So far in this course we have learned about how network endpoints create data and utilize different
network protocols behind us and point data from one host to another.
This is where network devices come into play.
There are many networked devices in our networks and each of them play a specific role to forward traffic
between endpoints.
Here are some of the most common now work devices that are on almost every network.
Let's take a brief look at each of these now devices.
The first network device we're going to talk about are hubs hubs are legacy layer 1 devices that were
used to just simply interconnect devices so that they can communicate with each other.
So like in the slide if I wanted these two computers and this printer to be able to talk I could plug
them into a hub and they would be able to reach each other.
Well the problem with hubs is that unlike modern day switches they didn't have any intelligence on how
to forward frame's hubs work by simply forwarding any received frames of all interfaces which is a terrible
design because regardless of which endpoint the frame was destined to every host on the network receives
a copy of the frame.
This can obviously degrade performance on the network.
Well to solve this problem switches were introduced switches forward layer to either not frames between
switch ports based on MAC addresses once a switch learns a MAC address it can determine which switch
poor to afford the frame out of based on its MAC address table entry.
Also known as the camp table.
So in this example based on the MAC address table entries that the switch has it would know to forward
two frames dust into the phone on a port 1 0 8.
One very important switching concept is a broadcast domain a broadcast domain as a boundary for layer
to traffic when a broadcast frame is forwarded onto a LAN.
It can only be sent within its local broadcast domain.
Broadcast domains can improve network performance and security by limiting traffic between hosts to
create multiple broadcast domains on a switch.
The lands are used villans archaeological division of labor to traffic within a switch network.
They are frequently used to secure traffic at a layer 2 level.
For example if I had servers and guest devices coexisting on my corporate network I would not want the
potentially vulnerable guest devices to be able to talk to my secure servers.
So by simply placing these different traffic types on separate villans you can begin to enforce traffic
borders to help secure the network.
Avi plan best practice is to actually assign different villains to each device type.
Next we have routers.
Routers are used to route IP packets between different networks.
The entire internet is actually made up of thousands of routers used to sign IP packets between houses
and Web sites like Google and Facebook.
Even though routers are primarily used to route IP packets they can also be used to secure networks
with features like IP filtering and IPX.
Finally we have wireless devices wireless connectivity is a major concern when it comes to securing
a network and should be protected with strong encryption and authentication methods wireless access
point deployments can be Autonomy's or lightweight autonomous apes are configured and managed individually
and do not scale well lightweight APC's are centrally controlled by a wireless LAN controller for security
alone.
This is a big advantage for monitoring and maintaining consistent secure configurations across the wireless
network.
Now that you know what networks are and how they work you're ready to learn how to protect them in the
next section.
We will talk about network security devices like firewalls and IP UPSs.