Dragging Telephone Numbers Into the Internet Age

azoblue writes with this teaser from Ars Technica, presenting a tempting suggestion for online consolidation: "E-mail, IM, Facebook, phones—what if all of these ways to reach you over a network could be condensed into a single, unique number? The ENUM proposal aims to do just that, by giving everyone a single phone number that maps to all of their identifiers. Here's how it works, and why it isn't already widely used."

Comments

Been done: .tel domain

[benwiggy]

You mean like the .tel domain?

.tel provides all contact information: phone numbers, postal addresses, email, web addresses, etc -- all within the DNS.

Re:DNS

[TheRaven64]

I didn't RTFA, but it's not a new idea, and both you and the submitter seem to be missing the point. You can store arbitrary contact addresses in NAPTR records in DNS, so you can store email, SIP, POTS addresses, or anything else that can be represented by a URI. The other part of this is allowing reverse mappings, from telephone numbers to something less archaic.

Telephone numbers, like IP addresses, are globally unique network endpoint identifiers. They are assigned by the UN (specifically the ITU-T, which assigns prefixes to countries) and allow you to call any telephone from any other telephone in the world. The problem comes when you have an endpoint that is really a SIP account, for example. Currently, that mapping has to be done in quite a static way.

The idea of the proposal is that the e164.arpa. domain will be reserved for resolving telephone numbers to domains, just as in-addr.arpa is used for resolving IP addresses to names. This doesn't need to be government run, but it does need to be authoritative. That means that e164.arpa will be controlled by the ITU, 1.e164.arpa will be controlled by the USA, 4.4.e164.arpa by the UK and so on. You will then get a subdomain of this. Telephone companies that have large assignments of phone numbers get large ones, individuals may get a single 15-digit number. This can then map to any other resource.

It's not intended as a long-term solution. Eventually, the POTS network is going away (large chunks of it are IP internally already) and you will just use DNS to map directly to SIP, but while interoperability with the POTS network is desirable - say, for the next couple of decades - this lets people with POTS phones initiate calls to SIP phones without having to define a specific bridge or static routing. You'll dial a number on your phone, your telco will look up the SIP address and then route the call there via their bridge.

I currently have a phone number connected to a SIP address, but it only works from POTS lines because my SIP provider operates a SIP to POTS bridge. With this proposal, anyone can operate one trivially. You will just need to get an e164 number assigned to you and configure the DNS entries to point to your Asterisk (or whatever) server.