Subject: [Enum] ENUM non-terminals

From: Lawrence Conroy <[email-masked]>
Date: Fri, 24 May 2002 19:09:53 +0100

Hi folks,
   I have a question for the people who understand non-terminal
processing within ENUM (i.e. not me :).
As I get it, a D3S application is selected by some user program
with a D3S application tag. In the case of ENUM, this is 'E2U'.
The D3S application has a key (by some means) and submits a
query of its database (the ENUM portion of DNS space) using
this key, receiving a set of NAPTRs in response. Some or all
of these may have an empty flags field (i.e. are non-terminal).

I guess that the D3S application will be looking for its
D3S application tag within the service field of the NAPTRs.
I had assumed that it would discard any NAPTRs that did not
have this tag, but I'm no longer sure. For now, let's assume
that it does only consider those NAPTRs that have its tag in
their service field - anything else is in the process of
exiting ENUM and doing something else, and so is out of scope
for this group.

If there is a "tie" for order and preference, the D3S application
can use the rest of the service field to help it select which
path to follow (i.e. which NAPTR to use). It could run parallel
or sequential processing on each of them (follow all paths),
or some, or just one, or reject them all and abort.

Now, each of these NAPTRs will have at least one enumservice
sub-field (it could have more). Given that the enumservice
is supposed to indicate the likely outcome of further processing
it should (I guess from prior threads) include an indication of
the URI scheme that will occur at the "end of this path".
Patrik's examples were "telvoice" and/or "sipvoice", implying
tel: or sip: URIs will result.

I'm quite possibly losing it in the recursion, but: how does
one ensure that a non-terminal NAPTR has an honest enumservice
value? Given that a non-terminal, by definition, will (after
regexp translation) result in a new key, and that that key will
be used to query the ENUM DNS space, then there could be a set
of NAPTRs at the domain queried as a result of the non-terminal
regexp processing. Any one of these could be selected "in the next
round", and the result could actually be a different path with
a different enumservice. It seems to me that this is at best
an administrative nightmare, and at worst an impossibility.

Thus, help please - what am I missing here?

all the best from a spinlocked
   Lawrence

-- 
[email-masked]: +44 1794 833666::<my opinions>:

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