Re: [martini] Proposed work split: tackletelephone-numberregistration first

["Brian Lindsay" <[e-mail]>]

Hi Spencer,

   I am not sure if this is going down the path that the actual register
request uses a Tel: URI.

   If so, I don't see why that needs to be the case. The REGISTER itself
can still be done per Martini-Shaken with a SIP URI representing the SIP
PBX. In fact, I am not sure too much has to change with Martini-Shaken
unless you want to enforce use of a Tel URI format for requests sent
towards the SIP PBX.

   Thanks
      Brian



-----Original Message-----
From: [e-mail] [mailto:[e-mail]] On
Behalf Of Spencer Dawkins
Sent: Thursday, January 28, 2010 4:39 PM
To: Eric Burger; Dean Willis
Cc: [e-mail]
Subject: Re: [martini] Proposed work split:
tackletelephone-numberregistration first

OK, this discussion continues to be lovely. Thanks again for listening
to the people you're talking to ("plays well with others" is
under-appreciated, once we get out of primary school, but *I* appreciate
it!)

After reading this thread down through Eric's note below, I have a few
requests, as co-chair.

We're talking about E.164 numbers like we can easily identify them. My
understanding from Tuesday's call was that people on the call thought
the only way we could unambiguously know that we had an E.164 number was
if we had a tel: URI. If people on this list want to challenge that
assertion, this would be a great time to say so - please push back Real
Soon Now.

If that's true, we're talking about using Tel: URIs. Dean has asserted
that this would require an update to 3261. I'm not a genius of 3261, but
some of you guys are - could you point us to what you think needs to be
updated?

My quick read turned up this text in Section 4, page 17:

   Registration is another common operation in SIP.  Registration is one
   way that the biloxi.com server can learn the current location of Bob.
   Upon initialization, and at periodic intervals, Bob's SIP phone sends
   REGISTER messages to a server in the biloxi.com domain known as a SIP
   registrar.  The REGISTER messages associate Bob's SIP or SIPS URI
   (sip:[e-mail]) with the machine into which he is currently
   logged (conveyed as a SIP or SIPS URI in the Contact header field).

Dean, Is this what you were thinking of? Are there other places that
also need to change?

As I read http://www.ietf.org/id/draft-peterson-rai-rfc3427bis-04.txt,
Section 2.1, this change would have to go through SIPCORE, because it's
an update to 3261. If you know of obvious land mines that we would be
walking into if we propose this change, please say so Real Soon Now.
(One obvious land mine is that DISPATCH isn't meeting in Anaheim, so the
proposal would have to be DISPATCHed on the mailing list in order to do
something before IETF 78 - are there OTHERS?)

Finally, if you believe that embracing tel: URIs is the wrong thing to
do, please say so, Real Soon Now.

The milestones that we committed to in
http://tools.ietf.org/wg/martini/charters have us adopting a working
group SOLUTION draft in January. We're not late yet, but it's the 28th
of January in my time zone. If we are late, where late is measured in
days, I can live with that, but if we are late, where late is measured
in IETF meeting cycles, that's going to be a problem.

Thanks,

Spencer, as co-chair

----- Original Message -----
From: "Eric Burger" <[e-mail]>
To: "Dean Willis" <[e-mail]>
Cc: <[e-mail]>
Sent: Thursday, January 28, 2010 12:32 PM
Subject: Re: [martini] Proposed work split: tackle
telephone-numberregistration first


