rfc 3343 the application exchange (apex) presence service.htm

有关IMS SIP及Presence应用的RFC文档包

  <EM><A name=page-17>Page 17</A></EM>
  <DD>
  <P></P>
  <DT><STRONG><A name=sec-3>3</A> A "reply" element having code 250 is sent to 
  the originator.</STRONG>
  <DD>
  <P>When sending the "reply" element, the "transID" attribute is identical to 
  the value found in the "publish" element sent by the originator. 
  <P></P>
  <DT><STRONG><A name=sec-4.5>4.5</A> The Terminate Operation</STRONG>
  <DD>
  <P>When an application no longer wishes to subscribe to presence information 
  or to watch endpoints that are subscribed to receive presence information, it 
  sends a "terminate" element to the service; similarly, when the service no 
  longer considers an application to be subscribing or watching, a "terminate" 
  element is sent to the application. 
  <P>The "terminate" element contains only a "transID" attribute that specifies 
  the transaction-identifier associated an in-progress subscribe or watch 
  operation. Section 9.1 of [1] defines the syntax for the "terminate" element. 
  <P>When the service receives a "terminate" element, it performs these steps: 
  <P></P>
  <DT><STRONG><A name=sec-1>1</A> If the transaction-identifier does not refer 
  to a previous</STRONG>
  <DD>subscribe or watch operation for the originator, an "error" element having 
  code 550 is returned. 
  <P></P>
  <DT><STRONG><A name=sec-2>2</A> Otherwise, the previous subscribe or watch 
  operation for the</STRONG>
  <DD>originator is terminated, and a "reply" element having code 250 is sent to 
  the originator. 
  <P>Note that following a terminate operation, the originator may receive 
  further presence or watcher updates. Although the service will send no further 
  updates after processing a terminate operation and sending the reply 
  operation, earlier updates may be in transit. 
  <P></P>
  <DT><STRONG><A name=sec-4.6>4.6</A> The Notify Operation</STRONG>
  <DD>
  <P>The service sends a "notify" element to endpoints that are watching other 
  endpoints subscribed to presence information (c.f., Section 4.3). 
  <P>The "notify" element has a "subscriber" attribute, a "transID" attribute, a 
  "duration" attribute, an "action" attribute, and no content: 
  <P>
  <UL>
    <LI>the "subscriber" attribute specifies the endpoint that is subscribed to 
    presence information; and, </LI></UL>
  <P></P>
  <DT>
  <HR>
  <EM><A name=page-18>Page 18</A></EM>
  <DD>
  <P>
  <UL>
    <LI>the "transID" attribute specifies the transaction-identifier associated 
    with the watch operation that caused this "notify" element to be sent; 
    <P></P>
    <LI>the "action" attribute specifies whether a subscription or its 
    termination has occurred; and, 
    <P></P>
    <LI>if a subscription is being reported, the "duration" attribute specifies 
    the requested duration of the subscription. </LI></UL>
  <P>No reply is sent by the receiving endpoint. 
  <P></P>
  <DT><STRONG><A name=sec-4.7>4.7</A> The Reply Operation</STRONG>
  <DD>
  <P>While processing operations, the service may respond with a "reply" 
  element. Consult Sections 10.2 and 6.1.2 of [1], respectively, for the 
  definition and an exposition of the syntax of the reply element. 
  <P></P>
  <DT><STRONG><A name=sec-5>5</A> Registration: The Presence Service</STRONG>
  <DD>
  <P>Well-Known Endpoint: apex=presence 
  <P>Syntax of Messages Exchanged: c.f., <A 
  href="http://www.apps.ietf.org/rfc/rfc3343.html#sec-6">Section 6</A> 
  <P>Sequence of Messages Exchanged: c.f., <A 
  href="http://www.apps.ietf.org/rfc/rfc3343.html#sec-4">Section 4</A> 
  <P>Access Control Tokens: presence:subscribe, presence:watch, presence:publish 

  <P>Contact Information: c.f., the "Authors' Addresses" section of this memo 
  <P></P>
  <DT><STRONG><A name=sec-6>6</A> The Presence Service DTD</STRONG>
  <DD>
  <P><PRE>   &lt;!--
     DTD for the APEX presence service, as of 2001-05-08
</PRE>
  <P>Refer to this DTD as: 
  <P><PRE>       &lt;!ENTITY % APEXPRESENCE PUBLIC "-//IETF//DTD APEX PRESENCE//EN"
                  ""&gt;
       %APEXPRESENCE;
     --&gt;

   &lt;!ENTITY % APEXCORE PUBLIC "-//IETF//DTD APEX CORE//EN" ""&gt;
   %APEXCORE;
</PRE>
  <P></P>
  <DT>
  <HR>
  <EM><A name=page-19>Page 19</A></EM>
  <DD>
  <P><PRE>   &lt;!--
     Synopsis of the APEX presence service
</PRE>
  <P>service WKE: apex=presence 
  <P>message exchanges: 
  <P><PRE>           consumer initiates    service replies
           ==================    ================
           subscribe             publish or reply
           terminate             reply
           watch                 reply
           publish               reply

           service initiates     consumer replies
           =================     ================
           terminate             (nothing)
           publish               (nothing)
           notify                (nothing)
</PRE>
  <P>access control: 
  <P><PRE>           token                 target
           ==================    ======
           presence:subscribe    for "publisher" of "subscribe" element
           presence:watch        for "publisher" of "watch" element
           presence:publish      for "publisher" of "publish" element
     --&gt;

   &lt;!ELEMENT subscribe   EMPTY&gt;
   &lt;!ATTLIST subscribe
             publisher   %ENDPOINT;        #<STRONG>REQUIRED</STRONG>
             transID     %UNIQID;          #<STRONG>REQUIRED</STRONG>
             duration    %SECONDS;         #<STRONG>REQUIRED</STRONG>&gt;

