1. Location Configuration at Layer 7
Andrew Newton, SunRocket, Inc.
GEOPRIV Working Group Co-chair, IETF
SDO Emergency Services Coordination Workshop (ESW06)
Columbia University, New York, NY, US
6 October 2006

2. Overview Location Configuration at the UA
This is the first step in conveying information from the end user to the first responder.
In GEOPRIV terminology, the act of acquiring location information of a “target” is called “sighting”.
Numerous methods.
Manual
Sensor measurements.
From/with the network, associated with layer configuration
802 LLDP, DHCP, Layer 7 LCP, etc...

3. L7LCP (Layer 7 Location Configuration Protocol)
Justification: Lower layers do not always provide location configuration.
Desired by IP network operators.
Usable to VSPs.
Not restricted to subnet boundaries.
Potential to circumvent NATs.
Perceived extensibility (aka XML) and enhanced security (aka TLS, XML DSig) at application layer.

4. Challenges LIS discovery End host location retrieval identifier
because if the lower layer isn’t providing location information, it is likely not pointing to it either
End host location retrieval identifier
known to the end host and the LIS, but nobody else.
Location-by-Reference
pervades the GEOPRIV model, but starts here
Location signing. Useful or not?

5. Location-by-Reference
Push vs. Poll; pres: vs. http:
End host may off-load publication of location information to a 3rd party.
De-reference could offer tailored response to PSAP.
De-reference could be limited to PSAPs... but then how do you know it is a PSAP. Security & Privacy issue.
Network operator could keep location information out of the hands of the customer. For emergencies, this seems more harmful than helpful.
End host may subscribe to its own location from the network (useful for mobility).
Seems more palatable for location configuration, very controversial for location conveyance.

6. Location Signing
Signed location without an identity is not helpful. Easy to copy.
Too much coordination required for it to work at Internet scale.
Thousands of PSAPS, millions of voice service providers (aka businesses)
PSAPs may regard calls without signatures as suspect. Is that useful?
Only relevant to calls where no human contact is established?
Caller identity, not network identity, is more useful for accountability.

7. Work Status Design Team: drafted problem statement and requirements.
Next step: get approval of entire working group.
Then pick the protocol proposal that best matches our requirements.
Refine it.
Ratify it in the working group.
Ratify it in the IETF.

8. L7LCP Proposals HELD draft-winterbottom-http-location-delivery
location-delivery-03.txt
LCP
draft-linsner-geopriv-lcp-00
expired
RELO
draft-schulzrinne-geopriv-relo
geopriv-relo-00.txt
One more on the way...

9. References L7 LCP Problem Statement & Requirements
draft-tschofenig-geopriv-l7-lcp-ps
02.txt
GEOPRIV Requirements and Security Threats Analysis
IETF RFC 3693
IETF RFC 3694
DHCP Coordinate Based Location Configuration Information
IETF RFC 3825
DHCP Option for Civic Address Configuration
draft-ietf-geopriv-dhcp-civil