One document matched: draft-ietf-geopriv-loc-filters-11.xml


<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type='text/xsl' href='rfc2629.xslt' ?>
<!DOCTYPE rfc SYSTEM "rfc2629.dtd" []>
<rfc category="std" ipr="trust200902" docName="draft-ietf-geopriv-loc-filters-11.txt">
  <?rfc toc="yes" ?>
  <?rfc symrefs="yes" ?>
  <?rfc sortrefs="yes"?>
  <?rfc iprnotified="no" ?>
  <?rfc strict="yes" ?>
  <front>
    <title abbrev="Location Filters">Filtering Location Notifications in the Session Initiation
      Protocol (SIP)</title>
    <author initials="R." surname="Mahy" fullname="Rohan Mahy">
      <organization>Individual</organization>
      <address>
        <postal>
          <street/>
          <city/>
          <region/>
          <country/>
        </postal>
      	<email>rohan@ekabal.com</email>
      </address>
    </author>
    <author fullname="Brian Rosen" initials="B.R" surname="Rosen">
      <organization>NeuStar</organization>
      <address>
        <postal>
          <street>470 Conrad Dr.</street>
          <city>Mars</city>
          <region>PA</region>
          <code>16046</code>
          <country>US</country>
        </postal>
        <phone>+1 724 382 1051</phone>
        <email>br@brianrosen.net</email>
      </address>
    </author>
    <author initials="H." surname="Tschofenig" fullname="Hannes Tschofenig">
      <organization>Nokia Siemens Networks</organization>
      <address>
        <postal>
          <street>Linnoitustie 6</street>
          <city>Espoo</city>
          <code>02600</code>
          <country>Finland</country>
        </postal>
        <phone>+358 (50) 4871445</phone>
        <email>Hannes.Tschofenig@gmx.net</email>
        <uri>http://www.tschofenig.priv.at</uri>
      </address>
    </author>
    <date year="2010"/>
    <area>RAI</area>
    <workgroup>GEOPRIV</workgroup>
    <keyword>I-D</keyword>
    <keyword>Internet-Draft</keyword>
    <keyword>geopriv</keyword>
    <keyword>location</keyword>
    <abstract>
      <t>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, and based on RFC 3856, the SIP presence event package. The resulting
        location information is conveyed in existing location formats wrapped in the Presence
        Information Data Format Location Object (PIDF-LO).</t>
    </abstract>
  </front>
  <middle>

    <!-- ******************************************************************************* -->

    <section anchor="introduction" title="Introduction">
      <t> Conveying location information encapsulated with a <xref target="RFC4119">Presence
        Information Data Format Location Object (PIDF-LO)</xref>
        document within SIP is described in <xref target="I-D.ietf-sipcore-location-conveyance"/>.
        An alternative signaling approach to location conveyance, which uses asynchronous communication, is available with
        the SIP event notification mechanisms (see RFC 3265 <xref target="RFC3265"/>). This document
        focuses on the event notification paradigm. Event notifications are technically more complex
        since location may be measured as a continuous gradient and unlike notifications using
        discrete-valued quantities, it is difficult to know when a change in location is large enough to
        warrant a notification. Event notifications <xref target="RFC3265"/> can be used with
        filters (see RFC 4661 <xref target="RFC4661"/>) that allow the number of notifications to
        be reduced. The mechanism described in this document defines an extension to RFC 4661 <xref
          target="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 or when the subscription itself is terminated.</t>
      <t> 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 being flooded with a large number of
        notifications that are not important to the application.</t>
      <t> This document defines a new event filters and describes others using existing mechanisms
        that may be relevant to a subscriber in the context of location filtering. Based on the functionality defined in this document notifications can be provided in the following cases: <list
          style="numbers">
          <t>the Device moves more than a specified distance since the last notification (see <xref
              target="movement"/>).</t>
          <t>the Device exceeds a specified speed (see <xref target="speed"/>).</t>
          <t>the Device enters or exits a region, described by a circle or a polygon (see <xref
              target="enter"/>).</t>
          <t>one or more of the values of the specified address labels have changed for the location
            of the Device (see <xref target="value"/>). For example, the value of the
            <A1> civic address element has changed from 'California' to 'Nevada'.</t>
          <t>the type of location information being requested (see <xref target="type"/>).</t>
          <t>a certain amount of time passes (see <xref target="rate"
          />).</t>
        </list></t>
      <t>This document builds on the presence event package <xref target="RFC3856"/>, i. e. an
        existing event package for communicating location information inside the PIDF-LO.</t>
    </section>

