Japan plans to create 10B 14-digit phone numbers with 5G era approaching

[lifthrasiir]

As many seem to wonder about details, this is my understanding of the situation (I've posted some below, but this format would be better):

- 070, 080 and 090 prefixes are being used for mobile phones and M2M (machine-to-machine) communications since 1999. They are 11 digits long and the future shortage was expected.

- 020 prefix was created exclusively for M2M in 2017. The existing M2M numbers do not have to migrate, but it is recommended for most cases as 020 prefix has no requirement for the number portability and QoS. So the creation and expansion of 020 prefix is irrelevant to the population estimate.

- Since 0204 prefix was already used for pagers, and since 0 is a trunk prefix in Japan, there were initially 80 million numbers available, starting with 0201--0203 and 0205--0209.

- It was envisioned that 80 million numbers do not suffice for the future expansion of IoT devices, so there was already a plan for 13- or even 14-digit numbers at the time. Note that while 14-digit numbers are within the E.164 recommendation (e.g. +81-20-XXX-XXXXXXXX = 020-XXX-XXXXXXXX) it does seem to cause some serious engineering problems to tackle.

- 020 prefix was allocated in the increasing order, so numbers up to 020-536-XXXXX are allocated as of May 2019 [1]. It is expected that the digit expansion will happen in the remaining area.

- While 020 will greatly postpone the exhaustion, existing 070--090 prefixes would be eventually full in the future. 030, 040 and 060 prefixes once used but now vacant are reserved for this inevitability.

[1] http://www.soumu.go.jp/main_content/000477284.pdf

[JimboOmega]

But why would Japan run out of phone numbers with the population shrinking?

While of course IoT devices need to be addressable, that's more of an IPv6 problem than a phone number problem.... right? A person might have a few numbers, at most - and a flat if not shrinking number (I used to have home, work, cell; but have only had cell for a while now)

[sschueller]

What do we have IPv6 for? I thought these 4G/5G networks run a TCP stack and telephony on top of it. Why do we phone numbers for device to device communication?

[kalleboo]

> Why do we phone numbers for device to device communication?

For billing, mainly.

The phone number in 3GPP protocols is the IMSI = international mobile subscriber identity, which identifies a user on the phone network. You swap out your SIM card, and you swap out your IMSI. You roam abroad, and the foreign network knows who to send the bill to.

The alternative would be to keep an international database of IMEIs (device IDs) like CDMA networks did. Using SIM cards with IMSIs ended up being more consumer-friendly.

[lemcoe9]

Give me a call at [2607:f8b0:4004:802::200e] and I'll tell you.

[gcb0]

For the same reason we have DNS.

[srmarm]

Considering > about 32.6 million of the 80 million numbers starting with 020 had already been assigned

It seems a bit odd that they're putting the 14 digit numbers on the same 020 prefix that half the 11 digit numbers have already been released for. Seems like some chance for confusion where the first 11 digits collide. I'd have thought it'd make more sense to give a new 3 digit prefix for this class of numbers.

[toast0]

Someone mentioned they've been assigning prefixes in 020 to carriers in order. The thing to do then is make say 020 [0-3] be 11 digit numbers, and 020 [4-9] be 14 digit numbers. Then it's easy to validate.

I doubt they would assign 14 digit numbers where the 11 digit prefix was assigned to someone else, but, if they were desperate for space, they might make the 020 prefix all be maybe 11, maybe 14 and as 11 digit numbers were released, issue 14 digit numbers with the same prefix.

[avar]

How are these allocated under the hood? Wouldn't it make sense to stick all of these phone numbers in an IPv6 /64 at this point, with the "14 digit" just being a convention mapping to some range in that space?

[sametmax]

Is a simcard always supposed to have the same ip ? How would ip spoofing would affect the phone network ?

[tamrix]

It could even be cool to call someone by a domain name like an .id.jp that pointed to that address.

[andyjohnson0]

Regarding machine-to-machine communications, I'm wondering if these extra numbers are needed because mobile devices require a phone number to interface to mobile networks, even thought they typically only initiate data exchanges. Or‡ are there devices that actually receive phone calls - as in dial-up?

‡ not familiar with tech in Japanese infrastructure

[michaelt]

There are certainly cheap GPS trackers that send SMS messages. Of course, those are usually sold to consumers rather than into the M2M market.

[gumby]

M2M should just use IPv6 natively which would leave enough 11 digit numbers for human use.

And the fact that they are willing to go to 14 digit means they know that few people dial numbers manually anyway.

[throw0101a]

In case anyone is wondering, ITU E.164 specifies that maximum length of a phone number is 15 digits:

* https://en.wikipedia.org/wiki/E.164

* https://en.wikipedia.org/wiki/Telephone_number

Given that Japan's country code is +81, that leaves thirteen digits for however Japan wants to assign it internally.

