A NOTIFY is not sent to the subscriber in this case.

   Now, a third PIDF document is created when the IM status changes to
   "open":

   <?xml version="1.0" encoding="UTF-8"?>
      <presence xmlns="urn:ietf:params:xml:ns:pidf"
      xmlns:rpid="urn:ietf:params:xml:ns:pidf:rpid"
      entity="sip:presentity@example.com">
         <tuple id="432sd">
            <status>
               <basic>open</basic>
            </status>
            <rpid:class>IM</rpid:class>
            <contact>im:presentity@example.com</contact>
         </tuple>
         <tuple id="thr76jk">
            <status>
               <basic>closed</basic>
            </status>



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            <rpid:class>voice</rpid:class>
            <contact>tel:2224055555@example.com</contact>
         </tuple>
      </presence>

   Notification containing both tuples is sent to the subscriber in this
   case:

   NOTIFY sip:watcher@client.example.com SIP/2.0
   Via: SIP/2.0/TCP presence.example.com:5060;branch=z9hG4bKxjfder
   To: <sip:watcher@example.com>;tag:12341111
   From: <sip:presentity@example.com>;tag:232321
   Call-ID: 32432udfidfjmk342
   Cseq: 1 NOTIFY
   Event: Presence
   Subscription-State: active; expires=3599
   Contact: sip:presentity@server.example.com
   Content-Type: application/pidf+xml
   Content-Length: ...

   <?xml version="1.0" encoding="UTF-8"?>
      <presence xmlns="urn:ietf:params:xml:ns:pidf"
      xmlns:rpid="urn:ietf:params:xml:ns:pidf:rpid"
      entity="sip:presentity@example.com">
         <tuple id="432sd">
            <status>
               <basic>closed</basic>
            </status>
            <rpid:class>IM</rpid:class>
            <contact>im:presentity@example.com</contact>
         </tuple>
         <tuple id="thr76jk">
            <status>
               <basic>open</basic>
            </status>
            <rpid:class>voice</rpid:class>
            <contact>tel:2224055555@example.com</contact>
         </tuple>
      </presence>












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7.2.  Watcher Information Specific Examples

   The examples in this section use the winfo template-package with the
   presence event package [10].

   Watcher information to a Presentity:

      <?xml version="1.0"?>
        <watcherinfo xmlns="urn:ietf:params:xml:ns:watcherinfo"
      version="0" state="full">
        <watcher-list resource="sip:presentity@example.com"
                      package="presence">
            <watcher status="active"
               id="sr8fdsj"
               duration-subscribed="509"
               expiration="20"
               event="approved">sip:watcherA@example.com"</watcher>
            <watcher status="pending"
               id="sr8fdsj"
               duration-subscribed="501"
               expiration="100"
               event="subscribe">sip:watcherB@example.com"</watcher>
            <watcher status="terminated"
               id="sr8fdsj"
               duration-subscribed="500"
               expiration="0"
               event="rejected">sip:watcherC@example.com"</watcher>
            <watcher status="active"
               id="sr8fdsj"
               duration-subscribed="20"
               expiration="30"
               event="approved">sip:watcherD@example.com"</watcher>
        </watcher-list>
        </watcherinfo>

















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7.2.1.  Watcher Subscriber Makes Subscription to Get All the Information
        about Active Watchers

   SUBSCRIBE request from the presentity including the filter:

   SUBSCRIBE sip:presentity@example.com
   Via: SIP/2.0/TCP client.example.com:5060;branch=z9hG4bKxjfdsjfk
   To: <sip:presentity@example.com>
   From: <sip:presentity@example.com>;tag:12341111
   Call-ID: 32432udfidfjmk342
   Cseq: 1 SUBSCRIBE
   Expires: 3600
   Event: Presence.winfo
   Contact: sip:presentity@client.example.com
   Content-Type: application/simple-filter+xml
   Content-Length: ...

   <?xml version="1.0" encoding="UTF-8"?>
   <filter-set xmlns="urn:ietf:params:xml:ns:simple-filter">
     <ns-bindings>
       <ns-binding prefix="wi"
                          urn="urn:ietf:params:xml:ns:watcherinfo"/>
     </ns-bindings>
     <filter id="123" uri="sip:presentity@example.com">
       <what>
         <include>
           /wi:watcherinfo/wi:watcher-list[@package="presence"]/
           wi:watcher[@status="active"]
         </include>
   </what>
   </filter>
   </filter-set>

   Notification to the subscriber:

   NOTIFY sip:presentity@client.example.com SIP/2.0
   Via: SIP/2.0/TCP presence.example.com:5060;branch=z9hG4bKxjfder
   To: sip:presentity@example.com;tag:12341111
   From: sip:presentity@example.com;tag:232321
   Call-ID: 32432udfidfjmk342
   Cseq: 1 NOTIFY
   Contact: sip:presentity@server.example.com
   Event: Presence.winfo

   Content-Type: application/watcherinfo+xml
   Content-Length: ...





