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<!DOCTYPE html>
<html lang="en" class="RFC">
<head>
<meta charset="utf-8">
<meta content="Common,Latin" name="scripts">
<meta content="initial-scale=1.0" name="viewport">
<title>RFC 8786: Updated Rules for Processing Stateful PCE Request Parameters Flags</title>
<meta content="Adrian Farrel" name="author">
<meta content="
       Extensions to the Path Computation Element Communication Protocol
      (PCEP) to support stateful Path Computation Elements (PCEs) are defined
      in RFC 8231.  One of the extensions is the Stateful PCE Request
      Parameters (SRP) object.  That object includes a Flags field that is a
      set of 32 bit flags, and RFC 8281 defines an IANA registry for tracking
      assigned flags.  However, RFC 8231 does not explain how an
      implementation should set unassigned flags in transmitted messages, nor
      how an implementation should process unassigned, unknown, or unsupported
      flags in received messages. 
       This document updates RFC 8231 by defining the correct behaviors. 
    " name="description">
<meta content="xml2rfc 2.45.1" name="generator">
<meta content="PCEP" name="keyword">
<meta content="Path Computation Element" name="keyword">
<meta content="Stateful PCE" name="keyword">
<meta content="Flags" name="keyword">
<meta content="8786" name="rfc.number">
<link href="rfc8786.xml" rel="alternate" type="application/rfc+xml">
<link href="#copyright" rel="license">
<style type="text/css">/*

  NOTE: Changes at the bottom of this file overrides some earlier settings.

  Once the style has stabilized and has been adopted as an official RFC style,
  this can be consolidated so that style settings occur only in one place, but
  for now the contents of this file consists first of the initial CSS work as
  provided to the RFC Formatter (xml2rfc) work, followed by itemized and
  commented changes found necssary during the development of the v3
  formatters.

*/

/* fonts */
@import url('https://fonts.googleapis.com/css?family=Noto+Sans'); /* Sans-serif */
@import url('https://fonts.googleapis.com/css?family=Noto+Serif'); /* Serif (print) */
@import url('https://fonts.googleapis.com/css?family=Roboto+Mono'); /* Monospace */

@viewport {
  zoom: 1.0;
  width: extend-to-zoom;
}
@-ms-viewport {
  width: extend-to-zoom;
  zoom: 1.0;
}
/* general and mobile first */
html {
}
body {
  max-width: 90%;
  margin: 1.5em auto;
  color: #222;
  background-color: #fff;
  font-size: 14px;
  font-family: 'Noto Sans', Arial, Helvetica, sans-serif;
  line-height: 1.6;
  scroll-behavior: smooth;
}
.ears {
  display: none;
}

/* headings */
#title, h1, h2, h3, h4, h5, h6 {
  margin: 1em 0 0.5em;
  font-weight: bold;
  line-height: 1.3;
}
#title {
  clear: both;
  border-bottom: 1px solid #ddd;
  margin: 0 0 0.5em 0;
  padding: 1em 0 0.5em;
}
.author {
  padding-bottom: 4px;
}
h1 {
  font-size: 26px;
  margin: 1em 0;
}
h2 {
  font-size: 22px;
  margin-top: -20px;  /* provide offset for in-page anchors */
  padding-top: 33px;
}
h3 {
  font-size: 18px;
  margin-top: -36px;  /* provide offset for in-page anchors */
  padding-top: 42px;
}
h4 {
  font-size: 16px;
  margin-top: -36px;  /* provide offset for in-page anchors */
  padding-top: 42px;
}
h5, h6 {
  font-size: 14px;
}
#n-copyright-notice {
  border-bottom: 1px solid #ddd;
  padding-bottom: 1em;
  margin-bottom: 1em;
}
/* general structure */
p {
  padding: 0;
  margin: 0 0 1em 0;
  text-align: left;
}
div, span {
  position: relative;
}
div {
  margin: 0;
}
.alignRight.art-text {
  background-color: #f9f9f9;
  border: 1px solid #eee;
  border-radius: 3px;
  padding: 1em 1em 0;
  margin-bottom: 1.5em;
}
.alignRight.art-text pre {
  padding: 0;
}
.alignRight {
  margin: 1em 0;
}
.alignRight > *:first-child {
  border: none;
  margin: 0;
  float: right;
  clear: both;
}
.alignRight > *:nth-child(2) {
  clear: both;
  display: block;
  border: none;
}
svg {
  display: block;
}
.alignCenter.art-text {
  background-color: #f9f9f9;
  border: 1px solid #eee;
  border-radius: 3px;
  padding: 1em 1em 0;
  margin-bottom: 1.5em;
}
.alignCenter.art-text pre {
  padding: 0;
}
.alignCenter {
  margin: 1em 0;
}
.alignCenter > *:first-child {
  border: none;
  /* this isn't optimal, but it's an existence proof.  PrinceXML doesn't
     support flexbox yet.
  */
  display: table;
  margin: 0 auto;
}

/* lists */
ol, ul {
  padding: 0;
  margin: 0 0 1em 2em;
}
ol ol, ul ul, ol ul, ul ol {
  margin-left: 1em;
}
li {
  margin: 0 0 0.25em 0;
}
.ulCompact li {
  margin: 0;
}
ul.empty, .ulEmpty {
  list-style-type: none;
}
ul.empty li, .ulEmpty li {
  margin-top: 0.5em;
}
ul.compact, .ulCompact,
ol.compact, .olCompact {
  line-height: 100%;
  margin: 0 0 0 2em;
}

/* definition lists */
dl {
}
dl > dt {
  float: left;
  margin-right: 1em;
}
/* 
dl.nohang > dt {
  float: none;
}
*/
dl > dd {
  margin-bottom: .8em;
  min-height: 1.3em;
}
dl.compact > dd, .dlCompact > dd {
  margin-bottom: 0em;
}
dl > dd > dl {
  margin-top: 0.5em;
  margin-bottom: 0em;
}

/* links */
a {
  text-decoration: none;
}
a[href] {
  color: #22e; /* Arlen: WCAG 2019 */
}
a[href]:hover {
  background-color: #f2f2f2;
}
figcaption a[href],
a[href].selfRef {
  color: #222;
}
/* XXX probably not this:
a.selfRef:hover {
  background-color: transparent;
  cursor: default;
} */