    <!-- ******************************************************************************* -->

    <section title="Terminology">
      <t> 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 <xref target="RFC2119">RFC 2119</xref>.</t>
      <t>This document reuses terminology from <xref target="I-D.ietf-geopriv-arch"/>.</t>
    </section>

    <!-- ******************************************************************************* -->

    <section title="Filter Definitions">
      <t>This specification builds on top of a number of other specifications, as noted in <xref
          target="introduction"/>. In order to reduce the number of options (and thereby decrease
        the chance of interoperability problems), the functionality of <xref target="RFC4661"/>
        listed in the sub-sections below MUST be implemented, namely the <ns-bindings> (see
        Section 3.3 of <xref target="RFC4661"/>), the <filter> (Section 3.4 of <xref
          target="RFC4661"/>), and the <trigger> (Section 3.6 of <xref target="RFC4661"/>
        excluding the functionality of the <added> and <removed> element). </t>

      <section anchor="movement" title="Movement">
        <t> The <moved> element MUST contain a value in meters indicates the minimum
          distance that the resource must have moved from the location of the resource since the
          last notification was sent in order to trigger this event. 
          The distance MUST be measured
          in meters absolutely from the point of last notification, and must include vertical movement. The <moved>
          element MUST NOT appear more than once as a child element of the <filter>
          element. </t>
        <t>
          <figure anchor="movement-example" title="Movement Filter Example">
            <artwork><![CDATA[
<?xml version="1.0" encoding="UTF-8"?>
<filter-set 
    xmlns="urn:ietf:params:xml:ns:simple-filter"
    xmlns:lf="urn:ietf:params:xml:ns:location-filter">
    <filter id="123" uri="sip:presentity@example.com">
        <trigger>
            <lf:moved>300</lf:moved>
        </trigger>
    </filter>
</filter-set>
    ]]></artwork>
          </figure>
        </t>
      </section>

      <section anchor="speed" title="Speed Changes">
        <t>Speed changes can be filtered by combining functionality from RFC 4661 with the PIDF-LO extensions for spatial orientation, speed, heading, and acceleration defined in
            <xref target="I-D.singh-geopriv-pidf-lo-dynamic"/>.
          The value of the 
          <speed> element from <xref target="I-D.singh-geopriv-pidf-lo-dynamic"/> MUST be
          defined in meters per second. Note that the 
          condition could be met by a change in any axis including altitude.
        </t>
        <t><xref target="speed-example"/> shows an example for a trigger that fires when the speed
          of the Target changes by 3 meters per second.</t>
        <t>
          <figure anchor="speed-example" title="Speed Change Example">
            <artwork><![CDATA[
<?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>
]]></artwork>
          </figure>
        </t>
        <t>An implementation MUST support <ns-bindings> to replace the namespace prefix. The XPath expression MUST start with a '//' followed by a single element. No other form of XPath expression 
		is supported. The
          <changed> element comes with a few attributes but only the 'by' attribute
          MUST be implemented by this specification.</t>
      </section>

      <section anchor="value" title="Element Value Changes">
        <t>Changes in values, for example related to civic location information, is provided by the
          base functionality offered with RFC 4661 utilizing the <changed> element.</t>
        <t><xref target="value-change"/> shows an example where a notification is sent when the
          civic address tokens A1, A2, A3, and PC change (all four must change in order to let the
          <trigger> element evaluate to TRUE).        </t>
        
        <t>
          <figure anchor="value-change" title="Element Value Change Example">
            <preamble>(A change in ALL four tokens triggers an event.)</preamble>
            <artwork><![CDATA[
<?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:country</changed>
            <changed>//ca:A1</changed>
            <changed>//ca:A2</changed>
            <changed>//ca:A3</changed>
            <changed>//ca:PC</changed>
        </trigger>
    </filter>
</filter-set>
]]></artwork>
          </figure>
        </t>
        <t>Note: The civic address tokens country, A1, A2, ..., A6 are hierachical. It is likely that a change in one civic address token therefore leads to changes of tokens lower in the hiearchy, e.g., a change in A3 ('city or town') may cause a change in A4, A5, and A6.</t>
        <t>
        In times where it is desirable to know if any one element of a list of CAtypes changes,
        then they have to be put into separate <changes> filters to ensure you are
          notified when any of the element values change. <xref target="value-change-individual"/>
shows such an example that illustrates the difference.</t>
        
