Subject: question on fax protocols in NAPTRs for ENUM

From: Andy Gallant <[email-masked]>
Date: Mon, 18 Dec 2000 09:51:44 -0600

To the ietf-fax list:

Following up after the Fax WG session at IETF49, a quick survey of RFCs and
internet drafts did not readily produce an answer to the question:

How useful would it be for an Internet-aware fax device to use an ENUM query
to distinguish between the simple and extended modes of store-and-forward
(T.37) fax?

For now, I plan to refine "t37fax+E2U" and "t38fax+E2U" as the values for
the service field of NAPTR resource records for ENUM.  An internet-aware fax
device would use these to derive service-specific information after querying
DNS about the phone number (actually the ENUM name of the phone number).  

Using t37/t38 is a clear way to give to an IAF device the ability to
distinguish between store-and-forward and real-time fax at a very high
level.  Is there a need for more (or different) values?  So far, I don't see
anything else at this level, and I don't see how the ability to distinguish
between simple and extended modes would fit in here.

I'm hoping that Internet fax experts might think about the proposed use of
ENUM and give some feedback to the list or to me directly.

Thanks in advance for your comments, references, or advice.

-Andy Gallant

[email-masked]
+1-202-533-2812/2976 (tel/fax)

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From: Hiroshi Tamura <[email-masked]>
Date: Tue, 19 Dec 2000 08:43:52 +0900 (JST)

Andy,

If my understanding for ENUM is correct,

> between simple and extended modes would fit in here.

G3fax - (PSTN) - Gateway - (internet) - T37ifax

Gateway understands ENUM as well as T.30 and T.37.

When gateway is called from G3fax, it must issue DIS signal in T.30 to G3fax.
If T37ifax is "simple mode" ifax, it issues DIS that does NOT have
capabilites such as "MMR", 400dpi, etc.

If he is "full mode" ifax(eifax), it does DIS that may have them.
But, it is difficult to decide what kinds of DIS gateway should issue.
Because, there are lots of bit combinations in DIS.

Therefore, separating simply two values(or fields) for t37ifax does not
solve, I think. It depends upon the service or somthing. In that case,
only t37ifax may be enough,,, I do not know well.

Ideally, Rescap or something can solve. But, it's a long, long way.
Capabilities issues are always difficult.

Regards,
--
Hiroshi Tamura, Ricoh Company, LTD.
E-mail: [email-masked]