   &lt;!ELEMENT watch       EMPTY&gt;
   &lt;!ATTLIST watch
             publisher   %ENDPOINT;        #<STRONG>REQUIRED</STRONG>
             transID     %UNIQID;          #<STRONG>REQUIRED</STRONG>
             duration    %SECONDS;         #<STRONG>REQUIRED</STRONG>&gt;

   &lt;!-- publisher attributes must match in publish and presence --&gt;
   &lt;!ELEMENT publish     (presence)&gt;
   &lt;!ATTLIST publish
             publisher   %ENDPOINT;        #<STRONG>REQUIRED</STRONG>
             transID     %UNIQID;          #<STRONG>REQUIRED</STRONG>
             timeStamp   %TIMESTAMP;       #<STRONG>REQUIRED</STRONG>&gt;
</PRE>
  <P></P>
  <DT>
  <HR>
  <EM><A name=page-20>Page 20</A></EM>
  <DD>
  <P><PRE>   &lt;!ELEMENT notify      EMPTY&gt;
   &lt;!ATTLIST notify
             subscriber  %ENDPOINT;        #<STRONG>REQUIRED</STRONG>
             transID     %UNIQID;          #<STRONG>REQUIRED</STRONG>
             duration    %SECONDS;         "0"
             action     (subscribe|terminate)
                                           "subscribe"&gt;
   &lt;!--
     presence entries
     --&gt;

   &lt;!ELEMENT presence    (tuple+)&gt;
   &lt;!ATTLIST presence
             publisher   %ENDPOINT;        #<STRONG>REQUIRED</STRONG>
             lastUpdate  %TIMESTAMP;       #<STRONG>REQUIRED</STRONG>
             publisherInfo
                         %URI;             ""&gt;

   &lt;!ELEMENT tuple       (capability*)&gt;
   &lt;!ATTLIST tuple
             destination %URI;             #<STRONG>REQUIRED</STRONG>
             availableUntil
                         %TIMESTAMP;       #<STRONG>REQUIRED</STRONG>
             tupleInfo   %URI;             ""&gt;

   &lt;!-- e.g., baseline='urn:ietf:rfc:rfc2533' --&gt;
   &lt;!ELEMENT capability (#PCDATA)&gt;
   &lt;!ATTLIST capability
             baseline    %URI              #<STRONG>REQUIRED</STRONG>&gt;
</PRE>
  <P></P>
  <DT>
  <HR>
  <EM><A name=page-21>Page 21</A></EM>
  <DD>
  <P></P>
  <DT><STRONG><A name=sec-7>7</A> Security Considerations</STRONG>
  <DD>
  <P>Consult [1]'s <A 
  href="http://www.apps.ietf.org/rfc/rfc3343.html#sec-11">Section 11</A> for a 
  discussion of security issues. 
  <P>In addition, timestamps issued by the the presence service may disclose 
  location information. If this information is considered sensitive, the special 
  timezone value "-00:00" may be used (after converting the local time 
  accordingly). 
  <P></P>
  <DT>References
  <DD>
  <P><PRE>   [1]   Rose, M., Klyne, G. and D. Crocker, "The Application Exchange
         Core", <A href="http://www.apps.ietf.org/rfc/rfc3340.html">RFC 3340</A>, July 2002.

   [2]   Rose, M., "The Blocks Extensible Exchange Protocol Core", RFC
         3080, March 2001.

   [3]   Rose, M., Klyne, G. and D. Crocker, "The Application Exchange
         (APEX) Access Service", <A href="http://www.apps.ietf.org/rfc/rfc3341.html">RFC 3341</A>, July 2002.
</PRE>
  <P></P>
  <DT>
  <HR>
  <EM><A name=page-22>Page 22</A></EM>
  <DD>
  <P></P>
  <DT>Acknowledgements
  <DD>
  <P>The authors gratefully acknowledge the contributions of: Neil Cook, Eric 
  Dixon, Darren New, Scott Pead, and Bob Wyman. 
  <P></P>
  <DT>Authors' Addresses
  <DD>
  <P>Marshall T. Rose <BR>Dover Beach Consulting, Inc. <BR>POB 255268 
  <BR>Sacramento, CA 95865-5268 <BR>US 
  <P>Phone: [phone] <BR>EMail: [e-mail] 
  <P>Graham Klyne <BR>Nine by Nine 
  <P>EMail: [e-mail] 
  <P>David H. Crocker <BR>Brandenburg InternetWorking <BR>675 Spruce Drive 
  <BR>Sunnyvale, CA 94086 <BR>US 
  <P>Phone: [phone] <BR>EMail: [e-mail] <PRE>   URI:   http://www.brandenburg.com/
</PRE>
  <P></P>
  <DT>
  <HR>
  <EM><A name=page-23>Page 23</A></EM>
  <DD>
  <P></P>
  <DT>Full Copyright Statement
  <DD>
  <P>Copyright &copy; The Internet Society (2003). All Rights Reserved. 
  <P>This document and translations of it may be copied and furnished to others, 
  and derivative works that comment on or otherwise explain it or assist in its 
  implementation may be prepared, copied, published and distributed, in whole or 
  in part, without restriction of any kind, provided that the above copyright 
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  <P>The limited permissions granted above are perpetual and will not be revoked 
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  <P>This document and the information contained herein is provided on an "AS 
  IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE 
  DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY 
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  <P></P>
  <DT>Acknowledgement
  <DD>
  <P>Funding for the RFC Editor function is currently provided by the Internet 
  Society. 
  <P></P>
  <DT>
  <HR>

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