Subject: [Sipping] session-indep-policy-02

From: Cullen Jennings <[email-masked]>
Date: Fri, 04 Mar 2005 15:49:49 -0800

I'm suspicious that this mechanism is far more general and complicated than
anyone needs but we can ignore that.

Does not say what the UA should do when there is a conflict.

In the int-uri, i think you should figure out a way to specify both the RTP
and RTCP port numbers. We should move away from this implicit assumption
stuff.

Section 5.3.13 ip-in-ip stuff should ref RFC 2003.

There are a lot of ways to tunnel IP - seem like more than just 2003 should
be defined. 

Be nice to add TURN here.

In the QOS section, should be able to set the DSCP for a given media type

References need normative and informative section.

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From: Volker Hilt <[email-masked]>
Date: Sat, 05 Mar 2005 17:06:05 -0500

Cullen,

thanks much for the comments! Responses are inline.

> anyone needs but we can ignore that.
I think that's an important point and the goal is clearly to be as 
simple as possible.

The current mechanism uses a entirely flat structure. There are no 
policy hierarchies and it is not possible to combine elements (e.g., 
it's not possible to define a policy that says a session with codec 
G.711 should have a max bandwidth of 80kbit). Each element is a stand 
alone entity. Thus, a policy can define a max bandwidth or it can define 
a disallowed codec. But not combinations.

A possible change of the current structure could be to get rid of the 
attributes. For example, instead of the saying
      <codecs policy="allow">
        <codec policy="disallow">G729</codec>
        <codec policy="disallow">G723</codec>
      </codecs>
the structure could look like
      <default-codec-policy>allow</default-codec-policy>
      <disallowed-codec>G729</disallowed-codec>
      <disallowed-codec>G723</disallowed-codec>
But I'm not sure if this would really simplify policies or if this is 
just a different way of writing them down.

> Does not say what the UA should do when there is a conflict.
This probably has to be defined on a per element basis and could go into 
the "Merging policies" paragraphs. There might still be cases where the 
policies are mutually exclusive and the best a UA can do is to give it a 
try and violate one of the conflicting policies.

> and RTCP port numbers. We should move away from this implicit assumption
Agreed. Will add explicit RTCP port numbers in next rev.

> Section 5.3.13 ip-in-ip stuff should ref RFC 2003.
True.

> Be nice to add TURN here.
Good point. Will add TURN in next rev.

> References need normative and informative section.
Points noted for next rev.

Thanks,

Volker