- [Instructor] VLANs are virtual local area networks.
They provide a way to devices in a network
to improve such things as network performance,
network security, efficiency.
VLANs also limit broadcasts.
A broadcast is a type of frame
that is seen by every device
on the local area network.
VLANs also allow hosts to be grouped logically,
according to their function.
For example, grouping servers and printers,
their group membership.
So, all users in the security group, or an admin group,
or a research and development department,
as well as by the application used.
Modern networks typically include separate VLANs
for data traffic, voice traffic.
There's definitely always going to be a separate VLAN
for the wireless traffic
'cause wireless is a security issue on networks,
and a separate VLAN for management users.
Switches by default are only going to forward packets
between hosts on the same VLAN.
As such, VLANs isolate devices into VLAN groups,
which means that they're going to require a router
in order to communicate or to forward packets
between each of the VLANs that are created on a switch.