[address-policy-wg] 2008-05 Anycast for DLV zones

* Jim Reid:

>> Which part of the Internet depends on it?
>
> See above. Pretty much anything doing lookups in e164.arpa: Asterisk
> servers, various other SIP services, VoIP providers, smartphones, etc.
> ENUM may have a low usage. But unlike DLV, ENUM is not just for
> consenting adults: everything and anything can do an ENUM lookup
> straight out of the box.

I don't think this is how things work.  For sure, ENUM isn't enabled
by default on many devices.  Otherwise, a sizeable fraction of all
calls to +1 numbers leaked to the e164.arpa server operators.  This
doesn't seem to be the case.

Unfortunately, RIPE doesn't publish absolute query numbers, so it's
impossible to even approximate how much ENUM usage there is out there.

(Note that due to the way DNS works, the e164.arpa server operators
see full phone numbers for non-delegated subtrees, and resolvers can't
learn that a whole subtree does not exist, so negative caching only
helps if the same phone number is called twice within the negative
caching interval.)

> This is not the case for DLV because DNSSEC- aware validators -- a
> miniscule percentage of the world's resolving servers -- have to be
> specially configured, DLV policies need to be defined, key mangament
> issues have to be worked out, etc, etc.

ENUM has to be specifically enabled by the end user, too.  I would go
as far to say that a German operator which ships a smartphone which
performs ENUM lookups (perhaps indirectly) via e164.arpa has a very,
very hard time fulfilling its obligations under §88, 109 TKG.

> Well I know there are paying customers and commercial services
> dependent on ENUM in Austria, Romania and the UK. I expect this is
> also true other countries: I can't be bothered to look. FYI the
> Austrian regulator has set aside a block of their number space for
> ENUM-only telephony.

On the other hand, DENIC has been reporting for several years that
demand for ENUM is below expectations, despite continuous marketing
efforts.

-- 
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