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. They
may be willing to (or may be regulated to be required to) provide
location for emergency calls. However, they are not willing to give it
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 Skype
emergency call can be placed, but the access network can restrict what
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 work,
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 and
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 for
PSAPs, but could restrict other uses of location.
Hannes points out that we need one more thing: the calling network has
to be able to validate that the PSAP URI really is a PSAP URI so that
charging (emergency calls generally are free) is protected. We need a
mechanism for them to do that.
Perhaps we include in the LoST return a country code for a query with a
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 a
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 and
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 LbyV.
It may give up an LbyR that it will dereference for the endpoint. The
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, especially
when location is an LbyR. Instead of having to have the calling network
dereference, and then do a LoST query to validate, it can just do this
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 that
the access network are local to the PSAPs) as well as LoST query
services to their endpoints? Would this address the concerns raised by
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 were,
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 idea. I
think using LbyR for emergency calls is a bad idea.
But I can live with it.
Brian
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