Original subtitles

Ethan at 10 base to use as correction CAPLE The specifications are different to the coaxial cable used

in cable television.

But the point I'm trying to make is coaxial cable running a baseband signal can only transmit or receive

a single signal at any given time.

Broadband uses coaxial cable that allows for multiple signals to be sent across the wire at any given

time.

Ethernet uses baseband signaling.

In other words 10 base two or ten base five in the past.

So in ten based to correction cable was used.

But you can see connectors we use to connect devices to the network a BNC connector would connect the

cable to the PC.

Don't worry too much about this.

This is just a bit of history so that you can understand why things are done in certain ways today.

What's important to realize is that a single piece of cable would have been in-seat connectors which

would allow you to connect devices to a single cable.

Multiple devices were connected across a single cable and at the end you would have Terminators to stop

signals bouncing back and gives an example of a terminator.

So what it terminated did is essentially terminate the signal or destroy the signal when it got to the

end of the wire.

So when the signal is sent across the wire it shouldn't bounce back and cause collisions.

So the Terminator would terminate the signal to ensure that it didn't bounce back.

Once again the reason for doing this is because baseband is used baseband only allows a single signal

to be sent across the wire or cable at any time.

So we couldn't have a signal bouncing back and causing a collision hence terminate as we used.

Now before we continue discussing the transmission of data in more detail let's talk about what a MAC

addresses a Media Access Control address or MAC address also called a physical address is a unique identifier

assigned to network interfaces and MAC addresses a layer to address identifying a network interface

card or MC.

It is typically boltin by the manufacturer.

In other words it's Boente in to the network card Bhave Nic manufacturer and it's 48 bits in length

the 48 bits are divided into two portions.

The UI portion is 24 bits in length and the station address is also 24 bits in length.

The UI organizational unique identifier identifies a vendor such as Cisco or HP or Dell or other vendors

that manufacture network devices or PCs or servers.

Each manufacturer is assigned and why.

And each vendor in turn can create and assign and station addresses to Network Interface Cards the station

addresses should be unique.

Now they should be unique because there have been cases where addresses have been duplicated by manufacturers.

So you may end up having a network with duplicate MAC addresses which causes a lot of problems in an

Ethernet environment in an Ethernet environment on a segment or a piece of cable.

We're assuming that all devices have a unique MAC address.

It's also possible in software to change device MAC addresses.

So my interface card as an example I can go to properties go to configuration selected vaunts I can

then go to a locally administrated addresses and then I can change the valley so I could make it quadruple

a quadruple be quadruple see and click ok.

Opening ACMD prompt and tapping IP config for special and then scrolling up I'll be able to see that

my physical MAC address is now set to a b c I've just changed my MAC address from the phone to in the

address set by the manufacturer to something else.

Now if I did that on multiple PCs or multiple devices I would be causing an issue with duplicate MAC

addresses.

So once again the first portion of a MAC address is the UI.

And the second portion is a unique value assigned by a manufacturer.

So on my network card I'll set it back to the default.

So now when I run IP config less you'll notice the built in MAC address on my local area connection

uses the unique value assigned by the manufacturer.

Why Asharq has a nice tool to look at.

Oh you like coats.

So I've just added the 0 0 0 1 E6 and that should list the manufacturer for that MAC address.

In this case you can see it's HP some MAC addresses that start with triple 0 1 6 hp MAC addresses.

I can also look on the dribbly Web site to see similar information.

Notice that both E-6 and IE 7 codes are manufactured by HP.

There's a long list of different codes and you'll be able to see which codes are associated with which

vendor.