[GreaterFool]

Given that the population of Japan is <130M and is only going to go down from now on, what's the point? :)

14-digits?!?! Yikes. Not looking forward to using that!

[SenHeng]

For those that haven't RTFA Japanese phone numbers have 11 digits, 123-1234-1234, of which the first three are reserved as identifiers. A lot of people also carry two phones. Many companies also still have fax machines. Even my pocket wifi has its own phone number (can't be dialed).

8 digits is only 100,000,000 possible unique numbers. So it looks like they're simply running out of numbers.

[a_t48]

Maybe there will be a checksum digit. :) Given how rarely I enter contact information in manually, it doesn’t seem that unreasonable to have a larger phone number - nowadays it’s either clicking a link, opening a QR code, or copy pasting some text to make a new contact.

[onion2k]

I would guess that these numbers will be hard-wired to "Internet of Things" devices, and this is a move to centralize the control of them. If every device has it's own telephone number that can't be modified and a 5G modem built in then the government (via phone companies) has a huge amount of control - sending messages, commands, remotely monitoring them, bricking them...

[C1sc0cat]

15 is the ITU max BTW - something to be aware of for HN contributors when setting up DB Schemas that stope phone numbers.

[Someone]

”The communications ministry plans to create some 10 billion 14-digit phone numbers starting with “020” for assignment.”

I expect “020” isn’t currently a valid prefix in Japan. If so, this makes it a lot easier for software to know whether it has to wait for more digits in a phone number.

There probably are lots of other unused three-digit prefixes, but one has to assume what one deploys now will stay around forever (one century and counting), and that the future will demand space for things we have no idea of.

And 14 isn’t that bad. Bank accounts in Gibraltar (population 35,000 or so) have 23 characters, Kuwait’s (population 4,5 million) have 30, Malta’s (population about 500,000) 31 (https://en.m.wikipedia.org/wiki/International_Bank_Account_N...)

[manjana]

Machine-2-machine (M2M) communication might play a role in the big number of addresses, not sure though.

[fwn]

> Not looking forward to using that!

I thought that as well, but the more I think about it..: I'm pretty sure I did not type out a phone number for the last 5 years.

It's all numbers already saved in my contacts, new numbers I got via some form of text message or numbers on websites and the Google app.

It might be that people don't really type number all that often anymore.

[thefounder]

At some point we should stop using numbers and use something like an email address.

[Funes-]

Indeed. Using self-descriptive "handles" or usernames such as @name.surname or @company.city would be great for caller and texter identification, as well as user discovery--if they want it to be public, that is. That, and having to send a request before you can contact anyone would bring some control and protection back to the user.

[neilalexander]

Incidentally, this is already possible with SIP, which is behind most standardised VoIP signalling. In particular it allows for federation too.

[digitalsushi]

if we're going to reinvent PSTN, can we also include in that specification an arbitrary length numeric passcode that a number owner can set, and reset, to require for the call to ring through, or even return the SIT if the passcode fails?

[epanchin]

How would international calls work?

[lcnmrn]

What's wrong with case insensitive letters?

US-ABC-900-900 can be a beautiful phone number and global. 165,216,101,262,848 numbers per country.

US-ABCD-900E-900R in case we run out of numbers again.

[jasonhansel]

Most countries don't use the English alphabet, so I'm not sure if that would work outside the US.

[kalleboo]

It would be incompatible with everything that already exists

[lostmsu]

Can't we use email addresses instead?

[noselasd]

Why ?

[manjana]

14-digit!? No one can possibly remember that easily... Why not alphanumeric and make the address space so big that people can chose one that would be possible for a stranger to remember immediately - like we have domain names, e.g.: cecelia_alberto OR charlotte1231

[Ultramanoid]

Does anybody actually remember phone numbers these days ?

Edit : I do remember the half a dozen I use or might really need, and already feel like an outlier. ( And as pointed in another comment, they're already 11 digits each. Not that much of a difference. )

[majewsky]

> 14-digit!? No one can possibly remember that easily...

I have no problem at all remembering my 22-digit IBAN. I know people who memorize random-generated 30-character passphrases. But yeah, we don't seem to be the norm.

[kalleboo]

> Why not alphanumeric

Because that mean re-inventing the phone system and making it incompatible with all existing and future devices made for the whole rest of the world.

These are going to be for 5G IoT devices anyway, the phone number is just going to be for billing use, all the actual traffic is going to be over IP

[gpvos]

The numbers are for machine-to-machine communication. No one will be calling them.

[dageshi]

Memorising peoples phone numbers is about as ridiculous as memorising ipv6 addresses, sure you can do it, but what's the point? You've got a perfectly capable computer in your pocket to remember it for you.

[isostatic]

I remember 12 digit IP addresses all the time