File: rfc8825.html

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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 8825: Overview: Real-Time Protocols for Browser-Based Applications</title>
<meta content="Harald T. Alvestrand" name="author">
<meta content='
       This document gives an overview and context of a protocol suite
      intended for use with real-time applications that can be deployed in
      browsers -- "real-time communication on the Web". 
       It intends to serve as a starting and coordination point to make sure
      that (1) all the parts that are needed to achieve this goal are findable
      and (2) the parts that belong in the Internet protocol suite are fully
      specified and on the right publication track. 
       This document is an applicability statement -- it does not itself
      specify any protocol, but it specifies which other specifications
      implementations are supposed to follow to be compliant with Web
      Real-Time Communication (WebRTC). 
    ' name="description">
<meta content="xml2rfc 3.5.0" name="generator">
<meta content="8825" name="rfc.number">
<!-- Generator version information:
  xml2rfc 3.5.0
    Python 3.6.10
    appdirs 1.4.4
    ConfigArgParse 1.2.3
    google-i18n-address 2.3.5
    html5lib 1.0.1
    intervaltree 3.0.2
    Jinja2 2.11.2
    kitchen 1.2.6
    lxml 4.4.2
    pycairo 1.19.0
    pycountry 19.8.18
    pyflakes 2.1.1
    PyYAML 5.3.1
    requests 2.22.0
    setuptools 40.6.2
    six 1.14.0
    WeasyPrint 51
-->
<link href="rfc8825.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 {
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}
h1 {
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}
h2 {
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}
h3 {
  font-size: 18px;
  margin-top: -36px;  /* provide offset for in-page anchors */
  padding-top: 42px;
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h4 {
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  margin-top: -36px;  /* provide offset for in-page anchors */
  padding-top: 42px;
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h5, h6 {
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}
#n-copyright-notice {
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  padding-bottom: 1em;
  margin-bottom: 1em;
}
/* general structure */
p {
  padding: 0;
  margin: 0 0 1em 0;
  text-align: left;
}
div, span {
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}
div {
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.alignRight.art-text {
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.alignRight.art-text pre {
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.alignRight {
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}
.alignRight > *:first-child {
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  float: right;
  clear: both;
}
.alignRight > *:nth-child(2) {
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  border: none;
}
svg {
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}
.alignCenter.art-text {
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  border-radius: 3px;
  padding: 1em 1em 0;
  margin-bottom: 1.5em;
}
.alignCenter.art-text pre {
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}
.alignCenter {
  margin: 1em 0;
}
.alignCenter > *:first-child {
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  /* 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 {
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}
li {
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}
.ulCompact li {
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}
ul.empty, .ulEmpty {
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}
ul.empty li, .ulEmpty li {
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}
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 {
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}
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;
  }

}
/* 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 {
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<link href="https://dx.doi.org/10.17487/rfc8825" rel="alternate">
  <link href="urn:issn:2070-1721" rel="alternate">
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<table class="ears">
<thead><tr>
<td class="left">RFC 8825</td>
<td class="center">WebRTC Overview</td>
<td class="right">January 2021</td>
</tr></thead>
<tfoot><tr>
<td class="left">Alvestrand</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/rfc8825" class="eref">8825</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="2021-01" class="published">January 2021</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">H. Alvestrand</div>
<div class="org">Google</div>
</div>
</dd>
</dl>
</div>
<h1 id="rfcnum">RFC 8825</h1>
<h1 id="title">Overview: Real-Time Protocols for Browser-Based Applications</h1>
<section id="section-abstract">
      <h2 id="abstract"><a href="#abstract" class="selfRef">Abstract</a></h2>
<p id="section-abstract-1">This document gives an overview and context of a protocol suite
      intended for use with real-time applications that can be deployed in
      browsers -- "real-time communication on the Web".<a href="#section-abstract-1" class="pilcrow">¶</a></p>
<p id="section-abstract-2">It intends to serve as a starting and coordination point to make sure
      that (1) all the parts that are needed to achieve this goal are findable
      and (2) the parts that belong in the Internet protocol suite are fully
      specified and on the right publication track.<a href="#section-abstract-2" class="pilcrow">¶</a></p>
<p id="section-abstract-3">This document is an applicability statement -- it does not itself
      specify any protocol, but it specifies which other specifications
      implementations are supposed to follow to be compliant with Web
      Real-Time Communication (WebRTC).<a href="#section-abstract-3" 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/rfc8825">https://www.rfc-editor.org/info/rfc8825</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) 2021 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="compact toc ulEmpty">
<li class="compact 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="compact toc ulEmpty" id="section-toc.1-1.2">
            <p id="section-toc.1-1.2.1"><a href="#section-2" class="xref">2</a>.  <a href="#name-principles-and-terminology" class="xref">Principles and Terminology</a><a href="#section-toc.1-1.2.1" class="pilcrow">¶</a></p>
<ul class="compact toc ulEmpty">
<li class="compact toc ulEmpty" id="section-toc.1-1.2.2.1">
                <p id="section-toc.1-1.2.2.1.1" class="keepWithNext"><a href="#section-2.1" class="xref">2.1</a>.  <a href="#name-goals-of-this-document" class="xref">Goals of This Document</a><a href="#section-toc.1-1.2.2.1.1" class="pilcrow">¶</a></p>
</li>
              <li class="compact toc ulEmpty" id="section-toc.1-1.2.2.2">
                <p id="section-toc.1-1.2.2.2.1" class="keepWithNext"><a href="#section-2.2" class="xref">2.2</a>.  <a href="#name-relationship-between-api-an" class="xref">Relationship between API and Protocol</a><a href="#section-toc.1-1.2.2.2.1" class="pilcrow">¶</a></p>
</li>
              <li class="compact toc ulEmpty" id="section-toc.1-1.2.2.3">
                <p id="section-toc.1-1.2.2.3.1"><a href="#section-2.3" class="xref">2.3</a>.  <a href="#name-on-interoperability-and-inn" class="xref">On Interoperability and Innovation</a><a href="#section-toc.1-1.2.2.3.1" class="pilcrow">¶</a></p>
</li>
              <li class="compact toc ulEmpty" id="section-toc.1-1.2.2.4">
                <p id="section-toc.1-1.2.2.4.1"><a href="#section-2.4" class="xref">2.4</a>.  <a href="#name-terminology" class="xref">Terminology</a><a href="#section-toc.1-1.2.2.4.1" class="pilcrow">¶</a></p>
</li>
            </ul>
</li>
          <li class="compact 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-architecture-and-functional" class="xref">Architecture and Functionality Groups</a><a href="#section-toc.1-1.3.1" class="pilcrow">¶</a></p>
</li>
          <li class="compact 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-data-transport" class="xref">Data Transport</a><a href="#section-toc.1-1.4.1" class="pilcrow">¶</a></p>
</li>
          <li class="compact 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-data-framing-and-securing" class="xref">Data Framing and Securing</a><a href="#section-toc.1-1.5.1" class="pilcrow">¶</a></p>
</li>
          <li class="compact 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-data-formats" class="xref">Data Formats</a><a href="#section-toc.1-1.6.1" class="pilcrow">¶</a></p>
</li>
          <li class="compact 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-connection-management" class="xref">Connection Management</a><a href="#section-toc.1-1.7.1" class="pilcrow">¶</a></p>
</li>
          <li class="compact 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-presentation-and-control" class="xref">Presentation and Control</a><a href="#section-toc.1-1.8.1" class="pilcrow">¶</a></p>
</li>
          <li class="compact toc ulEmpty" id="section-toc.1-1.9">
            <p id="section-toc.1-1.9.1"><a href="#section-9" class="xref">9</a>.  <a href="#name-local-system-support-functi" class="xref">Local System Support Functions</a><a href="#section-toc.1-1.9.1" class="pilcrow">¶</a></p>
</li>
          <li class="compact toc ulEmpty" id="section-toc.1-1.10">
            <p id="section-toc.1-1.10.1"><a href="#section-10" class="xref">10</a>. <a href="#name-iana-considerations" class="xref">IANA Considerations</a><a href="#section-toc.1-1.10.1" class="pilcrow">¶</a></p>
</li>
          <li class="compact toc ulEmpty" id="section-toc.1-1.11">
            <p id="section-toc.1-1.11.1"><a href="#section-11" class="xref">11</a>. <a href="#name-security-considerations" class="xref">Security Considerations</a><a href="#section-toc.1-1.11.1" class="pilcrow">¶</a></p>
</li>
          <li class="compact toc ulEmpty" id="section-toc.1-1.12">
            <p id="section-toc.1-1.12.1"><a href="#section-12" class="xref">12</a>. <a href="#name-references" class="xref">References</a><a href="#section-toc.1-1.12.1" class="pilcrow">¶</a></p>
<ul class="compact toc ulEmpty">
<li class="compact toc ulEmpty" id="section-toc.1-1.12.2.1">
                <p id="section-toc.1-1.12.2.1.1"><a href="#section-12.1" class="xref">12.1</a>.  <a href="#name-normative-references" class="xref">Normative References</a><a href="#section-toc.1-1.12.2.1.1" class="pilcrow">¶</a></p>
</li>
              <li class="compact toc ulEmpty" id="section-toc.1-1.12.2.2">
