Service Manual

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.
Figure 119. Tagged Frame Format
The tag header contains some key information that Dell Networking OS uses:
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Virtual LANs (VLANs)