/* Figures */
tt, code, pre, code {
  background-color: #f9f9f9;
  font-family: 'Roboto Mono', monospace;
}
pre {
  border: 1px solid #eee;
  margin: 0;
  padding: 1em;
}
img {
  max-width: 100%;
}
figure {
  margin: 0;
}
figure blockquote {
  margin: 0.8em 0.4em 0.4em;
}
figcaption {
  font-style: italic;
  margin: 0 0 1em 0;
}
@media screen {
  pre {
    overflow-x: auto;
    max-width: 100%;
    max-width: calc(100% - 22px);
  }
}

/* aside, blockquote */
aside, blockquote {
  margin-left: 0;
  padding: 1.2em 2em;
}
blockquote {
  background-color: #f9f9f9;
  color: #111; /* Arlen: WCAG 2019 */
  border: 1px solid #ddd;
  border-radius: 3px;
  margin: 1em 0;
}
cite {
  display: block;
  text-align: right;
  font-style: italic;
}

/* tables */
table {
  width: 100%;
  margin: 0 0 1em;
  border-collapse: collapse;
  border: 1px solid #eee;
}
th, td {
  text-align: left;
  vertical-align: top;
  padding: 0.5em 0.75em;
}
th {
  text-align: left;
  background-color: #e9e9e9;
}
tr:nth-child(2n+1) > td {
  background-color: #f5f5f5;
}
table caption {
  font-style: italic;
  margin: 0;
  padding: 0;
  text-align: left;
}
table p {
  /* XXX to avoid bottom margin on table row signifiers. If paragraphs should
     be allowed within tables more generally, it would be far better to select on a class. */
  margin: 0;
}

/* pilcrow */
a.pilcrow {
  color: #666; /* Arlen: AHDJ 2019 */
  text-decoration: none;
  visibility: hidden;
  user-select: none;
  -ms-user-select: none;
  -o-user-select:none;
  -moz-user-select: none;
  -khtml-user-select: none;
  -webkit-user-select: none;
  -webkit-touch-callout: none;
}
@media screen {
  aside:hover > a.pilcrow,
  p:hover > a.pilcrow,
  blockquote:hover > a.pilcrow,
  div:hover > a.pilcrow,
  li:hover > a.pilcrow,
  pre:hover > a.pilcrow {
    visibility: visible;
  }
  a.pilcrow:hover {
    background-color: transparent;
  }
}

/* misc */
hr {
  border: 0;
  border-top: 1px solid #eee;
}
.bcp14 {
  font-variant: small-caps;
}

.role {
  font-variant: all-small-caps;
}

/* info block */
#identifiers {
  margin: 0;
  font-size: 0.9em;
}
#identifiers dt {
  width: 3em;
  clear: left;
}
#identifiers dd {
  float: left;
  margin-bottom: 0;
}
#identifiers .authors .author {
  display: inline-block;
  margin-right: 1.5em;
}
#identifiers .authors .org {
  font-style: italic;
}

/* The prepared/rendered info at the very bottom of the page */
.docInfo {
  color: #666; /* Arlen: WCAG 2019 */
  font-size: 0.9em;
  font-style: italic;
  margin-top: 2em;
}
.docInfo .prepared {
  float: left;
}
.docInfo .prepared {
  float: right;
}

/* table of contents */
#toc  {
  padding: 0.75em 0 2em 0;
  margin-bottom: 1em;
}
nav.toc ul {
  margin: 0 0.5em 0 0;
  padding: 0;
  list-style: none;
}
nav.toc li {
  line-height: 1.3em;
  margin: 0.75em 0;
  padding-left: 1.2em;
  text-indent: -1.2em;
}
/* references */
.references dt {
  text-align: right;
  font-weight: bold;
  min-width: 7em;
}
.references dd {
  margin-left: 8em;
  overflow: auto;
}

.refInstance {
  margin-bottom: 1.25em;
}

.references .ascii {
  margin-bottom: 0.25em;
}

/* index */
.index ul {
  margin: 0 0 0 1em;
  padding: 0;
  list-style: none;
}
.index ul ul {
  margin: 0;
}
.index li {
  margin: 0;
  text-indent: -2em;
  padding-left: 2em;
  padding-bottom: 5px;
}
.indexIndex {
  margin: 0.5em 0 1em;
}
.index a {
  font-weight: 700;
}
/* make the index two-column on all but the smallest screens */
@media (min-width: 600px) {
  .index ul {
    -moz-column-count: 2;
    -moz-column-gap: 20px;
  }
  .index ul ul {
    -moz-column-count: 1;
    -moz-column-gap: 0;
  }
}

/* authors */
address.vcard {
  font-style: normal;
  margin: 1em 0;
}

address.vcard .nameRole {
  font-weight: 700;
  margin-left: 0;
}
address.vcard .label {
  font-family: "Noto Sans",Arial,Helvetica,sans-serif;
  margin: 0.5em 0;
}
address.vcard .type {
  display: none;
}
.alternative-contact {
  margin: 1.5em 0 1em;
}
hr.addr {
  border-top: 1px dashed;
  margin: 0;
  color: #ddd;
  max-width: calc(100% - 16px);
}

/* temporary notes */
.rfcEditorRemove::before {
  position: absolute;
  top: 0.2em;
  right: 0.2em;
  padding: 0.2em;
  content: "The RFC Editor will remove this note";
  color: #9e2a00; /* Arlen: WCAG 2019 */
  background-color: #ffd; /* Arlen: WCAG 2019 */
}
.rfcEditorRemove {
  position: relative;
  padding-top: 1.8em;
  background-color: #ffd; /* Arlen: WCAG 2019 */
  border-radius: 3px;
}
.cref {
  background-color: #ffd; /* Arlen: WCAG 2019 */
  padding: 2px 4px;
}
.crefSource {
  font-style: italic;
}
/* alternative layout for smaller screens */
@media screen and (max-width: 1023px) {
  body {
    padding-top: 2em;
  }
  #title {
    padding: 1em 0;
  }
  h1 {
    font-size: 24px;
  }
  h2 {
    font-size: 20px;
    margin-top: -18px;  /* provide offset for in-page anchors */
    padding-top: 38px;
  }
  #identifiers dd {
    max-width: 60%;
  }
  #toc {
    position: fixed;
    z-index: 2;
    top: 0;
    right: 0;
    padding: 0;
    margin: 0;
    background-color: inherit;
    border-bottom: 1px solid #ccc;
  }
  #toc h2 {
    margin: -1px 0 0 0;
    padding: 4px 0 4px 6px;
    padding-right: 1em;
    min-width: 190px;
    font-size: 1.1em;
    text-align: right;
    background-color: #444;
    color: white;
    cursor: pointer;
  }
  #toc h2::before { /* css hamburger */
    float: right;
    position: relative;
    width: 1em;
    height: 1px;
    left: -164px;
    margin: 6px 0 0 0;
    background: white none repeat scroll 0 0;
    box-shadow: 0 4px 0 0 white, 0 8px 0 0 white;
    content: "";
  }
  #toc nav {
    display: none;
    padding: 0.5em 1em 1em;
    overflow: auto;
    height: calc(100vh - 48px);
    border-left: 1px solid #ddd;
  }
}

