Subject: [p2p-sip] P2P and 911 (again)

From: hannes.tschofenig at siemens.com (Tschofenig, Hannes)
Date: Wed Aug 17 09:23:17 2005

hi all, 

in ecrit working group we spoke about the impact of p2p on emergency
handling. there are a few issues to consider: 

1) the end host is able to use a mapping protocol to locate the psap.
the uri of the psap is determined based on the location of the end host.

2) the location must be available to the end host. various means can
provide you location information, such as gps, dhcp extensions, manual
configuration, etc.

as such, it is necessary that the following infrastucture is available: 

a) psaps (and the emergency staff)

b) a distributed database (location -> psap uri) that can be queried by
the mapping protocol 
 
c) protocols / protocol extensions to delivery location information to
the end host is required (unless you assume that everyone is able to
obtain location information by other means)

(a) and (b) are always required (regardless whether you use p2p or not).
with (a) you need to consider that end host contact the psaps directly
rather than indirectly via sip proxies. with (b) the difference is only
that the mapping protocol is initiated by the end host (rather than a
sip proxy or so). 

someone has to setup and maintain this infrastructure (=cost issue).
this is probably the most difficult part of the game but certainly not a
protocol question. 

now, one might argue that it is not really p2p because infrastructure
support is required. 
 
ciao
hannes

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From: jh at tutpro.com (Juha Heinanen)
Date: Wed Aug 17 09:38:24 2005

> the uri of the psap is determined based on the location of the end

if p2p sip client is in gsm/3g device, it could calculate its own
location provided that it knows coordinates of available gsm/3g base
stations.

i once suggested to authorities in finland that every mobile operator is
mandated to publish coordinates of their base stations on the internet.
this was rejected due to desire of mobile operators to hide such
information.

this is yet another example of the walled garden philosophy of mobile
operators.  they don't want to give control to intelligent p2p end
devices.

perhaps fcc in the u.s., if, as they claim, take emergency calling
seriously, could publish such ruling as an example to european
regulators.  if not, the only conclusion one can make, is that all this
fuzz about emergency calling is nothing but joke and in the end the only
thing that really matters is commercial interests of walled garden
operators.

-- juha