Reference Guide
Virtual LANs
VLANs segment a single at L2 broadcast domain into multiple logical L2 networks. Each VLAN is uniquely identied by a VLAN ID or tag
consisting of 12 bits in the Ethernet frame. VLAN IDs range from 1 to 4093 and can provide a total of 4093 logical networks.
You can assign ports on a single physical device to one or more VLANs creating multiple logical instances on a single physical device. The
virtual logical switches spanning across dierent physical devices emulate multiple logically segmented L2 networks on a single physical
network.
Each VLAN has its own broadcast domain and the unicast, multicast, and broadcast network trac from ports that belong to a VLAN is
forwarded or ooded to ports in the same VLAN only. Trac between VLANs must be routed from one VLAN to another. You can also
assign each VLAN an IP address to group all the ports within a single IP subnet.
Segment a L2 network using VLANs to:
• Minimize broadcast and multicast trac in the L2 network
• Increase security by isolating ports into dierent VLANs
• Ease network management
Default VLAN
All interface ports are administratively up (in L2 mode) and are automatically placed in the default VLAN as untagged interfaces.
When you assign a port to a non-default VLAN in Trunk mode, the interface remains an untagged member of the default VLAN and a
tagged member of the new VLAN. When you assign a port to a non-default VLAN in Access mode, it removes from the default VLAN and
is assigned to the new VLAN as an untagged member of the new VLAN.
• VLAN 1 is the default VLAN.
• You cannot delete the default VLAN. However, you can change the default VLAN ID number using the default vlan-id command.
Use the show vlan command to verify that the interface is part of the default VLAN (VLAN 1).
Default VLAN conguration
OS10# show vlan
Codes: * - Default VLAN, G-GVRP VLANs, R-Remote Port Mirroring VLANs, P-Primary, C-Community, I-
Isolated
Q: A-Access (Untagged), T-Tagged
x-Dot1x untagged, X-Dot1x tagged
G-GVRP tagged, M-Vlan-stack, H-VSN tagged
i-Internal untagged, I-Internal tagged, v-VLT untagged, V-VLT tagged
NUM Status Description Q Ports
* 1 up A Eth1/1/1-1/1/54
Create or remove VLANs
You can create VLANs and add physical interfaces or port-channel (LAG) interfaces to the VLAN as tagged or untagged members. You can
add an Ethernet interface as a trunk port or as an access port, but it cannot be added as both at the same time.
Multiple non-default vlans with physical and port channel ports in access and trunk modes
OS10# show vlan
Codes: * - Default VLAN, G-GVRP VLANs, R-Remote Port Mirroring VLANs, P-Primary, C-Community, I-
Isolated
Layer 2
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