1. RELO: Retrieving End System Location Information draft-schulzrinne-geopriv-relo-03
Henning Schulzrinne
March 2007
IETF68 - GEOPRIV

2. Motivation Layer-7 mapping of identifier to location
typically network termination equipment
DSL modem, AP
Believed to satisfy L7-LCP requirements
Narrowly-focused protocol -- one purpose
make it easier to specify interoperability
Since just mapping, could map SNR measurements to location…
March 2007
IETF68 - GEOPRIV

3. Discovery Currently, S-NAPTR should probably be U-NAPTR
domain from host configuration (DHCP) or reverse DNS
March 2007
IETF68 - GEOPRIV

4. Query Just send HTTP GET Uses GET parameters, as in Parameters:
TLS RECOMMENDED
Uses GET parameters, as in
Parameters:
by: value or reference
within: time willing to wait
type: civic or geo
retransmission-allowed: yes/no
retention-expiry: usage rule
external-ruleset: usage rule
note-well: usage rule
url: URL to renew
expires: LO/LR should expire
secret: secret for modification
assert: LO to store
March 2007
IETF68 - GEOPRIV

5. Identifiers Default: IP address of request mac: MAC address
cdp: Cisco Discovery Protocol string
msap: MAC service access point (LLDP)
March 2007
IETF68 - GEOPRIV

6. OBO/... LIS-LIS just variants of LbyR
Operations
OBO/... LIS-LIS just variants of LbyR
Retrieval
civic or geo, value or reference
Renewal of reference lifetime
provide URL and secret
Assertion
provide LO for storage and/or signature
March 2007
IETF68 - GEOPRIV

7. Response Returns location object or URI (reference)
text/uri-list
acceptable location types indicated by Accept header
Uses HTTP Expires header to indicate validity
If error, use HTTP response
sufficient for error detection, with HTTP response body
To subscribe to location, insert Subscribe HTTP header (and maybe Event)
see SIP configuration framework for HTTP Event header
March 2007
IETF68 - GEOPRIV

8. Design decisions No notion of context -- stateless
no need for state maintenance
PIDF-LO (or any other future LO)
First-party retrieval (mainly)
reduce privacy risks
Specify discovery mechanism -- see related draft
use S-NAPTR (or U-NAPTR) via host name
Allow other identifiers
Uses HTTP error codes and status line, rather than define own
Subscribe URL in response header
separate discussion (tactical and technical)
March 2007
IETF68 - GEOPRIV

9. Requirements L7-1: Identifier choice L7-2: Mobility choice
several, extensible
L7-2: Mobility choice
subscription or polling
L7-3: Layer 7 and Layer 2/3 Provider Relationship
none assumed
L7-4: Layer 2 and Layer 3 Provider Relationship
satisfied
L7-5: Legacy devices
March 2007
IETF68 - GEOPRIV

10. Requirements L7-6: VPN awareness L7-7: Network access authentication
prior to VPN attachment
L7-7: Network access authentication
none assumed
L7-8: Network topology unawareness
doesn’t care
March 2007
IETF68 - GEOPRIV