Network Working Group                                          T. Hardie
Internet-Draft                                            Qualcomm, Inc.
Intended status: Standards Track                               A. Newton
Expires: April 25, 2007                                        SunRocket
                                                          H. Schulzrinne
                                                             Columbia U.
                                                           H. Tschofenig
                                                                 Siemens
                                                        October 22, 2006


            LoST: A Location-to-Service Translation Protocol
                      draft-ietf-ecrit-lost-02.txt

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Copyright Notice

   Copyright (C) The Internet Society (2006).









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Abstract

   This document describes an XML-based protocol for mapping service
   identifiers and geodetic or civic location information to service
   contact URIs.  In particular, it can be used to determine the
   location-appropriate PSAP for emergency services.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Requirements Notation  . . . . . . . . . . . . . . . . . . . .  6
   3.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  7
   4.  Overview of Protocol Usage . . . . . . . . . . . . . . . . . .  8
   5.  LoST Uniform Resource Locators and Their Resolution  . . . . .  9
   6.  Mapping a Location and Service to URLs: <findService>  . . . . 10
     6.1.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . 10
     6.2.  Examples . . . . . . . . . . . . . . . . . . . . . . . . . 10
       6.2.1.  Example Using Geodetic Coordinates . . . . . . . . . . 10
       6.2.2.  Civic Address Mapping Example  . . . . . . . . . . . . 11
     6.3.  Components of <findService> Request  . . . . . . . . . . . 13
       6.3.1.  The <location> Element . . . . . . . . . . . . . . . . 13
       6.3.2.  The <service> Element  . . . . . . . . . . . . . . . . 13
       6.3.3.  Recursion or Redirection . . . . . . . . . . . . . . . 13
       6.3.4.  Configuring the Response . . . . . . . . . . . . . . . 14
     6.4.  Components of the Mapping Response
           <findServiceResponse>  . . . . . . . . . . . . . . . . . . 16
       6.4.1.  Source of Response:  <via> Element . . . . . . . . . . 16
       6.4.2.  Service URLs: the <uri> Element  . . . . . . . . . . . 16
       6.4.3.  Describing the Service with the <displayName>
               Element  . . . . . . . . . . . . . . . . . . . . . . . 17
       6.4.4.  Approximating Services:  the <service> Element . . . . 17
       6.4.5.  Defining the Service Region with the
               <serviceBoundary> Element  . . . . . . . . . . . . . . 17
       6.4.6.  Service Boundaries by Reference: the
               <serviceBoundaryReference> Element . . . . . . . . . . 17
       6.4.7.  The Service Number . . . . . . . . . . . . . . . . . . 18
       6.4.8.  Civic Address Validation . . . . . . . . . . . . . . . 18
       6.4.9.  Validity: The 'timeToLive' Attribute . . . . . . . . . 18
   7.  Retrieving the Service Boundary via <getServiceBoundary> . . . 19
   8.  List Services: <listServices>  . . . . . . . . . . . . . . . . 21
   9.  Location Profiles  . . . . . . . . . . . . . . . . . . . . . . 23
     9.1.  Location Profile Usage . . . . . . . . . . . . . . . . . . 23
     9.2.  Two Dimensional Geodetic Profile . . . . . . . . . . . . . 26
     9.3.  Basic Civic Profile  . . . . . . . . . . . . . . . . . . . 26
   10. Error Handling . . . . . . . . . . . . . . . . . . . . . . . . 27
     10.1. Basic Errors . . . . . . . . . . . . . . . . . . . . . . . 27
     10.2. Response Errors  . . . . . . . . . . . . . . . . . . . . . 27



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     10.3. Redirects  . . . . . . . . . . . . . . . . . . . . . . . . 28
   11. LoST Transport . . . . . . . . . . . . . . . . . . . . . . . . 29
   12. Relax NG Schema  . . . . . . . . . . . . . . . . . . . . . . . 30
   13. Internationalization Considerations  . . . . . . . . . . . . . 37
   14. IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 38
     14.1. U-NAPTR Registrations  . . . . . . . . . . . . . . . . . . 38
     14.2. Content-type registration for 'application/lost+xml' . . . 38
     14.3. LoST Relax NG Schema Registration  . . . . . . . . . . . . 40
     14.4. LoST Namespace Registration  . . . . . . . . . . . . . . . 40
     14.5. Registration Template  . . . . . . . . . . . . . . . . . . 41
     14.6. LoST Location Profile Registry . . . . . . . . . . . . . . 42
   15. Security Considerations  . . . . . . . . . . . . . . . . . . . 43
   16. Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 44
   17. Open Issues  . . . . . . . . . . . . . . . . . . . . . . . . . 45
   18. References . . . . . . . . . . . . . . . . . . . . . . . . . . 46
     18.1. Normative References . . . . . . . . . . . . . . . . . . . 46
     18.2. Informative References . . . . . . . . . . . . . . . . . . 47
   Appendix A.  Non-Normative RELAX NG Schema in XML Syntax . . . . . 48
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 61
   Intellectual Property and Copyright Statements . . . . . . . . . . 62































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1.  Introduction

   This document describes a protocol for mapping a service identifier
   [10] and location information compatible with PIDF-LO [8] to one or
   more service contact URIs.  Example contact URI schemes include sip
   [14], xmpp [15], and tel [16].  While the initial focus is on
   providing mapping functions for emergency services, it is likely that
   the protocol is applicable to any service URN.  For example, in the
   United States, the "2-1-1" and "3-1-1" services follow a similar
   location-to-service behavior as emergency services.

   This document names this protocol "LoST", for Location-to-Service
   Translation.  LoST Satisfies the requirements [18] for mapping
   protocols.  LoST provides a number of operations, centered around
   mapping locations and service URNs to URIs and associated
   information.  LoST mapping queries can contain either civic or
   geodetic location information.  For civic addresses, LoST can
   indicate which parts of the civic address are known to be valid or
   invalid, thus providing address validation.  LoST indicates errors in
   the location data to facilitate debugging and proper user feedback,
   but also provides best-effort answers.

   LoST queries can be resolved recursively or iteratively.  To minimize
   round trips, LoST caches individual mappings and indicates the region
   for which the same answer would be returned ("service region").

   As currently defined, LoST messages are carried in HTTP and HTTPS
   protocol exchanges, facilitating use of TLS for protecting the
   integrity and confidentiality of requests and responses.

   This document focuses on the description of the protocol between the
   mapping client (seeker or resolver) and the mapping server (resolver
   or other servers).  The relationship between other functions, such as
   discovery of mapping servers, data replication and the overall
   mapping server architecture are described in a separate document
   [19].

   The query message carries location information and a service
   identifier encoded as a Uniform Resource Name (URN) (see [10]) from
   the LoST client to the LoST server.  The LoST server uses its
   database to map the input values to one or more Uniform Resource
   Identifiers (URI) and returns those URIs along with optional
   information such as hints about the service boundary in a response
   message to the LoST client.  If the server cannot resolve the query
   itself, it may in turn query another server or return the address of
   another LoST server, identified by a LoST URL (Section 5).  In
   addition to the mapping function described in Section 6, the protocol
   also allows to retrieve the service boundary Section 7 and to list



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   the services available for a particular location Section 8.


















































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2.  Requirements Notation

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [1].














































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3.  Terminology

   This document furthermore uses the terminology defined in [18].

   In examples, the XML sent by the client is prepended with "C:" and
   the XML sent by the server is prepended with "S:".













































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4.  Overview of Protocol Usage

   The client may perform the mapping at any time.  Among the common
   triggers for mapping requests are:

   1.  When the client initially starts up or attaches to a network.

   2.  When the client detects that its location has changed
       sufficiently that it is outside the bounds of the service region
       returned in an earlier LoST query.

   3.  When cached mapping information has expired.

   4.  When invoking a particular service.  At that time, a client may
       omit requests for service boundaries or other auxiliary
       information.

   A service-specific BCP such as [20] governs whether a client is
   expected to invoke the mapping service just before needing the
   service or whether to rely on cached answers.  Cache entries expire
   according to their time-to-live value (see Section 6.4.9, or they
   become invalid if the caller's device moves beyond the boundaries of
   the service region.




























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5.  LoST Uniform Resource Locators and Their Resolution

   LoST servers are identified by LoST Uniform Resource Locators (URLs),
   which follow the format of URLs defined in RFC 3986 [7], with the
   following ABNF:

      LoST-URI = "lost:" host

   'host' is defined in Section 3.2.2 of RFC 3986 [7].

