Hello everyone, in this video we're going to talk
about the difference between subnets and VLANs. Now both of these do the same thing, they are
both used to separate or break down a network into smaller networks. And the main reasons for
doing this is to make a network perform better, to add security to a network, and to make a
network more manageable. However both subnets and VLANs do these things using different methods.
Subnets separate networks physically, while VLANs separate networks virtually. So let's talk about subnets first. Subnet stands for sub network. A subnetwork is a smaller network within a larger
network. And subnets are created by using routers. So for example let's look at a small local area
network that's typically used in a small business. So here we have some computers connected to
a switch. Now when these computers want to communicate with other computers on this network,
they will first send out a broadcast over the entire network and every computer that's connected
to this switch will receive the broadcast. This is known as a broadcast domain. Now this wouldn't
be a problem on a small network like this with only a few computers. But if this business got
larger and more computers were added, the amount of broadcast traffic would increase and flood the
network with data, potentially causing a slowdown. Now one way to prevent this is by creating sub
networks or subnets, which is known as subnetting. Creating subnets will separate and physically
break down this network into smaller networks and they are broken down and separated by using
routers. And by doing this, this would alleviate the problem of excess of traffic because
broadcasts do not go past routers, broadcasts only stay within a network. So as you can see,
the subnets are separated by routers and each of these subnets has their own broadcast domain
which will not interfere with the other networks. Another reason for separating a network is
for security. So for example let's say that a business has three departments, such as sales, I.T.,
and service. And in each of those departments are servers that contain sensitive data that no one
in the other departments are allowed to access. Now if this network was kept like this, meaning one
big network, where all the devices are connected using a switch, well that means that everyone
in all the departments are able to see all the computers and servers in the other departments.
So the network administrator needs to isolate the network traffic between the departments.
So that sales doesn't see traffic from I.T, I.T. doesn't see traffic from service, and so on.
And once again since there are three departments the administrator can break down this network
into three subnets using routers. So that each department has their own network. So now the
network traffic from the different departments stay within their network and each department
can only see their own computers and servers. They are not able to see the other devices in
the other departments. Now a VLAN will do the same thing. A VLAN or virtual local area network
will also break down and separate a network, but it will do it virtually. VLANs are created on a VLAN
enabled switch. The ports on the VLAN switch can be configured to separate network traffic without
using routers. So back to our business example with three departments, so if you as an administrator
wanted to break down and separate this network into three smaller networks according to their
department, there's no need to move the computers and cables or add additional routers. All we have
to do is configure three VLANs on the switch. So we'll configure four ports on the VLAN switch for
the sales department. And then we'll call this VLAN 1 and then we'll plug all the devices from the
sales department into these ports. And then we'll configure another four ports on the switch for
the service department and then we'll call this VLAN 2 and then we'll plug all the devices from
the service department into these ports. And then we'll configure four ports for the I.T. department and then we'll call this VLAN 3 and then we'll plug all the devices from the I.T. department into
those ports. And once that is complete, these are now three separate networks with three separate
broadcast domains. Each department can only see their own network traffic and their own devices
because the network traffic is separated between the departments using VLANs. So this is why VLANs
are so popular with medium to large businesses because they can separate networks without adding
routers, firewalls, cables, moving equipment around, or configuring IP addresses. They can just
separate networks virtually by using VLANs So guys if you never worked with VLANs before
there's only so much you can learn from a video I recently purchased a small VLAN switch from my
home and configured several VLANs as a refresher for this video. It's a great way to learn and see
how VLANs work. And if you're interested in getting one I'll put a link in the description below of
this video of the one I purchased. So I want to thank everyone for watching this video. Please
subscribe and I will see you in the next video.
