Re: [Tsvwg] <draft-lefaucheur-emergency-rsvp> : Preemption scope

Janet P Gunn <[email protected]> Fri, 9 Jun 2006 09:15:43 -0400
Newsgroups gmane.ietf.ieprep,gmane.ietf.tsvwg
Message-ID <OFBD837552.BDF31F48-ON85257186.005489D0-85257188.0048DA30@csc.com>



In line


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"Brian F. G. Bidulock" <[email protected]> wrote on 06/07/2006 02:28:51
AM:

> Janet,
>
>
> Also, it appears that the preemption that was excluded from PAS was
> preempting "established" calls.  Do you recall there anywhere being a
> definition of when a call is "established"?

I don't know about a "definition", but, from a practical perspective, in an
SS7 network, you could consider it when the destination returns an ISUP
Answer Message (ANM).  In an IP network, you could consider it to be when
"bearer packets" (as opposed to "signaling packets") start being
transmitted.
>
> Barring such a definition, one, I suppose, could assume that once
> participants in the call have exchanged greetings that it is
> established.  Because RSVP call admission is performed long before this
> point, there is a period of time after RSVP admits the call until the
> RTP channel is established and operational that RSVP could "preempt"
> the admission without preempting an "established" call.
>
> In fact, during a disaster which has stimulated a mass calling event,
> this is a critical period.
>
> > It also says explicitly "Our reasoning and conclusions set forth above
do
> > not necessarily extend to other priority schemes "
>
> Would not that also exclude, preemption or not, any scheme not precisely
> PAS?
>
> ETS for RSVP is certainly not precisely PAS.

Absolutely.

There is another "waiver" for the (landline) GETS features, but since i
wasn't actively involved when it came out, it isn't sitting on my hard
drive.  There would need to be another "waiver" for any substantially new
"special treatment".  But the point is that everyone involved anticipates
getting such a new waiver, as long as the new "special treatment" does not
include  "preemption".
>
> --brian
>
> --
> Brian F. G. Bidulock
> [email protected]
> http://www.openss7.org/