IPv4 Addresses: 5% Left

They’re disappearing at the rate of about one /8 block a month. And there’s
not much more than a dozen left
<http://www.zdnet.com/news/ipv4-addresses-hitting-critical-stage-5-percent-remain/475865>.

 

Lots of them are left, just release them.

 

What’s likely to happen, as people get more worried about them running low,
is they start to run out faster
<http://arstechnica.com/web/news/201...g-ipv4-address-blocks-quickly-running-dry.ars>.

 

Why are 224-255 unusable? What are they otherwise 'used' for which
makes them unusable.

There are probably 'kludges' available of the type, for example, where
the London telephone system was split into two concentric zones as an
interim measure until 8 digit numbers could be introduced.

 

Addresses starting with 224 through 239 are for multicasts. They can't
be reassigned because there will be existing devices that are using
addresses in those ranges for multicasts, and routers and hosts will
assume that is what they are for.

Addresses starting with 240 through 255 are "reserved for future use"
according to various networking/IP textbooks (I haven't hunted down the
RFCs), and at least 255.255.255.255 is used for local broadcast. Some
references suggest this range can be used for "research and development
purposes".

I expect a problem with reassigning 240 through 254 is that lots of
routers and hosts will not allow addresses in that range to be used,
because they are/were officially reserved.

 

It's a very basic flaw in system design to have a fixed length field
that eventually overflows, requiring a huge amount of work to make the
field larger, until the next time it overflows again.

 

In message

Given that IPv6 has room for roughly the same number of addresses as the
estimated number of atoms in the entire observable Universe, how soon will
it be do you think before we have to go through the pain all over again and
move to IPv7?

 

A very basic flaw in universe deign

 

The number of atoms in the Universe seems to have shrunk by a huge
margin.
Some programmers are very wasteful of resources. Whatever is
available, they will waste. However IPv6 should be enough.
Why didn't they use IPv6 in the first place?

 

Because IPV4 would have seemed ample at the time, so much so that some
large USA companies like IBM and MS were allocated a 'A' group eg
ccc.xxx.xxx.xxx where the whole x range was allocated to them.

Similarly phone companies thought that seven digit numbers and a USA
area code system with 128 or so area codes was adequate.

In such cases there was a requirement at the time to accommodate
technological and perceived human limitations, eg phone companies
considered a seven digit number was as much as a person could handle
(especially with the traditional spin dial), and even then the first
three should be a 'letter code' (even if random letters like in
Sydney, etc). Also for example 40-50 years ago it was considered that
people would never be able to dial international calls because of
alleged complexity.

 

Why did the phone company not start with 7 digit phone numbers from
first manual exchange?

 

We are all clever with hindsight.

 

Hardly. 128 bits is about 3e38 IPv6 addresses.

12 grams of carbon-12 contains 6e23 atoms, and the mass of the Earth is
5.9e24 kg (3.5e48 if it was all C-12), so there aren't enough IPv6
addresses for every atom on Earth, let alone the whole universe.

It works out to slightly less than one IPv6 address per square picometre
on Earth's surface. (Earth's surface area being 5.1e8 square
kilometres.)

 

The overhead of transmitting IPv6 sized addresses on the modems of the
day (1200 bps) would be one very good reason not to have used IPv6 sized
addresses. >20% of the bandwidth available would have been required
for transmitting addresses at one packet per second.

 

In message

We’re talking pre-PC era, back when computers, at least ones powerful
enought to be worth networking, were hefty boxes that had to live in their
own special rooms. Nobody ever thought we’d have a billion computers like
that. And indeed, we never did.

 

The resources of routers

 

They effectively did in big cities. You gave the operator the central
office name and number eg Pennsylvania 5000 for New York's
Pennsylvania Hotel. When the London and New York phone systems were
automated, the number became PENnsylvania 5000, and when NY Phone
Company ran out of relevant names, PEnnsylvnia 6-5000 (as in the Glen
Miller song), and finally 736 5000, so the hotel has effectively had
the same phone number for 100 years or so.

In these cities if you dialled a manual number from an automatic
phone, the last four digits were displayed to the 'B' operator who
then completed the call manually. This enabled central offices to be
progressively converted without the need to notify everyone of number
changes.

Letters on phone push buttons follow original USA practice. The
British moved the letter O to zero, and the French added Q to zero (eg
ROQuet 1234), and the Aussies went off on a real tangent having a
single letter on each dial hole so phone numbers were like number
plate numbers. The advent of international dialling (originally by
phone operators) brought these variations to a head - hence all digit
numbers.

 

Our old boat, Hinemoa, has a plate above the door with the boat builders
4 digit Auckland phone number.

 

Prolly need IPv7 within ten years, LOL

 

I invented a principle (but somebody else may have thought of it
first) that when you are designing something, assume that it is going
to succeed, and design accordingly to allow it to be scaled up.