There is potentially one other thing that springs to mind, and that is a
specific sos domain. If that were done, then the resulting URI itself
would be explicit that it was for emergency services.
Just a thought.
> -----Original Message-----
> From: Hannes Tschofenig [mailto:[email protected]]
> Sent: Saturday, 14 April 2007 12:43 AM
> To: Rosen, Brian
> Cc: [email protected]; [email protected]
> Subject: Re: [Ecrit] Not-so-grand compromise on how to do endpoint
> centricLCP without giving away the store
> Hi Brian,
> thanks for posting this message.
> When the end host is provided with LbyV and triggers the LoST lookup
> routes the call via its VSP then the VSP (in some circumstances*)
> want to verify that the PSAP URI in the message indeed corresponds to
> PSAP. The idea that was mentioned a long time ago already was to let
> VSP to use the location information for LoST and to compare the result
> with the content of the message.
> The main goal here is that the VSP does not need to have a "business"
> contract to the ASP/ISP.
> Since there is only a location reference that neither the end host nor
> the VSP can dereference it is necessary to enhance the existing
> procedures a bit (as Brian mentioned).
> I see two ways todo so:
> a) Enhance LoST
> b) Enhance the dereferencing protocol
> In both cases you want to have the LbyR as input and the PSAP URI (and
> potentially the service number) as output.
> For (a) you would have to address the LoST query to the LoST server in
> the ASP/ISP network and the result would be a nomal LoST response.
> For (b) you would have todo a dereferencing step with an additional
> parameter for "verify only". The response would be similar to the
> by the end host -- just the identity that is being used for the lookup
> would be different.
> Both approaches are possible and since the VSP has to support both
> protocols it does not make a big difference which one to use.
> In both cases you would have to compare the result of the lookup with
> the content of the message.
> *: It is only necessary when the VSP charges for individual calls or
> specific calls (with the given call falling into this category).
> Rosen, Brian wrote:
> > In the Emergency Services SDO Coordination workshop, a familiar
> > discussion took place: how does location get provided for emergency
> > calls? The real issue is revenue. Access networks have location.
> > may be willing to (or may be regulated to be required to) provide
> > location for emergency calls. However, they are not willing to give
> > away for free for other uses. The issue with that is how we support
> > calling networks that don't have relationships with access networks,
> > i.e. the Skype situation. How is location provided such that a
> > emergency call can be placed, but the access network can restrict
> > else may be done with the location it provides?
> > We have been wrapped around the axle on this for, dare I say, years.
> > So, I think Barbara Stark first described this, and it needs some
> > but suppose that, as an option, an access network could supply:
> > 1. A reference to location
> > 2. The results of a LoST query on the location value (viz, PSAP URI
> > local dialstring)
> > With this, an endpoint could recognize an emergency call and start
> > routing it to the right PSAP. The LIS would agree to dereference
> > PSAPs, but could restrict other uses of location.
> > Hannes points out that we need one more thing: the calling network
> > to be able to validate that the PSAP URI really is a PSAP URI so
> > charging (emergency calls generally are free) is protected. We need
> > mechanism for them to do that.
> > Perhaps we include in the LoST return a country code for a query
> > geo. We add a new operation to LoST that takes a service, a country
> > code and a PSAP URI and returns yes/no validation ("Yes, that URI is
> > valid URI for that service in that country").
> > What would we need to do to make this happen?
> > We need extensions to LCPs or some new protocol that returns an LbyR
> > the LoST results. I wonder if this is just more HELD work.
> > We need the PSAP URI validation.
> > Again, this is optional. The access network may well give up an
> > It may give up an LbyR that it will dereference for the endpoint.
> > access network may have a relationship with the calling network such
> > that the endpoint need not be involved.
> > The PSAP URI validation is actually useful without this idea,
> > when location is an LbyR. Instead of having to have the calling
> > dereference, and then do a LoST query to validate, it can just do
> > PSAP URI validation.
> > Would this solve our problem? Would access carriers concerned about
> > revenue issues with "giving away" location to it's subscribers be
> > willing to provide LbyR dereferenceable by PSAPs (again remembering
> > the access network are local to the PSAPs) as well as LoST query
> > services to their endpoints? Would this address the concerns raised
> > Deutsche Telecom on this issue?
> > Let me be very clear that I think this is an ugly solution. I think
> > that everyone will be much better off if endpoints knew where they
> > and apps could take advantage of that. I think we'll get there. I
> > think tying location configuration with the LoST query is a bad
> > think using LbyR for emergency calls is a bad idea.
> > But I can live with it.
> > Brian
> > _______________________________________________
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