Subject: RE: [Enum] DNS for E.164-IP Address Mapping

From: Richard Shockey <[email-masked]>
Date: Tue, 18 Jan 2000 10:05:56 -0600

At 10:58 AM 1/18/2000 +0100, BARNOLE Valerie CNET/DAC/ISS wrote:
>So, in the FAX application you quote, wouldn't it be just enough to have in
>NAPTR records (see Patrick's draft §3.1), with different priorities, the
>service fields "GSTN/T.30+FAX" and "SMTP+FAX" and "ITU/T.38+FAX" ?
>
>For instance, if the fax number is + 33 1 46 29 31 42 :
>
>2.8.0.4.6.2.6.5.8.6.4.e164.int
>IN NAPTR 10  10 s "SIP+FAX" "sip:[email-masked]"
>IN NAPTR 10 100 s "SMTP+FAX" "smtp._tcp.tele2.se"
>IN NAPTR 10 102 s "ITU/T.38+FAX" "t38._tcp.tele2.se"
>IN NAPTR 10 104 s "GSTN/T.30+FAX" "t30._tcp.tele2.se"
>IN NAPTR 10 106 s "IPP+FAX" "ipp._tcp.tele2.se"
>(I apologize, I may have written quite stupid replacement fields for the 3
>last items).

Yes you are quite correct the above scenario would be apprporiate for a 
future kind of multi-modal "fax machine"

>Excuse me for sticking to this question. To me, it looks a little strange to
>categorize E.164 numbers (names) according to the technology (pots, isdn,
>fax, maybe GSM or PCS, which does not appear in Vaha-Sipila draft but might,
>why not). I tend to consider URLs as names compared to IP addresses, so I
>tend to disconnect them from any technology. But maybe I am  wrong in
>considering URLs as names ?

I look at a URL as a name of a resource. Within that name are the 
assumptions of what protocols are to be used to access.  If the "fax" 
resource preference was IPP for instance and the NAPTR record contained the 
entry "ipp.foo.com/richard_shockey" the rewrite would under IPP 
rules  ipp://ipp.foo.com/richard_shockey. It is then assumed that the ENUM 
client resolver knows what IPP is (HTTP) or the client must either send the 
"fax" over the GSTN.

Maybe I'm not making myself too clear either....

Richard Shockey
Shockey Consulting LLC
8045 Big Bend Blvd. Suite 110
St. Louis, MO 63119
Voice 314.918.9020
eFAX Fax to EMail 815.333.1237 (Preferred for Fax)
INTERNET Mail & IFAX : [email-masked]
GSTN Fax 314.918.9015
MediaGate iPost VoiceMail and Fax 800.260.4464
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

_______________________________________________
enum mailing list
[email-masked]
http://www.ietf.org/mailman/listinfo/enum

---

From: Patrik Fältström <[email-masked]>
Date: Wed, 19 Jan 2000 04:00:43 +0100

--On 2000-01-18 10.05 -0600, Richard Shockey <[email-masked]> wrote:

> If the "fax" resource preference was IPP for instance and the NAPTR
> record contained the entry "ipp.foo.com/richard_shockey" the rewrite
> would under IPP rules  ipp://ipp.foo.com/richard_shockey. It is then
> assumed that the ENUM client resolver knows what IPP is (HTTP) or the
> client must either send the "fax" over the GSTN.

The ideas with a scheme name in the URI is that the client can make a
descision whether he "knows what to do with the scheme-specific data or
not". The scheme therefore distinguishes between services, methods to use,
what the data after "//" is, etc. Or combination thereof.

I personally rather see different schemes for different services, than
overloading existing ones, but I guess that is an extremely foggy answer to
what you talk about...

I guess a better answer is that yes, you do not have to have different
schemes if the algorithms via NAPTR/SRV in my draft are in use, as that by
itself tells what services exists, but it is also the case that it doesn't
hurt having different schemes either, or does it? I.e. I would not like to
have different schemes for "voice telephony" depending on what transmission
mechanism is in use (IP telephony, plain telephony etc). I would at the
same time not want to have different schemes depending on whether the fax
is in color or black&white.

   paf

---

From: Graham Klyne <[email-masked]>
Date: Wed, 19 Jan 2000 12:29:18 +0000

At 04:00 AM 1/19/00 +0100, Patrik Fältström wrote:
>overloading existing ones,

<cheer>

>is in color or black&white.

Did you really NOT want different schemes for different "voice telephony" 
transmission mechanisms?  (That looks like a typo to me :-)

I would suggest that different schemes ARE appropriate for different 
transfer mechanisms, but are NOT appropriate for distinguishing content types.

I think the case of telephony vs fax (via POTS) is interesting, because it 
could be viewed either way:  both use a standard telephone circuit.  BUT, I 
would suggest that fax is different than voice, because it uses additional 
layers of transfer protocol (T30, etc.) on top of the underlying circuit.

Also, there is a different interaction style involved:  voice transfers an 
isochronous real-time information stream;  fax transfers a message (by 
which I mean a data object whose information content is fully determined 
prior to transmission start -- you don't get to change your mind about what 
you are saying as a result of information coming back in the same 
communication session).

Another example:  I think the SAME scheme would be appropriate for fax and 
vice-messages transferred via e-mail protocols.

Just some thoughts.

#g

------------
Graham Klyne
([email-masked])