                <p id="section-toc.1-1.12.2.2.1"><a href="#section-12.2" class="xref">12.2</a>.  <a href="#name-informative-references" class="xref">Informative References</a><a href="#section-toc.1-1.12.2.2.1" class="pilcrow">¶</a></p>
</li>
            </ul>
</li>
          <li class="compact toc ulEmpty" id="section-toc.1-1.13">
            <p id="section-toc.1-1.13.1"><a href="#section-appendix.a" class="xref"></a><a href="#name-acknowledgements" class="xref">Acknowledgements</a><a href="#section-toc.1-1.13.1" class="pilcrow">¶</a></p>
</li>
          <li class="compact toc ulEmpty" id="section-toc.1-1.14">
            <p id="section-toc.1-1.14.1"><a href="#section-appendix.b" class="xref"></a><a href="#name-authors-address" class="xref">Author's Address</a><a href="#section-toc.1-1.14.1" class="pilcrow">¶</a></p>
</li>
        </ul>
</nav>
</section>
</div>
<div id="intro">
<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">The Internet was, from very early in its lifetime, considered a
      possible vehicle for the deployment of real-time, interactive
      applications -- with the most easily imaginable being audio conversations
      (aka "Internet telephony") and video conferencing.<a href="#section-1-1" class="pilcrow">¶</a></p>
<p id="section-1-2">The first attempts to build such applications were dependent on special networks,
      special hardware, and custom-built software, often at very high prices or
      of low quality, placing great demands on the infrastructure.<a href="#section-1-2" class="pilcrow">¶</a></p>
<p id="section-1-3">As the available bandwidth has increased, and as processors and other
      hardware have become ever faster, the barriers to participation have
      decreased, and it has become possible to deliver a satisfactory
      experience on commonly available computing hardware.<a href="#section-1-3" class="pilcrow">¶</a></p>
<p id="section-1-4">Still, there are a number of barriers to the ability to communicate
      universally -- one of these is that there is, as of yet, no single set of
      communication protocols that all agree should be made available for
      communication; another is the sheer lack of universal identification
      systems (such as is served by telephone numbers or email addresses in
      other communications systems).<a href="#section-1-4" class="pilcrow">¶</a></p>
<p id="section-1-5">Development of "The Universal Solution" has, however, proved hard.<a href="#section-1-5" class="pilcrow">¶</a></p>
<p id="section-1-6">The last few years have also seen a new platform rise for deployment
      of services: the browser-embedded application, or "web application". It
      turns out that as long as the browser platform has the necessary
      interfaces, it is possible to deliver almost any kind of service
      on it.<a href="#section-1-6" class="pilcrow">¶</a></p>
<p id="section-1-7">Traditionally, these interfaces have been delivered by plugins, which
      had to be downloaded and installed separately from the browser; in the
      development of HTML5 <span>[<a href="#HTML5" class="xref">HTML5</a>]</span>, application developers see much promise in the
      possibility of making those interfaces available in a standardized way
      within the browser.<a href="#section-1-7" class="pilcrow">¶</a></p>
<p id="section-1-8">This memo describes a set of building blocks that (1) can be made
      accessible and controllable through a JavaScript API in a browser and
      (2) together form a sufficient set of functions to allow the use of
      interactive audio and video in applications that communicate directly
      between browsers across the Internet. The resulting protocol suite is
      intended to enable all the applications that are described as required
      scenarios in the WebRTC "use cases" document <span>[<a href="#RFC7478" class="xref">RFC7478</a>]</span>.<a href="#section-1-8" class="pilcrow">¶</a></p>
<p id="section-1-9">Other efforts -- for instance, the W3C Web Real-Time Communications,
      Web Applications Security, and Devices and Sensors Working Groups -- focus
      on making standardized APIs and interfaces available, within or
      alongside the HTML5 effort, for those functions.  This memo concentrates
      on specifying the protocols and subprotocols that are needed to specify
      the interactions over the network.<a href="#section-1-9" class="pilcrow">¶</a></p>
<p id="section-1-10">Operators should note that deployment of WebRTC will result in a
      change in the nature of signaling for real-time media on the network
      and may result in a shift in the kinds of devices used to create and
      consume such media. In the case of signaling, WebRTC session setup
      will typically occur over TLS-secured web technologies using
      application-specific protocols.  Operational techniques that involve
      inserting network elements to interpret the Session Description Protocol
      (SDP) -- through either (1) the endpoint asking the network for a SIP server <span>[<a href="#RFC3361" class="xref">RFC3361</a>]</span> or (2) the transparent
      insertion of SIP Application Layer Gateways (ALGs) -- will not work
      with such signaling. In the case of networks using cooperative
      endpoints, the approaches defined in <span>[<a href="#RFC8155" class="xref">RFC8155</a>]</span> may serve
      as a suitable replacement for <span>[<a href="#RFC3361" class="xref">RFC3361</a>]</span>. The increase in
      browser-based communications may also lead to a shift away from
      dedicated real-time-communications hardware, such as SIP
      desk phones. This will diminish the efficacy of operational
      techniques that place dedicated real-time devices on their own
      network segment, address range, or VLAN for purposes such as
      applying traffic filtering and QoS. Applying the markings
      described in <span>[<a href="#RFC8837" class="xref">RFC8837</a>]</span> may be
      appropriate replacements for such techniques.<a href="#section-1-10" class="pilcrow">¶</a></p>
<p id="section-1-11">While this document formally relies on <span>[<a href="#RFC8445" class="xref">RFC8445</a>]</span>,
at the time of its publication, the majority of WebRTC implementations
support the version of Interactive Connectivity Establishment (ICE)
that is described in <span>[<a href="#RFC5245" class="xref">RFC5245</a>]</span> and use a
pre-standard version of the Trickle ICE mechanism described in
<span>[<a href="#RFC8838" class="xref">RFC8838</a>]</span>. The "ice2" attribute defined in <span>[<a href="#RFC8445" class="xref">RFC8445</a>]</span> can be used to detect the version in use by a
remote endpoint and to provide a smooth transition from the older
specification to the newer one.<a href="#section-1-11" class="pilcrow">¶</a></p>
<p id="section-1-12">This memo uses the term "WebRTC" (note the case used) to refer to the
      overall effort consisting of both IETF and W3C efforts.<a href="#section-1-12" class="pilcrow">¶</a></p>
</section>
</div>
<section id="section-2">
      <h2 id="name-principles-and-terminology">
<a href="#section-2" class="section-number selfRef">2. </a><a href="#name-principles-and-terminology" class="section-name selfRef">Principles and Terminology</a>
      </h2>
<p id="section-2-1"></p>
<section id="section-2.1">
        <h3 id="name-goals-of-this-document">
<a href="#section-2.1" class="section-number selfRef">2.1. </a><a href="#name-goals-of-this-document" class="section-name selfRef">Goals of This Document</a>
        </h3>
<p id="section-2.1-1">The goal of the WebRTC protocol specification is to specify a set
        of protocols that, if all are implemented, will allow an
        implementation to communicate with another implementation using audio,
        video, and data sent along the most direct possible path between the
        participants.<a href="#section-2.1-1" class="pilcrow">¶</a></p>
<p id="section-2.1-2">This document is intended to serve as the roadmap to the WebRTC
        specifications. It defines terms used by other parts of the WebRTC
        protocol specifications, lists references to other specifications that
        don't need further elaboration in the WebRTC context, and gives
        pointers to other documents that form part of the WebRTC suite.<a href="#section-2.1-2" class="pilcrow">¶</a></p>
<p id="section-2.1-3">By reading this document and the documents it refers to, it should
        be possible to have all information needed to implement a
        WebRTC-compatible implementation.<a href="#section-2.1-3" class="pilcrow">¶</a></p>
</section>
<section id="section-2.2">
        <h3 id="name-relationship-between-api-an">
<a href="#section-2.2" class="section-number selfRef">2.2. </a><a href="#name-relationship-between-api-an" class="section-name selfRef">Relationship between API and Protocol</a>
        </h3>
<p id="section-2.2-1">The total WebRTC effort consists of two major parts, each
        consisting of multiple documents:<a href="#section-2.2-1" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-2.2-2.1">A protocol specification, done in the IETF<a href="#section-2.2-2.1" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-2.2-2.2">A JavaScript API specification, defined in a series of W3C
            documents <span>[<a href="#W3C.WD-webrtc" class="xref">W3C.WD-webrtc</a>]</span>
            <span>[<a href="#W3C.WD-mediacapture-streams" class="xref">W3C.WD-mediacapture-streams</a>]</span><a href="#section-2.2-2.2" class="pilcrow">¶</a>
</li>
        </ul>
<p id="section-2.2-3">Together, these two specifications aim to provide an
        environment where JavaScript embedded in any page, when suitably
        authorized by its user, is able to set up communication using audio,
        video, and auxiliary data, as long as the browser supports these
        specifications. The browser environment does not constrain the types of
        application in which this functionality can be used.<a href="#section-2.2-3" class="pilcrow">¶</a></p>
<p id="section-2.2-4">The protocol specification does not assume that all implementations
        implement this API; it is not intended to be necessary for
        interoperation to know whether the entity one is communicating with is
        a browser or another device implementing the protocol specification.<a href="#section-2.2-4" class="pilcrow">¶</a></p>
<p id="section-2.2-5">The goal of cooperation between the protocol specification and the
        API specification is that for all options and features of the protocol
        specification, it should be clear which API calls to make to exercise
        that option or feature; similarly, for any sequence of API calls, it
        should be clear which protocol options and features will be invoked.
