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Versions: (draft-mahy-geopriv-loc-filters) 00 01 02 03 04 05 06 07 08 09 10 11 RFC 6447

GEOPRIV                                                          R. Mahy
Internet-Draft                                               Plantronics
Intended status: Standards Track                           B. Rosen, Ed.
Expires: January 28, 2010                                        NeuStar
                                                           H. Tschofenig
                                                  Nokia Siemens Networks
                                                           July 27, 2009


 A Document Format for Filtering and Reporting Location Notications in
   the Presence Information Document Format Location Object (PIDF-LO)
                 draft-ietf-geopriv-loc-filters-05.txt

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on January 28, 2010.

Copyright Notice

   Copyright (c) 2009 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.





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Abstract

   This document describes filters that limit asynchronous location
   notifications to compelling events, designed as an extension to RFC
   4661 "An XML-Based Format for Event Notification Filtering".  The
   resulting location information is conveyed in existing location
   formats wrapped in the Presence Information Document Format
   (PIDF-LO).


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Filter Definitions . . . . . . . . . . . . . . . . . . . . . .  5
     3.1.  Movement . . . . . . . . . . . . . . . . . . . . . . . . .  5
     3.2.  Speed Changes  . . . . . . . . . . . . . . . . . . . . . .  5
     3.3.  Element Value Changes  . . . . . . . . . . . . . . . . . .  6
     3.4.  Entering or Exiting a Region . . . . . . . . . . . . . . .  6
     3.5.  Location Type  . . . . . . . . . . . . . . . . . . . . . .  8
   4.  XML Schema . . . . . . . . . . . . . . . . . . . . . . . . . . 11
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . . 13
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 14
     6.1.  URN Sub-Namespace Registration for
           urn:ietf:params:xml:ns:location-filter . . . . . . . . . . 14
     6.2.  Schema Registration For location-filter  . . . . . . . . . 14
   7.  Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 16
   8.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 17
   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 18
     9.1.  Normative References . . . . . . . . . . . . . . . . . . . 18
     9.2.  Informational References . . . . . . . . . . . . . . . . . 18
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19



















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1.  Introduction

   Conveying location in PIDF-LO [RFC4119] bodies is described in
   [I-D.ietf-sip-location-conveyance].  Asynchronous notification of
   location information is unfortunately more complex since many forms
   of location are measured as a continuous gradient.  Unlike
   notifications using discret quantities, it is difficult to know when
   a change in location is large enough to warrant a notification.  The
   mechanism described in this document defines filters as an extension
   to RFC 4661 [RFC4661], which limits location notification to events
   that are of relevance to the subscriber.  These filters persist until
   they are changed with a replacement filter.

   The frequency of notifications necessary for various geographic
   location applications varies dramatically.  The subscriber should be
   able to get asynchronous notifications with appropriate frequency and
   granularity, without having to issue a large number of notifications
   that are not important to the application.

   This document defines the following as an initial list of events that
   are relevant to a subscriber:

   1.  the Target moves more than a specified distance since the last
       notification

   2.  the Target exceeds a specified speed

   3.  the Target enters or exits a region (described by a circle or a
       polygon)

   4.  one or more of the values of the specified address labels have
       changed for the location of the Target.  For example, the value
       of the <A1> civic address element has changed from 'California'
       to 'Nevada'.

   5.  the type of location information being requested.















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2.  Terminology

   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 RFC 2119 [RFC2119].














































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3.  Filter Definitions

3.1.  Movement

   The <moved> element with a value in meters indicates the minimum
   distance that the resource must have moved from the location of the
   resource when the last notification was sent in order to trigger this
   event.  The distance is measured in meters absolutely from the point
   of last notification rather than in terms of cumulative motion.  The
   <moved> element MUST only appear once as a child element of <filter>.


   <?xml version="1.0" encoding="UTF-8"?>
   <filter-set
       xmlns="urn:ietf:params:xml:ns:simple-filter"
       xmlns:ext="urn:ietf:params:xml:ns:location-filter">
       <filter id="123" uri="sip:presentity@example.com">
           <ext:moved>300</ext:moved>
       </filter>
   </filter-set>

                     Figure 1: Movement Filter Example

3.2.  Speed Changes

   Speed changes can be filtered with the help of RFC 4661 and the
   functionality provided in [I-D.singh-geopriv-pidf-lo-dynamic], which
   extends the PIDF-LO with support for spatial orientation, speed,
   heading, and acceleration.

   Figure 2 shows an example for a trigger that fires when the speed of
   the Target changes by 3 meters per second.



