   An example is 'lost:lostserver.example.com'

   If a LoST URL contains a host name rather than an IP address, clients
   need to use U-NAPTR [12] using the U-NAPTR specification described
   below to obtain a URI (indicating host and protocol) for the
   applicable LoST service.  In this document, only the HTTP and HTTPS
   URL schemes are defined.  Note that the HTTP URL can be any valid
   HTTP URL, including those containing path elements.

   The following two DNS entries resolve the LoST URL "lost:example.com"
   to the HTTPS URL https://lostserv.example.com/secure or the HTTP URL
   http://lostserver.example.com, with the former being preferred.


       example.com.

       IN NAPTR 100  10   "u"    "LoST:https"
            "!*.!https://lostserver.example.com/secure!"  ""

       IN NAPTR 200  10   "u"    "LoST:http"
            "!*.!http://lostserver.example.com!"  ""




















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6.  Mapping a Location and Service to URLs: <findService>

6.1.  Overview

   The <findService> query constitutes the core of the LoST
   functionality, mapping civic or geodetic locations to URLs and
   associated data.  After giving an example, we enumerate the elements
   of the query and response.

6.2.  Examples

6.2.1.  Example Using Geodetic Coordinates

   The following is an example of mapping a service to a location using
   geodetic coordinates, for the service associated with the police
   (urn:service:sos.police).


   <?xml version="1.0" encoding="UTF-8"?>
   <findService xmlns="urn:ietf:params:xml:ns:lost1"
     xmlns:p2="http://www.opengis.net/gml" recursive="true"
     include="uri service serviceNumber displayName serviceBoundary">
     <location
       profile="urn:ietf:params:lost:location-profile:geodetic-2d">
       <p2:Point id="point1" srsName="urn:ogc:def:crs:EPSG:4326">
          <p2:pos>40.8089897 -73.9612492</p2:pos>
       </p2:Point>
     </location>
     <service>urn:service:sos.police</service>
   </findService>

                 Figure 2: A <findService> Geodetic Query

   Given the query above, a server would respond with a service, and
   information related to that service.  In the example below, the
   server has mapped the location given by the client for a police
   service to the New York City Police Deparment, instructing the client
   that it may contact them via the URIs sip:nypd@example.com and
   xmpp:nypd@example.com.  The server has also given the client a
   geodetic, two-dimensional boundary for this service and time-to-live
   value of 3,600 seconds.  This instructs the client that if its
   location changes beyond the give service boundary or if 3,600 seconds
   has elapsed, it would need to requery for this information.








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   <?xml version="1.0" encoding="UTF-8"?>
   <findServiceResponse xmlns="urn:ietf:params:xml:ns:lost1"
     xmlns:p2="http://www.opengis.net/gml" timeToLive="3600">
     <displayName xml:lang="en">
       New York City Police Department
     </displayName>
     <service>urn:service:sos.police</service>
     <serviceBoundary
       profile="urn:ietf:params:lost:location-profile:geodetic-2d">
       <p2:Polygon srsName="urn:ogc:def::crs:EPSG::4326">
         <p2:exterior>
           <p2:LinearRing>
             <p2:pos>37.775 -122.4194</p2:pos>
             <p2:pos>37.555 -122.4194</p2:pos>
             <p2:pos>37.555 -122.4264</p2:pos>
             <p2:pos>37.775 -122.4264</p2:pos>
             <p2:pos>37.775 -122.4194</p2:pos>
           </p2:LinearRing>
         </p2:exterior>
       </p2:Polygon>
     </serviceBoundary>
     <uri>sip:nypd@example.com</uri>
     <uri>xmpp:nypd@example.com</uri>
     <serviceNumber>911</serviceNumber>
   </findServiceResponse>

             Figure 3: A <findServiceResponse> Geodetic Answer

6.2.2.  Civic Address Mapping Example

   The following is an example of mapping a service to a location much
   like the example in Section 6.2.1, but using civic address location
   information.  In this example, the client requests the service
   associated with police (urn:service:sos.police) along with a specific
   civic address (house number 96 on a street named Neu Perlach in
   Munich, Germany).















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   <?xml version="1.0" encoding="UTF-8"?>
   <findService xmlns="urn:ietf:params:xml:ns:lost1"
     recursive="true"
     include="uri serviceNumber displayName serviceBoundary" >
     <location
       profile="urn:ietf:params:lost:location-profile:basic-civic">
       <civicAddress
         xmlns="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr">
         <country>Germany</country>
         <A1>Bavaria</A1>
         <A3>Munich</A3>
         <A6>Neu Perlach</A6>
         <HNO>96</HNO>
         <PC>81675</PC>
       </civicAddress>
     </location>
     <service>urn:service:sos.police</service>
   </findService>

               Figure 4: A <findService> Civic Address Query

   Given the query above, a server would respond with a service, and
   information related to that service.  In the example below, the
   server has mapped the location given by the client for a police
   service to the M&#557;nchen Polizei-Abteilung, instructing the client
   that it may contact them via the URIs sip:munich-police@example.com
   and xmpp:munich-police@example.com.  The server has also given the
   client a civic address boundary (the city of Munich) for this service
   and time-to-live value of 3,600 seconds.  This instructs the client
   that if its location changes beyond the give service boundary (i.e.
   beyond the city of Munich) or if 3,600 seconds has elapsed, it would
   need to requery for this information.



















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   <?xml version="1.0" encoding="UTF-8"?>
   <findServiceResponse
     xmlns="urn:ietf:params:xml:ns:lost1" timeToLive="3600">
     <displayName xml:lang="de">
       M&#557;nchen Polizei-Abteilung
     </displayName>
     <service>urn:service:sos.police</service>
     <serviceBoundary
       profile="urn:ietf:params:lost:location-profile:basic-civic">
       <civicAddress
         xmlns="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr">
         <country>Germany</country>
         <A1>Bavaria</A1>
         <A3>Munich</A3>
         <PC>81675</PC>
       </civicAddress>
     </serviceBoundary>
     <uri>sip:munich-police@example.com</uri>
     <uri>xmpp:munich-police@example.com</uri>
     <serviceNumber>110</serviceNumber>
   </findServiceResponse>

          Figure 5: A <findServiceResponse> Civic Address Answer

6.3.  Components of <findService> Request

6.3.1.  The <location> Element

   The <findService> query communicates location using one or more
   <location> elements, which MUST conform to a location profile
   (Section 9).

6.3.2.  The <service> Element

   The type of service desired is specified by the <service> element.
   It contains service URNs from the registry established in [10].

6.3.3.  Recursion or Redirection

   LoST <findService> queries can be recursive or iterative, as
   indicated by the 'recursive' attribute.  A value of "true" indicates
   a recursive query, a value of "false" an iterative query, with
   iterative being the default.  When the LoST server cannot answer the
   query and the query requested iterative resolution, it will return an
   <iterativeSearchExhausted> (Section 10.3) error message with the LoST
   URI pointing to a different LoST server that the LoST client should
   contact.  In recursive mode, the LoST server initiates a query and
   returns the result to the original querier, inserting a <via> element



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   to track the response chain.

6.3.4.  Configuring the Response

   The 'include' attribute enumerates all the XML elements that the
   client wants the LoST server to provide in the mapping response.  The
   server ignores any element names that it does not understand.  The
   ordering of the tokens is immaterial.

   Among other features, it determines whether service boundaries are
   returned and whether they are returned by value or reference
   Section 7, and whether to validate civic locations.

   Address validation is requested by including the XML element names
   that provide address validation in the 'include' attribute, namely
   'valid', 'invalid' and 'unchecked'.  The following example
   demonstrates address validation.


