        <t>
          <figure anchor="value-change-individual" title="Element Value Change Example">
            <preamble>(A change in value of ANY of the four tokens triggers an event.)</preamble>            
            <artwork><![CDATA[
<?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:country</changed>
           </trigger>
           <trigger>
               <changed>//ca:A1</changed>
           </trigger>
           <trigger>
               <changed>//ca:A2</changed>
           </trigger>
           <trigger>
               <changed>//ca:A3</changed>
           </trigger>
           <trigger>
               <changed>//ca:PC</changed>
           </trigger>
    </filter>
</filter-set>
]]></artwork>
          </figure>
        </t>
        <t>The following example illustrates a filter that triggers when the Target's location
          changes from 'FR' (France) to some other country.</t>
        <t>
          <figure anchor="value-change2" title="Element Value Change Example (Country Change)">
            <artwork><![CDATA[
<?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 from="FR">//ca:country</changed>
        </trigger>
    </filter>
</filter-set>
]]></artwork>
          </figure>
        </t>
		
		<t>An implementation MUST support <ns-bindings> to replace the namespace prefix. The XPath expression MUST start with a '//' followed by a single element. No other form of XPath expression 
		is supported. 
		No other variant is supported. The
          <changed> element comes with a few attributes and the 'by', 'to' and 'from'
          attribute MUST be implemented to support this specification.</t>
      </section>
      <section anchor="enter" title="Entering or Exiting a Region">
        <t> 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 <xref
            target="RFC5491"/>), or a circle (as defined in Section 5.2.3 of <xref target="RFC5491"
          />). The <enterOrExit> element MUST contain either a polygon or a circle as a child
          element. The <enterOrExit> element MUST NOT have more than one polygon
          and/or circle. </t>
        <t> If the Target was previously outside the region, the notifier sends a notification when
          the Target's location is within the region with at least 50% confidence. Similarly, when a
          Target starts within the region, a notification is sent when the Target's location moves
          outside the region with at least 50% confidence.</t>
        <t> Note that having 50% confidence that the Target is inside the area does not correspond
          to 50% outside. 
		  The confidence that the location is within the region, plus the confidence that the location is outside the region is limited to the confidence of the location.  The total confidence depends on the confidence in the location, which is always less than 100% (95% is recommended in <xref target="RFC5491"/>).
		  The benefit of this is that notifications are naturally
          limited: small movements (relative to the uncertainty of the location) at the borders of the region do not trigger notifications. </t>
        <t><xref target="containment-circle"/> shows filter examples whereby a notification is sent
          when the Target enters or exits an area described by a circle and <xref
            target="containment-polygon"/> describes an area using a polygon.</t>
        <t>
          <figure anchor="containment-circle"
            title="<enterOrExit> Circle Filter Example">
            <artwork><![CDATA[
<?xml version="1.0" encoding="UTF-8"?>
<filter-set 
    xmlns="urn:ietf:params:xml:ns:simple-filter"
    xmlns:lf="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">
        <trigger>
            <lf: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>
            </lf:enterOrExit>
        </trigger>
    </filter>
</filter-set>
              
            ]]></artwork>
          </figure>
        </t>
        <t>
          <figure anchor="containment-polygon"
            title="<enterOrExit> Polygon Filter Example">
            <artwork><![CDATA[
<?xml version="1.0" encoding="UTF-8"?>
<filter-set 
    xmlns="urn:ietf:params:xml:ns:simple-filter"
    xmlns:lf="urn:ietf:params:xml:ns:location-filter" 
    xmlns:gml="http://www.opengis.net/gml">
    
