H.323 Implementers Guide Edits

Jim Toga jim.toga at metatel.com
Fri Apr 9 09:50:20 EDT 1999


There is actually a good reason for the RequestID. It basically enables you
to determine whether a notification was issued before or after the
reception of a given request for the notification. As an example where this
is important, consider what we refer to as "lockstep mode". It essentially
states that a given request can at most generate one Notify, which implies
that after receiving a Notify you must send down a new request. Without a
RequestID you cannot determine whether that request has already been
received or not. This is not only protocol-wise important but semantically
as well, as your new request may contain instructions to look for a new set
of events that all of a sudden either became important to know about, or
you no longer want to hear about. Thus we should keep the RequestID.


Regards

          Flemming Andreasen










Brian Rosen <brosen at ENG.FORE.COM> on 04/09/99 08:18:46 AM

Please respond to Mailing list for parties associated with ITU-T Study
      Group 16 <ITU-SG16 at mailbag.cps.intel.com>

To:   ITU-SG16 at mailbag.cps.intel.com
cc:    (bcc: Flemming Andreasen/Bellcore)
Subject:  Re: Event reporting (was audio call Thursday: Minutes)




As the protocol is currently defined, there is
thus thing we called a RequestID.  You supply
a RequestID with the EventDescriptor, and it is
returned by the Notify.  A RequestID is a 32 bit
integer.  The syntax defines the requestID, and
uses it in the Notify, but does not show it in
the EventDescriptor.  That should be fixed, but...

As I noted, TerminationID + EventName is logically
equivalent to an MGC assigned RequestID if you
can only have one instance of an event on a
termination.  Implementation seems to be simple
in either case at both ends.  At the MG, storing
the requestID is easy, but not storing is easier.
At the MGC, the RequestID would be a separate table,
but it would have to have TerminationID and
EventName at least implicitly, and probably
explicitly in it.  Searching a structure by
TerminationID and then EventName (or the other way
around) is also easy.Thinking about it overnight, if it
really is the same, then it would be best to
eliminate the RequestID artifice and use Termination
ID + EventName.

At the time, I believed we thought that there were
circumstances where there was not uniqueness.  Right
now, I can't see how that can occur.

Brian

> -----Original Message-----
> From: Chip Sharp [mailto:chsharp at cisco.com]
> Sent: Thursday, April 08, 1999 5:46 PM
> To: ITU-SG16 at mailbag.cps.intel.com
> Subject: Re: Event reporting (was audio call Thursday: Minutes)
>
>
> Yes that was my understanding as well.  The TerminationID
> would be used to
> associate the event to the termination.  Thus the event report would
> contain the Termination ID and the event ID.
>
> Chip
>
> At 02:21 PM 4/8/99 -0700, Rex Coldren wrote:
> >Actually I believe this item was not correctly written.  I
> believe the
> >discussion was about how you associate a reported event to a given
> >Termination.  There was talk that notifications come back with a
> >RequestID, which must be somehow associated to a Termination.
> >Paul suggested using TerminationID directly.
> >
> >Christian Huitema wrote:
> >
> >> > 5) event handling
> >> > - currently an event is identified to the MGC with an
> eventId - Paul
> >> > Sijben suggested that it would be better to use a terminationId
> >>
> >> Sorry for missing the call, but let's comment on that
> specific point.  We
> >> discussed the event reporting model at length during the
> IETF meetings and
> >> in the following week, and I don't beleive that there is
> any advantage in
> >> opening the debate again.
> >>
> >> Termination Id and event names just do not belong to the
> same space.
> >>  Terminations are defined on a per MG basis; events are defined
> >> independently of the MG, and in many cases independently of the
> >> termination class.
> >>
> >> The current notifications identify both the termination on
> which the event
> >> was observed and the name of the event.  There is a lot of
> experience to
> >> show that this is a very efficient decomposition, and I
> don't see any
> >> reason whatsoever for ditching the experience in favor of
> an unproven
> >> theoretical design.
> >>
> >> --
> >> Christian Huitema
> >> ------------------------------
> >> Please note my new address: huitema at research.telcordia.com
> >> http://www.telcordia.com/
> >
> >
> --------------------------------------------------
> Chip Sharp                 voice: +1 (919) 851-2085
> Cisco Systems              Consulting Eng. - Telco
> Reality - Love it or Leave it.
> --------------------------------------------------
>



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