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   <?xml version="1.0" encoding="UTF-8"?>
   <filter-set xmlns="urn:ietf:params:xml:ns:simple-filter">
       <ns-bindings>
           <ns-binding prefix="dyn"
               urn="urn:ietf:params:xml:schema:pidf:dynamic"/>
       </ns-bindings>
       <filter id="123" uri="sip:presentity@example.com">
           <trigger>
               <changed by="3">
                 //dyn:speed
               </changed>
           </trigger>
       </filter>
   </filter-set>

                      Figure 2: Speed Change Example

3.3.  Element Value Changes

   Changes in values, for example related to civic location information,
   can be provided by the base functionality offered with RFC 4661.
   Figure 3 shows an example where a notification is sent when the civic
   address tokens A1, A2, A3, or PC change.


   <?xml version="1.0" encoding="UTF-8"?>
   <filter-set xmlns="urn:ietf:params:xml:ns:simple-filter">
       <ns-bindings>
           <ns-binding prefix="ca"
               urn="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr"/>
       </ns-bindings>
       <filter id="123" uri="sip:presentity@example.com">
           <trigger>
               <changed>//ca:A1</changed>
               <changed>//ca:A2</changed>
               <changed>//ca:A3</changed>
               <changed>//ca:PC</changed>
           </trigger>
       </filter>
   </filter-set>

                      Figure 3: Speed Change Example

3.4.  Entering or Exiting a Region

   The <enterOrExit> condition is satisfied when the Target enters or
   exits a named 2-dimensional region described by a polygon (as defined
   in Section 5.2.2 of [RFC5491]), or a circle (as defined in Section



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   5.2.3 of [RFC5491]).

   Figure 4 shows filter examples whereby a notification is sent when
   the Target enters or exits an area described by a circle and Figure 5
   describes an area using a polygon.


   <?xml version="1.0" encoding="UTF-8"?>
   <filter-set
       xmlns="urn:ietf:params:xml:ns:simple-filter"
       xmlns:ext="urn:ietf:params:xml:ns:location-filter"
       xmlns:gml="http://www.opengis.net/gml"
       xmlns:gs="http://www.opengis.net/pidflo/1.0">

       <filter id="123" uri="sip:presentity@example.com">
           <ext:enterOrExit>
               <gs:Circle srsName="urn:ogc:def:crs:EPSG::4326">
                   <gml:pos>42.5463 -73.2512</gml:pos>
                   <gs:radius uom="urn:ogc:def:uom:EPSG::9001">
                       850.24
                   </gs:radius>
               </gs:Circle>
           </ext:enterOrExit>
       </filter>
   </filter-set>

               Figure 4: <enterOrExit> Circle Filter Example
























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   <?xml version="1.0" encoding="UTF-8"?>
   <filter-set xmlns="urn:ietf:params:xml:ns:simple-filter"
       xmlns:ext="urn:ietf:params:xml:ns:location-filter"
       xmlns:gml="http://www.opengis.net/gml">

       <filter id="123" uri="sip:presentity@example.com">
           <ext:enterOrExit>
               <gml:Polygon srsName="urn:ogc:def:crs:EPSG::4326">
                   <gml:exterior>
                       <gml:LinearRing>
                           <gml:posList>
                           43.311 -73.422 43.111 -73.322
                           43.111 -73.222 43.311 -73.122
                           43.411 -73.222 43.411 -73.322
                           43.311 -73.422
                       </gml:posList>
                       </gml:LinearRing>
                   </gml:exterior>
               </gml:Polygon>
           </ext:enterOrExit>
       </filter>
   </filter-set>

              Figure 5: <enterOrExit> Polygon Filter Example

3.5.  Location Type

   The <locationType> element MAY be included as a child element of the
   <filter> element and it contains a list of location information types
   that are requested by the subscriber.  The following list describes
   the possible values:

   any:  The Notifier SHOULD attempt to provide LI in all forms
      available to it.

   geodetic:  The Notifier SHOULD return a location by value in the form
      of a geodetic location.

   civic:  The Notifier SHOULD return a location by value in the form of
      a civic address.

   The Notifier SHOULD return the requested location type or types.  The
   location types the LIS returns also depend on the setting of the
   optional "exact" attribute.  If the 'exact' attribute is set to
   "true" then the Notifier MUST return either the requested location
   type or provide an error response.  The 'exact' attribute does not
   apply (is ignored) for a request for a location type of "any".




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   In the case of a request for specific locationType(s) and the 'exact'
   attribute is false, the Notifier MAY provide additional location
   types, or it MAY provide alternative types if the request cannot be
   satisfied for a requested location type.  The "SHOULD"-strength
   requirements on this parameter for specific location types are
   included to allow for soft-failover.

   If the <locationType> element is absent, a value of "any" MUST be
   assumed as the default.

