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Changeset 792


Ignore:
Timestamp:
2010-03-17 03:11:28 (5 years ago)
Author:
julian.reschke@gmx.de
Message:

make age calculation a bit less conservative (related to #29)

Location:
draft-ietf-httpbis/latest
Files:
2 edited

Legend:

Unmodified
Added
Removed
  • draft-ietf-httpbis/latest/p6-cache.html

    r786 r792  
    402402      <meta name="dct.creator" content="Reschke, J. F."> 
    403403      <meta name="dct.identifier" content="urn:ietf:id:draft-ietf-httpbis-p6-cache-latest"> 
    404       <meta name="dct.issued" scheme="ISO8601" content="2010-03-10"> 
     404      <meta name="dct.issued" scheme="ISO8601" content="2010-03-17"> 
    405405      <meta name="dct.replaces" content="urn:ietf:rfc:2616"> 
    406406      <meta name="dct.abstract" content="The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypermedia information systems. This document is Part 6 of the seven-part specification that defines the protocol referred to as &#34;HTTP/1.1&#34; and, taken together, obsoletes RFC 2616. Part 6 defines requirements on HTTP caches and the associated header fields that control cache behavior or indicate cacheable response messages."> 
     
    428428            </tr> 
    429429            <tr> 
    430                <td class="left">Expires: September 11, 2010</td> 
     430               <td class="left">Expires: September 18, 2010</td> 
    431431               <td class="right">J. Mogul</td> 
    432432            </tr> 
     
    489489            <tr> 
    490490               <td class="left"></td> 
    491                <td class="right">March 10, 2010</td> 
     491               <td class="right">March 17, 2010</td> 
    492492            </tr> 
    493493         </tbody> 
     
    519519      <p>The list of Internet-Draft Shadow Directories can be accessed at <a href="http://www.ietf.org/shadow.html">http://www.ietf.org/shadow.html</a>. 
    520520      </p> 
    521       <p>This Internet-Draft will expire in September 11, 2010.</p> 
     521      <p>This Internet-Draft will expire in September 18, 2010.</p> 
    522522      <h1><a id="rfc.copyrightnotice" href="#rfc.copyrightnotice">Copyright Notice</a></h1> 
    523523      <p>Copyright © 2010 IETF Trust and the persons identified as the document authors. All rights reserved.</p> 
     
    887887            clock. If the result is negative, the result is replaced by zero. 
    888888         </li> 
    889          <li>age_value, if all of the caches along the response path implement HTTP/1.1.</li> 
     889         <li>the "corrected_age_value", if all of the caches along the response path implement HTTP/1.1; note this value <em class="bcp14">MUST</em> be interpreted relative to the time the request was initiated, not the time that the response was received. 
     890         </li> 
    890891      </ol> 
    891       <div id="rfc.figure.u.4"></div>  
    892       <p>These are combined as</p>  <pre class="text">  apparent_age = max(0, response_time - date_value); 
    893   corrected_received_age = max(apparent_age, age_value); 
    894 </pre><p id="rfc.section.2.3.2.p.10">When an Age value is received, it <em class="bcp14">MUST</em> be interpreted relative to the time the request was initiated, not the time that the response was received. 
    895       </p> 
    896       <div id="rfc.figure.u.5"></div><pre class="text">  response_delay = response_time - request_time; 
    897   corrected_initial_age = corrected_received_age + response_delay; 
    898 </pre><p id="rfc.section.2.3.2.p.12">The current_age of a stored response can then be calculated by adding the amount of time (in seconds) since the stored response 
     892      <div id="rfc.figure.u.4"></div> <pre class="text">  apparent_age = max(0, response_time - date_value); 
     893 
     894  response_delay = response_time - request_time; 
     895  corrected_age_value = age_value + response_delay;   
     896</pre> <div id="rfc.figure.u.5"></div>  
     897      <p>These are combined as</p>  <pre class="text">  corrected_initial_age = max(apparent_age, corrected_age_value); 
     898</pre><p id="rfc.section.2.3.2.p.11">The current_age of a stored response can then be calculated by adding the amount of time (in seconds) since the stored response 
    899899         was last validated by the origin server to the corrected_initial_age. 
    900900      </p> 
     
    17721772      </ul> 
    17731773      <h2 id="rfc.section.C.11"><a href="#rfc.section.C.11">C.11</a>&nbsp;<a id="changes.since.09" href="#changes.since.09">Since draft-ietf-httpbis-p6-cache-09</a></h2> 
    1774       <p id="rfc.section.C.11.p.1">No significant changes.</p> 
     1774      <p id="rfc.section.C.11.p.1">Closed issues: </p> 
     1775      <ul> 
     1776         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/29">http://tools.ietf.org/wg/httpbis/trac/ticket/29</a>&gt;: "Age calculation" 
     1777         </li> 
     1778      </ul> 
    17751779      <h1 id="rfc.index"><a href="#rfc.index">Index</a></h1> 
    17761780      <p class="noprint"><a href="#rfc.index.A">A</a> <a href="#rfc.index.C">C</a> <a href="#rfc.index.E">E</a> <a href="#rfc.index.F">F</a> <a href="#rfc.index.G">G</a> <a href="#rfc.index.H">H</a> <a href="#rfc.index.M">M</a> <a href="#rfc.index.N">N</a> <a href="#rfc.index.O">O</a> <a href="#rfc.index.P">P</a> <a href="#rfc.index.R">R</a> <a href="#rfc.index.S">S</a> <a href="#rfc.index.V">V</a> <a href="#rfc.index.W">W</a>  
  • draft-ietf-httpbis/latest/p6-cache.xml

    r786 r792  
    687687    <t>the "apparent_age": response_time minus date_value, if the local clock is reasonably well synchronized to the 
    688688      origin server's clock. If the result is negative, the result is replaced by zero.</t> 
    689     <t>age_value, if all of the caches along the response path implement HTTP/1.1.</t> 
    690   </list> 
    691 </t> 
     689    <t>the "corrected_age_value", if all of the caches along the response path implement HTTP/1.1; 
     690      note this value &MUST; be interpreted relative to the time the 
     691      request was initiated, not the time that the response was received.</t> 
     692  </list> 
     693</t> 
     694<figure> 
     695<artwork type="code"> 
     696  apparent_age = max(0, response_time - date_value); 
     697 
     698  response_delay = response_time - request_time; 
     699  corrected_age_value = age_value + response_delay;   
     700</artwork> 
     701</figure> 
    692702<figure> 
    693703<preamble>These are combined as</preamble> 
    694704<artwork type="code"> 
    695   apparent_age = max(0, response_time - date_value); 
    696   corrected_received_age = max(apparent_age, age_value); 
    697 </artwork></figure> 
    698 <t> 
    699   When an Age value is received, it &MUST; be interpreted relative to the time the 
    700   request was initiated, not the time that the response was received. 
    701 </t> 
    702 <figure><artwork type="code"> 
    703   response_delay = response_time - request_time; 
    704   corrected_initial_age = corrected_received_age + response_delay; 
     705  corrected_initial_age = max(apparent_age, corrected_age_value); 
    705706</artwork></figure> 
    706707<t> 
     
    23302331<section title="Since draft-ietf-httpbis-p6-cache-09" anchor="changes.since.09"> 
    23312332<t> 
    2332   No significant changes. 
     2333  Closed issues: 
     2334  <list style="symbols">  
     2335    <t> 
     2336      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/29" />: 
     2337      "Age calculation" 
     2338    </t> 
     2339  </list> 
    23332340</t> 
    23342341</section> 
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