Subject: RE: [Sipping] Question regarding Redirect reason and SIP

From: "Eric Burger" <[email-masked]>
Date: Wed, 19 Jun 2002 03:12:03 -0400

This discussion reminds me of explaining to undergraduates the difference
between an Entity and an Attribute in Entity-Relationship Design.
Mathematically, they are isomorphic: they both end up as columns in a table.

One could see this discussion as "how do I code what I want".  E.g., that a
request to
"sip:deposit-voice-mail-play-eat-it-greeting-no-zero-allowed-for-dean-willis
@voice-mail.carrier.net" is the same as sending a request to
"sip:[email-masked]" with the appropriate parameters to
say "play the eat-it" greeting and no transfers allowed.

However, there is a subtle difference.  If we want a prayer of having
interoperable proxies and application servers, there will have to be a major
set of URI conventions.  This stuff IS NOT amenable to "just provision it".
There are too many variations: either the proxy or the application won't
know what to do.  For example, if my voice mail system doesn't do "transfer
on zero", then will I have to provision the system for every combination of
request URI that has "no-zero-allowed" and "zero-allowed"?  In theory, I
could do that.  In practice, it is insane.  [jdr - is this where you were
going when you said URI conventions would be more important for applications
than network services?]

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]On Behalf Of
Dean Willis
Sent: Thursday, May 23, 2002 5:19 PM
To: 'Mark Watson'; [email-masked]; [email-masked]
Cc: [email-masked]
Subject: RE: [Sipping] Question regarding Redirect reason and SIP
[snip]

While there might be applications that can make reasonable use of a
history mechanism, using such a mechanism to implement general purpose
voice mail treatment selection is at best backward, retrograde, and
childish, and is at worst a direct attempt to debase the SIP protocol
definition in order to perpetuate the antiquated and demonstrably flawed
service model of the PSTN.

In other words, I think it's a plain-and-simple BAD idea and will
continue to "whack it" every time it pops up.

--
Dean

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