        Both are subject to constraints of the implementation, of course.<a href="#section-2.2-5" class="pilcrow">¶</a></p>
<p id="section-2.2-6">The following terms are used across the documents specifying the
        WebRTC suite, with the specific meanings given here. Not all terms are
        used in this document. Other terms are used per their commonly used
        meanings.<a href="#section-2.2-6" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel" id="section-2.2-7">
          <dt id="section-2.2-7.1">Agent:</dt>
          <dd style="margin-left: 1.5em" id="section-2.2-7.2">Undefined term. See "SDP Agent" and "ICE
            Agent".<a href="#section-2.2-7.2" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.2-7.3">Application Programming Interface (API):</dt>
          <dd style="margin-left: 1.5em" id="section-2.2-7.4">A
            specification of a set of calls and events, usually tied to a
            programming language or an abstract formal specification such as
            WebIDL, with its defined semantics.<a href="#section-2.2-7.4" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.2-7.5">Browser:</dt>
          <dd style="margin-left: 1.5em" id="section-2.2-7.6">Used synonymously with "interactive user
            agent" as defined in <span>[<a href="#HTML5" class="xref">HTML5</a>]</span>.
 See also the "WebRTC Browser" (aka "WebRTC User Agent") definition below.<a href="#section-2.2-7.6" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.2-7.7">Data Channel:</dt>
          <dd style="margin-left: 1.5em" id="section-2.2-7.8">An abstraction that allows data to be
            sent between WebRTC endpoints in the form of messages. Two
            endpoints can have multiple data channels between them.<a href="#section-2.2-7.8" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.2-7.9">ICE Agent:</dt>
          <dd style="margin-left: 1.5em" id="section-2.2-7.10">An implementation of the Interactive Connectivity Establishment (ICE) protocol <span>[<a href="#RFC8445" class="xref">RFC8445</a>]</span>. An ICE Agent may also
            be an SDP Agent, but there exist ICE Agents that do not use SDP
            (for instance, those that use Jingle <span>[<a href="#XEP-0166" class="xref">XEP-0166</a>]</span>).<a href="#section-2.2-7.10" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.2-7.11">Interactive:</dt>
          <dd style="margin-left: 1.5em" id="section-2.2-7.12">Communication between multiple parties,
            where the expectation is that an action from one party can cause a
            reaction by another party, and the reaction can be observed by the
            first party, where the total time required for the
            action/reaction/observation is on the order of no more than
            hundreds of milliseconds.<a href="#section-2.2-7.12" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.2-7.13">Media:</dt>
          <dd style="margin-left: 1.5em" id="section-2.2-7.14">Audio and video content. Not to be confused
            with "transmission media" such as wires.<a href="#section-2.2-7.14" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.2-7.15">Media Path:</dt>
          <dd style="margin-left: 1.5em" id="section-2.2-7.16">The path that media data follows from
            one WebRTC endpoint to another.<a href="#section-2.2-7.16" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.2-7.17">Protocol:</dt>
          <dd style="margin-left: 1.5em" id="section-2.2-7.18">A specification of a set of data units,
            their representation, and rules for their transmission, with their
            defined semantics. A protocol is usually thought of as going
            between systems.<a href="#section-2.2-7.18" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.2-7.19">Real-Time Media:</dt>
          <dd style="margin-left: 1.5em" id="section-2.2-7.20">Media where the generation
            and display of content are intended to occur closely together in
            time (on the order of no more than hundreds of milliseconds).
            Real-time media can be used to support interactive
            communication.<a href="#section-2.2-7.20" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.2-7.21">SDP Agent:</dt>
          <dd style="margin-left: 1.5em" id="section-2.2-7.22">The protocol implementation involved in
            the Session Description Protocol (SDP) offer/answer exchange, as
            defined in <span>[<a href="#RFC3264" class="xref">RFC3264</a>], <a href="https://www.rfc-editor.org/rfc/rfc3264#section-3" class="relref">Section 3</a></span>.<a href="#section-2.2-7.22" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.2-7.23">Signaling:</dt>
          <dd style="margin-left: 1.5em" id="section-2.2-7.24">Communication that happens in order to
            establish, manage, and control media paths and data paths.<a href="#section-2.2-7.24" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.2-7.25">Signaling Path:</dt>
          <dd style="margin-left: 1.5em" id="section-2.2-7.26">The communication channels used
            between entities participating in signaling to transfer signaling.