/* alternative layout for wide screens */
@media screen and (min-width: 1024px) {
  body {
    max-width: 724px;
    margin: 42px auto;
    padding-left: 1.5em;
    padding-right: 29em;
  }
  #toc {
    position: fixed;
    top: 42px;
    right: 42px;
    width: 25%;
    margin: 0;
    padding: 0 1em;
    z-index: 1;
  }
  #toc h2 {
    border-top: none;
    border-bottom: 1px solid #ddd;
    font-size: 1em;
    font-weight: normal;
    margin: 0;
    padding: 0.25em 1em 1em 0;
  }
  #toc nav {
    display: block;
    height: calc(90vh - 84px);
    bottom: 0;
    padding: 0.5em 0 0;
    overflow: auto;
  }
  img { /* future proofing */
    max-width: 100%;
    height: auto;
  }
}

/* pagination */
@media print {
  body {

    width: 100%;
  }
  p {
    orphans: 3;
    widows: 3;
  }
  #n-copyright-notice {
    border-bottom: none;
  }
  #toc, #n-introduction {
    page-break-before: always;
  }
  #toc {
    border-top: none;
    padding-top: 0;
  }
  figure, pre {
    page-break-inside: avoid;
  }
  figure {
    overflow: scroll;
  }
  h1, h2, h3, h4, h5, h6 {
    page-break-after: avoid;
  }
  h2+*, h3+*, h4+*, h5+*, h6+* {
    page-break-before: avoid;
  }
  pre {
    white-space: pre-wrap;
    word-wrap: break-word;
    font-size: 10pt;
  }
  table {
    border: 1px solid #ddd;
  }
  td {
    border-top: 1px solid #ddd;
  }
}

/* This is commented out here, as the string-set: doesn't
   pass W3C validation currently */
/*
.ears thead .left {
  string-set: ears-top-left content();
}

.ears thead .center {
  string-set: ears-top-center content();
}

.ears thead .right {
  string-set: ears-top-right content();
}

.ears tfoot .left {
  string-set: ears-bottom-left content();
}

.ears tfoot .center {
  string-set: ears-bottom-center content();
}

.ears tfoot .right {
  string-set: ears-bottom-right content();
}
*/

@page :first {
  padding-top: 0;
  @top-left {
    content: normal;
    border: none;
  }
  @top-center {
    content: normal;
    border: none;
  }
  @top-right {
    content: normal;
    border: none;
  }
}

@page {
  size: A4;
  margin-bottom: 45mm;
  padding-top: 20px;
  /* The follwing is commented out here, but set appropriately by in code, as
     the content depends on the document */
  /*
  @top-left {
    content: 'Internet-Draft';
    vertical-align: bottom;
    border-bottom: solid 1px #ccc;
  }
  @top-left {
    content: string(ears-top-left);
    vertical-align: bottom;
    border-bottom: solid 1px #ccc;
  }
  @top-center {
    content: string(ears-top-center);
    vertical-align: bottom;
    border-bottom: solid 1px #ccc;
  }
  @top-right {
    content: string(ears-top-right);
    vertical-align: bottom;
    border-bottom: solid 1px #ccc;
  }
  @bottom-left {
    content: string(ears-bottom-left);
    vertical-align: top;
    border-top: solid 1px #ccc;
  }
  @bottom-center {
    content: string(ears-bottom-center);
    vertical-align: top;
    border-top: solid 1px #ccc;
  }
  @bottom-right {
      content: '[Page ' counter(page) ']';
      vertical-align: top;
      border-top: solid 1px #ccc;
  }
  */

}

/* Changes introduced to fix issues found during implementation */
/* Make sure links are clickable even if overlapped by following H* */
a {
  z-index: 2;
}
/* Separate body from document info even without intervening H1 */
section {
  clear: both;
}


/* Top align author divs, to avoid names without organization dropping level with org names */
.author {
  vertical-align: top;
}

/* Leave room in document info to show Internet-Draft on one line */
#identifiers dt {
  width: 8em;
}

/* Don't waste quite as much whitespace between label and value in doc info */
#identifiers dd {
  margin-left: 1em;
}

/* Give floating toc a background color (needed when it's a div inside section */
#toc {
  background-color: white;
}

/* Make the collapsed ToC header render white on gray also when it's a link */
@media screen and (max-width: 1023px) {
  #toc h2 a,
  #toc h2 a:link,
  #toc h2 a:focus,
  #toc h2 a:hover,
  #toc a.toplink,
  #toc a.toplink:hover {
    color: white;
    background-color: #444;
    text-decoration: none;
  }
}

/* Give the bottom of the ToC some whitespace */
@media screen and (min-width: 1024px) {
  #toc {
    padding: 0 0 1em 1em;
  }
}

/* Style section numbers with more space between number and title */
.section-number {
  padding-right: 0.5em;
}

/* prevent monospace from becoming overly large */
tt, code, pre, code {
  font-size: 95%;
}

/* Fix the height/width aspect for ascii art*/
pre.sourcecode,
.art-text pre {
  line-height: 1.12;
}


/* Add styling for a link in the ToC that points to the top of the document */
a.toplink {
  float: right;
  margin-right: 0.5em;
}

/* Fix the dl styling to match the RFC 7992 attributes */
dl > dt,
dl.dlParallel > dt {
  float: left;
  margin-right: 1em;
}
dl.dlNewline > dt {
  float: none;
}