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   C: <?xml version="1.0" encoding="UTF-8"?>
   C: <findService
   C:   xmlns="urn:ietf:params:xml:ns:lost1"
   C:   recursive="true"
   C:   include="uri serviceNumber invalid valid unchecked">
   C:   <location
   C:     profile="urn:ietf:params:lost:location-profile:basic-civic">
   C:     <civicAddress
   C:       xmlns="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr">
   C:       <country>Germany</country>
   C:       <A1>Bavaria</A1>
   C:       <A3>Munich</A3>
   C:       <A6>Neu Perlach</A6>
   C:       <HNO>96</HNO>
   C:       <PC>81675</PC>
   C:     </civicAddress>
   C:   </location>
   C:   <service>urn:service:sos.police</service>
   C: </findService>

   S: <?xml version="1.0" encoding="UTF-8"?>
   S: <findServiceResponse
   S:   xmlns="urn:ietf:params:xml:ns:lost1" timeToLive="3600">
   S:   <displayName xml:lang="de">
   S:     M&#557;nchen Polizei-Abteilung
   S:   </displayName>
   S:   <service>urn:service:sos.police</service>
   S:   <serviceBoundary
   S:     profile="urn:ietf:params:lost:location-profile:basic-civic">
   S:     <civicAddress
   S:        xmlns="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr">
   S:        <country>Germany</country>
   S:        <A1>Bavaria</A1>
   S:        <A3>Munich</A3>
   S:        <PC>81675</PC>
   S:     </civicAddress>
   S:   </serviceBoundary>
   S:   <uri>sip:munich-police@example.com</uri>
   S:   <uri>xmpp:munich-police@example.com</uri>
   S:   <serviceNumber>110</serviceNumber>
   S:   <valid>country A1 A3 A6</valid>
   S:   <invalid>PC</invalid>
   S: </findServiceResponse>

                   Figure 6: Address Validation Exchange






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6.4.  Components of the Mapping Response <findServiceResponse>

6.4.1.  Source of Response:  <via> Element

   A <findServiceResponse> indicates the source of the response by
   including a <via> element with a LoST URL as the first <via> element.
   Thus, each server "initials" its own response.  Thus, responses to
   iterative queries contain one <via> element, while responses to
   recursive queries may reach the original querier with multiple <via>
   elements, one for each server that was used in the resolution.  The
   following <findServiceResponse> example illustrates the use of <via>:


   <?xml version="1.0" encoding="UTF-8"?>
   <findServiceResponse
     xmlns="urn:ietf:params:xml:ns:lost1" timeToLive="3600">
     <via>lost:esgw.uber-110.de.example</via>
     <via>lost:polizei.munchen.de.example</via>
     <displayName xml:lang="de">
       M&#557;nchen Polizei-Abteilung
     </displayName>
     <service>urn:service:sos.police</service>
     <serviceBoundary
       profile="urn:ietf:params:lost:location-profile:basic-civic">
       <civicAddress
         xmlns="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr">
         <country>Germany</country>
         <A1>Bavaria</A1>
         <A3>Munich</A3>
         <PC>81675</PC>
       </civicAddress>
     </serviceBoundary>
     <uri>sip:munich-police@example.com</uri>
     <uri>xmpp:munich-police@example.com</uri>
     <serviceNumber>110</serviceNumber>
   </findServiceResponse>

              Figure 7: An Example of a Response Using <via>

   The example above indicates that the this answer was given to the
   responding server by the LoST server at esgw.uber-110.de.example,
   which got the answer from the LoST server at
   polizei.munchen.de.example.

6.4.2.  Service URLs: the <uri> Element

   The response returns the service URLs in one or more <uri> elements.
   The URLs MUST be absolute URLs.



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6.4.3.  Describing the Service with the <displayName> Element

   The <displayName> element describes the service with a string that is
   suitable for display to human users, annotated with the 'xml:lang'
   attribute that contains a language tag to aid in the rendering of
   text.

6.4.4.  Approximating Services:  the <service> Element

   If the requested service, identified by the service URN [10] in the
   <service> element in the request, does not exist for the location
   indicated, the server can either return an <serviceNotImplemented>
   (Section 10.2) error or can provide an alternate service that
   approximates the desired service for that location.  In the latter
   case, the server MUST include a <service> element with the
   alternative service URN.  The choice of service URN is left to local
   policy, but the alternate service should be able to satisfy the
   original service request.

6.4.5.  Defining the Service Region with the <serviceBoundary> Element

   A response can indicate the region for which the service URL returned
   would be the same as in the actual query, the so-called service
   region.  The service region can be indicated by value or by reference
   Section 6.4.6.  If a client moves outside the service area, it MUST
   send a new query with its current location to obtain valid service
   data.  The service region is described by value in one or more
   <serviceBoundary> elements, each formatted according to a different
   location profile.  The client only processes the first element that
   it can understand according to its list of supported location
   profiles.  Thus, the elements are alternative descriptions of the
   same service region, not additive geometries.

   The server returns all suitable service regions, using all available
   location profiles, so that intermediate caches have this information
   available for future queries.

6.4.6.  Service Boundaries by Reference: the <serviceBoundaryReference>
        Element

   Since geodetic service boundaries may contain thousands of points and
   thus be quite large, clients may opt to conserve bandwidth and
   request a reference to the service boundary instead of the value
   described in Section 6.4.5.  The identifier of the service boundary
   is returned in the <serviceBoundaryReference> element, along with a
   LoST URL identifying the server from where it can be retrieved.  The
   actual value of the service boundary is then retrieved with the
   getServiceBoundary (Section 7) request.



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   The identifier is a random token with at least 128 bits of entropy
   and can be assumed to be globally unique.  The identifier uniquely
   references a particular boundary; if the boundary changes, a new
   identifier must be chosen.  Because of these properties, a client
   receiving a mapping response can simply check if it already has a
   copy of the boundary with that identifier.  If so, it can skip
   checking with the server whether the boundary has been updated.
   Since service boundaries are likely to remain unchanged for extended
   periods of time, possibly exceeding the normal lifetime of the
   service URL, this approach avoids refreshing the boundary information
   even if the cached service response has gotten stale.

6.4.7.  The Service Number

   The service number is returned in the optional <serviceNumber>
   element.  It contains a string of digits, * and # that a user on a
   device with a 12-key dial pad could use to reach that particular
   service.

6.4.8.  Civic Address Validation

   A server can indicate in its response which civic address elements it
   has recognized as valid, which ones it has ignored and which ones it
   has checked and found to be invalid.  Each element contains a list of
   tokens separated by white space, enumerating the civic location
   lables used in child elements of the <civicAddress> element.  The
   <valid> element enumerates those civic address elements that have
   been recognized as valid by the LoST server and that have been used
   to determine the mapping.  The <unchecked> elements enumerates the
   civic address elements that the server did not check and that were
   not used in determining the response.  The <invalid> element
   enumerate civic address elements that the server attempted to check,
   but that did not match the other civic address elements found in the
   <valid> list.

   The example (Figure 6) indicates that the tokens 'country', 'A1',
   'A3', and 'A6' have been validated by the LoST server.  The server
   considered the postal code 81675 in the <PC> element as not valid for
   this location.

6.4.9.  Validity: The 'timeToLive' Attribute

   The timeToLive attribute contains the number of seconds the response
   is to be considered valid.  The contents of this attribute is a
   positive integer.  See Section 4 regarding how this value is to be
   utilized with a cache.  [TBD: This could also be an absolute time.]





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7.  Retrieving the Service Boundary via <getServiceBoundary>

   As discussed in Section 6.4.5, the <findService> response can return
   a globally unique identifier that can be used to retrieve the service
   boundary, rather than returning the boundary by value.  This is shown
   in the example in Figure 8.  The client can then retrieve the
   boundary using the <getServiceBoundary> request and obtains the
   boundary in the <getServiceBoundaryResponse>, illustrated in the
   example in Section 7.  The client issues the request to the server
   identified in the 'server' attribute of the
   <serviceBoundaryReference> element.


   C: <?xml version="1.0" encoding="UTF-8"?>
   C: <findService xmlns="urn:ietf:params:xml:ns:lost1"
   C:   xmlns:p2="http://www.opengis.net/gml" recursive="true"
   C:   include="uri service serviceNumber displayName
   C:   serviceBoundaryReference">
   C:   <location
   C:     profile="urn:ietf:params:lost:location-profile:geodetic-2d">
   C:     <p2:Point id="point1" srsName="urn:ogc:def:crs:EPSG:4326">
   C:     <p2:pos>40.809 -73.9612</p2:pos>
   C:     </p2:Point>
   C:   </location>
   C:   <service>urn:service:sos.police</service>
   C: </findService>

   S: <?xml version="1.0" encoding="UTF-8"?>
   S: <findServiceResponse xmlns="urn:ietf:params:xml:ns:lost1"
   S:   timeToLive="3600">
   S:   <displayName xml:lang="en">
   S:     New York City Police Department
   S:   </displayName>
   S:   <service>urn:service:sos.police</service>
   S:   <serviceBoundaryReference server="lost:nypd.example.com"
   S:     key="7214148E0433AFE2FA2D48003D31172E"/>
   S:   <uri>sip:nypd@example.com</uri>
   S:   <uri>xmpp:nypd@example.com</uri>
   S:   <serviceNumber>911</serviceNumber>
   S: </findServiceResponse>

           Figure 8: findService with Service Boundary Reference









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   C: <?xml version="1.0" encoding="UTF-8"?>
   C: <getServiceBoundary xmlns="urn:ietf:params:xml:ns:lost1"
   C:  key="7214148E0433AFE2FA2D48003D31172E"/>

