Fortinet fortigate-100a Betriebsanweisung

A VLAN is group of PCs, servers, and other network devices that communicate as if 
they were on the same LAN segment, even though they may not be. For example, the 
workstations and servers for an accounting department could be scattered throughout 
an office, connected to numerous network segments, but they can still belong to the 
same VLAN.

A VLAN segregates devices logically instead of physically. Each VLAN is treated as a 
broadcast domain. Devices in VLAN 1 can connect with other devices in VLAN 1, but 
cannot connect with devices in other VLANs. The communication among devices on a 
VLAN is independent of the physical network.

A VLAN segregates devices by adding 802.1Q VLAN tags to all of the packets sent 
and received by the devices in the VLAN. VLAN tags are 4-byte frame extensions that 
contain a VLAN identifier as well as other information.

VLANs allow highly flexible, efficient network segmentation, enabling users and 
resources to be grouped logically, regardless of physical locations.