    <filter id="123" uri="sip:presentity@example.com">
        <trigger>
            <lf:enterOrExit>
                <gml:Polygon srsName="urn:ogc:def:crs:EPSG::4326">
                    <gml:exterior>
                        <gml:LinearRing>
                            <gml:pos>43.311 -73.422</gml:pos>
                            <!--A-->
                            <gml:pos>43.111 -73.322</gml:pos>
                            <!--F-->
                            <gml:pos>43.111 -73.222</gml:pos>
                            <!--E-->
                            <gml:pos>43.311 -73.122</gml:pos>
                            <!--D-->
                            <gml:pos>43.411 -73.222</gml:pos>
                            <!--C-->
                            <gml:pos>43.411 -73.322</gml:pos>
                            <!--B-->
                            <gml:pos>43.311 -73.422</gml:pos>
                            <!--A-->
                        </gml:LinearRing>
                    </gml:exterior>
                </gml:Polygon>
            </lf:enterOrExit>
        </trigger>
    </filter>
</filter-set>
            ]]></artwork>
          </figure>
        </t>
      </section>

      <section anchor="type" title="Location Type">
        <t> The <locationType> element MAY be included as a child element of the
          <what> element and it contains a list of location information types that
          are requested by the subscriber. The following list describes the possible values: </t>
        <t>
          <list style="hanging">
            <t hangText="any:">The Notifier SHOULD attempt to provide LI in all forms available to
              it.</t>
            <t hangText="geodetic:">The Notifier SHOULD return a location by value in the form of a
              geodetic location. </t>
            <t hangText="civic:">The Notifier SHOULD return a location by value in the form of a
              civic address. </t>
          </list>
        </t>
        <t> The Notifier SHOULD return the requested location type or types. The location types the
          Notifier returns also depends 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 no location information. The 'exact' attribute does not apply (is
          ignored) for a request for a location type of "any". </t>
        <t> 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.</t>
        <t>If the <locationType> element is absent, a value of "any" MUST be assumed
          as the default. </t>
        <t> 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: </t>
        <t>
          <list style="symbols">
            <t>civic</t>
            <t>civic, geodetic</t>
            <t>geodetic (only if civic is not available)</t>
          </list>
        </t>
        <t> The default value of "false" for the 'exact' attribute 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.</t>
        <t>An example is shown in <xref target="locationType"/> that utilizes the
          <locationType> element with the 'exact' and the 'responseTime' attribute. </t>
        <t>
          <figure anchor="locationType" title="<locationType> Filter Example">
            <artwork><![CDATA[
<?xml version="1.0" encoding="UTF-8"?>
<filter-set 
    xmlns="urn:ietf:params:xml:ns:simple-filter"
    xmlns:lf="urn:ietf:params:xml:ns:location-filter">
    <filter id="123" uri="sip:presentity@example.com">
        <what>
            <lf:locationType exact="true">
              geodetic
            </lf:locationType>
        </what>
    </filter>
</filter-set>
            ]]></artwork>
          </figure>
        </t>
      </section>

