| Paul Kyzivat <pkyzivat@xxxxxxxxx>
2009-03-02 12:04 |
|
I don't understand your point at all.
If the UAs have a media stream that works, then there is no reason why
they should not use it if they wish. The main point of the signaling is
for the two of them to negotiate what they want to do. That need have
nothing to do with billing/charging/paying. Its quite possible that
there is no incremental cost for using the stream vs. not using it.
(This is the case when I make a sip call over my internet connect - that
I pay for monthly regardless of use.)
[Gao] I think if user rejected the modification, UAs MUST NOT still let the modification works.
If the modification still works and the user think he/she has rejected it, some info can be sent beyond user's view.
For example, A and B have audio talk and A requests B to add vedio. B thinks he/she does not prefer vedio now, so rejects it.
B think he/she has rejected, so he/she would do something. But all the thing is under A's eyes.
I think system should close the door for B, that's the reason I said "Let alone the modification" is not a nice system behavior.
If an entity in the middle of the network is providing resources for
transporting the media, and charges for that, then it had better ensure
that it knows when that resource is being used, and charge accordingly.
If there is a way for the two endpoints to use the media resource and
not be charged for it, then you can be quite certain that some will find
a way to exploit that.
[Gao] Yes. But if B just not send a new Re-INVITE(as Holmberg said) to close the door. Do you think it is B's/*B's UA's* fault, or the operator can charge it.
Of course the converse situation exists as well. If the entity in the
middle charges for a resource that it believes it is providing and is
being used, but the endpoints don't know that they are being charged,
then they will eventually discover this and will argue that the bill is
in error.
[Gao] Yes. We can find user's rejecting by signal of 4xx, and the "using media" footprint.
If the user forgetting to send a new Re-INVITE, we should not charge it.
If the user just using it for means, we can charge it.
But it is hard to distinguish it.
The worst situation, IMO, is when some entity in the middle bills for
the transport of media yet provides no extra service to convey the
media. It is then simply charging for an illusory "service" which is
unjustified. It may have provided a service of helping in the exchange
of the signaling messages, and so should perhaps get a fee for that, but
not for the media itself.
[Gao] Yes.
Thanks,
Paul
gao.yang2@xxxxxxxxxx wrote:
>
> /********* the mail to Tom ************
> Tom:
>
> Thanks for you attention.
>
> Answer for you:
> In fact, by the original mail from the Chair, the modification will be
> letted alone, without any help of hacked software.
>
> And the only way is waiting for user's *Self-discipline *Re-INVITE.
>
> If we make new UA equipment, I can do it. (althogh I do not prefer)
> But for current using ones, it will be *Compatible* issue.
>
> There is no fault from users and current UA equipment.
>
> That's the difference, I think.
>
> Waiting for you more comments. And I like talking this style.
>
> Gao.
> ********end of the mail to Tom ***********/
>
>
>
> By my view, there are two main points:
>
> 1. "hacker way" is user's behavior, but "Let alone the modification" is
> system behavior.
>
> 2. If user think they rejected the modification, "Let alone the
> modification" can send information which user do not want to be sent.
>
>
>
>
> *Paul Kyzivat <pkyzivat@xxxxxxxxx>*
>
> 2009-03-02 04:42
>
>
> 收件人
> gaoyang <gao.yang.seu@xxxxxxxxxxx>
> 抄送
> gonzalo.camarillo@xxxxxxxxxxxx, gao.yang2@xxxxxxxxxx,
> sipping-bounces@xxxxxxxx, sipping@xxxxxxxx, christer.holmberg@xxxxxxxxxxxx
> 主题
> Re: [Sipping] Closing the offer/answer rollback issue -- New drawbacks
>
>
>
>
>
>
>
>
> I just tried to catch up on the discussion here. I mostly see circular
> argument/counterargument with no changing of position.
>
> The only thing I have seen here that seems new is Gonzalo's proposal
> about "media in use".
>
> I see a lot of issues raised about UAs using media they are not being
> charged for. As Tom Taylor said, this is not a new argument, or unique
> to this situation. There is always the possibility that two UAs will
> attempt to communicate using media they did not signal in an obvious way
> in the signaling channel. If they succeed in doing so, it is presumably
> because they are using a media path that they have access to independent
> of the signaling. In that case the intermediary who feels it should be
> charging for this is simply hoping to charge for a service it is not
> providing, and so has no real grievance.
>
> The case where this might be a real problem is if a middlebox controls
> the media path (what resources are assigned, and whether media is /
> isn't permitted to flow), and yet the rules about session state are such
> that the middlebox and the endpoints have differing understandings of
> whether the active session includes a given media path or not. IMO that
> is the key issue that needs to be nailed down.
>
> Thanks,
> Paul
>
> gaoyang wrote:
> >
> > New drawbacks:
> >
> > 1. In the original mail, "in use" is after O/A and can be used.
> > In RFC3261,
> > If the session description has changed, the UAS
> > MUST adjust the session parameters accordingly, possibly *after asking
> > the user for confirmation*.
> > "*asking the user for confirmation*" can be user's preference(as Local
> > Policy).
> >
> > Then, the "in use" can be depend on "Local Policy".
> >
> > 2. As your original example:
> > some with precondition not OK, some without precondition or precondition
> > has been OK.
