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A Lo cation-to- S ervice T ranslation Protocol (LoST) & Mapping Protocol Architecture. Ted Hardie Andrew Newton Henning Schulzrinne Hannes Tschofenig. Overview. LoST is a simple XML-based query and response protocol running on top of HTTP either “naked” HTTP or SOAP
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A Location-to-Service Translation Protocol (LoST)& Mapping Protocol Architecture Ted Hardie Andrew Newton Henning Schulzrinne Hannes Tschofenig SDO Emergency Services Coordination Workshop (ESW06)
Overview • LoST is a simple XML-based query and response protocol running on top of HTTP • either “naked” HTTP or SOAP • Main Purpose: Return URIs for given location information and service identifier • i.e., service URN + location URIs • Status: Work in progress • Expected WGLC in Nov. 2006 SDO Emergency Services Coordination Workshop (ESW06)
Finding the correct PSAP • Which PSAP should the e-call go to? • Usually to the PSAP that serves the geographic area • Sometimes to a backup PSAP • If no location, then ‘default’ PSAP SDO Emergency Services Coordination Workshop (ESW06)
LoST Functionality • Satisfies the requirements (draft-ietf-ecrit-requirements) for mapping protocols • Civic as well as geospatial queries • civic address validation • Recursive and iterative resolution • Fully distributed and hierarchical deployment • can be split by any geographic or civic boundary • same civic region can span multiple LoST servers • Indicates errors in civic location data debugging • but provides best-effort resolution • Supports overlapping service regions SDO Emergency Services Coordination Workshop (ESW06)
LoST Properties • Minimizes round trips: • caching individual mappings • returns coverage regions (“hinting”) • civic (“all of C=US, A1=NY”) or geo (polygon) • Facilitates reuse of Transport Layer Security (TLS) • Returns emergency service numbers for a region • Query for supported Service URN types SDO Emergency Services Coordination Workshop (ESW06)
Protocol request (mapping) <?xml version="1.0" encoding="UTF-8"?> <findServiceByLocation xmlns="urn:ietf:params:xml:ns:lost1" validate="false" operation="recursive"> <locationInfo> <civicLocation> <country>US</country> <A1>New York</A1> <A3>New York</A3> <A6>Broadway</A6> <LOC>Suite 75</LOC> <PC>10027-0401</PC> </civicLocation> </locationInfo> <service>urn:service:sos.police</service> </findServiceByLocation> details likely to change SDO Emergency Services Coordination Workshop (ESW06)
Protocol response (mapping) <?xml version="1.0" encoding="UTF-8"?> <response xmlns="urn:ietf:params:xml:ns:lost1"> <result status="200" message="OK" xml:lang="en" timeToLive="10000"> <displayName xml:lang="en"> New York City Police Department </displayName> <service>unknown</service> <serviceBoundary> <civicLocation> <country>US</country> <A1>New York</A1> <A3>New York</A3> </civicLocation> </serviceBoundary> <uri>sip:nypd@example.com</uri> <uri>xmpp:nypd@example.com</uri> <service-number>911</service-number> </result> </response> SDO Emergency Services Coordination Workshop (ESW06)
Validation • Determine if civic location is (partially) valid • Returns XML tag names of components: • validated and used for mapping • no attempt to validate (and not used) • e.g., house number • known to be invalid • Return (default) PSAP based on validated elements • May return list of guesses for correct addresses, if requested SDO Emergency Services Coordination Workshop (ESW06)
Geo support • Which geo types should be supported? • Point (3D) • Polygon? may yield ambiguous answers • more complicated shapes? • Current proposal • always include 3D-point • may include other shapes SDO Emergency Services Coordination Workshop (ESW06)
LoST: Location-to-URL Mapping VSP1 cluster serving VSP1 replicate root information cluster serves VSP2 123 Broad Ave Leonia Bergen County NJ US LoST root nodes NJ US NY US sip:psap@leonianj.gov search referral Bergen County NJ US Leonia NJ US SDO Emergency Services Coordination Workshop (ESW06)
LoST Architecture G tree guide G G G broadcast (gossip) T1: .us T2: .de G resolver T2 (.de) seeker 313 Westview Leonia, NJ US T3 (.dk) T1 (.us) Leonia, NJ sip:psap@leonianj.gov SDO Emergency Services Coordination Workshop (ESW06)
Conclusion • Mapping is core component of emergency calling problem • LoST fully international and distributed • tries to avoid “who runs the root” problem • optimized for efficient use in mobile end systems SDO Emergency Services Coordination Workshop (ESW06)
References and Contact Info • IETF ECRIT Working Grouphttp://www.ietf.org/html.charters/ecrit-charter.html • LoST draft http://tools.ietf.org/wg/ecrit/draft-ietf-ecrit-lost/ • Mapping architecture draft: http://tools.ietf.org/wg/ecrit/draft-ietf-ecrit-mapping-arch • Prototype implementation work in progress (see demo) • First interoperability tests planned for early 2006 / beginning 2007. SDO Emergency Services Coordination Workshop (ESW06)