            There may be more entities in the signaling path than in the media
            path.<a href="#section-2.2-7.26" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.2-7.27">WebRTC Browser (also called a "WebRTC User Agent" or "WebRTC UA"):</dt>
          <dd style="margin-left: 1.5em" id="section-2.2-7.28"> Something that conforms to both the protocol
            specification and the JavaScript API cited above.<a href="#section-2.2-7.28" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.2-7.29">WebRTC Non-Browser:</dt>
          <dd style="margin-left: 1.5em" id="section-2.2-7.30"> Something that conforms to
            the protocol specification but does not claim to implement the
            JavaScript API.  This can also be called a "WebRTC device" or
            "WebRTC native application".<a href="#section-2.2-7.30" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.2-7.31">WebRTC Endpoint:</dt>
          <dd style="margin-left: 1.5em" id="section-2.2-7.32"> Either a WebRTC browser or a
            WebRTC non-browser. It conforms to the protocol specification.<a href="#section-2.2-7.32" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.2-7.33">WebRTC-Compatible Endpoint:</dt>
          <dd style="margin-left: 1.5em" id="section-2.2-7.34"> An endpoint that is able
            to successfully communicate with a WebRTC endpoint but may fail to
            meet some requirements of a WebRTC endpoint. This may limit where
            in the network such an endpoint can be attached or may limit the
            security guarantees that it offers to others. It is not
            constrained by this specification; when it is mentioned at all, it
            is to note the implications on WebRTC-compatible endpoints of the
            requirements placed on WebRTC endpoints.<a href="#section-2.2-7.34" class="pilcrow">¶</a>
</dd>
          <dd class="break"></dd>
<dt id="section-2.2-7.35">WebRTC Gateway:</dt>
          <dd style="margin-left: 1.5em" id="section-2.2-7.36"> A WebRTC-compatible endpoint that
            mediates media traffic to non-WebRTC entities.<a href="#section-2.2-7.36" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
</dl>
<p id="section-2.2-8">All WebRTC browsers are WebRTC endpoints, so any requirement
        on a WebRTC endpoint also applies to a WebRTC browser.<a href="#section-2.2-8" class="pilcrow">¶</a></p>
<p id="section-2.2-9">A WebRTC non-browser may be capable of hosting applications in a
        way that is similar to the way in which a browser can host JavaScript
        applications, typically by offering APIs in other languages. For
        instance, it may be implemented as a library that offers a C++ API
        intended to be loaded into applications. In this case, 
        security considerations similar to those for JavaScript may be needed; however,
        since such APIs are not defined or referenced here, this document
        cannot give any specific rules for those interfaces.<a href="#section-2.2-9" class="pilcrow">¶</a></p>
<p id="section-2.2-10">WebRTC gateways are described in a separate document <span>[<a href="#I-D.ietf-rtcweb-gateways" class="xref">WebRTC-Gateways</a>]</span>.<a href="#section-2.2-10" class="pilcrow">¶</a></p>
</section>
<section id="section-2.3">
        <h3 id="name-on-interoperability-and-inn">
<a href="#section-2.3" class="section-number selfRef">2.3. </a><a href="#name-on-interoperability-and-inn" class="section-name selfRef">On Interoperability and Innovation</a>
        </h3>
<p id="section-2.3-1">The "Mission statement for the IETF" <span>[<a href="#RFC3935" class="xref">RFC3935</a>]</span> states
        that "The benefit of a standard to the Internet is in interoperability
        - that multiple products implementing a standard are able to work
        together in order to deliver valuable functions to the Internet's
        users."<a href="#section-2.3-1" class="pilcrow">¶</a></p>
<p id="section-2.3-2">Communication on the Internet frequently occurs in two phases:<a href="#section-2.3-2" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-2.3-3.1">Two parties communicate, through some mechanism, what
            functionality they are both able to support.<a href="#section-2.3-3.1" class="pilcrow">¶</a>
</li>
          <li class="normal" id="section-2.3-3.2">They use that shared communicative functionality to
            communicate or, failing to find anything in common, give up on
            communication.<a href="#section-2.3-3.2" class="pilcrow">¶</a>
</li>
        </ul>
<p id="section-2.3-4">There are often many choices that can be made for
        communicative functionality; the history of the Internet is rife with
        the proposal, standardization, implementation, and success or failure
        of many types of options, in all sorts of protocols.<a href="#section-2.3-4" class="pilcrow">¶</a></p>
<p id="section-2.3-5">The goal of having a mandatory-to-implement function set is to
        prevent negotiation failure, not to preempt or prevent
        negotiation.<a href="#section-2.3-5" class="pilcrow">¶</a></p>
<p id="section-2.3-6">The presence of a mandatory-to-implement function set serves as a
        strong changer of the marketplace of deployment in that it gives a
        guarantee that you can communicate successfully as long as (1) you conform to a specification and
        (2) the other party is willing to accept communication at the base level of
        that specification.<a href="#section-2.3-6" class="pilcrow">¶</a></p>
<p id="section-2.3-7">The alternative (that is, not having a mandatory-to-implement
 function) does not mean that you cannot communicate; it merely
 means that in order to be part of the communications partnership,
 you have to implement the standard "and then some". The "and then some" is usually called a
        profile of some sort; in the version most antithetical to the Internet
        ethos, that "and then some" consists of having to use a specific
        vendor's product only.<a href="#section-2.3-7" class="pilcrow">¶</a></p>
</section>
<section id="section-2.4">
        <h3 id="name-terminology">
<a href="#section-2.4" class="section-number selfRef">2.4. </a><a href="#name-terminology" class="section-name selfRef">Terminology</a>
        </h3>
<p id="section-2.4-1">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-2.4-1" class="pilcrow">¶</a></p>
</section>
</section>
<div id="arch-func-grps">
<section id="section-3">
      <h2 id="name-architecture-and-functional">
<a href="#section-3" class="section-number selfRef">3. </a><a href="#name-architecture-and-functional" class="section-name selfRef">Architecture and Functionality Groups</a>
      </h2>
<p id="section-3-1">For browser-based applications, the model for real-time support does
     not assume that the browser will contain all the functions needed for
     an application such as a telephone or a video conference.  The vision is
     that the browser will have the functions needed for a web application,
     working in conjunction with its backend servers, to implement these
     functions.<a href="#section-3-1" class="pilcrow">¶</a></p>
<p id="section-3-2">This means that two vital interfaces need specification: the
      protocols that browsers use to talk to each other, without any
      intervening servers; and the APIs that are offered for a JavaScript
      application to take advantage of the browser's functionality.<a href="#section-3-2" class="pilcrow">¶</a></p>
<span id="name-browser-model"></span><div id="fig-browser-model">
<figure id="figure-1">
        <div class="artwork art-text alignLeft" id="section-3-3.1">
<pre>
                  +------------------------+  On-the-wire
                  |                        |  Protocols
                  |      Servers           |---------&gt;
                  |                        |
                  |                        |
                  +------------------------+
                              ^
                              |
                              |
                              | HTTPS/
                              | WebSockets
                              |
                              |
                +----------------------------+
                |    JavaScript/HTML/CSS     |
                +----------------------------+
             Other  ^                 ^ RTC
             APIs   |                 | APIs
                +---|-----------------|------+
                |   |                 |      |
                |                 +---------+|
                |                 | Browser ||  On-the-wire
                | Browser         | RTC     ||  Protocols
                |                 | Function|-----------&gt;
                |                 |         ||
                |                 |         ||
                |                 +---------+|
                +---------------------|------+
                                      |
                                      V
                                 Native OS Services</pre>
</div>
<figcaption><a href="#figure-1" class="selfRef">Figure 1</a>:
<a href="#name-browser-model" class="selfRef">Browser Model</a>
        </figcaption></figure>
</div>
<p id="section-3-4">Note that HTTPS and WebSockets are also offered to the JavaScript
      application through browser APIs.<a href="#section-3-4" class="pilcrow">¶</a></p>
<p id="section-3-5">As for all protocol and API specifications, there is no restriction
      that the protocols can only be used to talk to another browser; since
      they are fully specified, any endpoint that implements the protocols
      faithfully should be able to interoperate with the application running
      in the browser.<a href="#section-3-5" class="pilcrow">¶</a></p>
<p id="section-3-6">A commonly imagined model of deployment is depicted in <a href="#fig-webtrapezoid" class="xref">Figure 2</a>. ("JS" stands for JavaScript.)<a href="#section-3-6" class="pilcrow">¶</a></p>
<span id="name-browser-rtc-trapezoid"></span><div id="fig-webtrapezoid">
<figure id="figure-2">
        <div class="artwork art-text alignLeft" id="section-3-7.1">
<pre>
        +-----------+                  +-----------+
        |   Web     |                  |   Web     |
        |           |                  |           |
        |           |------------------|           |
        |  Server   |  Signaling Path  |  Server   |
        |           |                  |           |
        +-----------+                  +-----------+
             /                                \
            /                                  \ Application-defined
           /                                    \ over
          /                                      \ HTTPS/WebSockets
         /  Application-defined over              \
        /   HTTPS/WebSockets                       \
       /                                            \
