ECRIT Architectural
Considerations
draft-polk-newton-ecrit-archconsiderations-01
James Polk
Andrew Newton
Genesis
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An observation about the ECRIT meeting in
Paris:
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New comers were confused
Old hands speak about differing universes
The intent of this document:
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Provide enough information for new comers
Specify common parameters for the old hands
In the process, identify some issues.
Architecture
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There is no one, single type of network in which
ECRIT will be deployed.
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There are many.
However, we can identify processes that occur
within each type of network on which ECRIT must
rely:
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Bootstrapping
Conversion
Mapping
Conveyance
Bootstrapping
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Delivery of configuration and location
information to “seekers”.
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DHCP
PPP
LLDP
Manual
There are multiple configuration protocols.
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The ECRIT requirements upon bootstrapping are
not clear.
Conversion
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Syntactic
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If no PIDF-LO compatible mapping protocol, from the
binary bootstrapping scheme to mapping scheme.
From the binary bootstrapping scheme to PIDF-LO XML for
conveyance.
Geocoding & Reverse Geocoding
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x,y,z <--> 123 Main St.
Civic addresses are user friendly
But geospatial coordinates can be more precise
No requirements for the delivery of both.
Mapping
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Location Context Mapping System (LCMS)
Static:
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Dynamic
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“fixed location” devices can have the mapping done
beforehand and handed to them.
When location is known to be fluid, mapping can be done
“on-the-fly”.
Combination
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Endsystem always asks (same) trusted server where it is
(before or during call), even when it moves within the local
network
Conveyance
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Information sent to the PSAP during the
emergency call
Location Conveyance
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PIDF-LO
A URI to PIDF-LO?
Identity Conveyance
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An authenticated identity
A call-back reference
Unresolved Issues
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Emergency Identifiers
Security Considerations
Data Distribution
Extensibility
Conflation
Emergency Call Identifier(s)
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Is there just: One? Three? Seven?
What about adhoc identifiers specific to
certain regions?
Must these identifiers take any certain form to
fit into protocol elements?
Security Considerations
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LCMS volume is likely to be orders of
magnitude higher than PSTN emergency call
volume.
If bootstrapping protocols are insecure, what
is the point anyway?
What is the real problem?
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Mapping forgery
Mapping denial of service
Data Distribution
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Most likely resolved with new ‘Re5’
requirement.
Extensibility
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Resolved by new ‘Ma15’ requirement:
The mapping protocol MUST be extensible to
allow for the inclusion of new location fields.
Conflation
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No requirements regarding the resilience of
the emergency call resolution process as it
relates to inputs that have not been designed
for this specific purpose.
E.g.
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ECRIT may require streets to be abbreviated or
postal names to be absent, but other location
based applications require “typical” addresses.