   S: <?xml version="1.0" encoding="UTF-8"?>
   S: <getServiceBoundaryResponse
   S:   xmlns="urn:ietf:params:xml:ns:lost1"
   S:   xmlns:p2="http://www.opengis.net/gml">
   S:
   S:   <serviceBoundary
   S:     profile="urn:ietf:params:lost:location-profile:geodetic-2d">
   S:     <p2:Polygon srsName="urn:ogc:def::crs:EPSG::4326">
   S:       <p2:exterior>
   S:         <p2:LinearRing>
   S:           <p2:pos>40.701 -74.020</p2:pos>
   S:           <p2:pos>40.876 -73.926</p2:pos>
   S:           <p2:pos>40.797 -73.936</p2:pos>
   S:           <p2:pos>40.714 -73.984</p2:pos>
   S:           <p2:pos>40.701 -74.020</p2:pos>
   S:         </p2:LinearRing>
   S:       </p2:exterior>
   S:     </p2:Polygon>
   S:   </serviceBoundary>
   S:
   S: </getServiceBoundaryResponse>

      Figure 9: Requesting a Service Boundary with getServiceBoundary

   The <getServiceBoundary> request may also be used to retrieve service
   boundaries that are expressed as civic addresses, as illustrated in
   Figure 10.


   <?xml version="1.0" encoding="UTF-8"?>
   <getServiceBoundaryResponse
     xmlns="urn:ietf:params:xml:ns:lost1">
     <serviceBoundary
       profile="urn:ietf:params:lost:location-profile:basic-civic">
       <civicAddress
         xmlns="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr">
         <country>US</country>
         <A1>New York</A1>
         <A3>New York</A3>
       </civicAddress>
     </serviceBoundary>
   </getServiceBoundaryResponse>

            Figure 10: Civic Address Service Boundary Response



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8.  List Services: <listServices>

   A LoST client can ask a LoST server for the list of services it
   supports.  The <listServices> query contains one or more <location>
   elements, each from a different location profile (Section 9), and may
   contain the <service> element.  If the query contains the <service>
   element the LoST server returns only immediate child services of the
   queried service that are available for the provided location.  If the
   <service> element is absent, the LoST service returns all top-level
   services available for the provided location that it knows about.

   A server responds to this query with a <listServicesResponse>
   response.  This response has may contain <via> elements
   (Section 6.4.1) and must contain a <serviceList> element, consisting
   of a whitespace-separated list of service URNs.  The query and
   response are illustrated in Figure 11.


   C: <?xml version="1.0" encoding="UTF-8"?>
   C: <listServices
   C:   xmlns="urn:ietf:params:xml:ns:lost1"
   C:   xmlns:p2="http://www.opengis.net/gml"
   C:   recursive="false">
   C:   <location
   C:     profile="urn:ietf:params:lost:location-profile:basic-civic">
   C:     <p2:Point id="point1" srsName="epsg:4326">
   C:       <p2:coordinates>37:46:30N 122:25:10W</p2:coordinates>
   C:     </p2:Point>
   C:   </location>
   C:   <service>urn:service:sos</service>
   C: </listServices>

   S: <?xml version="1.0" encoding="UTF-8"?>
   S: <listServicesResponse xmlns="urn:ietf:params:xml:ns:lost1">
   S:     <serviceList>
   S:       urn:service:sos.ambulance
   S:       urn:service:sos.animal-control
   S:       urn:service:sos.fire
   S:       urn:service:sos.gas
   S:       urn:service:sos.mountain
   S:       urn:service:sos.marine
   S:       urn:service:sos.physician
   S:       urn:service:sos.poison
   S:       urn:service:sos.police
   S:       urn:service:sos.suicide
   S:     </serviceList>
   S: </listServicesResponse>




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                   Figure 11: ListService Query Example


















































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9.  Location Profiles

   Currently, LoST uses location information in <location> elements in
   requests and <serviceBoundary> elements in responses.  Such location
   information may be expressed in a variety of ways.  This variety can
   cause interoperability problems where a request or response contains
   location information in a format not understood by the server or
   client, respectively.  To achieve interoperability, LoST defines two
   must-implement baseline location profiles to define the manner in
   which location information is transmitted and makes it possible to
   standardize other profiles in the future.  The two baseline profiles
   are:

   geodetic-2d:  a simple profile for two-dimensional geodetic location
      information, described in Section 9.2);

   civic:  a profile consisting of civic address location information,
      described in Section 9.3.

   Requests and responses containing <location> or <serviceBoundary>
   elements MUST contain location information in exactly one of the two
   baseline profiles, in addition to zero or more additional profiles.
   The ordering of location information indicates a preference on the
   part of the sender.

   Standards action may create other profiles.  A location profile MUST
   define:

   1.  The token identifying it in the LoST location profile registry;

   2.  The formal definition of the XML to be used in requests, i.e., an
       enumeration and definition of the XML child elements of the
       <location> element;

   3.  The formal definition of the XML to be used in responses, i.e.,
       an enumeration and definition of the XML child elements of the
       the <serviceBoundary> element;

   4.  The declaration of whether geodetic-2d or civic is to be used as
       the baseline profile.  It is necessary to explicitly declare the
       baseline profile as future profiles may be combinations of
       geodetic and civic location information.

9.1.  Location Profile Usage

   A location profile is identified by a URN in the
   urn:ietf:params:lost:location-profile registry.  (Note that this is
   not an XML schema or namespace identifier.)  Clients send location



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   information compliant with a location profile, and servers respond
   with location information compliant with that same location profile.

   When a LoST client sends a request which provides location
   information, it contains one or more <location> elements.  Each of
   these elements contains location information compliant with a
   location profile and specifies which profile has been used in the
   'profile' attribute.  This allows the client to convey location
   information for multiple location profiles in the same request.

   When a LoST server sends a response which contains location
   information, it uses the <serviceBoundary> elements much like the
   client uses the <location> elements.  Each <serviceBoundary> element
   contains location information conformant to the location profile
   specified in the 'profile' attribute.  This allows the server to send
   location information compliant with multiple location profiles.

   Using the location profiles defined in this document, the following
   rules insure basic interoperatiblity between clients and servers:

   1.  A client MUST be capable of understanding the response for the
       baseline profiles it used in the request.

   2.  If a client sends location information conformant to any location
       profile other than geodetic-2d or civic, it MUST also send, in
       the same request, location information conformant to one of the
       baseline profiles.  Otherwise, the server might not be able to
       understand the request.

   3.  Servers MUST implement the geodetic-2d and civic profiles.

   4.  A server ignores any location information using non-baseline
       profiles it does not understand.

   5.  If a server receives a request that only contains location
       information using profiles it does not understand, the server
       responds with a <locationProfileError> (Section 10.2).

   These rules enable the use of location profiles not yet specified,
   while ensuring baseline interoperability.  Take, for example, this
   scenario.  Client X has had its firmware upgraded to support the
   uber-complex-3D location profile.  Client X sends location
   information to Server Y, which does not understand the
   uber-complex-3D location profile.  If Client X also sends location
   information using the geodetic-2D baseline profile, then Server Y
   will still be able to understand the request and provide an
   understandable response, though with location information that might
   not be as precise or expressive as desired.  This is possible because



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   both Client X and Server Y understand the baseline profile.  The
   following transaction, where the XML sent by the client is prepended
   with 'C:' and the XML sent by the server is prepended with 'S:',
   demonstrates this:


   C: <?xml version="1.0" encoding="UTF-8"?>
   C: <findService xmlns="urn:ietf:params:xml:ns:lost1"
   C:   xmlns:p2="http://www.opengis.net/gml"
   C:   recursive="true" include="uri serviceNumber">
   C:   <location
   C:     profile="urn:ietf:params:lost:location-profile:geodetic-2d">
   C:     <p2:Point id="point1" srsName="urn:ogc:def:crs:EPSG:4326">
   C:        <p2:pos>40.8089897 -73.9612492</p2:pos>
   C:     </p2:Point>
   C:   </location>
   C:   <location
   C:     profile="
   C:       urn:ietf:params:lost:location-profile:uber-complex-3d">
   C:     <p2:Point id="point1" srsName="urn:ogc:def:crs:EPSG:4326">
   C:        <p2:pos>37.775 -122.422 25</p2:pos>
   C:     </p2:Point>
   C:     <p2:Polygon srsName="urn:ogc:def::crs:EPSG::4326">
   C:       <p2:exterior>
   C:         <p2:LinearRing>
   C:           <p2:pos>40.80 -73.96 24</p2:pos>
   C:           <p2:pos>40.81 -73.95 27</p2:pos>
   C:           <p2:pos>40.80 -73.96 24</p2:pos>
   C:         </p2:LinearRing>
   C:       </p2:exterior>
   C:     </p2:Polygon>
   C:   </location>
   C:   <service>urn:service:sos.police</service>
   C: </findService>