/* Provide styling for table cell text alignment */
table td.text-left,
table th.text-left {
  text-align: left;
}
table td.text-center,
table th.text-center {
  text-align: center;
}
table td.text-right,
table th.text-right {
  text-align: right;
}

/* Make the alternative author contact informatio look less like just another
   author, and group it closer with the primary author contact information */
.alternative-contact {
  margin: 0.5em 0 0.25em 0;
}
address .non-ascii {
  margin: 0 0 0 2em;
}

/* With it being possible to set tables with alignment
  left, center, and right, { width: 100%; } does not make sense */
table {
  width: auto;
}

/* Avoid reference text that sits in a block with very wide left margin,
   because of a long floating dt label.*/
.references dd {
  overflow: visible;
}

/* Control caption placement */
caption {
  caption-side: bottom;
}

/* Limit the width of the author address vcard, so names in right-to-left
   script don't end up on the other side of the page. */

address.vcard {
  max-width: 30em;
  margin-right: auto;
}

/* For address alignment dependent on LTR or RTL scripts */
address div.left {
  text-align: left;
}
address div.right {
  text-align: right;
}

/* Provide table alignment support.  We can't use the alignX classes above
   since they do unwanted things with caption and other styling. */
table.right {
 margin-left: auto;
 margin-right: 0;
}
table.center {
 margin-left: auto;
 margin-right: auto;
}
table.left {
 margin-left: 0;
 margin-right: auto;
}

/* Give the table caption label the same styling as the figcaption */
caption a[href] {
  color: #222;
}

@media print {
  .toplink {
    display: none;
  }

  /* avoid overwriting the top border line with the ToC header */
  #toc {
    padding-top: 1px;
  }

  /* Avoid page breaks inside dl and author address entries */
  .vcard {
    page-break-inside: avoid;
  }

