broadcast domain dened by dierent ports or interfaces. In Dell Networking OS, a port-based VLAN can contain
interfaces from dierent line cards within the chassis. Dell Networking OS supports 4094 port-based VLANs.
Port-based VLANs oer increased security for trac, conserve bandwidth, and allow switch segmentation. Interfaces in dierent VLANs
do not communicate with each other, adding some security to the trac on those interfaces. Dierent VLANs can communicate between
each other by means of IP routing. Because trac is only broadcast or ooded to the interfaces within a VLAN, the VLAN conserves
bandwidth. Finally, you can have multiple VLANs congured on one switch, thus segmenting the device.
Interfaces within a port-based VLAN must be in Layer 2 mode and can be tagged or untagged in the VLAN ID.
VLANs and Port Tagging
To add an interface to a VLAN, the interface must be in Layer 2 mode. After you place an interface in Layer 2 mode, the interface is
automatically placed in the Default VLAN.
Dell Networking OS supports IEEE 802.1Q tagging at the interface level to lter trac. When you enable tagging, a tag header is added to
the frame after the destination and source MAC addresses. That information is preserved as the frame moves through the network. The
following example shows the structure of a frame with a tag header. The VLAN ID is inserted in the tag header.
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Virtual LANs (VLANs)