Subject: RE: [Sipping] Redirection on busy and History Info

From: "Francois Audet" <[email-masked]>
Date: Tue, 1 Nov 2005 17:33:59 -0600

> -----Original Message-----
> From: [email-masked] 
> [mailto:[email-masked]] On Behalf Of Dean Willis
> Sent: Tuesday, November 01, 2005 15:26
> To: Audet, Francois [SC100:9T51:EXCH]
> Cc: sipping; Elwell, John; Gonzalo Camarillo; Barnes, Mary 
> [RICH2:B601:EXCH]
> Subject: Re: [Sipping] Redirection on busy and History Info
>
> Why not fake some history-infos, as long as the result is a valid  
> model of the internal process?

Presumably, there was a reason why we designed History-Info to reflect
what happened in SIP...

What if you actually really wanted to know what happened? (As opposed
to what service you want)?

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---

From: Dean Willis <[email-masked]>
Date: Tue, 1 Nov 2005 17:46:14 -0600

> to what service you want)?

I'm reminded of that movie line" You want the truth? You can't handle  
the truth!"

History-info doesn't really tell us what happened -- it gives us an  
abstraction of what happened that can be (relatively) concisely  
described in SIP. If that abstraction provides adequate information  
for building the specific services in question, do we need more? (We  
may -- what other services do we think we might need to build?).

If you take the example far enough (and are willing to badly  
paraphrase Wolfram) "the whole truth" would apparently require having  
had someone OUTSIDE the universe attach a hardware-assisted trace  
module onto the universe and log everything from the Big Bang  
forward. It would give us more state information than we're prepared  
to deal with.

It's fair  to question whether all information that can be contained  
in a H-I can be mapped to PSTN signaling. Of course it can't -- the  
two dialects have different expressive ranges.  One can't "say" SIP  
URLs in PSTN-speak. But if we have a consistent mapping of cause  
codes, does that gives us enough to work with?

--
Dean