> > The modification part of the later(without precondition or precondition
> > has been OK) can need for "*asking the user for confirmation*".
> >
> > But the Re-INVITE failed for precondition not satisfied, and the user
> > will not be alerted or hinted. But the modification would go on beyond
> > user's idea.
> >
> > Another "Let alone" drawback, it is more serious than "rejected but
> > still let alone".
> > For "rejected but still let alone", user at least know what happened.
> >
> > 3. Partially comit and partially rollback of O/A which is considered
> atomic.
> > The impact is unknown now.
> >
> >
> >
> >
> > > Date: Fri, 27 Feb 2009 12:38:14 +0200
> > > From: Gonzalo.Camarillo@xxxxxxxxxxxx
> > > To: gao.yang2@xxxxxxxxxx
> > > CC: sipping-bounces@xxxxxxxx; sipping@xxxxxxxx;
> > christer.holmberg@xxxxxxxxxxxx
> > > Subject: Re: [Sipping] 答复: Re: 答复: Re: 答复: Re: ??: Re: ??: Re:
> > ??: Re: ??: Re: ??: Re: ??: Re: ??: Re: Closing the offer/answer
> > rollback issue
> > >
> > > Hi,
> > >
> > > at this point, the discussions are going in circles and are not
> > > productive any longer. No new ideas are being introduced.
> > >
> > > I think I now understand your main points (media synchronization and
> > > session continuity) so that I can put together a more formal
> description
> > > of the straw-man proposal in my original email that meets all the
> > > requirements brought up here.
> > >
> > > The proposal will be what the WG had agreed on before with slight
> > > modifications (e.g., a clarification of the "in use" concept) in order
> > > to better address your concerns.
> > >
> > > Thanks for your input,
> > >
> > > Gonzalo
> > >
> > > gao.yang2@xxxxxxxxxx wrote:
> > > >
> > > > Yes. I think it is can, not MUST.
> > > >
> > > > And with precondition, the user can be hinted the new modification
> > just
> > > > after Offer/Answer pairs.
> > > >
> > > >
> > > >
> > > >
> > > > *Gonzalo Camarillo <Gonzalo.Camarillo@xxxxxxxxxxxx>*
> > > >
> > > > 2009-02-27 18:22
> > > >
> > > >
> > > > 收件人
> > > > wang.libo@xxxxxxxxxx
> > > > 抄送
> > > > christer.holmberg@xxxxxxxxxxxx, gao.yang2@xxxxxxxxxx,
> > sipping@xxxxxxxx,
> > > > sipping-bounces@xxxxxxxx, Eric.wangxr@xxxxxxxxx
> > > > 主题
> > > > Re: 答复: Re: 答复: Re: ??: Re: [Sipping] ??: Re: ??: Re: ??:
> Re: ??:
> > > > Re: ??: Re: ??: Re: Closing the offer/answer rollback issue
> > > >
> > > >
> > > >
> > & gt; >
> > > >
> > > >
> > > >
> > > >
> > > > Hi,
> > > >
> > > > UEB would have rejected the video stream in the 183 response.
> > > >
> > > > Gonzalo
> > > >
> > > > wang.libo@xxxxxxxxxx wrote:
> > > > >
> > > > > HI,
> > > > >
> > > > > I think the video will be established.The figure below shows the
> > case.
> > > > >
> > > > >
> > > > > 1. REINVITE(audio，vedio)
> > > > > ----------------------------->
> > > > > 2. 183
> > > > > <-----------------------------
> > > > > 3. PRACK/200
> > > > > <------------------------------>
> > > > > 4. UPDATE(audio，vedio)
> > > > > ----------------------------->
> > > > > 5. 200(audio，vedio)
> > > > > <-----------------------------
> > > > >
> > > > > 6. 4XX
> > > > > <-----------------------------
> > > > >
> > > > > After step 5, UEs' precondition are met ,and the video stream is
> > > > > established too.
> > > > > But UE-B send 4xx to reject 4XX (step 6).
> > > > >
> > > > > Regards.
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > *Gonzalo Camarillo <Gonzalo.Camarillo@xxxxxxxxxxxx>*
> > > > >
> > > > > 2009-02-27 17:30
> > > > >
> > > > >
> > > > > 收件人
> > > > > wang.libo@xxxxxxxxxx
> > > > > 抄送
> > > > > christer.holmberg@xxxxxxxxxxxx,
> > > > gao.yang2@xxxxxxxxxx, sipping@xxxxxxxx,
> > > > > sipping-bounces@xxxxxxxx
> > > > > 主题
> > > > > Re: 答复: Re: ??: Re: [Sipping] ??: Re: ??: Re: ??:
> > > > Re: ??: Re: ??:
> > > > > Re: ??: Re: Closing the offer/answer rollback issue
> > > > >
> > > > >
> > > > >
> > > > >
> > > > ; >
> > > > >
> > > > >
> > > > >
> > > > > Hi,
> > > > >
> > > > > > If UE-A wants to communicate with UE-B by video, but UE-B only
> > > > want to
> > > > > > communicate by audio.
> > > > >
> > > > > then UE-B rejects the video stream and the video stream is never
> > > > > established.
> > > > >
> > > > > Cheers,
> > > > >
> > > > > Gonzalo
> > > > >
> > > > >
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