}
/* Avoid wrapping of URLs in references */
@media screen {
  .references a {
    white-space: nowrap;
  }
}
/* Tweak the bcp14 keyword presentation */
.bcp14 {
  font-variant: small-caps;
  font-weight: bold;
  font-size: 0.9em;
}
/* Tweak the invisible space above H* in order not to overlay links in text above */
 h2 {
  margin-top: -18px;  /* provide offset for in-page anchors */
  padding-top: 31px;
 }
 h3 {
  margin-top: -18px;  /* provide offset for in-page anchors */
  padding-top: 24px;
 }
 h4 {
  margin-top: -18px;  /* provide offset for in-page anchors */
  padding-top: 24px;
 }
/* Float artwork pilcrow to the right */
@media screen {
  .artwork a.pilcrow {
    display: block;
    line-height: 0.7;
    margin-top: 0.15em;
  }
}
/* Make pilcrows on dd visible */
@media screen {
  dd:hover > a.pilcrow {
    visibility: visible;
  }
}
/* Make the placement of figcaption match that of a table's caption
   by removing the figure's added bottom margin */
.alignLeft.art-text,
.alignCenter.art-text,
.alignRight.art-text {
   margin-bottom: 0;
}
.alignLeft,
.alignCenter,
.alignRight {
  margin: 1em 0 0 0;
}
/* In print, the pilcrow won't show on hover, so prevent it from taking up space,
   possibly even requiring a new line */
@media print {
  a.pilcrow {
    display: none;
  }
}
/* Styling for the external metadata */
div#external-metadata {
  background-color: #eee;
  padding: 0.5em;
  margin-bottom: 0.5em;
  display: none;
}
div#internal-metadata {
  padding: 0.5em;                       /* to match the external-metadata padding */
}
/* Styling for title RFC Number */
h1#rfcnum {
  clear: both;
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<table class="ears">
<thead><tr>
<td class="left">RFC 8786</td>
<td class="center">Stateful PCEP Flags</td>
<td class="right">May 2020</td>
</tr></thead>
<tfoot><tr>
<td class="left">Farrel</td>
<td class="center">Standards Track</td>
<td class="right">[Page]</td>
</tr></tfoot>
</table>
<div id="external-metadata" class="document-information"></div>
<div id="internal-metadata" class="document-information">
<dl id="identifiers">
<dt class="label-stream">Stream:</dt>
<dd class="stream">Internet Engineering Task Force (IETF)</dd>
<dt class="label-rfc">RFC:</dt>
<dd class="rfc"><a href="https://www.rfc-editor.org/rfc/rfc8786" class="eref">8786</a></dd>
<dt class="label-updates">Updates:</dt>
<dd class="updates">
<a href="https://www.rfc-editor.org/rfc/rfc8231" class="eref">8231</a> </dd>
<dt class="label-category">Category:</dt>
<dd class="category">Standards Track</dd>
<dt class="label-published">Published:</dt>
<dd class="published">
<time datetime="2020-05" class="published">May 2020</time>
    </dd>
<dt class="label-issn">ISSN:</dt>
<dd class="issn">2070-1721</dd>
<dt class="label-authors">Author:</dt>
<dd class="authors">
<div class="author">
      <div class="author-name">A. Farrel</div>
<div class="org">Old Dog Consulting</div>
</div>
</dd>
</dl>
</div>
<h1 id="rfcnum">RFC 8786</h1>
<h1 id="title">Updated Rules for Processing Stateful PCE Request Parameters Flags</h1>
<section id="section-abstract">
      <h2 id="abstract"><a href="#abstract" class="selfRef">Abstract</a></h2>
<p id="section-abstract-1">Extensions to the Path Computation Element Communication Protocol
      (PCEP) to support stateful Path Computation Elements (PCEs) are defined
      in RFC 8231.  One of the extensions is the Stateful PCE Request
      Parameters (SRP) object.  That object includes a Flags field that is a
      set of 32 bit flags, and RFC 8281 defines an IANA registry for tracking
      assigned flags.  However, RFC 8231 does not explain how an
      implementation should set unassigned flags in transmitted messages, nor
      how an implementation should process unassigned, unknown, or unsupported
      flags in received messages.<a href="#section-abstract-1" class="pilcrow">¶</a></p>
<p id="section-abstract-2">This document updates RFC 8231 by defining the correct behaviors.<a href="#section-abstract-2" class="pilcrow">¶</a></p>
</section>
<div id="status-of-memo">
<section id="section-boilerplate.1">
        <h2 id="name-status-of-this-memo">
<a href="#name-status-of-this-memo" class="section-name selfRef">Status of This Memo</a>
        </h2>
<p id="section-boilerplate.1-1">
            This is an Internet Standards Track document.<a href="#section-boilerplate.1-1" class="pilcrow">¶</a></p>
<p id="section-boilerplate.1-2">
            This document is a product of the Internet Engineering Task Force
            (IETF).  It represents the consensus of the IETF community.  It has
            received public review and has been approved for publication by
            the Internet Engineering Steering Group (IESG).  Further
            information on Internet Standards is available in Section 2 of 
            RFC 7841.<a href="#section-boilerplate.1-2" class="pilcrow">¶</a></p>
<p id="section-boilerplate.1-3">
            Information about the current status of this document, any
            errata, and how to provide feedback on it may be obtained at
            <span><a href="https://www.rfc-editor.org/info/rfc8786">https://www.rfc-editor.org/info/rfc8786</a></span>.<a href="#section-boilerplate.1-3" class="pilcrow">¶</a></p>
</section>
</div>
<div id="copyright">
<section id="section-boilerplate.2">
        <h2 id="name-copyright-notice">
<a href="#name-copyright-notice" class="section-name selfRef">Copyright Notice</a>
        </h2>
<p id="section-boilerplate.2-1">
            Copyright (c) 2020 IETF Trust and the persons identified as the
            document authors. All rights reserved.<a href="#section-boilerplate.2-1" class="pilcrow">¶</a></p>
<p id="section-boilerplate.2-2">
            This document is subject to BCP 78 and the IETF Trust's Legal
            Provisions Relating to IETF Documents
            (<span><a href="https://trustee.ietf.org/license-info">https://trustee.ietf.org/license-info</a></span>) in effect on the date of
            publication of this document. Please review these documents
            carefully, as they describe your rights and restrictions with
            respect to this document. Code Components extracted from this
            document must include Simplified BSD License text as described in
            Section 4.e of the Trust Legal Provisions and are provided without
            warranty as described in the Simplified BSD License.<a href="#section-boilerplate.2-2" class="pilcrow">¶</a></p>
</section>
</div>
<div id="toc">
<section id="section-toc.1">
        <a href="#" onclick="scroll(0,0)" class="toplink">▲</a><h2 id="name-table-of-contents">
<a href="#name-table-of-contents" class="section-name selfRef">Table of Contents</a>
        </h2>
<nav class="toc"><ul class="toc ulEmpty">
<li class="toc ulEmpty" id="section-toc.1-1.1">
            <p id="section-toc.1-1.1.1" class="keepWithNext"><a href="#section-1" class="xref">1</a>.  <a href="#name-introduction" class="xref">Introduction</a><a href="#section-toc.1-1.1.1" class="pilcrow">¶</a></p>
</li>
<li class="toc ulEmpty" id="section-toc.1-1.2">
            <p id="section-toc.1-1.2.1" class="keepWithNext"><a href="#section-2" class="xref">2</a>.  <a href="#name-requirements-language" class="xref">Requirements Language</a><a href="#section-toc.1-1.2.1" class="pilcrow">¶</a></p>
