Re: [Ieprep] proposed charter 5 priority levels

At 01:29 AM 9/28/2006 -0400, Curtis Villamizar wrote:

>In message <6.2.1.2.0.20060927173433.0323abd0@ihmail.ih.lucent.com>
>John Rosenberg writes:
>
>It's been mentioned that both RSVP and NSIS can carry both SIp priority and
>DSCP.

RSVP does not carry a SIP RPH text based namespace or priority-value, and 
NSIS (I believe) does not carry a RPH namespace in text, just a registered 
equivalent of the priority-value

<snip>

> > Thanks,
> >
> > John
>
>
>I'm not sure why the above example is special.  An RSVP PATH message
>and RESV response (passed back from the IP egress) should precede any
>SIP control traffic

SIP messages are always first, prior to any RSVP or NSIS messages, how else 
would a called party know what bandwidth to request in the RESV?

It also doesn't make a lot of sense sending a NSIS REQUEST message 
reserving resources if the called party isn't going to accept the call (for 
whatever reason).  This would be a waste of BW, and could case existing 
calls to be preempted unnecessarily.

>to avoid losing the control traffic.  You'd need
>to do that once for all SIP traffic, not per flow.  The requested
>bandwidth for the control traffic can be tiny.  An RSVP PATH message
>and RESV response should precede any RTP data flow (bearer packets) to
>avoid losing the voice payload.  The traffic must be policed to
>conform to the parameters sent in RSVP and should be marked with a
>fixed DSCP value appropriate for the service.
>
>The SIP priority and DSCP value would be in the RSVP PATH message

"SIP Priority" isn't in any RSVP message. RSVP has its own priority 
indication. They can be mapped to mean the same thing, but they aren't 
always the same thing.  RSVP has no "namespace" equivalent.

>sent
>before beginning to send RTP traffic (bearer packets).
>
>For any sort of traffic which didn't involve a SIP setup (or any setup
>protocol) you'd just send an RSVP PATH message and wait for the RESV
>before sending traffic.  If SIP wasn't used then there is no need for
>a SIP priority in the RSVP PATH message.

"SIP priority" in a PATH is not correct

>Am I missing something?

see above

>Perhaps an authorization or authentication
>issue?
>
>Curtis
>
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