 +-----------+                                +-----------+
 |JS/HTML/CSS|                                |JS/HTML/CSS|
 +-----------+                                +-----------+
 +-----------+                                +-----------+
 |           |                                |           |
 |           |                                |           |
 |  Browser  |--------------------------------|  Browser  |
 |           |          Media Path            |           |
 |           |                                |           |
 +-----------+                                +-----------+</pre>
</div>
<figcaption><a href="#figure-2" class="selfRef">Figure 2</a>:
<a href="#name-browser-rtc-trapezoid" class="selfRef">Browser RTC Trapezoid</a>
        </figcaption></figure>
</div>
<p id="section-3-8">In this drawing, the critical part to note is that the media path
      ("low path") goes directly between the browsers, so it has to be
      conformant to the specifications of the WebRTC protocol suite; the
      signaling path ("high path") goes via servers that can modify, translate,
      or manipulate the signals as needed.<a href="#section-3-8" class="pilcrow">¶</a></p>
<p id="section-3-9">If the two web servers are operated by different entities, the
      inter-server signaling mechanism needs to be agreed upon, by either
      standardization or other means of agreement. Existing protocols
      (e.g., SIP <span>[<a href="#RFC3261" class="xref">RFC3261</a>]</span> or the Extensible
      Messaging and Presence Protocol (XMPP) <span>[<a href="#RFC6120" class="xref">RFC6120</a>]</span>)
      could be used between servers, while either a standards-based or
      proprietary protocol could be used between the browser and the web
      server.<a href="#section-3-9" class="pilcrow">¶</a></p>
<p id="section-3-10">For example, if both operators' servers implement SIP, SIP could be
      used for communication between servers, along with either a standardized
      signaling mechanism (e.g., SIP over WebSockets) or a proprietary
      signaling mechanism used between the application running in the browser
      and the web server. Similarly, if both operators' servers implement
      XMPP, XMPP could be used
      for communication between XMPP servers, with either a standardized
      signaling mechanism (e.g., XMPP over WebSockets or Bidirectional-streams
      Over Synchronous HTTP (BOSH) <span>[<a href="#XEP-0124" class="xref">XEP-0124</a>]</span>) or a proprietary signaling mechanism used between the
      application running in the browser and the web server.<a href="#section-3-10" class="pilcrow">¶</a></p>
<p id="section-3-11">The choice of protocols for client-server and inter-server
      signaling, and the definition of the translation between them, are outside
      the scope of the WebRTC protocol suite described in this document.<a href="#section-3-11" class="pilcrow">¶</a></p>
<p id="section-3-12">The functionality groups that are needed in the browser can be
      specified, more or less from the bottom up, as:<a href="#section-3-12" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel" id="section-3-13">
        <dt id="section-3-13.1">Data transport:</dt>
        <dd style="margin-left: 1.5em" id="section-3-13.2">For example, TCP and UDP, and the means to securely set up
          connections between entities, as well as the functions for deciding
          when to send data: congestion management, bandwidth estimation, and
          so on.<a href="#section-3-13.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-3-13.3">Data framing:</dt>
        <dd style="margin-left: 1.5em" id="section-3-13.4">RTP, the Stream Control Transmission Protocol (SCTP), DTLS, and other data formats that serve
          as containers, and their functions for data confidentiality and
          integrity.<a href="#section-3-13.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-3-13.5">Data formats:</dt>
        <dd style="margin-left: 1.5em" id="section-3-13.6">Codec specifications, format specifications, and
          functionality specifications for the data passed between systems.
          Audio and video codecs, as well as formats for data and document
          sharing, belong in this category. In order to make use of data
          formats, a way to describe them (e.g., a session description) is
          needed.<a href="#section-3-13.6" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-3-13.7">Connection management:</dt>
        <dd style="margin-left: 1.5em" id="section-3-13.8">For example, setting up connections, agreeing on data
          formats, changing data formats during the duration of a call. SDP,
          SIP, and Jingle/XMPP belong in this category.<a href="#section-3-13.8" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-3-13.9">Presentation and control:</dt>
        <dd style="margin-left: 1.5em" id="section-3-13.10">What needs to happen in order to ensure
          that interactions behave in an unsurprising manner. This can
          include floor control, screen layout, voice-activated image
          switching, and other such functions, where part of the system
          requires cooperation between parties. Centralized Conferencing
          (XCON) <span>[<a href="#RFC6501" class="xref">RFC6501</a>]</span> and Cisco⁠/Tandberg's Telepresence Interoperability Protocol
          (TIP) were some attempts at specifying this kind of functionality;
          many applications have been built without standardized interfaces to
          these functions.<a href="#section-3-13.10" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-3-13.11">Local system support functions:</dt>
        <dd style="margin-left: 1.5em" id="section-3-13.12">Functions that need not be
          specified uniformly, because each participant may implement these
          functions as they choose, without affecting the bits
          on the wire in a way that others have to be cognizant of. Examples
          in this category include echo cancellation (some forms of it), local
          authentication and authorization mechanisms, OS access control, and
          the ability to do local recording of conversations.<a href="#section-3-13.12" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<p id="section-3-14">Within each functionality group, it is important to preserve
      both freedom to innovate and the ability for global communication.
      Freedom to innovate is helped by doing the specification in terms of
      interfaces, not implementation; any implementation able to communicate
      according to the interfaces is a valid implementation. The ability to
      communicate globally is helped by both (1) having core specifications be
      unencumbered by IPR issues and (2) having the formats and protocols be
      fully enough specified to allow for independent implementation.<a href="#section-3-14" class="pilcrow">¶</a></p>
<p id="section-3-15">One can think of the first three groups as forming a "media transport
      infrastructure" and of the last three groups as forming a "media
      service". In many contexts, it makes sense to use a common specification
      for the media transport infrastructure, which can be embedded in
      browsers and accessed using standard interfaces, and "let a thousand
      flowers bloom" in the "media service" layer; to achieve interoperable
      services, however, at least the first five of the six groups need to be
      specified.<a href="#section-3-15" class="pilcrow">¶</a></p>
</section>
</div>
<div id="ch-transport">
<section id="section-4">
      <h2 id="name-data-transport">
<a href="#section-4" class="section-number selfRef">4. </a><a href="#name-data-transport" class="section-name selfRef">Data Transport</a>
      </h2>
<p id="section-4-1">Data transport refers to the sending and receiving of data over the
      network interfaces, the choice of network-layer addresses at each end of
      the communication, and the interaction with any intermediate entities
      that handle the data but do not modify it (such as Traversal Using
      Relays around NAT (TURN) relays).<a href="#section-4-1" class="pilcrow">¶</a></p>
<p id="section-4-2">It includes necessary functions for congestion control,
      retransmission, and in-order delivery.<a href="#section-4-2" class="pilcrow">¶</a></p>
<p id="section-4-3">WebRTC endpoints <span class="bcp14">MUST</span> implement the transport protocols described in
      <span>[<a href="#RFC8835" class="xref">RFC8835</a>]</span>.<a href="#section-4-3" class="pilcrow">¶</a></p>
</section>
</div>
<section id="section-5">
      <h2 id="name-data-framing-and-securing">
<a href="#section-5" class="section-number selfRef">5. </a><a href="#name-data-framing-and-securing" class="section-name selfRef">Data Framing and Securing</a>
      </h2>
<p id="section-5-1">The format for media transport is RTP <span>[<a href="#RFC3550" class="xref">RFC3550</a>]</span>.
      Implementation of the Secure Real-time Transport Protocol (SRTP) <span>[<a href="#RFC3711" class="xref">RFC3711</a>]</span> is <span class="bcp14">REQUIRED</span> for all
      implementations.<a href="#section-5-1" class="pilcrow">¶</a></p>
<p id="section-5-2">The detailed considerations for usage of functions from RTP and SRTP
      are given in <span>[<a href="#RFC8834" class="xref">RFC8834</a>]</span>. The security
      considerations for the WebRTC use case are provided in <span>[<a href="#RFC8826" class="xref">RFC8826</a>]</span>, and the resulting security
      functions are described in <span>[<a href="#RFC8827" class="xref">RFC8827</a>]</span>.<a href="#section-5-2" class="pilcrow">¶</a></p>
<p id="section-5-3">Considerations for the transfer of data that is not in RTP format are
      described in <span>[<a href="#RFC8831" class="xref">RFC8831</a>]</span>, and a
      supporting protocol for establishing individual data channels is
      described in <span>[<a href="#RFC8832" class="xref">RFC8832</a>]</span>. WebRTC
      endpoints <span class="bcp14">MUST</span> implement these two specifications.<a href="#section-5-3" class="pilcrow">¶</a></p>
<p id="section-5-4">WebRTC endpoints <span class="bcp14">MUST</span> implement <span>[<a href="#RFC8834" class="xref">RFC8834</a>]</span>, <span>[<a href="#RFC8826" class="xref">RFC8826</a>]</span>, <span>[<a href="#RFC8827" class="xref">RFC8827</a>]</span>, and the requirements they
      include.<a href="#section-5-4" class="pilcrow">¶</a></p>
</section>
<div id="ch-data">
<section id="section-6">
      <h2 id="name-data-formats">
<a href="#section-6" class="section-number selfRef">6. </a><a href="#name-data-formats" class="section-name selfRef">Data Formats</a>
      </h2>
<p id="section-6-1">The intent of this specification is to allow each communications
      event to use the data formats that are best suited for that particular
      instance, where a format is supported by both sides of the connection.
