In the beginning, the Internet protocol was part of TCP.
There was no separation.
There was no Layer two and layer three.
It all worked as one.
When I say the beginning, I'm talking about 1973
and the protocol was called TCP version one.
Fast forward to 1977.
Computer scientist John Postel splits the TCP protocol into TCP
and IP. Two separate distinct layers
and the birth of the internet protocol
After a few revisions, TCP/IP
finally went live in 1982 when the US Department of Defense
made TCP IP the official standard for military networking.
The fourth generation of IP, the Internet Protocol
was the first to be formally used across the globe.
The internet has officially been born,
even though IP v4 has been in use for 40 years.
It is still the most popular version of the Internet protocol.
But IPv4 has a dark side
In the decade following IPv4's introduction,
a critical flaw was discovered.
The original IP v4 architecture used 32 bit addresses
This supports about 4.2 billion
unique IP addresses
This would have seemed like a lot back in 1983.
But then the internet started becoming popular.
It wasn't just for the U.S.
military and universities anymore.
It was gaining global appeal.
The World Wide Web was invented.
Businesses got online.
Some people even had Internet access in their own homes!
By the end of the decade, it was predicted
that the global IP address pool would soon be exhausted.
Something needed to be done.
In 1992, the first official document outlined some conservation strategies
to combat the unexpected explosive growth of the internet.
Additional attempts to extend the IPv4 pool were made
1993 saw the introduction of classes
inter-domain routing. In 1994
NAT was introduced.
NAT, along with private IP addressing,
further conserves the number of public IP addresses that a site needs.
NAT, CIDR, and other techniques have certainly helped
to extend the life of IPv4
the permanent solution is IPv6.
It can work alongside IPv4, but the ultimate goal is to entirely
replace IPv4.
In this section of the CCNA series,
we're going to demystify IPv6.
We're going to cover the basics of IPv6.
The new address format.
The different types of addresses such as public and others.
IPv6 configuration and finally, routing
IPv6 traffic
One of the most
obvious changes in IPv6 is the format of addresses.
We'll see how they work in detail in the next video.
The reason for this change is the size of the address space.
IPv4 addresses are 32 bit numbers,
while IPv6 addresses are 128 bits.
This might sound like it's four times bigger,
but when you think about how binary numbers work, you'll realize that
IPv6 addresses are a lot bigger.
Let's put that into perspective.
There are nearly 4.3 billion unique IPv4 addresses.
Of course, some of these are reserved for special uses.
At the time I'm recording this.
Earth's population is approaching 8 billion people,
so we don't even have enough IPv4 addresses.
For everyone.
Let's think bigger to get our heads around this.
Let's look at the Milky Way galaxy.
This has about 100 billion stars.
That's a drop in the bucket compared to the whole universe,
which, according to one estimate, has about 200 billion, trillion stars.
How does this compare to IPv6? Any guesses?
There are 340 undecillion IPv6 addresses.
That's about 1.7 million billion
unique IP addresses for every star in the universe.
So if IPv6 solves the exhaustion problem,
as well as adding other features why don't we just use it?
Why didn't we start using it back in the 90s?
Well, there's a problem.
IPv4 and IPv6 are completely independent
of each other.
That is, a host with only an IPv4 address
cannot communicate with a host
That's only IPv6.
So it's not simply a matter of turning it on.
All networks across the globe need to migrate to IPv6,
and there are a few ways this can be done.
One of the simplest options called dual stack is to configure devices
to have both IPv6 and IPv4 addresses.
Okay. So we need to migrate.
Why don't we just do that then?
Well, we are doing that, but it is a very slow process.
Imagine a large company or service provider with links across the entire
country.
There's a lot of planning, effort and expense in changing the configuration
of their entire infrastructure.
Another reason is that there is a lot
of applications that haven't been written with IPv6 in mind.
If you're already working in IT, you'll
probably have noticed that people don't like change all that much.
A lot of people are still using old applications which need to be updated
and unfortunately,
many people are frightened by IPv6.
Seeing IPv6 address for the first time can be intimidating
since it looks quite different But you don't have to be scared.
It's just something new.
By the end of the next few videos, you will feel more comfortable,
I guarantee it.
So even though IPv6 adoption
has been slow in past, it is gaining momentum.
This is a graph of the IPv6 devices that connect to Google services.
It really speaks for itself.
More and more people are using IPv6.
So love it or hate it.
As network engineers, we need to know how it works and how to support it.
Is a common
question that often comes up when we discuss IPv6.
Are we really running out of IPv4 addresses?
Haven't we been hearing about this for years?
It has been years, yes.
As we've said, IPv4 exhaustion was predicted back in the eighties,
and a lot of steps were put into place in the nineties
thanks to that work being done in the nineties.
IPv4 exhaustion was pushed out by years.
So let me illustrate.
There have been over 4.2 billion IPv4 addresses.
Some are reserved for special uses, but let's just work
with the approximate 4.2 billion addresses for now.
There are nearly 8 billion people on Earth.
If half the population had only one device like a smartphone,
there's 4 billion devices right there and IPv4 is exhausted.
NAT and private IP has helped with that,
which allows several devices to connect to the Internet with a single public IP.
But most of us have more than one device, don't we?
We have phones, PCs, laptops,
tablets, TVs and other devices.
And that's on top of all
the infrastructure devices like routers, switches and servers.
I found an article from 2014
that said that 10 billion devices were connected to the Internet,
and we now have a technology called IoT or Internet of Things.
This dramatically changes the number of connected devices.
In 2019, there were nearly 8 billion IoT devices connected to the Internet
with a prediction of 16 billion by 2025.
So just how close are we?
Well, in order to understand this better, let me explain where IP addresses
come from
You see kids, when two protocols love each other very much, they...
No. I'm just kidding. At the very top of the family
tree is an organization called IANA, and
they hand out large blocks of IP addresses
to regional Internet registries.
These RIRs handle IP
address allocations
in their geographical regions.
They hand out blocks of IP
address to large organizations and Internet providers.
Smaller businesses and home users get their IP from their Internet providers.
This can be as little as a single IP address.
So back to the main question then,
how close are we to running out of IPv4 addresses?
Well, in January of 2011, that's over ten years ago,
IANA handed out their last /8
block to the RIRs.
APNIC was the first to exhaust its allocation of freely available IP blocks
That means they were down to a single slash eight block.
It doesn't mean there's nothing left.
It just means the quantity they have is extremely limited and difficult
to acquire.
This happened later on in 2011.
RIPE
followed in 2012, LACNIC 2014,
ARIN in 2015 and finally AfriNIC in 2017.
Now that doesn't mean IPv4 is completely dead.
There are still some attempts to keep it going.
For example, some ranges
that were previously reserved for special use have been made public.
Some institutions, including Stanford University, have returned
some /8 blocks that they were given in the early years of the Internet.
And as you can imagine, there's a bit of a marketplace
for buying and selling blocks of IPv4 addresses.
IPv4 exhaustion sometimes seems slow,
like climate change, but it's inevitable.
The long term solution, of course, is IPv6
So what's new?
What's changed? What's the same?
Well, IPv6 is still routable, just like IPv4
It's still part of the Internet protocol and still works at layer three.
We can even use IPv4 alongside IPv6.
This is called dual stack and it makes migration much easier.
The most obvious change is the size
of the address space, as we've seen in this video.
Along with that comes a different address format. The addresses
look quite different as they're written in hexadecimal.
We'll see how this works in the next video.
NAT was intended to be a short term solution.
For IPv4 address exhaustion.
So there's no NAT or PAT as we currently think of it, in IPv6.
There are some types of NAT, such as NAT64 and NAT46.
These translate between IPv4 four and IPv6 addresses,
but these are really only there to help with the migration from IPv4 to IPv6.
There is a NAT 66, which is like old fashioned NAT,
but it's really not recommended.
A few of the older technologies have been refreshed
in place of ICMP is ICMPv6.
We'll see how this has grown in upcoming videos.
DHCP and DNS have been enhanced
to make the DHCPv6 and DNSv6.
DNSv6 even comes with a new record type called the Quad A record
and of course routing protocols have been extended to support IPv6.
In a later video, we'll see how to use OSPFv3.
An interesting one is ARP, the Address
Resolution Protocol. It's gone.
It has been replaced by NDP, The Neighbour Discovery Protocol,
and we'll definitely be looking at that one further.
And finally, I want to mention broadcasts.
There are no broadcasts anymore.
"What?!?" I hear you say... "No broadcast???"
"How??" Well broadcasts really weren't that efficient.
Now, with better protocols like NDP,
everything to be done with multicast messages.
And you better believe that we'll be looking at those too
We've got a few more videos on IPv6 after this one.
So I invite you
to continue on with the series when you're ready to see how IPv6 works.
Starting with the new address format.