</li>
<li class="toc ulEmpty" id="section-toc.1-1.3">
            <p id="section-toc.1-1.3.1"><a href="#section-3" class="xref">3</a>.  <a href="#name-updated-procedures" class="xref">Updated Procedures</a><a href="#section-toc.1-1.3.1" class="pilcrow">¶</a></p>
<ul class="toc ulEmpty">
<li class="toc ulEmpty" id="section-toc.1-1.3.2.1">
                <p id="section-toc.1-1.3.2.1.1" class="keepWithNext"><a href="#section-3.1" class="xref">3.1</a>.  <a href="#name-advice-for-specification-of" class="xref">Advice for Specification of New Flags</a><a href="#section-toc.1-1.3.2.1.1" class="pilcrow">¶</a></p>
</li>
<li class="toc ulEmpty" id="section-toc.1-1.3.2.2">
                <p id="section-toc.1-1.3.2.2.1"><a href="#section-3.2" class="xref">3.2</a>.  <a href="#name-flags-field-of-the-srp-obje" class="xref">Flags Field of the SRP Object</a><a href="#section-toc.1-1.3.2.2.1" class="pilcrow">¶</a></p>
</li>
</ul>
</li>
<li class="toc ulEmpty" id="section-toc.1-1.4">
            <p id="section-toc.1-1.4.1"><a href="#section-4" class="xref">4</a>.  <a href="#name-compatibility-consideration" class="xref">Compatibility Considerations</a><a href="#section-toc.1-1.4.1" class="pilcrow">¶</a></p>
</li>
<li class="toc ulEmpty" id="section-toc.1-1.5">
            <p id="section-toc.1-1.5.1"><a href="#section-5" class="xref">5</a>.  <a href="#name-management-considerations" class="xref">Management Considerations</a><a href="#section-toc.1-1.5.1" class="pilcrow">¶</a></p>
</li>
<li class="toc ulEmpty" id="section-toc.1-1.6">
            <p id="section-toc.1-1.6.1"><a href="#section-6" class="xref">6</a>.  <a href="#name-security-considerations" class="xref">Security Considerations</a><a href="#section-toc.1-1.6.1" class="pilcrow">¶</a></p>
</li>
<li class="toc ulEmpty" id="section-toc.1-1.7">
            <p id="section-toc.1-1.7.1"><a href="#section-7" class="xref">7</a>.  <a href="#name-iana-considerations" class="xref">IANA Considerations</a><a href="#section-toc.1-1.7.1" class="pilcrow">¶</a></p>
</li>
<li class="toc ulEmpty" id="section-toc.1-1.8">
            <p id="section-toc.1-1.8.1"><a href="#section-8" class="xref">8</a>.  <a href="#name-references" class="xref">References</a><a href="#section-toc.1-1.8.1" class="pilcrow">¶</a></p>
<ul class="toc ulEmpty">
<li class="toc ulEmpty" id="section-toc.1-1.8.2.1">
                <p id="section-toc.1-1.8.2.1.1"><a href="#section-8.1" class="xref">8.1</a>.  <a href="#name-normative-references" class="xref">Normative References</a><a href="#section-toc.1-1.8.2.1.1" class="pilcrow">¶</a></p>
</li>
<li class="toc ulEmpty" id="section-toc.1-1.8.2.2">
                <p id="section-toc.1-1.8.2.2.1"><a href="#section-8.2" class="xref">8.2</a>.  <a href="#name-informative-references" class="xref">Informative References</a><a href="#section-toc.1-1.8.2.2.1" class="pilcrow">¶</a></p>
</li>
</ul>
</li>
<li class="toc ulEmpty" id="section-toc.1-1.9">
            <p id="section-toc.1-1.9.1"><a href="#section-appendix.a" class="xref"></a><a href="#name-acknowledgements" class="xref">Acknowledgements</a><a href="#section-toc.1-1.9.1" class="pilcrow">¶</a></p>
</li>
<li class="toc ulEmpty" id="section-toc.1-1.10">
            <p id="section-toc.1-1.10.1"><a href="#section-appendix.b" class="xref"></a><a href="#name-authors-address" class="xref">Author's Address</a><a href="#section-toc.1-1.10.1" class="pilcrow">¶</a></p>
</li>
</ul>
</nav>
</section>
</div>
<section id="section-1">
      <h2 id="name-introduction">
<a href="#section-1" class="section-number selfRef">1. </a><a href="#name-introduction" class="section-name selfRef">Introduction</a>
      </h2>
<p id="section-1-1"><span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span> describes the Path
      Computation Element Communication Protocol (PCEP).  PCEP defines the
      communication between a Path Computation Client (PCC) and a Path
      Computation Element (PCE), or between PCEs, enabling computation of
      Multiprotocol Label Switching (MPLS) for Traffic Engineering Label
      Switched Path (TE LSP) characteristics.<a href="#section-1-1" class="pilcrow">¶</a></p>
<p id="section-1-2"><span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span> specifies a set of
      extensions to PCEP to enable stateful control of LSPs within and across
      PCEP sessions in compliance with <span>[<a href="#RFC4657" class="xref">RFC4657</a>]</span>.  It includes mechanisms to effect Label Switched
      Path (LSP) State Synchronization between PCCs and PCEs, delegation of
      control over LSPs to PCEs, and PCE control of timing and sequence of
      path computations within and across PCEP sessions.<a href="#section-1-2" class="pilcrow">¶</a></p>
<p id="section-1-3">One of the extensions defined in <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span> is the Stateful PCE Request Parameters (SRP) object.
      That object includes a Flags field that is a set of 32 bit flags, and
      RFC 8281 defines an IANA registry for tracking assigned
      flags.  However, RFC 8231 does not explain how an
      implementation should set unassigned flags in transmitted messages, nor
      how an implementation should process unassigned or unknown flags in
      received messages.<a href="#section-1-3" class="pilcrow">¶</a></p>
<p id="section-1-4">Furthermore, <span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span> gives no
      guidance to the authors of future specifications about how to describe
      the interaction between flags that have already been defined and flags
      being defined in the new specifications.<a href="#section-1-4" class="pilcrow">¶</a></p>
<p id="section-1-5">This document updates RFC 8231 by defining the correct behaviors.<a href="#section-1-5" class="pilcrow">¶</a></p>
</section>
<section id="section-2">
      <h2 id="name-requirements-language">
<a href="#section-2" class="section-number selfRef">2. </a><a href="#name-requirements-language" class="section-name selfRef">Requirements Language</a>
      </h2>
<p id="section-2-1">
    The key words "<span class="bcp14">MUST</span>", "<span class="bcp14">MUST NOT</span>",
    "<span class="bcp14">REQUIRED</span>", "<span class="bcp14">SHALL</span>", "<span class="bcp14">SHALL NOT</span>", "<span class="bcp14">SHOULD</span>", "<span class="bcp14">SHOULD NOT</span>",
    "<span class="bcp14">RECOMMENDED</span>", "<span class="bcp14">NOT RECOMMENDED</span>",
    "<span class="bcp14">MAY</span>", and "<span class="bcp14">OPTIONAL</span>" in this document are
    to be interpreted as described in BCP 14 <span>[<a href="#RFC2119" class="xref">RFC2119</a>]</span>
        <span>[<a href="#RFC8174" class="xref">RFC8174</a>]</span> when, and only when, they appear in all capitals,
    as shown here.<a href="#section-2-1" class="pilcrow">¶</a></p>
</section>
<div id="update">
<section id="section-3">
      <h2 id="name-updated-procedures">
<a href="#section-3" class="section-number selfRef">3. </a><a href="#name-updated-procedures" class="section-name selfRef">Updated Procedures</a>
      </h2>
<div id="advice">
<section id="section-3.1">
        <h3 id="name-advice-for-specification-of">