   The Notifier SHOULD provide location in the response in the same
   order in which they were included in the "locationType" element in
   the request.  Indeed, the primary advantage of including specific
   location types in a request when the 'exact' attribute is set to
   "false" is to ensure that one receives the available locations in a
   specific order.  For example, a subscription for "civic" (with the
   'exact' attribute set to "false") could yield any of the following
   location types in the response:

   o  civic

   o  civic, geodetic

   o  geodetic (only if civic is not available)

   For the example above, if the 'exact' attribute was "true", then the
   only possible response is either a "civic" location or an error
   message.

   As stated above, the <locationType> element MAY carry the 'exact'
   attribute.  When the 'exact' attribute is set to "true", it indicates
   to the Notifier that the contents of the <locationType> element MUST
   be strictly followed.  The default value of "false" allows the
   Notifier the option of returning something beyond what is specified,
   such as a set of location URIs when only a civic location was
   requested.  A value of "true" indicates that the Notifier MUST
   provide a location of the requested type or types or MUST provide an
   error.

   The <locationType> element MAY carry another attribute, the
   'responseTime' attribute, to provide a time value indicating to the
   Notifier how long the Subscriber is prepared to wait for a response
   or a purpose for which the Subscriber needs the location.  The former
   functionality is more useful for a single SUBSCRIBE / NOTIFY
   interaction.

   In the case of emergency services, the purpose of obtaining the
   location information could be either for routing a call to the



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   appropriate Public Safety Answering Point (PSAP) or indicating the
   location to which responders should be dispatched.  The values
   defined for the purpose, "emergencyRouting" and "emergencyDispatch",
   will likely be governed by jurisdictional policies, and should be
   configurable on the Notifier.

   The time value in the 'responseTime' attribute is expressed as a non-
   negative integer in units of milliseconds.  The time value is
   indicative only and the Notifier is under no obligation to strictly
   adhere to the time limit implied; any enforcement of the time limit
   is left to the requesting Subscriber.  The Notifier provides the most
   accurate location information that can be determined within the
   specified interval for the specific service.

   The Notifier may use the value of the time in the 'responseTime'
   attribute as input when selecting the method of location
   determination, where multiple such methods exist.  If the
   'responseTime' attribute is absent, then the Notifier should return
   the most precise location information it is capable of determining,
   with the time interval being implementation dependent.

   An example is shown in Figure 6 that utilizes the <locationType>
   element with the 'exact' and the 'responseTime' attribute.


 <?xml version="1.0" encoding="UTF-8"?>
 <filter-set
     xmlns="urn:ietf:params:xml:ns:simple-filter"
     xmlns:ext="urn:ietf:params:xml:ns:location-filter">
     <filter id="123" uri="sip:presentity@example.com">
         <ext:locationType exact="true" responseTime="emergencyRouting">
               geodetic
         </ext:locationType>
     </filter>
 </filter-set>

                  Figure 6: <locationType> Filter Example














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4.  XML Schema


  <?xml version="1.0" encoding="UTF-8"?>
  <xs:schema
      targetNamespace="urn:ietf:params:xml:ns:location-filter"
      xmlns:filter="urn:ietf:params:xml:ns:location-filter"
      xmlns:xs="http://www.w3.org/2001/XMLSchema"
      xmlns:gml="http://www.opengis.net/gml">

      <!-- These elements are child elements of the RFC 4661
           <filter> element.
      -->

      <xs:element name="enterOrExit" type="gml:GeometryPropertyType"/>

      <xs:element name="moved" type="filter:movedType"/>

      <xs:complexType name="movedType">
         <xs:simpleContent>
            <xs:extension base="xs:double">
              <xs:anyAttribute namespace="##any" processContents="lax"/>
            </xs:extension>
         </xs:simpleContent>
      </xs:complexType>

      <xs:element name="locationType" type="filter:locationTypeType"/>

      <xs:simpleType name="locationTypeBase">
          <xs:union>
              <xs:simpleType>
                  <xs:restriction base="xs:token">
                      <xs:enumeration value="any"/>
                  </xs:restriction>
              </xs:simpleType>
              <xs:simpleType>
                  <xs:restriction base="filter:locationTypeList">
                      <xs:minLength value="1"/>
                  </xs:restriction>
              </xs:simpleType>
          </xs:union>
      </xs:simpleType>

      <xs:simpleType name="locationTypeList">
          <xs:list>
              <xs:simpleType>
                  <xs:restriction base="xs:token">
                      <xs:enumeration value="civic"/>



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                      <xs:enumeration value="geodetic"/>
                  </xs:restriction>
              </xs:simpleType>
          </xs:list>
      </xs:simpleType>

      <xs:complexType name="locationTypeType">
          <xs:simpleContent>
              <xs:extension base="filter:locationTypeBase">
                  <xs:attribute name="exact" type="xs:boolean"
                      use="optional" default="false"/>
                  <xs:attribute name="responseTime"
                      type="filter:responseTimeType"
                      use="optional"/>
              </xs:extension>
          </xs:simpleContent>
      </xs:complexType>

