> -----Original Message-----
> From: Paul Kyzivat [mailto:[EMAIL PROTECTED]
>
> In this case what I had in mind (by referring to a "call back") was that
>   I gave it to you in a From-URI.

Ah, ok.  The only issue then is that when a UAC generates a request, it's not 
really clear how it should know when it wants things back *only* via SIP, or 
when it doesn't care.  For example, if you make a phone call, why would your 
UAC use a From-URI of TEL?

It would (typically) be your registered AoR, and sip:[EMAIL PROTECTED]  And yet 
I doubt very much that most phones, or their users, really care whether people 
calling them *back* go through the PSTN or not to reach their SIP phone.  I bet 
most of them have no idea they're even *using* a SIP phone.


> >> If you want some server on the originating end to do something for the
> >> outbound call, then you should put a Route header in the request
> >> identifying the server.
> >
> > And I wish that would work, but in many cases it won't.
>
> AFAIK we are in the business of determining the valid ways of doing
> things. If implementations choose to do otherwise all we can do is keep
> encouraging.

Absolutely.  But pragmatism has its place too. (I'm not saying this is one of 
those times though)


> The problem with trying to make up for the inadequacies of the neighbors
> is - how do you know which ones do it right and which do it wrong?

With some things it's part of the peering agreement (e.g., a "profile"), with 
some things it's based on device-specific config or vendor-profiles.  But for 
some things it's a lowest-common-denominator: change it to what works with 
every device.


> I guess you SBC guys can keep getting the business to try to solve that
> problem. But it really means a bunch of configuration about the
> idiosyncrasies of all the peers. That only works when there are a
> limited number of them.

Yup, and why I'm trying to get things to stop needing to be "fixed".  It's not 
core to an SBC's value prop, and not a good long-term strategy for such.

-hadriel
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