      However, a minimum standard is greatly helpful in order to ensure that
      communication can be achieved. This document specifies a minimum
      baseline that will be supported by all implementations of this
      specification and leaves further codecs to be included at the will of
      the implementer.<a href="#section-6-1" class="pilcrow">¶</a></p>
<p id="section-6-2">WebRTC endpoints that support audio and/or video <span class="bcp14">MUST</span> implement the
      codecs and profiles required in <span>[<a href="#RFC7874" class="xref">RFC7874</a>]</span> and <span>[<a href="#RFC7742" class="xref">RFC7742</a>]</span>.<a href="#section-6-2" class="pilcrow">¶</a></p>
</section>
</div>
<section id="section-7">
      <h2 id="name-connection-management">
<a href="#section-7" class="section-number selfRef">7. </a><a href="#name-connection-management" class="section-name selfRef">Connection Management</a>
      </h2>
<p id="section-7-1">The methods, mechanisms, and requirements for setting up, negotiating,
      and tearing down connections comprise a large subject, and one where it is
      desirable to have both interoperability and freedom to innovate.<a href="#section-7-1" class="pilcrow">¶</a></p>
<p id="section-7-2">The following principles apply:<a href="#section-7-2" class="pilcrow">¶</a></p>
<ol start="1" type="1" class="normal type-1" id="section-7-3">
        <li id="section-7-3.1">The WebRTC media negotiations will be capable of representing the
          same SDP offer/answer semantics <span>[<a href="#RFC3264" class="xref">RFC3264</a>]</span> that are
          used in SIP, in such a way that it is possible to build a
          signaling gateway between SIP and the WebRTC media negotiation.<a href="#section-7-3.1" class="pilcrow">¶</a>
</li>
        <li id="section-7-3.2">It will be possible to gateway between legacy SIP devices that
          support ICE and appropriate RTP/SDP mechanisms, codecs, and
          security mechanisms without using a media gateway. A signaling
          gateway to convert between the signaling on the web side and the SIP
          signaling may be needed.<a href="#section-7-3.2" class="pilcrow">¶</a>
</li>
        <li id="section-7-3.3">When an SDP for a new codec is specified, no other standardization
          should be required for it to be possible to use that codec in the web
          browsers. Adding new codecs that might have new SDP parameters should
          not change the APIs between the browser and the JavaScript application. As
          soon as the browsers support the new codecs, old applications
          written before the codecs were specified should automatically be
          able to use the new codecs where appropriate, with no changes to the
          JavaScript applications.<a href="#section-7-3.3" class="pilcrow">¶</a>
</li>
      </ol>
<p id="section-7-4">The particular choices made for WebRTC, and their implications
      for the API offered by a browser implementing WebRTC, are described in
      <span>[<a href="#RFC8829" class="xref">RFC8829</a>]</span>.<a href="#section-7-4" class="pilcrow">¶</a></p>
<p id="section-7-5">WebRTC browsers <span class="bcp14">MUST</span> implement <span>[<a href="#RFC8829" class="xref">RFC8829</a>]</span>.<a href="#section-7-5" class="pilcrow">¶</a></p>
<p id="section-7-6">WebRTC endpoints <span class="bcp14">MUST</span> implement those functions
      described in <span>[<a href="#RFC8829" class="xref">RFC8829</a>]</span> that relate to the network layer (e.g., BUNDLE <span>[<a href="#RFC8843" class="xref">RFC8843</a>]</span>, "rtcp-mux" <span>[<a href="#RFC5761" class="xref">RFC5761</a>]</span>, and Trickle ICE <span>[<a href="#RFC8838" class="xref">RFC8838</a>]</span>), but these endpoints do not need to support the API
      functionality described in <span>[<a href="#RFC8829" class="xref">RFC8829</a>]</span>.<a href="#section-7-6" class="pilcrow">¶</a></p>
</section>
<section id="section-8">
      <h2 id="name-presentation-and-control">
<a href="#section-8" class="section-number selfRef">8. </a><a href="#name-presentation-and-control" class="section-name selfRef">Presentation and Control</a>
      </h2>
<p id="section-8-1">The most important part of control is the users' control over the
      browser's interaction with input/output devices and communications
      channels. It is important that the users have some way of figuring out
      where their audio, video, or texting is being sent; for what purported
      reason; and what guarantees are made by the parties that form part of
      this control channel. This is largely a local function between the
      browser, the underlying operating system, and the user interface; this is
      specified in the peer connection API <span>[<a href="#W3C.WD-webrtc" class="xref">W3C.WD-webrtc</a>]</span> and the media capture API <span>[<a href="#W3C.WD-mediacapture-streams" class="xref">W3C.WD-mediacapture-streams</a>]</span>.<a href="#section-8-1" class="pilcrow">¶</a></p>
<p id="section-8-2">WebRTC browsers <span class="bcp14">MUST</span> implement these two specifications.<a href="#section-8-2" class="pilcrow">¶</a></p>
</section>
<section id="section-9">
      <h2 id="name-local-system-support-functi">
<a href="#section-9" class="section-number selfRef">9. </a><a href="#name-local-system-support-functi" class="section-name selfRef">Local System Support Functions</a>
      </h2>
<p id="section-9-1">These functions are characterized by the fact that the quality of an implementation strongly influences the user experience, but the exact
      algorithm does not need coordination. In some cases (for instance, echo
      cancellation, as described below), the overall system definition may
      need to specify that the overall system needs to have some
      characteristics for which these facilities are useful, without requiring
      them to be implemented a certain way.<a href="#section-9-1" class="pilcrow">¶</a></p>
<p id="section-9-2">Local functions include echo cancellation; volume control; camera
      management, including focus, zoom, and pan/tilt controls (if available); and
      more.<a href="#section-9-2" class="pilcrow">¶</a></p>
<p id="section-9-3">One would want to see certain parts of the system conform to certain
      properties; for instance:<a href="#section-9-3" class="pilcrow">¶</a></p>
<ul class="normal">
<li class="normal" id="section-9-4.1">Echo cancellation should be good enough to achieve the
          suppression of acoustical feedback loops below a perceptually
          noticeable level.<a href="#section-9-4.1" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-9-4.2">Privacy concerns <span class="bcp14">MUST</span> be satisfied; for instance, if remote
          control of a camera is offered, the APIs should be available to let
          the local participant figure out who's controlling the camera and
          possibly decide to revoke the permission for camera usage.<a href="#section-9-4.2" class="pilcrow">¶</a>
</li>
        <li class="normal" id="section-9-4.3">Automatic Gain Control (AGC), if present, should normalize a speaking
          voice into a reasonable dB range.<a href="#section-9-4.3" class="pilcrow">¶</a>
</li>
      </ul>
<p id="section-9-5">The requirements on WebRTC systems with regard to audio
      processing are found in <span>[<a href="#RFC7874" class="xref">RFC7874</a>]</span>,
and that document includes more
      guidance about echo cancellation and AGC; the APIs for control
      of local devices are found in <span>[<a href="#W3C.WD-mediacapture-streams" class="xref">W3C.WD-mediacapture-streams</a>]</span>.<a href="#section-9-5" class="pilcrow">¶</a></p>
<p id="section-9-6">WebRTC endpoints <span class="bcp14">MUST</span> implement the processing functions in <span>[<a href="#RFC7874" class="xref">RFC7874</a>]</span>. (Together with the requirement in <a href="#ch-data" class="xref">Section 6</a>, this means that WebRTC endpoints <span class="bcp14">MUST</span> implement the
      whole document.)<a href="#section-9-6" class="pilcrow">¶</a></p>
</section>
<div id="IANA">
<section id="section-10">
      <h2 id="name-iana-considerations">
<a href="#section-10" class="section-number selfRef">10. </a><a href="#name-iana-considerations" class="section-name selfRef">IANA Considerations</a>
      </h2>
<p id="section-10-1">This document has no IANA actions.<a href="#section-10-1" class="pilcrow">¶</a></p>
</section>
</div>
<div id="Security">
<section id="section-11">
      <h2 id="name-security-considerations">