> If you ask me (why can't I stay in retirement?), the E.164 situation
is
> not only a simplification, but just about the only thing that is
sensible
> for MARTINI to work on.
>
> The E.164 situation is a clear, present, industry-is-begging-for-a-
> solution problem.  It is so pressing, the industry will tell us (the
> IETF) to get stuffed and do something stupid if we cannot deliver
> something that is not at its core fundamentally broken.
>
> I do not think anyone can have an issue with mechanisms that translate
a
> string of digits into an AOR that might cross domain boundaries.
This is
> the E.164 problem statement.
>
> If think everyone (with a brain) SHOULD have issues with a mechanism
that
> magically mungs "sip:[e-mail]" into
"sip:[e-mail] "
> while at the same time www.neustar.biz is really a neustar.biz
domain.
> That really would be creating a parallel DNS, which, as one  of the
major
> DNS operators, would really, really be "less than ideal"  and have a
whole
> host of security and integrity issues.
>
> THEREFORE, I would propose that we split this work into two phases:
>   Phase 1: Deliver an E.164 solution, preferably in the next few
months,
> so the industry does not ignore the IETF.
>
>   Phase 2: Deliver the generic solution in the normal, 3-5 year IETF
> cycle.  This generic solution may or may not encompass E.164 numbers.
As
> Doug Sauder points out, E.164 numbers and their infrastructure are
> different.  Thus a different E.164 registration model from generic SIP
> URI provisioning models would neither be a burden on industry nor
create
> backwards-compatibility issues for the generic solution.
>
> Note that if we do not deliver Phase 1 in a very, very timely manner,
the
> less-than-idea industry solution just might blow up the  possibility
for
> the generic solution, which would be considerably less  than ideal.
>
> On Jan 27, 2010, at 1:16 AM, Dean Willis wrote:
>
>>
>> We seem to have an urgent need for a near-term solution for dealing
with
>> the subset of the MARTINI problem that, loosely defined, covers  the
>> "telephone number" problem.
>>
>> The typical scenario here is SIP trunking, wherein a SIP Service
>> Provider (SSP) provides an ISDN-PRI like service over IP to a
customer's
>> PBX (or PBXes). In this model, the SSP maps a whole  bunch  of phone
>> numbers to the PBXes. This mapping is somewhat  dynamic, because the
>> PBXes usually have DHCP addresses, and don't  have DNS entries that
point
>> A records at the PBX in any sort of  particularly useful way (maybe
>> something like dhcp-10-1-2-3- example.com).
>>
>> So what we need is a way for a PBX, when it reboots (or perhaps
>> periodically) to say to the SSP "Here I Am; You may now send any
calls
>> for my assigned phone numbers to my current Contact."
>>
>> This is indeed a "registration" problem, but it isn't necessarily a
>> "domain registration problem". The only reason domains get mixed
into
>> this scenario at all is that we sometimes encode telephone  numbers
as
>> the user parts of SIP URIs, and those SIP URIs have a  domain part
>> attached to them.
>>
>> More interestingly, this problem is a tiny subset of the whole
MARTINI
>> dynamic binding problem, and it potentially can be solved  much more
>> simply than the general problem.
>>
>> On today's Interim II call, Richard, Adam and I raised the idea of
>> dividing our problem space, and taking on a near-term milestone for
>> delivering a MARTINI solution for registering contacts to a proxy,
where
>> that proxy maps one or more telephone numbers to the contact.
>>
>> We certainly intend to go on and tackle the more general domain-
>> registration problem, but I (and I believe Adam and Richard) believe
>> that we get a lot out of tackling the telephone-number subset first.
>>
>> In particular, we believe that this approach solves many of the
domain
>> "responsibility" questions, simplifies the TLS keying/ certification
>> model immensely, eliminates the cognitive overload of  using REGISTER
to
>> bind a "domain" to a Contact, "route  authentication", and a good
many
>> other open issues that plague our  current drafts.
>>
>>
>> Open questions relating to this approach include:
>>
>> 1) Do we deal only with E.164 numbers, or do we need to deal with
>> private-number "phone contexts"?
>>
>> 2) D owe need to explicitly encode the telephone numbers being
>> registered in the REGISTER request (either directly or through some
sort
>> of regexp), or is it adequate to rely on provisioning of the  SSP and
PBX
>> (and any UAs) to statically bind the numbers to the PBX  identity,
and
>> then dynamically only register the PBX identity to the  PBX contact?
>>
>> 3) Can we "register" with a tel: URI as the "To" value? (this seems
to
>> require extending RFC 3261)? Note that "tel:" can express both E. 164
>> numbers and private phone-contexts in one format.
>>
>> 4) What happens with GRUUs?
>>
>> I believe all of these issues are quite tractable, if we accept the
>> fundamental idea of splitting the phone-number problem off from the
more
>> general domain-registration, and recognize the possibility that  the
>> solutions to the two problem may reasonably be quite different  from
each
>> other.
>>
>> So, what do you people think? Is it worth trying to drink the
MARTINI
>> elephant one sip at a time, or are we going to treat the  whole thing
>> like a tequila shot and just slam it down?
>>
>> --
>> Dean
>>
>>
>>
>>
>>
>>
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