Everybody in this video we're gonna be going over the switch.
So what is a switch switch is a commonly used network device that takes packets in and redirects them
to their next stop in the hub.
So briefly what a hop is a hop is a destination or network device that a packet has reached at a certain
point.
So for example there might be a 30 hop limit so it can only go through 30 network devices before it's
considered expired just as a packet itself but what I want to understand here is that most your home
network if you're using a wireless network or a home network of any kind the router that you the modem
or router that you have plugged in is also acting as a switch.
So if you look at the back of it you'll probably see three or four ports on the back.
Now a switch is normally used in a large array of networks from anything from the house to an enterprise
now.
Ports can have between normally there's a minimum absolute minimum of two however and most common ports
you'll see switches you'll see as it starts at 4 and it can go all the way to 100 fifty.
So depending on the size of the network you might need more ports.
Now each port is a physical socket that you plug in some sort of network medium too.
So this is whether it's a fibre node or a fiber link or it's a twisted pair type cable a regular Ethernet
Cat 4 Cat 5 cable whatever the whatever the type of medium is as long as the switch supports it on a
particular port you can plug the medium into it.
Now this is a pretty rough look of what a catalyst switch looks like.
So it's just a standard switch so you can see there's quite a few ports on this particular switch.
Now the two on the right are considered the uplinks and the ones on the left.
The two groupings of ports on the left of one on each side is what would be connected to physical machines
for example.
So the uplinks tend to go to another switch which and then eventually get to something called a Tor
which is a top of rack switch and then that switch is connected to the actual backbone of the network.
So switches normally talk to each other.
And so when traffic doesn't make it through one and it can't find out where it needs to go it'll go
through the uplink port now a packet will look a switch will look at the packets IP header as which
includes the source and destination address as well as the MAC address now based on the Mac and the
IP address.
It will look locally do I know where this is.
So is one of the ports that has a machine connected to it or a node connected to it does it does the
IP and MAC address match one of these.
If it does it sends it that way.
If it does not it will send it to its uplink port and then that switch will do the same thing if it
can't it'll go to its next uplink and then its next uplink and eventually the top of rack switch will
point to some sort of router and then that router will be able to get it to the correct path that it
should be whether that's going out to the Internet or whether that's down to a different network segment
so I just want you understand what a switch is at a high level.
Now physically you may never touch one.
However understanding what they are and how they work is important.
So if you have any questions feel free to jump over to the Facebook group.
At this point we're not going to go too deep too much deeper into what a switch is just because of the
sheer massive amount of data that you could roll into when it comes to looking at which is because different
types of switches are configured differently which have different requirements which have different
features.
So in this case I'm going to leave switches as they are.
Feel free to look into more specific information that you want to know about switches themselves.