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   <?xml version="1.0"?>
     <watcherinfo xmlns="urn:ietf:params:xml:ns:watcherinfo"
   version="0" state="full">
     <watcher-list resource="sip:presentity@example.com"
                   package="presence">
         <watcher status="active"
            id="sr8fdsj"
            duration-subscribed="509"
            expiration="20"
            event="approved">sip:watcherA@example.com"</watcher>
         <watcher status="active"
            id="sr8fdsj"
            duration-subscribed="20"
            expiration="30"
            event="approved">sip:watcherD@example.com"</watcher>
     </watcher-list>
     </watcherinfo>

7.2.2.  Watcher Subscriber Requests Information of Watchers with
        Specific Subscription Duration Conditions

   SUBSCRIBE request from the presentity including the filter:

   SUBSCRIBE sip:presentity@example.com
   Via: SIP/2.0/TCP client.example.com:5060;branch=z9hG4bKxjfdsjfk
   To: <sip:presentity@example.com>;tag:12341111
   From: <sip:presentity@example.com>
   Call-ID: 32432udfidfjmk342
   Cseq: 1 SUBSCRIBE
   Expires: 0
   Event: Presence.winfo
   Contact: <sip:presentity@client.example.com>
   Content-Type: application/simple-filter+xml
   Content-Length: ...

   <?xml version="1.0" encoding="UTF-8"?>
   <filter-set xmlns="urn:ietf:params:xml:ns:simple-filter">
     <ns-bindings>
       <ns-binding prefix="wi"
                          urn="urn:ietf:params:xml:ns:watcherinfo"/>
     </ns-bindings>
     <filter id="123" uri="sip:presentity@example.com">
       <what>
         <include>
           /wi:watcherinfo/wi:watcher-list[@package="presence"]/
           wi:watcher[@duration-subscribed>500]
         </include>
       </what>



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     </filter>
   </filter-set>

   Notification to the subscriber:

   NOTIFY sip:presentity@client.example.com SIP/2.0
   Via: SIP/2.0/TCP presence.example.com:5060;branch=z9hG4bKxjfder
   To: sip:presentity@example.com;tag:12341111
   From: sip:presentity@example.com;tag:232321
   Call-ID: 32432udfidfjmk342
   Cseq: 1 NOTIFY
   Contact: sip:presentity@server.example.com
   Event: Presence.winfo

   Content-Type: application/watcherinfo+xml
   Content-Length: ...

   <?xml version="1.0"?>
     <watcherinfo xmlns="urn:ietf:params:xml:ns:watcherinfo"
   version="0" state="full">
     <watcher-list resource="sip:presentity@example.com"
                   package="presence">
         <watcher status="active"
            id="sr8fdsj"
            duration-subscribed="509"
            expiration="20"
            event="approved">sip:watcherA@example.com"</watcher>
         <watcher status="pending"
            id="sr8fdsj"
            duration-subscribed="501"
            expiration="100"
            event="subscribe">sip:watcherB@example.com"</watcher>
     </watcher-list>
     </watcherinfo>

7.2.3.  Watcher Subscriber Requests Specific Watcher Info on Specific
        Triggers

   This filter selects watcher information notifications [9] to be sent
   when the pending subscription status has changed from "pending" to
   "terminated".  In the notification, only the watchers that have a
   status of "terminated" and an event of "rejected" are included.

   SUBSCRIBE request from the Watcher Subscriber including the filter:

   SUBSCRIBE sip:presentity@example.com
   Via: SIP/2.0/TCP client.example.com:5060;branch=z9hG4bKxjfdsjfk
   To: <sip:presentity@example.com>;tag:12341111



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   From: <sip:presentity@example.com>
   Call-ID: 32432udfidfjmk342
   Cseq: 1 SUBSCRIBE
   Expires: 0
   Event: Presence.winfo
   Contact: <sip:presentity@client.example.com>
   Content-Type: application/simple-filter+xml
   Content-Length: ...

   <?xml version="1.0" encoding="UTF-8"?>
   <filter-set xmlns="urn:ietf:params:xml:ns:simple-winfo-filter">
     <ns-bindings>
       <ns-binding prefix="wi"
                          urn="urn:ietf:params:xml:ns:watcherinfo"/>
     </ns-bindings>
     <filter id="123" uri="sip:presentity@example.com">
       <what>
         <include>
           /wi:watcherinfo/wi:watcher-list[@package="presence"]/
           wi:watcher[@status="terminated" and @event="rejected"]
         </include>
       </what>
       <trigger>
         <changed from="pending"
                                             to="terminated">
           //@status
         </changed>
       </trigger>
     </filter>
   </filter-set>

   At some point during the subscription, a second Winfo document is
   created due to some change:

    <?xml version="1.0"?>
        <watcherinfo xmlns="urn:ietf:params:xml:ns:watcherinfo"
      version="0" state="full">
        <watcher-list resource="sip:presentity@example.com"
                      package="presence">