      <section anchor="rate" title="Rate Control">
        <t>
          <xref target="I-D.ietf-sipcore-event-rate-control"/> extends the SIP
          events framework by defining the following three "Event" header field parameters that allow a
          subscriber to set a minimum, a maximum and an average rate of event notifications
          generated by the notifier. This allows a subscriber to have overall control over the stream of notifications, for example to avoid being flooded. Two of the parameters, namely
          "min-interval" (which specifies a minimum notification time period between two
          notifications, in seconds) and "max-interval" (which specifies a maximum notification time
          period between two notifications, in seconds.) are used by this document. Only the implementation of these two 
attributes is required from the attributes defined in <xref
            target="I-D.ietf-sipcore-event-rate-control"/>. Whenever the time since the most recent
          notification exceeds the value in the "max-interval" parameter, the current state would be
          sent in its entirety, just like after a subscription refresh. </t>
        <t>
 A notifier is required to send a NOTIFY request immediately after creation of a subscription. If state is not available at that time, then the NOTIFY request may be sent with no content. 
A separate NOTIFY containing location is subsequently generated some time between the time included in 'min-interval' and the time in 'max-interval'.  An important use case 
for
          location based applications focuses on the behavior of the initial NOTIFY message(s) and
          the information it returns, for example in case of emergency call routing. When an initial
          NOTIFY is transmitted it might not include complete state. </t>
        <t>
          <figure anchor="rate-fig" title="SUBSCRIBE/NOTIFY with Rate Control">
            <artwork><![CDATA[           
Subscriber          Notifier
    |---SUBSCRIBE(1)--->|     Create subscription (w/small value
    |<-------200--------|         for min-interval and max-interval)
    |<-----NOTIFY(2)----|     Return initial notify with no state
    |--------200------->|
    |<-----NOTIFY(3)----|     Return full state (between min-interval
    |--------200------->|         and max-interval)
    |---SUBSCRIBE(4)--->|     Update subscription (to update
    |<-------200--------|         min-interval and max-interval)
	]]></artwork>
          </figure>
        </t>
        <t>
          <xref target="rate-fig"/> shows a SUBSCRIBE/NOTIFY exchange. The initial SUBSCRIBE message (1)
          has filters attached and contains a 'max-interval' rate control parameter. In certain
          situations it is important to obtain some amount of location information within a
          relatively short and pre-defined period of time even if the obtained location information
          contains a high amount of uncertainty and location information with less uncertainty at a
          later point in time. An example is emergency call routing where a emergency services
          routing proxy may need to obtain location information suitable for routing rather quickly
          and subsequently a Public Safety Answering Point requests location information for
          dispatch. </t>
        <t>To obtain location information in a timely fashion using the SUBSCRIBE/NOTIFY mechanism,
          it is RECOMMENDED that the initial SUBSCRIBE contains a 'max-interval' rate control
          parameter (with a small value) that is in a later message updated to a more sensible
          value. This provides equivalent functionality to the 'responseTime' attribute in Section 6.1 of <xref target="I-D.ietf-geopriv-http-location-delivery"/>. The 'max-interval' for this first request is therefore much lower than thereafter.
          Updating the 'max-interval' for the subscription can be performed in the 200 response (see
          message 3) to the NOTIFY that contains state. Depending on the value in the 'max-interval'
          parameter the Notifier may create a NOTIFY message (see message 2) immediately in response
          to the SUBSCRIBE that might be empty in case no location information is available at this
          point in time. The desired location information may then arrive in the subsequent NOTIFY
          message (see message 4). </t>
      </section>

    </section>

    <!-- ******************************************************************************* -->

    <section anchor="schema" title="XML Schema">
      <t>
        <figure anchor="schema-fig" title="XML Schema">
          <artwork><![CDATA[
<?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">
 
    <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"/>
                    <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:extension>
          </xs:simpleContent>
      </xs:complexType>        
</xs:schema>
            ]]></artwork>
        </figure>
      </t>

    </section>

    <!-- ******************************************************************************* -->

    <section title="Security Considerations">

      <t>This document specifies one piece, namely filters, utilized in larger system. As such, this
        document builds on a number of specifications for the security of the complete solution,
        namely </t>
      <t>
        <list style="symbols">
          <t> the SIP event notification mechanism, described in RFC 3265 <xref target="RFC3265"/>,
            defining the SUBSCRIBE/NOTIFY messages. </t>
          <t>the presence event package, described in RFC 3856 <xref target="RFC3856"/>, which is a
            concrete instantiation of the general event notification framework.</t>
          <t>the filter framework, described in RFC 4661 <xref target="RFC4661"/>, to offer the
            ability to reduce the amount of notifications being sent. </t>
        </list>
      </t>
      <t>Finally, this document indirectly (via the SIP presence event package) relies on PIDF-LO,
        described in RFC 4119 <xref target="RFC4119"/>, as the XML container that carries location
        information.</t>
      <t>Each of these documents listed above comes with a security consideration section but the
        security and privacy aspects are best covered by the SIP presence event package, see Section
        9 of <xref target="RFC3856"/>, and with the GEOPRIV architectural description found in <xref
          target="I-D.ietf-geopriv-arch"/>.</t>