<a href="#section-3.1" class="section-number selfRef">3.1. </a><a href="#name-advice-for-specification-of" class="section-name selfRef">Advice for Specification of New Flags</a>
        </h3>
<p id="section-3.1-1"><span><a href="https://www.rfc-editor.org/rfc/rfc8231#section-7" class="relref">Section 7</a> of [<a href="#RFC8231" class="xref">RFC8231</a>]</span> introduces
        changes to existing PCEP objects and defines new PCEP objects and TLVs
        in support of stateful PCE functionality.  That text does not advise
        future specifications on how to describe the interaction between flags
        that may be defined.<a href="#section-3.1-1" class="pilcrow">¶</a></p>
<p id="section-3.1-2">The text in <span><a href="https://www.rfc-editor.org/rfc/rfc8231#section-7" class="relref">Section 7</a> of [<a href="#RFC8231" class="xref">RFC8231</a>]</span>
        is updated to read as follows:<a href="#section-3.1-2" class="pilcrow">¶</a></p>
<ul class="ulEmpty">
<li class="ulEmpty" id="section-3.1-3.1">The PCEP objects defined in this document are compliant with the
          PCEP object format defined in <span>[<a href="#RFC5440" class="xref">RFC5440</a>]</span>.  The P and I flags of the PCEP objects defined
          in the current document <span class="bcp14">MUST</span> be set to 0 on
          transmission and <span class="bcp14">SHOULD</span> be ignored on receipt since
          they are exclusively related to path computation requests.<a href="#section-3.1-3.1" class="pilcrow">¶</a>
</li>
<li class="ulEmpty" id="section-3.1-3.2">The sections that follow define PCEP objects and TLVs that
          contain Flags fields, and some flag values are defined.  Future
          specifications may define further flags, and each new specification
          that defines additional flags is expected to describe the
          interaction between these new flags and any existing flags.  In
          particular, new specifications are expected to explain how to handle
          the cases when both new and pre-existing flags are set.<a href="#section-3.1-3.2" class="pilcrow">¶</a>
</li>
</ul>
</section>
</div>
<div id="SRPflags">
<section id="section-3.2">
        <h3 id="name-flags-field-of-the-srp-obje">
<a href="#section-3.2" class="section-number selfRef">3.2. </a><a href="#name-flags-field-of-the-srp-obje" class="section-name selfRef">Flags Field of the SRP Object</a>
        </h3>
<p id="section-3.2-1"><span><a href="https://www.rfc-editor.org/rfc/rfc8231#section-7.2" class="relref">Section 7.2</a> of [<a href="#RFC8231" class="xref">RFC8231</a>]</span> defines the PCEP SRP object.  It describes
           the Flags field as:<a href="#section-3.2-1" class="pilcrow">¶</a></p>
<ul class="ulEmpty">
<li class="ulEmpty" id="section-3.2-2.1">Flags (32 bits): None defined yet.<a href="#section-3.2-2.1" class="pilcrow">¶</a>
</li>
</ul>
<p id="section-3.2-3">This document updates that text as follows:<a href="#section-3.2-3" class="pilcrow">¶</a></p>
<ul class="ulEmpty">
<li class="ulEmpty" id="section-3.2-4.1">Flags (32 bits): This document does not define any flags.  Unassigned flags
                 <span class="bcp14">MUST</span> be set to zero on transmission and <span class="bcp14">MUST</span> be ignored on receipt.
                 Implementations that do not understand any particular flag <span class="bcp14">MUST</span> ignore the
                 flag.<a href="#section-3.2-4.1" class="pilcrow">¶</a>
</li>
</ul>
</section>
</div>
</section>
</div>
<div id="Backward">
<section id="section-4">
      <h2 id="name-compatibility-consideration">
<a href="#section-4" class="section-number selfRef">4. </a><a href="#name-compatibility-consideration" class="section-name selfRef">Compatibility Considerations</a>
      </h2>
<p id="section-4-1">While one of the main objectives of the changes made by this document
      is to enable backward compatibility, there remains an issue of
      compatibility between existing implementations of RFC 8231 and
      implementations that are consistent with this document.<a href="#section-4-1" class="pilcrow">¶</a></p>
<p id="section-4-2">It should be noted that common behavior for Flags fields is as
      described by the updated text presented in <a href="#update" class="xref">Section 3</a>.  Thus, many implementations, lacking guidance from
      RFC 8231, will still have implemented a consistent and future-proof
      approach.  However, for completeness, it is worth noting how behaviors
      might interact between implementations.<a href="#section-4-2" class="pilcrow">¶</a></p>
<p id="section-4-3">SRP objects generated by an implementation of this document will set
      all unknown flag bits to zero and will therefore cause no issues to an
      older implementation even if it inspects those bits.  Similarly, an
      implementation of this document will not inspect any unknown flag bits
      and will therefore be unaffected by older implementations no matter how
      they set the flags.<a href="#section-4-3" class="pilcrow">¶</a></p>
<p id="section-4-4">There will remain an issue with compatibility between implementations
      and how they set the flags. An implementation of RFC 8231 might set any
      of the unassigned flags, but an implementation of a future or current
      specification (such as <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span> or
      <span>[<a href="#RFC8741" class="xref">RFC8741</a>]</span>) assigns specific meanings to
      a flag if set. That problem cannot be fixed in old implementations by
      any amount of documentation and can only be handled for future
      specifications by obsoleting the Flags field and using a new technique.
      Fortunately, however, most implementations will have been constructed to
      set unused flags to zero, which is consistent with the behavior
      described in this document, and so the risk of bad interactions is
      sufficiently small that there is no need to obsolete the existing Flags
      field.<a href="#section-4-4" class="pilcrow">¶</a></p>
</section>
</div>
<div id="Management">
<section id="section-5">
      <h2 id="name-management-considerations">
<a href="#section-5" class="section-number selfRef">5. </a><a href="#name-management-considerations" class="section-name selfRef">Management Considerations</a>
      </h2>
<p id="section-5-1">Implementations receiving set SRP flags that they do not recognize <span class="bcp14">MAY</span> log this.  That could
          be helpful for diagnosing backward compatibility issues with future features that utilize those
          flags.<a href="#section-5-1" class="pilcrow">¶</a></p>
</section>
</div>
<div id="Security">
<section id="section-6">
      <h2 id="name-security-considerations">
<a href="#section-6" class="section-number selfRef">6. </a><a href="#name-security-considerations" class="section-name selfRef">Security Considerations</a>
      </h2>
<p id="section-6-1"><span>[<a href="#RFC8231" class="xref">RFC8231</a>]</span> sets out security considerations for PCEP when used for communication
         with a stateful PCE.  This document does not change those considerations.<a href="#section-6-1" class="pilcrow">¶</a></p>
<p id="section-6-2">However, by defining the expected behavior of implementations, this