      <xs:simpleType name="responseTimeType">
          <xs:union>
              <xs:simpleType>
                  <xs:restriction base="xs:token">
                      <xs:enumeration value="emergencyRouting"/>
                      <xs:enumeration value="emergencyDispatch"/>
                  </xs:restriction>
              </xs:simpleType>
              <xs:simpleType>
                  <xs:restriction base="xs:nonNegativeInteger">
                      <xs:minInclusive value="0"/>
                  </xs:restriction>
              </xs:simpleType>
          </xs:union>
      </xs:simpleType>

  </xs:schema>

                           Figure 7: XML Schema














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5.  Security Considerations

   Location information is typically very privacy sensitive.  As such,
   notifications MUST be encrypted and integrity protected.

   Additional privacy and security considerations are discussed in
   detail in [RFC5491].












































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6.  IANA Considerations

6.1.  URN Sub-Namespace Registration for
      urn:ietf:params:xml:ns:location-filter

   This section registers a new XML namespace, as per the guidelines in
   [RFC3688].

   URI:  urn:ietf:params:xml:ns:location-filter

   Registrant Contact:  IETF, GEOPRIV working group, <geopriv@ietf.org>,
      as delegated by the IESG <iesg@ietf.org>.

   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>Location Filter Namespace</title>
   </head>
   <body>
     <h1>Namespace for PIDF-LO Location Filters</h1>
     <h2>urn:ietf:params:xml:ns:location-filter</h2>
     <p>See <a href="[[[URL of published RFC]]]">RFCXXXX</a>.</p>
   </body>
   </html>
   END


6.2.  Schema Registration For location-filter

   This specification registers a schema, as per the guidelines in
   [RFC3688].

      URI: urn:ietf:params:xml:schema:location-filter

      Registrant Contact: IETF, GEOPRIV Working Group
      (geopriv@ietf.org), as delegated by the IESG (iesg@ietf.org).







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      XML: The XML can be found as the sole content of Section 4.


















































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7.  Contributors

   We would like to thank Martin Thomson and James Polk for their
   contributions to this document.















































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8.  Acknowledgments

   Thanks to Allan Thomson, James Winterbottom, Richard Barnes and
   Alissa Cooper for their comments.















































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9.  References

9.1.  Normative References

   [GML]      OpenGIS, "Open Geography Markup Language (GML)
              Implementation Specification", OpenGIS OGC 02-023r4,
              January 2003,
              <http://www.opengis.org/techno/implementation.htm>.

   [I-D.singh-geopriv-pidf-lo-dynamic]
              Schulzrinne, H., Singh, V., Tschofenig, H., and M.
              Thomson, "Dynamic Extensions to the Presence Information
              Data Format Location Object  (PIDF-LO)",
              draft-singh-geopriv-pidf-lo-dynamic-06 (work in progress),
              June 2009.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3023]  Murata, M., St. Laurent, S., and D. Kohn, "XML Media
              Types", RFC 3023, January 2001.

   [RFC4119]  Peterson, J., "A Presence-based GEOPRIV Location Object
              Format", RFC 4119, December 2005.

   [RFC4288]  Freed, N. and J. Klensin, "Media Type Specifications and
              Registration Procedures", BCP 13, RFC 4288, December 2005.

   [RFC4661]  Khartabil, H., Leppanen, E., Lonnfors, M., and J. Costa-
              Requena, "An Extensible Markup Language (XML)-Based Format
              for Event Notification Filtering", RFC 4661,
              September 2006.

   [RFC5491]  Winterbottom, J., Thomson, M., and H. Tschofenig, "GEOPRIV
              Presence Information Data Format Location Object (PIDF-LO)
              Usage Clarification, Considerations, and Recommendations",
              RFC 5491, March 2009.

9.2.  Informational References

   [I-D.ietf-sip-location-conveyance]
              Polk, J. and B. Rosen, "Location Conveyance for the
              Session Initiation Protocol",
              draft-ietf-sip-location-conveyance-13 (work in progress),
              March 2009.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              January 2004.



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Authors' Addresses

   Rohan Mahy
   Plantronics
   345 Encincal Street
   Santa Cruz, CA
   USA

   Email: rohan@ekabal.com


   Brian Rosen (editor)
   NeuStar
   470 Conrad Dr.
   Mars, PA  16046
   US

   Phone: +1 724 382 1051
   Email: br@brianrosen.net


   Hannes Tschofenig
   Nokia Siemens Networks
   Linnoitustie 6
   Espoo  02600
   Finland

   Phone: +358 (50) 4871445
   Email: Hannes.Tschofenig@gmx.net
   URI:   http://www.tschofenig.priv.at





















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