<a href="#section-11" class="section-number selfRef">11. </a><a href="#name-security-considerations" class="section-name selfRef">Security Considerations</a>
      </h2>
<p id="section-11-1">Security of the web-enabled real-time communications comes in several
      pieces:<a href="#section-11-1" class="pilcrow">¶</a></p>
<span class="break"></span><dl class="dlParallel" id="section-11-2">
        <dt id="section-11-2.1">Security of the components:</dt>
        <dd style="margin-left: 1.5em" id="section-11-2.2">The browsers, and other servers
          involved. The most target-rich environment here is probably the
          browser; the aim here should be that the introduction of these
          components introduces no additional vulnerability.<a href="#section-11-2.2" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-11-2.3">Security of the communication channels:</dt>
        <dd style="margin-left: 1.5em" id="section-11-2.4">It should be easy for participants to reassure themselves of the
  security of their communication
          -- by verifying the crypto parameters of the links that they
          participate in, and to get reassurances from the other parties to
          the communication that those parties promise that appropriate measures are
          taken.<a href="#section-11-2.4" class="pilcrow">¶</a>
</dd>
        <dd class="break"></dd>
<dt id="section-11-2.5">Security of the partners' identities:</dt>
        <dd style="margin-left: 1.5em" id="section-11-2.6">Verifying that the
          participants are who they say they are (when positive identification
          is appropriate) or that their identities cannot be uncovered (when
          anonymity is a goal of the application).<a href="#section-11-2.6" class="pilcrow">¶</a>
</dd>
      <dd class="break"></dd>
</dl>
<p id="section-11-3">The security analysis, and the requirements derived from that
      analysis, are contained in <span>[<a href="#RFC8826" class="xref">RFC8826</a>]</span>.<a href="#section-11-3" class="pilcrow">¶</a></p>
<p id="section-11-4">It is also important to read the security sections of <span>[<a href="#W3C.WD-mediacapture-streams" class="xref">W3C.WD-mediacapture-streams</a>]</span> and <span>[<a href="#W3C.WD-webrtc" class="xref">W3C.WD-webrtc</a>]</span>.<a href="#section-11-4" class="pilcrow">¶</a></p>
</section>
</div>
<section id="section-12">
      <h2 id="name-references">
<a href="#section-12" class="section-number selfRef">12. </a><a href="#name-references" class="section-name selfRef">References</a>
      </h2>
<section id="section-12.1">
        <h3 id="name-normative-references">
<a href="#section-12.1" class="section-number selfRef">12.1. </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" class="refDate">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="RFC3264">[RFC3264]</dt>
        <dd>
<span class="refAuthor">Rosenberg, J.</span><span class="refAuthor"> and H. Schulzrinne</span>, <span class="refTitle">"An Offer/Answer Model with Session Description Protocol (SDP)"</span>, <span class="seriesInfo">RFC 3264</span>, <span class="seriesInfo">DOI 10.17487/RFC3264</span>, <time datetime="2002-06" class="refDate">June 2002</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc3264">https://www.rfc-editor.org/info/rfc3264</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC3550">[RFC3550]</dt>
        <dd>
<span class="refAuthor">Schulzrinne, H.</span><span class="refAuthor">, Casner, S.</span><span class="refAuthor">, Frederick, R.</span><span class="refAuthor">, and V. Jacobson</span>, <span class="refTitle">"RTP: A Transport Protocol for Real-Time Applications"</span>, <span class="seriesInfo">STD 64</span>, <span class="seriesInfo">RFC 3550</span>, <span class="seriesInfo">DOI 10.17487/RFC3550</span>, <time datetime="2003-07" class="refDate">July 2003</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc3550">https://www.rfc-editor.org/info/rfc3550</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC3711">[RFC3711]</dt>
        <dd>
<span class="refAuthor">Baugher, M.</span><span class="refAuthor">, McGrew, D.</span><span class="refAuthor">, Naslund, M.</span><span class="refAuthor">, Carrara, E.</span><span class="refAuthor">, and K. Norrman</span>, <span class="refTitle">"The Secure Real-time Transport Protocol (SRTP)"</span>, <span class="seriesInfo">RFC 3711</span>, <span class="seriesInfo">DOI 10.17487/RFC3711</span>, <time datetime="2004-03" class="refDate">March 2004</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc3711">https://www.rfc-editor.org/info/rfc3711</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC7742">[RFC7742]</dt>
        <dd>
<span class="refAuthor">Roach, A.B.</span>, <span class="refTitle">"WebRTC Video Processing and Codec Requirements"</span>, <span class="seriesInfo">RFC 7742</span>, <span class="seriesInfo">DOI 10.17487/RFC7742</span>, <time datetime="2016-03" class="refDate">March 2016</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc7742">https://www.rfc-editor.org/info/rfc7742</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC7874">[RFC7874]</dt>
        <dd>
<span class="refAuthor">Valin, JM.</span><span class="refAuthor"> and C. Bran</span>, <span class="refTitle">"WebRTC Audio Codec and Processing Requirements"</span>, <span class="seriesInfo">RFC 7874</span>, <span class="seriesInfo">DOI 10.17487/RFC7874</span>, <time datetime="2016-05" class="refDate">May 2016</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc7874">https://www.rfc-editor.org/info/rfc7874</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" class="refDate">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="RFC8445">[RFC8445]</dt>
        <dd>
<span class="refAuthor">Keranen, A.</span><span class="refAuthor">, Holmberg, C.</span><span class="refAuthor">, and J. Rosenberg</span>, <span class="refTitle">"Interactive Connectivity Establishment (ICE): A Protocol for Network Address Translator (NAT) Traversal"</span>, <span class="seriesInfo">RFC 8445</span>, <span class="seriesInfo">DOI 10.17487/RFC8445</span>, <time datetime="2018-07" class="refDate">July 2018</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8445">https://www.rfc-editor.org/info/rfc8445</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8826">[RFC8826]</dt>
        <dd>
<span class="refAuthor">Rescorla, E.</span>, <span class="refTitle">"Security Considerations for WebRTC"</span>, <span class="seriesInfo">RFC 8826</span>, <span class="seriesInfo">DOI 10.17487/RFC8826</span>, <time datetime="2021-01" class="refDate">January 2021</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8826">https://www.rfc-editor.org/info/rfc8826</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8827">[RFC8827]</dt>
        <dd>
<span class="refAuthor">Rescorla, E.</span>, <span class="refTitle">"WebRTC Security Architecture"</span>, <span class="seriesInfo">RFC 8827</span>, <span class="seriesInfo">DOI 10.17487/RFC8827</span>, <time datetime="2021-01" class="refDate">January 2021</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8827">https://www.rfc-editor.org/info/rfc8827</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8829">[RFC8829]</dt>
        <dd>
<span class="refAuthor">Uberti, J.</span><span class="refAuthor">, Jennings, C.</span><span class="refAuthor">, and E. Rescorla, Ed.</span>, <span class="refTitle">"JavaScript Session Establishment Protocol (JSEP)"</span>, <span class="seriesInfo">RFC 8829</span>, <span class="seriesInfo">DOI 10.17487/RFC8829</span>, <time datetime="2021-01" class="refDate">January 2021</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8829">https://www.rfc-editor.org/info/rfc8829</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8831">[RFC8831]</dt>
        <dd>
<span class="refAuthor">Jesup, R.</span><span class="refAuthor">, Loreto, S.</span><span class="refAuthor">, and M. Tüxen</span>, <span class="refTitle">"WebRTC Data Channels"</span>, <span class="seriesInfo">RFC 8831</span>, <span class="seriesInfo">DOI 10.17487/RFC8831</span>, <time datetime="2021-01" class="refDate">January 2021</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8831">https://www.rfc-editor.org/info/rfc8831</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8832">[RFC8832]</dt>
        <dd>
<span class="refAuthor">Jesup, R.</span><span class="refAuthor">, Loreto, S.</span><span class="refAuthor">, and M. Tüxen</span>, <span class="refTitle">"WebRTC Data Channel Establishment Protocol"</span>, <span class="seriesInfo">RFC 8832</span>, <span class="seriesInfo">DOI 10.17487/RFC8832</span>, <time datetime="2021-01" class="refDate">January 2021</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8832">https://www.rfc-editor.org/info/rfc8832</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8834">[RFC8834]</dt>
