Original subtitles

Now a network consists of 2 main categories or 2 main components

We have what’s called the Physical Components that are used

to create a physical topology and here we are physically

connecting devices to each other using various types of cables

We may be using Ethernet cables as shown here,

we may be using optical cables or fiber cables and more and more

these days we used the air to connect devices to each other

We also have the logical connection or logical topology

and these discusses how data is transported across physical cables or

across the air in the wireless environment

So how data is actually transferred or transported from one device to another?

that’s the logical connection made between devices

Various protocols are used to do this, think of a protocol as a type of language

So at the moment I am speaking English but a protocol called IP

or Internet Protocol is used for communication in a lot of networks today

When physical cabling is used you would plug an Ethernet cable such as

in this example into what’s called a Network Interface Card or NIC on a PC

Network Interface Card gives your PC the physical capability to connect to a network

If a wireless device such an iPad or an iPhone or a MAC

was used to connect to a wireless network a wireless Network Interface Card

is used to enable that device to send and receive data

through wireless transmission across the air

That’s very similar to a traditional radio receiving radio signals

from a broadcaster so that you can listen to music while driving

in the same way you’re iPad is receiving data through the use of airwaves

and is also transmitting back to wireless routers as an example

A traditional radio just receives signals but other devices can

transmit and receive and in the same way your iPad or PC

is transmitting and receiving data through the use of radio waves