Subject: Re: Quack! - from the gateway

From: [email-masked]
Date: Mon, 8 Feb 1999 12:04:30 -0500

I would tend to avoid having T.37 images diverge from the images carried
over T.38.  While T.37 will get used in some applications that do not at
all involve the GSTN, it will also be used in store and forward gateways.
Some gateway vendors will use T.37 as a fallback from a failed T.38
session, or each user could pick between the two for different levels of
service.  While the underlying technologies are quite different, the end
user need not be presented with this difference.  The transition between
the two is not completely clear cut, either; an end to end session on T.38
can fall back to overlapped sending (with broken notification integrity) if
the net delays get too long, and then can further fall back to T.37 if the
session breaks down altogether - all potentially without the sender
noticing the change.

So I would argue that a fax recipient from an off ramp gateway should not
need to be made aware of how the image got to the gateway, and should see
the same image in either case.  Of course, the gateway can be given the
responsibility of rendering an image from a T.37 originator.  But at least
all the relevant information would need to be available in the email
header, and a consistent policy for what is already in the T.37 image
should be set.

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From: Dan Wing <[email-masked]>
Date: Wed, 10 Feb 1999 08:39:52 -0800 (PST)

> session breaks down altogether - all potentially without the sender

Not trivial to implement, but yes, that could be done.

> header, and a consistent policy for what is already in the T.37 image

Any situation where the document goes from:
  
 +----------------+     +--------+     
 | GSTN-based fax | --> | onramp | --> ...
 +----------------+     +--------+

will have a coverpage, or one of those tiny Post-It (tm) stickers, or
nothing at all -- depending on what the human thought was appropriate for
the telephone number they dialed into the GSTN-based fax (or PC-based fax
software which functions exactly like a GSTN-based fax machine).

-Dan Wing

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From: "Larry Masinter" <[email-masked]>
Date: Wed, 10 Feb 1999 09:57:42 PST

> Any situation where the document goes from:

This might argue for having messages from an 'onramp' where
the sender has likely already included sender information in the
image be marked in the email (mail header?) in such a way that
a recipient offramp or network printer might know; in such cases,
sender identification based on email headers isn't as useful.

Larry

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From: Dan Wing <[email-masked]>
Date: Wed, 10 Feb 1999 11:23:02 -0800 (PST)

> sender identification based on email headers isn't as useful.

Mike Ruhl has an I-D he is preparing which discusses this very topic.  It
should be published 'soon'.

-Dan Wing