Subject: [Sipping] Load control event package

From: "Phelan, Tom" <[email-masked]>
Date: Mon, 28 Jul 2008 05:20:56 -0400

Hi All,

The points I was going to bring up when we cut off the queue were:

Is the purpose of this package to describe the kinds of filters that can
be communicated or the mechanisms for communicating or both?

Assuming that it's about the kinds of filters -- the PSTN uses a
"standard" set of these sorts of things.  There are a handful or so of
defined filters such as CANT (CANcel To), CANF (Cancel From), SKIP, and
a few others.  If we define filters I think they should not be trivially
different from these.  If something new or different is needed, so be
it, but there needs to be good reasons for the differences.

Assuming it's about distributing the filters -- I'll note that as far as
I know the PSTN doesn't define how to distribute the filters.  Mostly
it's done through switch-by-switch manual configuration, I believe.  I
think some automatic distribution might be desirable, but we should
watch out for complexity-versus-benefit tradeoffs.  The point was raised
that, due to trust issues, it's unlikely that cross-domain communication
will be welcomed, and that will limit the usefulness of automatic
distribution.

Tom P.
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From: Henning Schulzrinne <[email-masked]>
Date: Thu, 31 Jul 2008 08:39:06 -0400

We are trying to address both content and distribution; both need to  
be made more concrete as the draft matures.

It would certainly be helpful to learn from the PSTN experience  
related to load filters. References or brief descriptions would be  
appreciated.

I agree that cross-domain distribution may not work in all cases, but  
I would claim that it can work in many semi-friendly environments  
(e.g., enterprise connected to service provider). Also, unlike in the  
PSTN, we would want to involve various edge proxies and maybe even  
user agents, so a distribution mechanism is required.

Henning