        <dd>
<span class="refAuthor">Perkins, C.</span><span class="refAuthor">, Westerlund, M.</span><span class="refAuthor">, and J. Ott</span>, <span class="refTitle">"Media Transport and Use of RTP in WebRTC"</span>, <span class="seriesInfo">RFC 8834</span>, <span class="seriesInfo">DOI 10.17487/RFC8834</span>, <time datetime="2021-01" class="refDate">January 2021</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8834">https://www.rfc-editor.org/info/rfc8834</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8835">[RFC8835]</dt>
        <dd>
<span class="refAuthor">Alvestrand, H.</span>, <span class="refTitle">"Transports for WebRTC"</span>, <span class="seriesInfo">RFC 8835</span>, <span class="seriesInfo">DOI 10.17487/RFC8835</span>, <time datetime="2021-01" class="refDate">January 2021</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8835">https://www.rfc-editor.org/info/rfc8835</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="W3C.WD-mediacapture-streams">[W3C.WD-mediacapture-streams]</dt>
        <dd>
<span class="refAuthor">Jennings, C.</span><span class="refAuthor">, Aboba, B.</span><span class="refAuthor">, Bruaroey, J-I.</span><span class="refAuthor">, and H. Boström</span>, <span class="refTitle">"Media Capture and Streams"</span>, <span class="refContent">W3C Candidate Recommendation</span>, <span>&lt;<a href="https://www.w3.org/TR/mediacapture-streams/">https://www.w3.org/TR/mediacapture-streams/</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="W3C.WD-webrtc">[W3C.WD-webrtc]</dt>
      <dd>
<span class="refAuthor">Jennings, C.</span><span class="refAuthor">, Boström, H.</span><span class="refAuthor">, and J-I. Bruaroey</span>, <span class="refTitle">"WebRTC 1.0: Real-time Communication Between Browsers"</span>, <span class="refContent">W3C Proposed Recommendation</span>, <span>&lt;<a href="https://www.w3.org/TR/webrtc/">https://www.w3.org/TR/webrtc/</a>&gt;</span>. </dd>
<dd class="break"></dd>
</dl>
</section>
<section id="section-12.2">
        <h3 id="name-informative-references">
<a href="#section-12.2" class="section-number selfRef">12.2. </a><a href="#name-informative-references" class="section-name selfRef">Informative References</a>
        </h3>
<dl class="references">
<dt id="HTML5">[HTML5]</dt>
        <dd>
<span class="refAuthor">WHATWG</span>, <span class="refTitle">"HTML - Living Standard"</span>, <time datetime="2021-01" class="refDate">January 2021</time>, <span>&lt;<a href="https://html.spec.whatwg.org/">https://html.spec.whatwg.org/</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC3261">[RFC3261]</dt>
        <dd>
<span class="refAuthor">Rosenberg, J.</span><span class="refAuthor">, Schulzrinne, H.</span><span class="refAuthor">, Camarillo, G.</span><span class="refAuthor">, Johnston, A.</span><span class="refAuthor">, Peterson, J.</span><span class="refAuthor">, Sparks, R.</span><span class="refAuthor">, Handley, M.</span><span class="refAuthor">, and E. Schooler</span>, <span class="refTitle">"SIP: Session Initiation Protocol"</span>, <span class="seriesInfo">RFC 3261</span>, <span class="seriesInfo">DOI 10.17487/RFC3261</span>, <time datetime="2002-06" class="refDate">June 2002</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc3261">https://www.rfc-editor.org/info/rfc3261</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC3361">[RFC3361]</dt>
        <dd>
<span class="refAuthor">Schulzrinne, H.</span>, <span class="refTitle">"Dynamic Host Configuration Protocol (DHCP-for-IPv4) Option for Session Initiation Protocol (SIP) Servers"</span>, <span class="seriesInfo">RFC 3361</span>, <span class="seriesInfo">DOI 10.17487/RFC3361</span>, <time datetime="2002-08" class="refDate">August 2002</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc3361">https://www.rfc-editor.org/info/rfc3361</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC3935">[RFC3935]</dt>
        <dd>
<span class="refAuthor">Alvestrand, H.</span>, <span class="refTitle">"A Mission Statement for the IETF"</span>, <span class="seriesInfo">BCP 95</span>, <span class="seriesInfo">RFC 3935</span>, <span class="seriesInfo">DOI 10.17487/RFC3935</span>, <time datetime="2004-10" class="refDate">October 2004</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc3935">https://www.rfc-editor.org/info/rfc3935</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC5245">[RFC5245]</dt>
        <dd>
<span class="refAuthor">Rosenberg, J.</span>, <span class="refTitle">"Interactive Connectivity Establishment (ICE): A Protocol for Network Address Translator (NAT) Traversal for Offer/Answer Protocols"</span>, <span class="seriesInfo">RFC 5245</span>, <span class="seriesInfo">DOI 10.17487/RFC5245</span>, <time datetime="2010-04" class="refDate">April 2010</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5245">https://www.rfc-editor.org/info/rfc5245</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC5761">[RFC5761]</dt>
        <dd>
<span class="refAuthor">Perkins, C.</span><span class="refAuthor"> and M. Westerlund</span>, <span class="refTitle">"Multiplexing RTP Data and Control Packets on a Single Port"</span>, <span class="seriesInfo">RFC 5761</span>, <span class="seriesInfo">DOI 10.17487/RFC5761</span>, <time datetime="2010-04" class="refDate">April 2010</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc5761">https://www.rfc-editor.org/info/rfc5761</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC6120">[RFC6120]</dt>
        <dd>
<span class="refAuthor">Saint-Andre, P.</span>, <span class="refTitle">"Extensible Messaging and Presence Protocol (XMPP): Core"</span>, <span class="seriesInfo">RFC 6120</span>, <span class="seriesInfo">DOI 10.17487/RFC6120</span>, <time datetime="2011-03" class="refDate">March 2011</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc6120">https://www.rfc-editor.org/info/rfc6120</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC6501">[RFC6501]</dt>
        <dd>
<span class="refAuthor">Novo, O.</span><span class="refAuthor">, Camarillo, G.</span><span class="refAuthor">, Morgan, D.</span><span class="refAuthor">, and J. Urpalainen</span>, <span class="refTitle">"Conference Information Data Model for Centralized Conferencing (XCON)"</span>, <span class="seriesInfo">RFC 6501</span>, <span class="seriesInfo">DOI 10.17487/RFC6501</span>, <time datetime="2012-03" class="refDate">March 2012</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc6501">https://www.rfc-editor.org/info/rfc6501</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC7478">[RFC7478]</dt>
        <dd>
<span class="refAuthor">Holmberg, C.</span><span class="refAuthor">, Hakansson, S.</span><span class="refAuthor">, and G. Eriksson</span>, <span class="refTitle">"Web Real-Time Communication Use Cases and Requirements"</span>, <span class="seriesInfo">RFC 7478</span>, <span class="seriesInfo">DOI 10.17487/RFC7478</span>, <time datetime="2015-03" class="refDate">March 2015</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc7478">https://www.rfc-editor.org/info/rfc7478</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8155">[RFC8155]</dt>
        <dd>
<span class="refAuthor">Patil, P.</span><span class="refAuthor">, Reddy, T.</span><span class="refAuthor">, and D. Wing</span>, <span class="refTitle">"Traversal Using Relays around NAT (TURN) Server Auto Discovery"</span>, <span class="seriesInfo">RFC 8155</span>, <span class="seriesInfo">DOI 10.17487/RFC8155</span>, <time datetime="2017-04" class="refDate">April 2017</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8155">https://www.rfc-editor.org/info/rfc8155</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8837">[RFC8837]</dt>
        <dd>
<span class="refAuthor">Jones, P.</span><span class="refAuthor">, Dhesikan, S.</span><span class="refAuthor">, Jennings, C.</span><span class="refAuthor">, and D. Druta</span>, <span class="refTitle">"Differentiated Services Code Point (DSCP) Packet Markings for WebRTC QoS"</span>, <span class="seriesInfo">RFC 8837</span>, <span class="seriesInfo">DOI 10.17487/RFC8837</span>, <time datetime="2021-01" class="refDate">January 2021</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8837">https://www.rfc-editor.org/info/rfc8837</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8838">[RFC8838]</dt>
        <dd>
<span class="refAuthor">Ivov, E.</span><span class="refAuthor">, