RE: [XCON] CPCP Requirement: Repeat times

[hisham.khartabil at nokia.com]

> -----Original Message-----
> From: ext Michael Hammer [mailto:mhammer@cisco.com]
> Sent: 09.February.2004 18:25
> To: Khartabil Hisham (Nokia-TP/Helsinki)
> Cc: Brian.Rosen@marconi.com; Koskelainen Petri (Nokia-NRC/Tampere);
> fluffy@cisco.com; Brian.Rosen@marconi.com; drage@lucent.com;
> klantz@cisco.com; xcon@ietf.org; dbieseli@cisco.com
> Subject: RE: [XCON] CPCP Requirement: Repeat times 
> 
> 
> Hisham,
> 
> Thanks.  This fits my view of what is expected.  One quick 
> comment however 
> (very minor nit) in 18.3:
> 
> "When saying that a conference starts, or becomes active 
> (start-time), it 
> means that the mixing starts."  [... as soon as one or more 
> inputs are 
> available?]
> 
> Is it not possible that the start time has passed, yet no one 
> has called in 
> yet?  So could it not be possible that no bridge resource (although 
> assigned or reserved) is in use?  How do you mix 0 inputs and outputs?

Ok, I get your point. I'll fix the text. Thanks.

Hisham
> 
> Mike
> 
> 
> 
> At 12:45 PM 2/9/2004 +0200, hisham.khartabil@nokia.com wrote:
> >Admittedly, the current solution specifies that a convener 
> needs to change 
> >the stop time in order to terminate the conference, if he wants the 
> >conference to end as he leaves. I sense that people want the 
> convener to 
> >explicitly indicate that instead of just modifying the 
> stop-time. Am I 
> >correct? I know Brian wants it so.
> >
> >I also would like to encourage people to read sections 12 
> and 18.3 of the 
> >solution draft. Those sections discuss exactly what this 
> thread is all about.
> >
> >http://www.ietf.org/internet-drafts/draft-koskelainen-xcon-xc
> ap-cpcp-usage-02.txt
> >
> >Regards,
> >Hisham
> >
> > > -----Original Message-----
> > > From: xcon-admin@ietf.org [mailto:xcon-admin@ietf.org]On 
> Behalf Of ext
> > > Michael Hammer
> > > Sent: 06.February.2004 21:49
> > > To: Rosen, Brian
> > > Cc: Koskelainen Petri (Nokia-NRC/Tampere); 
> fluffy@cisco.com; Rosen,
> > > Brian; drage@lucent.com; klantz@cisco.com; xcon@ietf.org;
> > > dbieseli@cisco.com
> > > Subject: RE: [XCON] CPCP Requirement: Repeat times
> > >
> > >
> > > Brian,
> > >
> > > I may be a little confused by what is meant by policy and policy
> > > manipulation with respect to how that translates into 
> resources being
> > > invoked and released.  My vision (delusion) as to how that
> > > might work might
> > > have to wait to see the actual protocol develop.  But, I
> > > suspect that your
> > > answers to my comments below will help clear this up for me.
> > >
> > > Mike
> > >
> > >
> > > At 01:33 PM 2/6/2004 -0500, Rosen, Brian wrote:
> > > > > >End when last person leaves is the way many bridges work.
> > > > >
> > > > > Is that a technical justification?
> > > >Actually, I think it means there is a requirement for that
> > > to be possible.
> > >
> > > Agree.  Don't see that as not possible.
> > >
> > >
> > > > >
> > > > > >You might
> > > > > >not like it, but that's the way they work.  Most 
> bridges don't
> > > > > >start if the convener is not there.  If he arrives, and
> > > then leaves,
> > > > > >the conference is over.
> > > > >
> > > > > What is the meaning of conference policy then?  I thought
> > > > > that it was an
> > > > > authorization for something to take place.  If the conference
> > > > > is authorized
> > > > > to start and someone shows up, then it starts.  If it is
> > > > > authorized to
> > > > > stop, and the bridge resources are needed elsewhere, then
> > > it stops.
> > > >CPCP has two elements, and they each have a role in policy.
> > > >A particular implementation, or more properly, a particular
> > > administrative
> > > >action, may restrict the range of possible policy requests
> > > the convener
> > > >may ask for.   The bridge may not respond the way the
> > > convener would like
> > > >it to.  It must be possible for the bridge to have local
> > > policy, and yet
> > > >allow the convener to manipulate whatever freedoms the 
> local policy
> > > >permits.
> > >
> > > I agree with this part.  The local "uber-policy" determines if the
> > > convener's policy request is accepted or rejected.
> > >
> > >
> > > >You could have the bridge change the start/stop time itself
> > >
> > > I don't follow this part.  It seems to confuse the role of
> > > the bridge in
> > > committing to the use of resources and the role of the convener in
> > > committing to pay for what he has asked for.  If it is the
> > > intent of the
> > > requester to terminate the conference upon his leaving, then
> > > that should
> > > be  an option of the request he makes to the bridge.
> > >
> > > If he is requesting that the bridge terminate upon his
> > > departure, shouldn't
> > > that be an update to his policy?  Same for other options.
> > > The bridge of
> > > course may have resource limitations, and thus there may be
> > > conditional
> > > authorizations to what is requested.  Where I think I have
> > > some confusion
> > > is that some of these options/authorizations are implicit not
> > > explicit.
> > >
> > > >to implement
> > > >its local policy, but that makes the function even more twisted.
> > > >Better to have explicit mechanisms, and let the bridge
> > > implement, or permit
> > > >a subset of them if it wishes.
> > > >
> > > > >
> > > > > >It also doesn't work to manipulate stop time to end the
> > > > > conference because
> > > > > >its the bridge that wants to enforce its policy and not
> > > the convener.
> > > > >
> > > > > Who is the authority here?  Isnt' the bridge-providing
> > > > > service supposed to
> > > > > obey policy?
> > > >As above, local policy must override.
> > >
> > > I agree, in the sense that local policy drives convener
> > > policy that drives
> > > bridge resource provided/withheld.
> > >
> > >
> > > >....snip...
> > > > > strategy, and an implementation detail.  It seems the
> > > > > confusion here stems
> > > > > from not separating:
> > > > >
> > > > > Is a conference authorized at the moment,
> > > > > Is a bridge needed at the moment,
> > > > > and should a bridge be reserved at the moment.
> > > >I don't see it that way.  I see it as the bridge has 
> local policy,
> > > >the convener wants to exert whatever freedom the local
> > > policy permits,
> > > >and the participants have to have some way to understand what is
> > > >going to happen.
> > >
> > > But, isn't the time at which the local policy interacts with
> > > the convener
> > > request independent of when a particular bridge resource gets
> > > assigned?  A
> > > convener request could be accepted so long as there are
> > > enough resources
> > > available/reserved in the pool, whether or not a resource is
> > > actually put
> > > to use.
> > >
> > >
> > > > >
> > > > > >We have to be explicit.
> > > > >
> > > > > Yes, particularly as to the semantics of policy.  What does
> > > > > start time
> > > > > mean?  What does stop time mean?  I keep seeing primary
> > > > > meanings tangled up
> > > > > with secondary and tertiary implementation implications.
> > > >I've proposed that start time is the earliest time at which
> > > >mixing starts.
> > >
> > > I thought this was a policy?  This would mean that the start
> > > time would be
> > > the earliest time at which mixing is permitted to start.  
> Isn't this
> > > independent of whether a resource was invoked?  Note, it may
> > > be reserved
> > > un-occupied and billed for, but that may not be the most
> > > efficient use of
> > > resources.  (No statistical over-booking allowed.)
> > >
> > >
> > > >I've proposed that stop time is interpreted by the stop time
> > > >enumeration.  It could be a hard stop of mixing resources, or it
> > > >could be only advisory.
> > >
> > > Could this not be defined as the latest time at which mixing
> > > is permitted
> > > to be used, i.e. that the enumeration option is whether the
> > > stop time may
> > > get updated explicitly by the convener or another party or
> > > implicitly by a
> > > convener agent (could be the bridge)?
> > >
> > >
> > > > >
> > > > > >As to Cullen's objection, what you are worried about is
> > > start time,
> > > > > >and not stop time.  By your definition, the conference
> > > never started.
> > > > > >If it did start, then it ends when whoever showed up leaves
> > > > > (if that's
> > > > > >what the conference policy was set to), or when the
> > > convener leaves,
> > > > > >which is surely the right thing.  I don't know how to fix
> > > > > your problem
> > > > > >actually.   Maybe some kind of action that resets start.
> > > > >
> > > > > The bridge may need to be released and re-captured, but that
> > > > > does not mean
> > > > > the conference is re-started.
> > > >Possibly a minor semantic argument.  I think we both agree that
> > > >the scheduled conference did not take place.
> > >
> > > Are we talking when a convener was authorized to invoke a 
> conference
> > > resource or accounting for when resources were actually used?
> > > I believe that some conference services still charge as the
> > > resources where
> > > reserved and represent an opportunity cost.
> > >
> > > >What is the
> > > >difference between "release and recapture" and "reset start"?
> > >
> > > One appears to be a new conference instance, while the other
> > > appears to be
> > > a modification of an existing conference.
> > >
> > >
> > > > >
> > > > > >   The problem is,
> > > > > >that would have to be a convener action; you wouldn't want a
> > > > > participant
> > > > > >to invoke it.
> > > > > >
> > > > > >Also, Petri, you can't implement a "Meet Me" with
> > > > > start/stop.  MeetMes don't
> > > > > >have start and stop times.
> > > > >
> > > > > You are asserting what the group is attempting to define.
> > > >Well, we can twist start and stop, but to any person, a 
> meet me, by
> > > >definition, does not have start and stop times.  Could we
> > > implement it
> > > >by twisting start/stop?  I guess, but I don't think its 
> a good idea.
> > > >
> > > > >
> > > > > >   They start whenever the convener arrives,
> > > > >
> > > > > What if the convener never arrives, but the rest of the group
> > > > > does?  To say
> > > > > it never starts seems rather limiting in an unnecessary way.
> > > >That's the way Meet Me (notice the word "Me") services 