      document may improve the stability of networks and thus reduce the
      attack surface.  That is, by reminding implementations to ignore unset
      bits, it is less possible to attack them by randomly tweaking bits.
      Furthermore, by reminding implementations to leave undefined bits unset,
      the network is future-proofed against new definitions of previously
      undefined bits.<a href="#section-6-2" class="pilcrow">¶</a></p>
</section>
</div>
<div id="IANA">
<section id="section-7">
      <h2 id="name-iana-considerations">
<a href="#section-7" class="section-number selfRef">7. </a><a href="#name-iana-considerations" class="section-name selfRef">IANA Considerations</a>
      </h2>
<p id="section-7-1">IANA maintains a registry called the "Path Computation Element
      Protocol (PCEP) Numbers" registry with a subregistry called "SRP Object
      Flag Field". IANA has updated the reference for that
      subregistry to list this document in addition to
      <span>[<a href="#RFC8281" class="xref">RFC8281</a>]</span>.<a href="#section-7-1" class="pilcrow">¶</a></p>
</section>
</div>
<section id="section-8">
      <h2 id="name-references">
<a href="#section-8" class="section-number selfRef">8. </a><a href="#name-references" class="section-name selfRef">References</a>
      </h2>
<section id="section-8.1">
        <h3 id="name-normative-references">
<a href="#section-8.1" class="section-number selfRef">8.1. </a><a href="#name-normative-references" class="section-name selfRef">Normative References</a>
        </h3>
<dl class="references">
<dt id="RFC2119">[RFC2119]</dt>
<dd>
<span class="refAuthor">Bradner, S.</span>, <span class="refTitle">"Key words for use in RFCs to Indicate Requirement Levels"</span>, <span class="seriesInfo">BCP 14</span>, <span class="seriesInfo">RFC 2119</span>, <span class="seriesInfo">DOI 10.17487/RFC2119</span>, <time datetime="1997-03">March 1997</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc2119">https://www.rfc-editor.org/info/rfc2119</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8174">[RFC8174]</dt>
<dd>
<span class="refAuthor">Leiba, B.</span>, <span class="refTitle">"Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words"</span>, <span class="seriesInfo">BCP 14</span>, <span class="seriesInfo">RFC 8174</span>, <span class="seriesInfo">DOI 10.17487/RFC8174</span>, <time datetime="2017-05">May 2017</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8174">https://www.rfc-editor.org/info/rfc8174</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8231">[RFC8231]</dt>
<dd>
<span class="refAuthor">Crabbe, E.</span><span class="refAuthor">, Minei, I.</span><span class="refAuthor">, Medved, J.</span><span class="refAuthor">, and R. Varga</span>, <span class="refTitle">"Path Computation Element Communication Protocol (PCEP) Extensions for Stateful PCE"</span>, <span class="seriesInfo">RFC 8231</span>, <span class="seriesInfo">DOI 10.17487/RFC8231</span>, <time datetime="2017-09">September 2017</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8231">https://www.rfc-editor.org/info/rfc8231</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8281">[RFC8281]</dt>
<dd>
<span class="refAuthor">Crabbe, E.</span><span class="refAuthor">, Minei, I.</span><span class="refAuthor">, Sivabalan, S.</span><span class="refAuthor">, and R. Varga</span>, <span class="refTitle">"Path Computation Element Communication Protocol (PCEP) Extensions for PCE-Initiated LSP Setup in a Stateful PCE Model"</span>, <span class="seriesInfo">RFC 8281</span>, <span class="seriesInfo">DOI 10.17487/RFC8281</span>, <time datetime="2017-12">December 2017</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8281">https://www.rfc-editor.org/info/rfc8281</a>&gt;</span>. </dd>
<dd class="break"></dd>
</dl>
</section>
<section id="section-8.2">
        <h3 id="name-informative-references">
<a href="#section-8.2" class="section-number selfRef">8.2. </a><a href="#name-informative-references" class="section-name selfRef">Informative References</a>
        </h3>
<dl class="references">
<dt id="RFC4657">[RFC4657]</dt>
<dd>
<span class="refAuthor">Ash, J., Ed.</span><span class="refAuthor"> and J.L. Le Roux, Ed.</span>, <span class="refTitle">"Path Computation Element (PCE) Communication Protocol Generic Requirements"</span>, <span class="seriesInfo">RFC 4657</span>, <span class="seriesInfo">DOI 10.17487/RFC4657</span>, <time datetime="2006-09">September 2006</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc4657">https://www.rfc-editor.org/info/rfc4657</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC5440">[RFC5440]</dt>
<dd>
<span class="refAuthor">Vasseur, JP., Ed.</span><span class="refAuthor"> and JL. Le Roux, Ed.</span>, <span class="refTitle">"Path Computation Element (PCE) Communication Protocol (PCEP)"</span>, <span class="seriesInfo">RFC 5440</span>, <span class="seriesInfo">DOI 10.17487/RFC5440</span>, <time datetime="2009-03">March 2009</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5440">https://www.rfc-editor.org/info/rfc5440</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8741">[RFC8741]</dt>
<dd>
<span class="refAuthor">Raghuram, A.</span><span class="refAuthor">, Goddard, A.</span><span class="refAuthor">, Karthik, J.</span><span class="refAuthor">, Sivabalan, S.</span><span class="refAuthor">, and M. Negi</span>, <span class="refTitle">"Ability for a Stateful Path Computation Element (PCE) to Request and Obtain Control of a Label Switched Path (LSP)"</span>, <span class="seriesInfo">RFC 8741</span>, <span class="seriesInfo">DOI 10.17487/RFC8741</span>, <time datetime="2020-03">March 2020</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8741">https://www.rfc-editor.org/info/rfc8741</a>&gt;</span>. </dd>
<dd class="break"></dd>
</dl>
</section>
</section>
<div id="Acknowledgements">
<section id="section-appendix.a">
      <h2 id="name-acknowledgements">
<a href="#name-acknowledgements" class="section-name selfRef">Acknowledgements</a>
      </h2>
<p id="section-appendix.a-1">Thanks to the authors of <span>[<a href="#RFC8741" class="xref">RFC8741</a>]</span>
      for exposing the need for this work.  Thanks to <span class="contact-name">Dhruv       Dhody</span> and <span class="contact-name">Julien Meuric</span> for discussing the
      solution.  Additional thanks to <span class="contact-name">Hariharan       Ananthakrishnan</span> for his Shepherd's review.  Thanks to <span class="contact-name">Benjamin Kaduk</span> and <span class="contact-name">Alvaro Retana</span> for
      helpful comments during IESG review.<a href="#section-appendix.a-1" class="pilcrow">¶</a></p>
</section>
</div>
<div id="authors-addresses">
<section id="section-appendix.b">
      <h2 id="name-authors-address">
<a href="#name-authors-address" class="section-name selfRef">Author's Address</a>
      </h2>
<address class="vcard">
        <div dir="auto" class="left"><span class="fn nameRole">Adrian Farrel</span></div>
<div dir="auto" class="left"><span class="org">Old Dog Consulting</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:adrian@olddog.co.uk" class="email">adrian@olddog.co.uk</a>
</div>
</address>
</section>
</div>
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