- [Craig] In this video, we look at the use of IP addressing and MAC addressing
and discuss the differences between IP version 4 and IP version 6.
(uplifting piano jingle)
Every device on the network has a network interface card, although this may be built into the motherboard.
Every network interface card has a media access control address or a MAC address,
and it's used to route the frames on a local area network.
Traditional MAC addresses are 12 digits; that's 48-bit hex numbers.
They're written in six pairs separated by colons, as shown here.
If the local area network is connected to a wide area network such as the internet,
then a different addressing technique is needed, and IP addressing is used to route frames.
On a wide area network, these frames are actually referred to as packets.
You will sometimes see them referred to as the same thing and used interchangeably,
although this is not technically correct.
So, let's turn our attention back to IP addresses and look at them in a little more detail.
As mentioned already, an IP address is essentially a unique number
which is used to address or identify a host computer or node which communicates over IP on the internet.
There are actually two versions of IP in use today; IP version 4 and IP version 6.
Here's an example of a typical IPv4 address; it is written as four numbers separated by periods,
and each number can be in the range 0 to 255.
In total, an IPv4 address is 32 bits in size - or 4 bytes.
These denary numbers obviously resolve into binary behind the scenes
and provide us with a range of around 4 billion addresses.
The actual number available for use is slightly lower than this, as some of the addresses are reserved for special uses,
but this is beyond the GCSE specification.
There are two parts to every IP address.
The first part is used to identify the network the traffic needs to go to,
and the second part identifies the specific host device within that network the traffic needs to go to.
In this example, we can see the first 3 bytes, 107.56.94, is being set aside to represent the network,
and the final byte, 111, is being used to represent the host within the network.
The split between network and host identifier doesn't always have to be made in the same way as shown here.
This is just an example, but again, it's more than enough at GCSE
to just appreciate that an IP address is made up of a network and a host component.
Now, the 4 billion possible addresses available for use by IP version 4 sounds like a lot,
but a quick look at this graph shows a problem.
Back in 1992, there were around 1 million devices, give or take, connected to the internet, each with their own IP address.
By 2012, we had the advent of smartphones, wireless tablets and laptops,
and many other connected devices, and the number shot up to almost 9 billion.
Now, the reason why we didn't switch over completely to IP version 6 way back in 2012,
as this number's clearly already bigger than 4 billion,
is we've been using all sorts of tricks and workarounds to reuse
and make use of the fact that we have more devices connected to the internet at any given time
than we actually had available IPv4 addresses.
Now, that's 2012; fast-forward to 2018 and we have almost 35 billion connected devices requiring IP addresses.
You may have also come across the term the Internet of Things,
and with that, we're going to see an explosion of IP devices over the next decade
which will want an internet connection.
Already, we have light bulbs which can be assigned IP addresses and can be controlled remotely via apps on phones.
The current estimation - and I made this video in 2019 - is that we will already exceed 50 billion connected devices by 2020,
and the number is simply going to skyrocket.
As you can see, it was identified quite early on that a replacement for IP version 4 was going to be needed.
And that is why IP version 6 was invented.
Essentially, it works the same as IP version 4 but this time, it's using 128 bits.
You can see now that we encode these as eight groups of four hexadecimal digits separated by colons,
but again, behind the scenes, the number is still being stored as a 128-bit or 16-byte binary number.
This gives us an approximate 340 trillion trillion trillion combinations of IP version 6 addresses,
which hopefully should be more than enough for the foreseeable future.
So, let's have a quick recap.
MAC addressing is used to route frames on a local area network.
Each MAC address is unique to every network interface card.
IP addressing is used to route packets on a wide area network, and there are two versions of IP addressing.
IP version 4, which is 32 bits in size, is written as 4 numbers separated by periods,
with each number in the range of 0 to 255.
A router will have a unique WAN-facing IP address and a LAN-facing IP address.
This enables a LAN device to have the same IP address as another device on another LAN.
IP version 4 is being replaced by IP version 6 because unique static addresses are running out.
IP version 6 is 128 bits in size and it's written as 8 groups separated by colons,
with each group made up of 4 hexadecimal values representing 16 bits.
(uplifting piano jingle)