   S: <?xml version="1.0" encoding="UTF-8"?>
   S: <findServiceResponse xmlns="urn:ietf:params:xml:ns:lost1"
   S:   xmlns:p2="http://www.opengis.net/" timeToLive="3600">
   S:   <locationProfileError
   S:     unsupportedProfiles="
   S:      urn:ietf:params:lost:location-profile:uber-complex-3d"
   S:     message="Too sophisticated for us." xml:lang="en"/>
   S:   <displayName xml:lang="en">
   S:     New York City Police Department
   S:   </displayName>
   S:   <service>urn:service:sos.police</service>
   S:   <serviceBoundary
   S:     profile="urn:ietf:params:lost:location-profile:geodetic-2d">



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   S:     <p2:Polygon srsName="urn:ogc:def::crs:EPSG::4326">
   S:     <p2:exterior>
   S:       <p2:LinearRing>
   S:         <p2:pos>40.701 -74.020</p2:pos>
   S:         <p2:pos>40.876 -73.926</p2:pos>
   S:         <p2:pos>40.797 -73.936</p2:pos>
   S:         <p2:pos>40.714 -73.984</p2:pos>
   S:         <p2:pos>40.701 -74.020</p2:pos>
   S:       </p2:LinearRing>
   S:     </p2:exterior>
   S:     </p2:Polygon>
   S:   </serviceBoundary>
   S:   <uri>sip:nypd@example.com</uri>
   S: </findServiceResponse>

     Figure 12: Example of a findServices query with baseline profile
                             interoperability

9.2.  Two Dimensional Geodetic Profile

   The geodetic-2d location profile is identified by geodetic-2d.
   Clients use this profile by placing a GML [13] <position> element
   within the <location> element.  This is defined by the 'point2D'
   pattern in the LoST schema (see Section 12).

   Servers use this profile by placing a GML [13] <Polygon> element
   within the <serviceBoundary> element.  This is defined by the
   'polygon' pattern in the LoST schema (see Section 12).

9.3.  Basic Civic Profile

   The basic-civic location profile is identified by the token 'civic'.
   Clients use this profile by placing a <civicAddress> element, defined
   in [11], within the <location> element.

   Servers use this profile by placing a <civicAddress> element, defined
   in [11], within the <serviceBoundary> element.














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10.  Error Handling

   Errors are indicated by error-specific elements.  Depending on the
   nature of the error, the error element may occur along with other
   response elements, indicating that the request was only partially
   satisfied and that not all information in the request was processed
   correctly.  Errors labeled as fatal means

10.1.  Basic Errors

   LoST defines a pattern for errors, defined as "errors" in the Relax
   NG schema.  This pattern defines a 'message' attribute containing
   human readable text and an 'xml:lang' attribute denoting the language
   of the human readable text.

   LoST defines the following elements as following this pattern:

   badRequest  The server could not parse or otherwise understand a
      request.  This is a top-level element, and is returned if the
      server did not understand the outermost LoST XML element
      identifying the request.

   serviceSubstitution  The server substituted one service for another.
      See Section 6.4.4.

10.2.  Response Errors

   LoST defines a pattern for errors that may generated by referrent
   LoST serves queried on behalf of seekers by a resolving LoST server.
   This pattern builds on the basic errors pattern (Section 10.1).  It
   also provides the option of specifying the source server using the
   'source' attribute, as well as specifying the query that caused the
   error.

   LoST defines the following elements as following this pattern:

   forbidden  The server refused to send an answer.

   notFound  The server could not find an answer to the query.

   serviceNotImplemented  The requested service is not implemented.

   internalError  The server could not satisfy a request due to
      misconfiguration or other operational and non-protocol related
      reasons.






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   serverTimeout  A time out occurred before an answer was received.

   serverError  An answer was received but it could not be parsed or
      otherwise understood.

   locationProfileError  A location profile in the query given is not
      recognized.  The element may also have an 'unsupportedProfiles'
      attribute, which contains a whitespace separated list of profile
      URNs.  See Section 9.

10.3.  Redirects

   LoST defines a pattern for redirect responses.  This pattern builds
   on the basic error pattern (Section 10.1) and includes a 'url'
   attribute indicating the LoST URL that the client should be
   contacting next.

   Currently, LoST only defines the <redirect> element along this
   pattern.
































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11.  LoST Transport

   LoST needs an underlying protocol transport mechanisms to carry
   requests and responses.  This document defines the use of LoST over
   HTTP and HTTP-over-TLS; other mechanisms are left to future
   documents.  The available transport mechanisms are determined through
   the use of the LoST U-NAPTR application.  In protocols that support
   content type indication, LoST uses the media type application/
   lost+xml.

   When using HTTP [3] and HTTP-over-TLS [5], LoST requests use the HTTP
   POST method.  All HTTP responses are applicable.  The HTTP URL is
   derived from the LoST URL via U-NAPTR application, as discussed in
   Section 5.





































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12.  Relax NG Schema

   This section provides the Relax NG schema used by LoST protocol in
   the compact form.  The verbose form is included in Appendix A.


   default namespace = "http://www.opengis.net/gml"
   namespace a = "http://relaxng.org/ns/compatibility/annotations/1.0"
   namespace ns1 = "urn:ietf:params:xml:ns:lost1"


   ##
   ##       Location-to-Service Translation Protocol (LoST)
   ##
   ##       A LoST XML instance has three request types, each with
   ##       a cooresponding response type: find service, list services,
   ##       and get service boundary.
   ##
   start =
     findService
     | listServices
     | getServiceBoundary
     | findServiceResponse
     | listServicesResponse
     | getServiceBoundaryResponse

   ##
   ##       The queries.
   ##
   div {
     findService =
       element ns1:findService {
         query,
         attribute include {
           list {
             ("uri"
              | "serviceNumber"
              | "displayName"
              | "service"
              | "valid"
              | "invalid"
              | "unchecked"
              | "serviceBoundary"
              | "serviceBoundaryReference")*
           }
           >> a:defaultValue [ "uri serviceNumber" ]
         }?
       }



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     listServices = element ns1:listServices { query }
     getServiceBoundary =
       element ns1:getServiceBoundary {
         serviceBoundaryKey, extensionPoint
       }
   }

   ##
   ##       The responses.
   ##
   div {
     findServiceResponse =
       element ns1:findServiceResponse {
         via,
         ((locationProfileError?, serviceSubstitution?, serviceResult)
          | badRequest
          | internalError
          | forbidden
          | notFound
          | serviceNotImplemented
          | serverTimeout
          | serverError
          | movedPermenantly
          | movedTemporarily
          | iterativeSearchExhausted),
         extensionPoint
       }
     listServicesResponse =
       element ns1:listServicesResponse {
         via,
         ((locationProfileError?,
           element ns1:serviceList {
             list { xsd:anyURI* }
           })),
         extensionPoint
       }
     getServiceBoundaryResponse =
       element ns1:getServiceBoundaryResponse {
         (serviceBoundary
          | badRequest
          | internalError
          | forbidden
          | notFound),
         extensionPoint
       }
   }

   ##



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   ##       A pattern common to some of the queries.
   ##
   div {
     query =
       element ns1:location { locationInformation }+,
       element ns1:service { xsd:anyURI }?,
       extensionPoint,
       attribute recursive { xsd:boolean >> a:defaultValue [ "true" ] }?
   }

   ##
   ##       Location Information
   ##
   div {
     locationInformation =
       extensionPoint+,
       attribute profile { xsd:anyURI }
   }

   ##
   ##       Service Boundary
   ##
   div {
     serviceBoundary = element ns1:serviceBoundary
       { locationInformation }+
   }

   ##
   ##       Service Boundary Key
   ##
   div {
     serviceBoundaryKey =
       attribute key {
         xsd:string { pattern = "[a-zA-Z0-9/+=]+" }
       }
   }

   ##
   ##       Via - list of places through which information flowed
   ##
   div {
     via = element ns1:via { xsd:anyURI }*
   }

   ##
   ##       Time-to-live pattern
   ##
   div {



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     timeToLive = attribute timeToLive { xsd:positiveInteger }
   }