> are defined.
> > >
> > > I should note that the term "meet me" has been used in a more
> > > broad way to
> > > mean any pre-scheduled conference for which a number
> > > (address) has be setup
> > > and to which users are asked to call into at some future
> > > time.  You seem to
> > > have something more specific in mind.  I have no problem with
> > > a specific,
> > > maybe trademarked, service to be more narrowly defined, but
> > > see no reason
> > > to limit other possibilities.
> > >
> > > >I happen to think its an excellent service.  I would not 
> want anyone
> > > >to be able to use my Meet Me conference if I was not there.
> > > >I am charged for it.  If 4 people know my MeetMe URI, 
> they can decide
> > > >to have a conference (on my nickle) any time they want 
> if there is
> > > >not a restriction that convener starts.  That is 
> precisely why MeetMe
> > > >works the way it does.  Its not a current technology limitation.
> > >
> > > I have not problem with this being possible, just don't think
> > > CPCP should
> > > be restricted for being used in other ways.  Protocol should
> > > be generally
> > > usable for many types of services.
> > >
> > > >I have no problem at all in allowing CPCP to facilitate an ad-hoc
> > > >conference, which is what I think you are looking for.  Ad-hoc is
> > > >a conference starts either by promoting a one on one to 
> a three way,
> > > >or by the first person connecting to the conference, and 
> it ends when
> > > >the last person leaves (or for some, when the number of 
> participants
> > > >drops below 3).  Ad-hoc is also a useful service, but 
> usually we use
> > > >ad-hoc internally where charging issues are simpler.
> > > > >
> > > > > >end
> > > > > >when he leaves (usually),
> > > > >
> > > > > This again is not necessary.  A convener (payer) may want to
> > > > > start the
> > > > > conference, but not stay for the full discussion.  No reason
> > > > > the conference
> > > > > can not continue without that person, if the policy 
> says it can.
> > > >Agree, but I want you to explicitly say that, and I want 
> local policy
> > > >to be able to permit you to say that, or deny you the
> > > ability to say that.
> > >
> > > OK
> > >
> > >
> > > > >
> > > > > >but restart when he arrives again with out regard
> > > > > >to start and stop.
> > > > >
> > > > > A new start and stop time is a new conference, 
> perhaps an ad hoc
> > > > > one.  There is no reason the conference policy would restrict
> > > > > the convener
> > > > > from scheduling multiple conferences, unless there is other
> > > > > local policy
> > > > > that over-rides the ability to do so.  But, that again is
> > > > > implementation.
> > > >Well, a new start/stop MAY be a new conference, or it could
> > > be a reschedule
> > > >of an existing one.  Take a scenario where a couple of
> > > participants show,
> > > >the convener doesn't, and the participants leave.
> > >
> > > Hopefully, the convener could show up late and the conference
> > > is still
> > > active and resources get invoked for him and whoever else
> > > shows up late.
> > >
> > > >The convener pushes
> > > >start and stop an hour.  If its a new conference, there is a
> > > new conference
> > > >URI.
> > > >If its a reschedule, then its the same conference, and the
> > > same URI.  I
> > > >think
> > > >that is preferable.
> > >
> > > So long as the convener shows up within the hour it was originally
> > > scheduled, could it be neither a new conference nor a
> > > reschedule?  Suppose
> > > he shows 20 minutes late, but only needs 40 minutes to get
> > > the work done,
> > > why should any policy change take place?
> > >
> > >
> > > >Local policy, as I advocate, is indeed a controlling factor.
> > >  However, to be
> > > >successful, the convener and the participants have to know
> > > what the local
> > > >policy is, so that their expectations are met.  That means
> > > CPCP has to have
> > > >ways of the participants including the convener to 
> learning the local
> > > >policy,
> > > >which means the language has to have the ability to express
> > > it.  It's not
> > > >just implementation.
> > > >
> > > > >
> > > > > I hope the tone of the above does not sound harsh.  I just
> > > > > think it would
> > > > > be useful to separate the definition of "what" the conference
> > > > > is from the
> > > > > definition of "how" it is to be supported.
> > > >Confused about "what a conference is".  I think we are all
> > > working on the
> > > >"how it is to be supported".  I don't even want to think
> > > about a definition
> > > >of what it is.  For example, if I play music on hold to you
> > > while you are
> > > >waiting for a conference to start, is that part of the 
> conference?
> > >
> > > That sounds like a service description which may be
> > > implementation dependent.
> > >
> > > >You got
> > > >there with the conference URI, you can probably manipulate
> > > some resources
> > >
> > >
> > > _______________________________________________
> > > XCON mailing list
> > > XCON@ietf.org
> > > https://www1.ietf.org/mailman/listinfo/xcon
> > >
> 
> 

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