      <t>The functionality offered by authorization policies to limit access to location information
        are provided by other protocols, such Common Policy <xref target="RFC4745"/>, Geolocation
        Policy <xref target="I-D.ietf-geopriv-policy"/> or more recent work around HELD context
          <xref target="I-D.winterbottom-geopriv-held-context"/>. Although <xref
          target="I-D.ietf-geopriv-policy"/> defines a standardized format for geolocation
        authorization policies it does not define specific policies for controlling filters.</t>
      <t> The functionality described in this document extends the filter framework with location
        specific filters. Local policies might be associated with the usage of certain filter
        constructs and with the amount of notifications specific filter settings might cause.
        Uploading filters have a significant effect on the ways in which the request is handled at a
        server. As a result, it is especially important that messages containing this extension be
        authenticated and authorised. RFC 4661 <xref target="RFC4661"/> discusses this security
        threat and proposed authentication and authorization solutions applicable by this
        specification. </t>
    </section>

    <!-- ******************************************************************************* -->

    <section title="IANA Considerations">

      <section title="URN Sub-Namespace Registration for
urn:ietf:params:xml:ns:location-filter">
        <t> This section registers a new XML namespace, as per the guidelines in <xref
            target="RFC3688"/>. </t>
        <t>
          <list style="hanging">
            <t hangText="URI:"> urn:ietf:params:xml:ns:location-filter</t>
            <t hangText="Registrant Contact:"> IETF, GEOPRIV working group,
              <geopriv@ietf.org>, as delegated by the IESG
              <iesg@ietf.org>. </t>
            <t hangText="XML:">
              <figure>
                <artwork>
                  <![CDATA[
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
]]>
                </artwork>
              </figure>
            </t>
          </list>
        </t>
      </section>


      <section title="Schema Registration For location-filter">
        <t>This specification registers a schema, as per the guidelines in <xref target="RFC3688"/>.</t>
        <t>
          <list style="hanging">
            <t>URI: urn:ietf:params:xml:schema:location-filter</t>
            <t>Registrant Contact: IETF, GEOPRIV Working Group (geopriv@ietf.org), as delegated by
              the IESG (iesg@ietf.org).</t>
            <t>XML: The XML can be found as the sole content of <xref target="schema"/>.</t>
          </list>
        </t>
      </section>

    </section>

    <!-- ******************************************************************************* -->

    <section title="Contributors">
      <t>We would like to thank Martin Thomson and James Polk for their contributions to this
        document. </t>
    </section>

    <!-- ******************************************************************************* -->

    <section title="Acknowledgments">
      <t> Thanks to Richard Barnes and Alissa Cooper, Randall Gellens, Carl Reed, Ben Campbell, Adam Roach, Allan Thomson, James
        Winterbottom for their comments.</t>
      
      <t>Furthermore, we would like to thank Alexey Melnikov for his IESG review comments.</t>
    </section>

    <!-- ******************************************************************************* -->

  </middle>

  <back>
    <references title="Normative References">
      <?rfc include="reference.RFC.2119" ?>
      <?rfc include="reference.RFC.4119" ?>
      <?rfc include="reference.RFC.4661" ?>
      <?rfc include="reference.RFC.3265" ?>
      <?rfc include="reference.RFC.3856" ?>
      <?rfc include="reference.RFC.5491" ?>
	  <?rfc include="reference.I-D.ietf-geopriv-arch" ?>
      <?rfc include="reference.I-D.ietf-sipcore-event-rate-control" ?>
      <?rfc include="reference.I-D.singh-geopriv-pidf-lo-dynamic" ?>
      <reference anchor="GML" target="http://www.opengis.org/techno/implementation.htm">
        <front>
          <title>Open Geography Markup Language (GML) Implementation Specification</title>
          <author>
            <organization> OpenGIS </organization>
          </author>
          <date month="January" year="2003"/>
        </front>
        <seriesInfo name="OpenGIS" value="OGC 02-023r4"/>
      </reference>
    </references>
    <references title="Informational References">
      <?rfc include="reference.RFC.3688" ?>
      <?rfc include="reference.RFC.4745" ?>
      <?rfc include="reference.I-D.ietf-geopriv-policy" ?>
      <?rfc include="reference.I-D.ietf-sipcore-location-conveyance" ?>
      <?rfc include="reference.I-D.winterbottom-geopriv-held-context" ?>
	  <?rfc include="reference.I-D.ietf-geopriv-http-location-delivery" ?>
    </references>
  </back>
</rfc>

PAFTECH AB 2003-20262026-04-21 21:25:46