   ##
   ##       A QName list
   ##
   div {
     qnameList = list { xsd:QName* }
   }

   ##
   ##       A location-to-service result.
   ##
   div {
     serviceResult =
       element ns1:displayName {
         xsd:string,
         attribute xml:lang { xsd:language }
       }?,
       element ns1:service { xsd:anyURI }?,
       (serviceBoundary
        | element ns1:serviceBoundaryReference { serviceBoundaryKey })?,
       element ns1:uri { xsd:anyURI }*,
       element ns1:serviceNumber {
         xsd:string { pattern = "[0-9]+" }
       }?,
       element ns1:valid { qnameList }?,
       element ns1:invalid { qnameList }?,
       element ns1:unchecked { qnameList }?,
       extensionPoint,
       timeToLive,
       message
   }

   ##
   ##       Basic Errors
   ##
   div {

     ##
     ##         Error pattern.
     ##
     error = message, extensionPoint
     badRequest = element ns1:badRequest { error }
     internalError = element ns1:internalError { error }
     serviceSubstitution = element ns1:serviceSubstitution { error }
   }




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   ##
   ##       Recursion Errors.
   ##
   div {

     ##
     ##         Recursion error.
     ##
     recursionError =
       attribute failedReferral { xsd:anyURI }?,
       (findService | listServices | getServiceBoundary)?,
       error
     forbidden =
       element ns1:forbidden { recursionError },
       timeToLive
     notFound =
       element ns1:notFound { recursionError },
       timeToLive
     serviceNotImplemented =
       element ns1:serviceNotImplemented { recursionError },
       timeToLive
     serverTimeout =
       element ns1:serverTimeout { recursionError },
       timeToLive
     serverError =
       element ns1:serverError { recursionError },
       timeToLive
     locationProfileError =
       element ns1:locationProfileError {
         attribute unsupportedProfiles {
           list { xsd:anyURI* }
         },
         recursionError
       }
   }

   ##
   ##       Redirects.
   ##
   div {

     ##
     ##         Redirect pattern
     ##
     redirect =
       attribute redirect { xsd:anyURI },
       error
     movedPermenantly = element ns1:movedPermanently { redirect }



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     movedTemporarily =
       element ns1:movedTemporarily { redirect },
       timeToLive
     iterativeSearchExhausted =
       element ns1:iterativeSearchExhausted { redirect },
       timeToLive
   }

   ##
   ##       Message pattern.
   ##
   div {
     message =
       (attribute message { xsd:string },
        attribute xml:lang { xsd:language })?
   }

   ##
   ##       Patterns for inclusion of elements from schemas in
   ##       other namespaces.
   ##
   div {

     ##
     ##         Any element not in the LoST namespace.
     ##
     notLost = element * - (ns1:* | ns1:*) { anyElement }

     ##
     ##         A wildcard pattern for including any element
     ##         from any other namespace.
     ##
     anyElement =
       (element * { anyElement }
        | attribute * { text }
        | text)*

     ##
     ##         A point where future extensions
     ##         (elements from other namespaces)
     ##         can be added.
     ##
     extensionPoint = notLost*

     ##
     ##         A 2D point from GML.
     ##
     point2d =



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       element position {
         element Point {
           attribute srsName { "urn:ogc:def:crs:EPSG:4326" },
           element pos { text }
         }
       }

     ##
     ##         A Linear Ring from GML.
     ##
     linearRing =
       element LinearRing {
         element pos { text }
       }

     ##
     ##         A Polygon from GML.
     ##
     polygon =
       element Polygon {
         attribute srsName { "urn:ogc:def:crs:EPSG:4979" },
         element exterior { linearRing },
         element interior { linearRing }*
       }
   }


























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13.  Internationalization Considerations

   This mechanism is largely for passing protocol information from one
   subsystem to another; as such, most of its elements are tokens not
   meant for direct human consumption.  If these tokens are presented to
   the end user, some localization may need to occur.  The content of
   the <displayName> element and the 'message' attributes may be
   displayed to the end user, and they are thus a complex types designed
   for this purpose.

   LoST exchanges information using XML.  All XML processors are
   required to understand UTF-8 and UTF-16 encodings, and therefore all
   LoST clients and servers MUST understand UTF-8 and UTF-16 encoded
   XML.  Additionally, LoST servers and clients MUST NOT encode XML with
   encodings other than UTF-8 or UTF-16.




































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14.  IANA Considerations

14.1.  U-NAPTR Registrations

   This document registers the following U-NAPTR application service
   tag:

   Application Service Tag:  LoST

   Defining Publication:  The specification contained within this
      document.

   This document registers the following U-NAPTR application protocol
   tags:

   o

      Application Protocol Tag:  http

      Defining Publication:  RFC 2616 [3]

   o

      Application Protocol Tag:  https

      Defining Publication:  RFC 2818 [5]

14.2.  Content-type registration for 'application/lost+xml'

   This specification requests the registration of a new MIME type
   according to the procedures of RFC 4288 [9] and guidelines in RFC
   3023 [6].

   MIME media type name:  application


   MIME subtype name:  lost+xml


   Mandatory parameters:  none


   Optional parameters:  charset

      Indicates the character encoding of enclosed XML.






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   Encoding considerations:

      Uses XML, which can employ 8-bit characters, depending on the
      character encoding used.  See RFC 3023 [6], Section 3.2.


   Security considerations:

      This content type is designed to carry LoST protocol payloads.


   Interoperability considerations:  None


   Published specification:  RFCXXXX [NOTE TO IANA/RFC-EDITOR: Please
      replace XXXX with the RFC number of this specification.] this
      document


   Applications which use this media type:

      Emergency and Location-based Systems


   Additional information:

      Magic Number:  None


      File Extension:  .lostxml


      Macintosh file type code:  'TEXT'


   Personal and email address for further information:  Hannes
      Tschofenig, Hannes.Tschofenig@siemens.com


   Intended usage:  LIMITED USE


   Author:

      This specification is a work item of the IETF ECRIT working group,
      with mailing list address <ecrit@ietf.org>.





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   Change controller:

      The IESG <iesg@ietf.org>

14.3.  LoST Relax NG Schema Registration

   URI:  urn:ietf:params:xml:ns:lost

   Registrant Contact:  IETF ECRIT Working Group, Hannes Tschofenig
      (Hannes.Tschofenig@siemens.com).

   Relax NG Schema:  The Relax NG schema to be registered is contained
      in Section 12.  Its first line is

   default namespace = "urn:ietf:params:xml:ns:lost1"

      and its last line is

   }

14.4.  LoST Namespace Registration

   URI:  urn:ietf:params:xml:ns:lost

   Registrant Contact:  IETF ECRIT Working Group, Hannes Tschofenig
      (Hannes.Tschofenig@siemens.com).

   XML:

   BEGIN
   <?xml version="1.0"?>
   <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.0//EN"
     "http://www.w3.org/TR/xhtml-basic/xhtml-basic10.dtd">
   <html xmlns="http://www.w3.org/1999/xhtml">
   <head>
     <meta http-equiv="content-type"
           content="text/html;charset=iso-8859-1"/>
     <title>LoST Namespace</title>
   </head>
   <body>
     <h1>Namespace for LoST</h1>
     <h2>urn:ietf:params:xml:ns:lost</h2>
   <p>See <a href="[URL of published RFC]">RFCXXXX
       [NOTE TO IANA/RFC-EDITOR:
        Please replace XXXX with the RFC number of this
       specification.]</a>.</p>
   </body>
   </html>



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   END

14.5.  Registration Template

   This registration template is in accordance with [4].

   URL scheme name:

      lost


   URL scheme syntax:

      See Section 5


   Character encoding considerations:

      See Section 5


   Intended Use:

      The intended usage is described in this document.


   Application and protocols which use this scheme:

      The usage of the LoST URL scheme is targeted for this document and
      hence for location-based services that make use of the mapping
      protocol specified in this document.


   Interoperability considerations:

      None


   Security considerations:

      See Section 15


   Relevant publications:

      This document provides the relevant context for this URL scheme.





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   Contact:

      Hannes Tschofenig, Hannes.Tschofenig@siemens.com


   Author/Change controller:

      The IESG <iesg@ietf.org>


14.6.  LoST Location Profile Registry

   This document seeks to create a registry of location profile names
   for the LoST protocol.  Profile names are XML tokens.  This registry
   will operate in accordance with RFC 2434 [2], Standards Action.

   geodetic-2d:  Defined in TBD

   civic:  Defined in TBD
































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15.  Security Considerations

   There are multiple threats to the overall system of which service
   mapping forms a part.  An attacker that can obtain service contact
   URIs can use those URIs to attempt to disrupt those services.  An
   attacker that can prevent the lookup of contact URIs can impair the
   reachability of such services.  An attacker that can eavesdrop on the
   communication requesting this lookup can surmise the existence of an
   emergency and possibly its nature, and may be able to use this to
   launch a physical attack on the caller.

