802.1Q/802.1ad VLAN Support

modulename: 8021q.ko

configname: CONFIG_VLAN_8021Q

Linux Kernel Configuration
└─>Networking support
└─>Networking options
└─>802.1Q/802.1ad VLAN Support
In linux kernel since version 2.6.12  
Select this and you will be able to create 802.1Q VLAN interfaces
on your Ethernet interfaces. 802.1Q VLAN supports almost
everything a regular Ethernet interface does, including
firewalling, bridging, and of course IP traffic. You will need
the 'ip' utility in order to effectively use VLANs.
See the VLAN web page for more information:

To compile this code as a module, choose M here: the module
will be called 8021q.

If unsure, say N.

source code: