[music]
Now, up until this point in time,
before classful networks
were developed,
when it was back in the old days
of just a single 8-bit number for
the network,
there were no governing bodies.
So you could run across this
situation right here.
Where more than one company used
the exact same network,
and that would lead to some
confusion.
Like in this particular case,
Router A is receiving a packet
with the destination address of
2.2.2.2
and as it just so happens,
there is two different companies
that are using that exact
same network.
Router A is confused.
He says,
Where do I forward this
packet to?
Should I forward it to Router B's
network or Router C's network?
So as networks continue to grow,
and especially as they developed
this whole classful scheme,
they said,
Look, we need some high level
organization to monitor and
regulate the use of IPv4 networks
to ensure that when one company
is given an IPv4 network for use,
nobody else in the world will get
their same IPv4 network.
So they will be uniquely
registered and allocated to
various different companies.
So this is what we're left with
today as a result of that,
our current IPv4
addressing structure.
So at the very top of the food
chain is the Internet Assigned
Numbers Authority.
This is the original top-level
organization that was in charge
of allocating all of the IPv4
and, currently,
IPv6 networks downstream,
so they own them all.
They also do other numbers,
not just IPv4 numbers but,
for example,
on your studies of your CCNA,
you've learned that at Layer 4,
there are TCP and
UDP port numbers.
TCP port 23 for Telnet,
port 80 for HTTP,
and so on and so forth.
Well the Internet Assigned
Numbers Authority also regulates
those numbers.
If you happen to be a software
developer and you're
watching this,
and you come up with some
creative idea for a new UDP or
TCP application or protocol,
and you want your own unique TCP
or UDP port number,
you will need to go to the
Internet Assigned Numbers
Authority, and they will
allocate a number for you.
So they're the top of the
food chain.
Now if you're a company,
if you are an enterprise
for example,
you're an enterprise company and
you need one or more networks for
your own use,
you're probably not going to go
to the Internet Assigned
Numbers Authority.
Instead, there are other
organizations beneath them which
are called
Regional Internet Registries.
RIR, Regional
Internet Registries,
and as you can see here there are
five of them throughout
the entire world.
You've got AfriNIC,
which stands for the African
Network Information Center.
You've got APNIC,
which is the Asian-Pacific
Network Information Center.
RIPE NCC,
I probably won't be able to do
that justice,
because that's actually French.
I can't even pronounce it.
Reseaux IP Europeens or something
like that.
It's basically French for
European IP Networks.
And then ARIN,
that's what we use here in
North America.
That's the American Registry for
Internet Numbers.
And then lastly you have LACNIC,
which is the Latin America and
Caribbean Network
Information Center.
So these are all considered as
regional Internet registries.
And then beneath them you have
your Internet service providers
like Comcast,
Time Warner Cable, Verizon,
Sprint and so on and so forth.
And at the very bottom of the
food chain is the end user,
you and me,
who are working for a company
that needs an IP network.
As an end user,
either a home user or you're a
network admin for a company,
when you need to get an
IPv4 network,
you basically got two choices:
you can get it from your ISP or
you can go directly to the
regional internet registry.
When you go to that,
now you might be wondering,
well, why would I do one
over the other?
Let's say you go to your
service provider.
Let's just say Keith's
service provider.
And I go to Keith's service
provider and say,
hey, I need some networks from
you to assign to my company,
so I get some networks from them.
They're basically leasing that--
I'm not really buying it.
It's like they're renting
it to me.
Now, I probably have to pay them
a monthly fee,
maybe a yearly fee,
so that that network is
registered as mine,
belonging to my company.
So great, I'm working along,
but over time I start getting a
little irritated with Keith's
service provider.
It goes down a lot.
I lose my network connectivity.
Whenever I call their
customer service,
I'm on hold for like
45 minutes on end,
and then I get somebody who's
totally rude and abusive to me.
Eventually I get to the point
where I say,
You know what,
I'm done with you.
I'm not going to use Keith's
service provider anymore.
I'm going to move to a different
service provider.
I'm going to move to
your competitor.
Well guess what,
if I got my network from them,
my IP addresses,
now I have to basically give it
back to them.
I can't take it with me,
and now when I move to another
service provider,
I've got to get a whole other
range of IP addresses which is
going to be a huge pain.
That means I have to go log into
all my routers,
all my switches, all my laptops,
all my DHCP servers,
and spend a considerable amount
of time readdressing my
entire network.
If we're talking about a large
network with thousands of
employees and devices,
that's going to be a monstrous
pain, as alternative to that I
could go directly to my regional
Internet registry.
I could contact the American
Registry of Internet Numbers -
ARIN - get a subnet or multiple
networks from them,
and now regardless of which
service provider I'm using it
doesn't matter because I got my
network directly from my regional
Internet registry.
There's actually a term for that,
they call that
provider-independent addressing.
If you ever hear that term -
provider-independent addressing -
that means you went directly to
your regional Internet registry,
got your address - your IP
networks - from them.
What's kind of interesting though
is that here we are in 2015 if
you go onto ARIN's website,
as an example,
and look up how to do that you'll
see that it's virtually
impossible these days because
IPv4 has been around for so long,
and the growth of networks has
been exponential every
single year,
pretty much almost all of the
IPv4 addressing spaces almost
used up.
If you go to ARIN's website,
it'll show you how much
addressing space is currently
available and there is almost
next to nothing.
So these days,
getting provider independent
addressing is kind of tough.
You've got to provide some really
strong justification to get that
from your regional
internet registry.
So 95% of the people these days
who need networks are forced to
go to their service provider
because those are the only
companies left that have free
networks to give out.
Also, you can see there there's a
link at the bottom of that page.
If you go to that,
you will see which one of those
regional internet registries were
allocated to blocks of networks
from the Internet Assigned
Numbers Authority,
which is kind of interesting
because that means that if you
ever see an IP address,
you can figure out which portion
of the world owns that
IP address.
Like if I'm going to a website
and I know that their IP address
begins with,
99-dot-something,
I can go to that website and I
can see the 99-block was
allocated from the Internet
Assigned Numbers Authority to
LACNIC. They own it.
So that website I'm going to must
be somewhere in the Caribbean or
Latin America.
It's kind of interesting, you can
play around with that.
[music]