   To avoid that an attacker can modify the query or its result, the use
   of channels security, such as TLS, is RECOMMENDED.

   A more detailed description of threats and security requirements are
   provided in [17].



































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16.  Acknowledgments

   [Editor's Note: Names need to be added here.  Forgot it...Sorry.]
















































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17.  Open Issues

   Please find open issues at: http://www.ietf-ecrit.org:8080/lost/
















































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18.  References

18.1.  Normative References

   [1]   Bradner, S., "Key words for use in RFCs to Indicate Requirement
         Levels", BCP 14, RFC 2119, March 1997.

   [2]   Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
         Considerations Section in RFCs", BCP 26, RFC 2434,
         October 1998.

   [3]   Fielding, R., Gettys, J., Mogul, J., Frystyk, H., Masinter, L.,
         Leach, P., and T. Berners-Lee, "Hypertext Transfer Protocol --
         HTTP/1.1", RFC 2616, June 1999.

   [4]   Petke, R. and I. King, "Registration Procedures for URL Scheme
         Names", BCP 35, RFC 2717, November 1999.

   [5]   Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.

   [6]   Murata, M., St. Laurent, S., and D. Kohn, "XML Media Types",
         RFC 3023, January 2001.

   [7]   Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
         Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986,
         January 2005.

   [8]   Peterson, J., "A Presence-based GEOPRIV Location Object
         Format", RFC 4119, December 2005.

   [9]   Freed, N. and J. Klensin, "Media Type Specifications and
         Registration Procedures", BCP 13, RFC 4288, December 2005.

   [10]  Schulzrinne, H., "A Uniform Resource Name (URN) for Services",
         draft-ietf-ecrit-service-urn-05 (work in progress),
         August 2006.

   [11]  Thomson, M. and J. Winterbottom, "Revised Civic Location Format
         for PIDF-LO", draft-ietf-geopriv-revised-civic-lo-04 (work in
         progress), September 2006.

   [12]  Daigle, L., "Domain-based Application Service Location Using
         URIs and the Dynamic  Delegation Discovery Service (DDDS)",
         draft-daigle-unaptr-00 (work in progress), June 2006.

   [13]  OpenGIS, "Open Geography Markup Language (GML) Implementation
         Specification", OGC OGC 02-023r4, January 2003.




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18.2.  Informative References

   [14]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A.,
         Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP:
         Session Initiation Protocol", RFC 3261, June 2002.

   [15]  Saint-Andre, P., Ed., "Extensible Messaging and Presence
         Protocol (XMPP): Instant Messaging and Presence", RFC 3921,
         October 2004.

   [16]  Schulzrinne, H., "The tel URI for Telephone Numbers", RFC 3966,
         December 2004.

   [17]  Taylor, T., "Security Threats and Requirements for Emergency
         Call Marking and Mapping", draft-ietf-ecrit-security-threats-03
         (work in progress), July 2006.

   [18]  Schulzrinne, H. and R. Marshall, "Requirements for Emergency
         Context Resolution with Internet Technologies",
         draft-ietf-ecrit-requirements-12 (work in progress),
         August 2006.

   [19]  Schulzrinne, H., "Location-to-URL Mapping Architecture and
         Framework", draft-ietf-ecrit-mapping-arch-00 (work in
         progress), August 2006.

   [20]  Rosen, B. and J. Polk, "Best Current Practice for
         Communications Services in support of Emergency Calling",
         draft-ietf-ecrit-phonebcp-00 (work in progress), October 2006.






















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Appendix A.  Non-Normative RELAX NG Schema in XML Syntax


   <?xml version="1.0" encoding="UTF-8"?>
   <grammar ns="urn:ietf:params:xml:ns:lost1"
     xmlns="http://relaxng.org/ns/structure/1.0"
     xmlns:a="http://relaxng.org/ns/compatibility/annotations/1.0"
     datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes">

     <start>
       <a:documentation>
         Location-to-Service Translation Protocol (LoST)

         A LoST XML instance has three request types, each with
         a cooresponding response type: find service, list services,
         and get service boundary.
       </a:documentation>
       <choice>
         <ref name="findService" />
         <ref name="listServices" />
         <ref name="getServiceBoundary" />
         <ref name="findServiceResponse" />
         <ref name="listServicesResponse" />
         <ref name="getServiceBoundaryResponse" />
       </choice>
     </start>

     <div>
       <a:documentation>
         The queries.
       </a:documentation>

       <define name="findService">
         <element name="findService">
           <ref name="query" />
           <optional>
             <attribute name="include">
               <list>
                 <zeroOrMore>
                   <choice>
                     <value>uri</value>
                     <value>serviceNumber</value>
                     <value>displayName</value>
                     <value>service</value>
                     <value>valid</value>
                     <value>invalid</value>
                     <value>unchecked</value>
                     <value>serviceBoundary</value>



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                     <value>serviceBoundaryReference</value>
                   </choice>
                 </zeroOrMore>
               </list>
               <a:defaultValue>uri serviceNumber</a:defaultValue>
             </attribute>
           </optional>
         </element>
       </define>

       <define name="listServices">
         <element name="listServices">
           <ref name="query" />
         </element>
       </define>

       <define name="getServiceBoundary">
         <element name="getServiceBoundary">
           <ref name="serviceBoundaryKey" />
           <ref name="extensionPoint" />
         </element>
       </define>

     </div>

     <div>
       <a:documentation>
         The responses.
       </a:documentation>


       <define name="findServiceResponse">
         <element name="findServiceResponse ">
           <ref name="via" />
           <choice>
             <group>
               <optional>
                 <ref name="locationProfileError"/>
               </optional>
               <optional>
                 <ref name="serviceSubstitution"/>
               </optional>
               <ref name="serviceResult" />
             </group>
             <ref name="badRequest"/>
             <ref name="internalError"/>
             <ref name="forbidden"/>
             <ref name="notFound"/>



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             <ref name="serviceNotImplemented"/>
             <ref name="serverTimeout"/>
             <ref name="serverError"/>
             <ref name="movedPermenantly"/>
             <ref name="movedTemporarily"/>
             <ref name="iterativeSearchExhausted"/>
           </choice>
           <ref name="extensionPoint" />
         </element>
       </define>


       <define name="listServicesResponse">
         <element name="listServicesResponse">
           <ref name="via" />
           <choice>
             <group>
               <optional>
                 <ref name="locationProfileError"/>
               </optional>
               <element name="serviceList">
                 <list>
                   <zeroOrMore>
                     <data type="anyURI" />
                   </zeroOrMore>
                 </list>
               </element>
             </group>
           </choice>
           <ref name="extensionPoint" />
         </element>
       </define>

       <define name="getServiceBoundaryResponse">
         <element name="getServiceBoundaryResponse">
           <choice>
             <group>
               <ref name="serviceBoundary"/>
             </group>
             <ref name="badRequest"/>
             <ref name="internalError"/>
             <ref name="forbidden"/>
             <ref name="notFound"/>
           </choice>
           <ref name="extensionPoint" />
         </element>
       </define>




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     </div>

     <div>
       <a:documentation>
         A pattern common to some of the queries.
       </a:documentation>

       <define name="query">
         <oneOrMore>
           <element name="location">
             <ref name="locationInformation" />
           </element>
         </oneOrMore>
         <optional>
           <element name="service">
             <data type="anyURI"/>
           </element>
         </optional>
         <ref name="extensionPoint" />
         <optional>
           <attribute name="recursive">
             <data type="boolean" />
               <a:defaultValue>true</a:defaultValue>
           </attribute>
         </optional>
       </define>

     </div>

     <div>
       <a:documentation>
         Location Information
       </a:documentation>

       <define name="locationInformation">
         <oneOrMore>
           <ref name="extensionPoint"/>
         </oneOrMore>
         <attribute name="profile">
           <data type="anyURI" />
         </attribute>
       </define>
     </div>

     <div>
       <a:documentation>
         Service Boundary
       </a:documentation>



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       <define name="serviceBoundary">
         <oneOrMore>
           <element name="serviceBoundary">
             <ref name="locationInformation" />
           </element>
         </oneOrMore>
       </define>
     </div>

     <div>
       <a:documentation>
         Service Boundary Key
       </a:documentation>

       <define name="serviceBoundaryKey">
         <attribute name="key">
           <data type="string">
             <param name="pattern">[a-zA-Z0-9/+=]+</param>
           </data>
         </attribute>
       </define>
     </div>

     <div>
       <a:documentation>
         Via - list of places through which information flowed
       </a:documentation>

       <define name="via">
         <zeroOrMore>
           <element name="via">
             <data type="anyURI"/>
           </element>
         </zeroOrMore>
       </define>
     </div>

     <div>
       <a:documentation>
         Time-to-live pattern
       </a:documentation>

       <define name="timeToLive">
         <attribute name="timeToLive">
           <data type="positiveInteger"/>
         </attribute>
       </define>
     </div>



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     <div>
       <a:documentation>
         A QName list
       </a:documentation>

       <define name="qnameList">
         <list>
           <zeroOrMore>
             <data type="QName"/>
           </zeroOrMore>
         </list>
       </define>
     </div>

     <div>
       <a:documentation>
         A location-to-service result.
       </a:documentation>

       <define name="serviceResult">
         <optional>
           <element name="displayName">
             <data type="string"/>
             <attribute name="xml:lang">
               <data type="language"/>
             </attribute>
           </element>
         </optional>
         <optional>
           <element name="service">
             <data type="anyURI"/>
           </element>
         </optional>
         <optional>
           <choice>
             <ref name="serviceBoundary"/>
             <element name="serviceBoundaryReference">
               <ref name="serviceBoundaryKey"/>
             </element>
           </choice>
         </optional>
         <zeroOrMore>
           <element name="uri">
             <data type="anyURI"/>
           </element>
         </zeroOrMore>
         <optional>
           <element name="serviceNumber">



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             <data type="string">
               <param name="pattern">[0-9]+</param>
             </data>
           </element>
         </optional>
         <optional>
           <element name="valid">
             <ref name="qnameList" />
           </element>
         </optional>
         <optional>
           <element name="invalid">
             <ref name="qnameList" />
           </element>
         </optional>
         <optional>
           <element name="unchecked">
             <ref name="qnameList" />
           </element>
         </optional>
         <ref name="extensionPoint"/>
         <ref name="timeToLive"/>
         <ref name="message"/>
       </define>

     </div>

     <div>
       <a:documentation>
         Basic Errors
       </a:documentation>

       <define name="error">
         <a:documentation>
           Error pattern.
         </a:documentation>
         <ref name="message"/>
         <ref name="extensionPoint" />
       </define>

       <define name="badRequest">
         <element name="badRequest">
           <ref name="error"/>
         </element>
       </define>

       <define name="internalError">
         <element name="internalError">



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           <ref name="error"/>
         </element>
       </define>

       <define name="serviceSubstitution">
         <element name="serviceSubstitution">
           <ref name="error"/>
         </element>
       </define>

     </div>

     <div>
       <a:documentation>
         Recursion Errors.
       </a:documentation>

       <define name="recursionError">
         <a:documentation>
           Recursion error.
         </a:documentation>
         <optional>
           <attribute name="failedReferral">
             <data type="anyURI"/>
           </attribute>
         </optional>
         <optional>
           <choice>
             <ref name="findService" />
             <ref name="listServices" />
             <ref name="getServiceBoundary" />
           </choice>
         </optional>
         <ref name="error"/>
       </define>

       <define name="forbidden">
         <element name="forbidden">
           <ref name="recursionError"/>
         </element>
         <ref name="timeToLive"/>
       </define>

       <define name="notFound">
         <element name="notFound">
           <ref name="recursionError"/>
         </element>
         <ref name="timeToLive"/>



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       </define>

       <define name="serviceNotImplemented">
         <element name="serviceNotImplemented">
           <ref name="recursionError"/>
         </element>
         <ref name="timeToLive"/>
       </define>

       <define name="serverTimeout">
         <element name="serverTimeout">
           <ref name="recursionError"/>
         </element>
         <ref name="timeToLive"/>
       </define>

       <define name="serverError">
         <element name="serverError">
           <ref name="recursionError"/>
         </element>
         <ref name="timeToLive"/>
       </define>

       <define name="locationProfileError">
         <element name="locationProfileError">
           <attribute name="unsupportedProfiles">
             <list>
               <zeroOrMore>
                 <data type="anyURI"/>
               </zeroOrMore>
             </list>
           </attribute>
           <ref name="recursionError"/>
         </element>
       </define>

     </div>

     <div>
       <a:documentation>
         Redirects.
       </a:documentation>

       <define name="redirect">
         <a:documentation>
           Redirect pattern
         </a:documentation>
         <attribute name="redirect">



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           <data type="anyURI"/>
         </attribute>
         <ref name="error"/>
       </define>

       <define name="movedPermenantly">
         <element name="movedPermanently">
           <ref name="redirect"/>
         </element>
       </define>

       <define name="movedTemporarily">
         <element name="movedTemporarily">
           <ref name="redirect"/>
         </element>
         <ref name="timeToLive" />
       </define>

       <define name="iterativeSearchExhausted">
         <element name="iterativeSearchExhausted">
           <ref name="redirect"/>
         </element>
         <ref name="timeToLive" />
       </define>

     </div>

     <div>
       <a:documentation>
         Message pattern.
       </a:documentation>

       <define name="message">
         <optional>
           <group>
             <attribute name="message">
               <data type="string"/>
             </attribute>
             <attribute name="xml:lang">
               <data type="language"/>
             </attribute>
           </group>
         </optional>
       </define>

     </div>

     <div>



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       <a:documentation>
         Patterns for inclusion of elements from schemas in
         other namespaces.
       </a:documentation>

       <define name="notLost">
         <a:documentation>
           Any element not in the LoST namespace.
         </a:documentation>
         <element>
           <anyName>
             <except>
               <nsName ns="urn:ietf:params:xml:ns:lost1"/>
               <nsName/>
             </except>
           </anyName>
           <ref name="anyElement"/>
         </element>
       </define>


       <define name="anyElement">
         <a:documentation>
           A wildcard pattern for including any element
           from any other namespace.
         </a:documentation>
         <zeroOrMore>
           <choice>
             <element>
               <anyName/>
               <ref name="anyElement"/>
             </element>
             <attribute>
               <anyName/>
             </attribute>
             <text/>
           </choice>
         </zeroOrMore>
       </define>

       <define name="extensionPoint">
         <a:documentation>
           A point where future extensions
           (elements from other namespaces)
           can be added.
         </a:documentation>
         <zeroOrMore>
           <ref name="notLost" />



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         </zeroOrMore>
       </define>

       <define name="point2d">
         <a:documentation>
           A 2D point from GML.
         </a:documentation>
         <element name="position" ns="http://www.opengis.net/gml">
           <element name="Point">
             <attribute name="srsName">
               <value>urn:ogc:def:crs:EPSG:4326</value>
             </attribute>
             <element name="pos">
               <text/>
             </element>
           </element>
         </element>
       </define>

       <define name="linearRing">
         <a:documentation>
           A Linear Ring from GML.
         </a:documentation>
         <element name="LinearRing" ns="http://www.opengis.net/gml">
           <element name="pos">
             <text/>
           </element>
         </element>
       </define>

       <define name="polygon">
         <a:documentation>
           A Polygon from GML.
         </a:documentation>
         <element name="Polygon" ns="http://www.opengis.net/gml">
           <attribute name="srsName">
             <value>urn:ogc:def:crs:EPSG:4979</value>
           </attribute>
           <element name="exterior">
             <ref name="linearRing"/>
           </element>
           <zeroOrMore>
             <element name="interior">
               <ref name="linearRing"/>
             </element>
           </zeroOrMore>
         </element>
       </define>



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     </div>

   </grammar>
















































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Authors' Addresses

   Ted Hardie
   Qualcomm, Inc.

   Email: hardie@qualcomm.com


   Andrew Newton
   SunRocket
   8045 Leesburg Pike, Suite 300
   Vienna, VA  22182
   US

   Phone: +1 703 636 0852
   Email: andy@hxr.us


   Henning Schulzrinne
   Columbia University
   Department of Computer Science
   450 Computer Science Building
   New York, NY  10027
   US

   Phone: +1 212 939 7004
   Email: hgs+ecrit@cs.columbia.edu
   URI:   http://www.cs.columbia.edu


   Hannes Tschofenig
   Siemens
   Otto-Hahn-Ring 6
   Munich, Bavaria  81739
   Germany

   Phone: +49 89 636 40390
   Email: Hannes.Tschofenig@siemens.com
   URI:   http://www.tschofenig.com












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