Subject: Re: [Ieprep] proposed charter 5 priority levels

From: "James M. Polk" <[email-masked]>
Date: Mon, 30 Oct 2006 10:38:43 -0600

At 05:39 PM 9/27/2006 -0500, John Rosenberg wrote:
>It's been mentioned that both RSVP and NSIS can carry both SIp priority 
>and DSCP.
>
>For the uninitiated (e.g. me!) would the use of either of these protocols 
>be used in a scenario where:
>
>1) an endpoint sent an INVITE to a call controller withtout RPH, but with 
>"dialed digits" that request a DSN precedence level (e.g. Flash);
>
>2) the call controller validated that the requested precedence level is 
>authorized;
>
>3) and the call controller then needs to inform the endpoint what specific 
>DSCP value (e.g. 41) to put in the bearer packets that the EP generates, 
>which value is based on a provisioned mapping resident in the call 
>controller between dsn precedence levels and DSCP values.

John

see http://www.ietf.org/internet-drafts/draft-polk-mmusic-dscp-attribute-00.txt

Anyone wanting to make comments, please do so on the MMUSIC list to show 
those chairs there is interest in this ID.

>Thanks,
>
>John
>
>
>
>At 09:15 PM 9/26/2006, Curtis Villamizar wrote:
> >
> >In message <[email-masked]>
> >John Rosenberg writes:
> >>
> >> At 05:52 PM 9/26/2006, [email-masked] wrote:
> >>
> >>  >Date: Tue, 26 Sep 2006 12:56:15 -0400
> >>  >From: Curtis Villamizar <[email-masked]>
> >>
> >>  >In message
> >> <[email-masked]>
> >>  >Janet P Gunn writes:
> >>  >>
> >>  >>
> >>  >> As RFC 4412 makes perfectly clear, the RPH serves a dual role of
> >signalling
> >>  >> priority across an IP network (e.g. from an originating circuit 
> switched
> >>  >> access network to a terminating circuit switched access network) as
> >well as
> >>  >> signalling  priority within the IP network.
> >>  >>
> >>  >> For each of the namespaces described in RFC 4412, the number of 
> priority
> >>  >> values (5 in most cases, 6 in one) is driven by the former role, 
> based on
> >>  >> the number of priority values in use, or being considered, in the 
> access
> >>  >> network priority scheme.
> >>  >>
> >>  >> The issue of how many priority levels to differentiate WITHIN the IP
> >>  >> network is an issue currently being addressed by vendors and 
> providers.
> >>  >>
> >>  >> Janet
> >>  >
> >>  >
> >>  >Janet,
> >>  >
> >>  >You are right, but you may be just focusing on SIP which is one peice
> >>  >of the puzzle.
> >>  >
> >>  >RFC 4412 does not make it perfectly clear whether we need 1 DSCP code
> >>  >point, EF, or 5 DSCP code points (IP Prec 0-4?)  or 15 DSCP code
> >>  >points (the 4 AF classes plus one more AF class.  Or is it some
> >>  >multiple of 6?  This RFC doesn't even mention DSCP.
> >>  >
> >>
> >> Let me add my voice and suggest that we're really in need of some 
> mechanism
> >> that allows the application (e.g. MLPP, ETS, whatever) to determine a
> >> "priority level" for a session and indicate to the endpoint that it's
> >> serving what DSCP value that the endpoint should use for its bearer 
> packets.
> >>
> >> It could be a header or parameter in some subset of SIP messages, it could
> >> be an attribute in SDP, it could be something else entirely. I think the
> >> whole question of how many and which DSCP values should be used for some
> >> arbitrary application is a little premature if we don't have a way for the
> >> application to get that value used.
> >>
> >> John Rosenberg
> >
> >
> >The discussion just went full circle.  We already have a SIP priority
> >in RFC4412.  Use of DSCP is only touched on in RFC4190.  Both the SIP
> >priority and DSCP value can be carried in microflow RSVP
> >(draft-briscoe-tsvwg-cl-architecture-03.txt).
> >
> >Which DSCP value seems to be an open issue for now.  Discussion seems
> >to favor a new DSCP EF-like value for ETS.
> >
> >Curtis
>
>
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