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IPv6, Phone Numbers and Analogies

My local area code (814) is running out of phone numbers. When discussing IPv6 with non-technical folks, I frequently use the hypothetical scenario of running out of phone numbers as an analogy for IPv4 address depletion. The conversation usually goes like this:

Imagine if we were running out of phone numbers. One way of solving that problem would be to make them bigger. Instead of ten digits, what if we made then thirty digits? If we did that, how many other things would we have to change? Some mundane things like business cards, letterhead, and phone books. But also more substantial things, like form processing software, backend provisioning software, and legal intercept software. All of that would take years to design, test, and deploy.

(By the way, we’re not running out of phone numbers. The NANP projects that the US is fine through at least 2039.)

All analogies break down at a certain point. Technically, the phone number analogy isn’t accurate, but it’s a reasonable way to explain to my parents what I do at work. Technical details aside, there’s (at least) one significant difference between running out of phone numbers and running out of IPv4 addresses: People don’t deny that we’ll run out of phone numbers.. As I said above, we’re in no danger of doing so right now, but the day will come when our population will grow to a point that it will exhaust the telephone numbering plan. That day is far away, but when it comes, we’ll have to start adding digits.

On the other hand, some people do deny that we’re running out of IPv4 addresses. I don’t understand this. The data is unequivocal: We are running out. Fortunately, over the past few years, the data became more clear, and most of the deniers have changed their opinions.

Still, we’ve never had people advocate for a telephone equivalent of NAT. We’ve never heard people claim that it’s a security threat to have their phone “exposed to the public telephone network.” When ten-digit-dialing was introduced years ago, some people complained about the hassle, but speed dial and phone address books solved that problem. (When it’s noticed at all) ten-digit-dialing is seen as a technological impact of population growth, whereas IPv6 is often seen as some sort of personal assault on the sysadmin asked to deploy it.

I am very concerned that the Internet community has waited too long to begin serious efforts for IPv6 deployment. Only 10% of the IPv4 address pool is left. It will probably be gone 2.5 years. Yet only 5% of the Internet supports IPv6 (as measured by BGP announcements). I just don’t see a way to get from 5% to 100% before we run out of IPv4. The next few years will be interesting, to say the least.

By Derek Morr, Senior Systems Programmer, Pennsylvania State University

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Always a good analogy Dan Campbell  –  Aug 14, 2009 8:45 PM

The phone number analogy is always good, mainly because even lay people understand what a phone number is, they’ve used them all their life, and they can grasp why the 7 digit (at least in the US) scheme was running out because of population growth and the introduction of fax, modems, computers, Internet, etc. that were using up numbers fast, necessitating a move to 10-digit dialing as well as additional prefixes and changes to area code rules and structures. But most lay people have no idea what a mysterious IP address is at all, and they fail to make the connection.

I guess we could say that the private 4 or 5 digit phone numbers that sit behind a PBX for the internal use within an organization are sort of like NAT, at least for organizations that don’t have DID lines to each staff member’s desk.  This is not unlike the numbering scheme for apartments in a single building or rooms in a hotel where each has its own internal 2 or 3 or 4 digit scheme that is certainly repeated all over the place but coupled with the building address remains unique.  Those schemes are NAT-like and reduce the amount of numbers used and the length of the identifier while eliminating the need for absolute uniqueness.

Many people are coming around on their misguided “we are not running out of IPv4 addresses” perspective, but many people still deny the impact of it all and the need to be moving towards IPv6 now.  It’s actually probably too late to do it sanely now.  There will be a mad rush.  We had time, but we blew it.  Now the clock is really ticking, and there will be some sorry procrastinators in the near future.

Rather not so good regarding NAT Jannis Andrija Schnitzer  –  Aug 17, 2009 4:02 PM

I don't think you can compare a numbering scheme as the one you described to NAT. For me, this rather looks like the standard way of internet routing: having a network part and a host part in your address. NAT itself doesn't really happen in other places than today's internet. That's why it's hard to tell people it's not what they want.

It Must Start With OEM's David Svendsen  –  Aug 18, 2009 4:23 AM

The migration will only happen when the OEM’s stop shipping devices that are IPv4 capable.  Much the same way they phased out floppy disk drives by simply no longer including them, they will need to do the same thing with PC NIC’s and wireless devices with IPv4.  Just get rid of it.  Or make it an “extra step” (read: cost) to get a device that includes it.  It will be painful at first, but I just don’t see any other way of getting big business to move on it.  The opinion out here (I work for a big company) is: “IPv6 is an ‘Internet’ problem.  It’s not our responsibility. Besides, we use NAT anyway.”

I would love to see a “Top 10” type of list distributed on why the “We use NAT” is not a valid argument in rejection of IPv6.

Furthermore, to buy us some time, some of the big entities sitting on millions of unused public IP’s need to pony them up.  The reason the phone number comparison is not fully analogous is that these entities don’t have to pay $30/month to sit on each of those millions of addresses as they would is they were phone numbers.

Namespace and Number Virendra Gandhi  –  Aug 24, 2009 10:58 PM

Today I read an article in the Times of India about the number predicament facing India, so I remember you blog here and started wondering why can’t this be solved once and for all,
Recently the UK government have introduced ID cards, which were frankly un-innovative, they were just plain names and number,apart from their other features.
As I mentioned in my blog on Forget TLDs, I am working on Namespace, and Numbering is also a part of it. I have had to change my Business Cards about 4 to 5 times in a matter say 15 -18 years, and it’s a hassle, the last time as the digits were of 6 numbers I went out and ordered a large stock and am still stuck with them. You made a statement that ‘People don’t deny that we’ll run out of phone numbers’, I disagree, I am quite confidant that we can never run out of numbers neither now or ever (forget 2039) if we change them with a different approach keeping the rules in mind of the application, whether it is ID cards, Internet Namespace or telephone numbers.
As for IPv4 addresses running out, I believe that we should move to link level and solve this problem once and for all, and forget IPV6. This I can confidently say because we are not thinking out of the box.

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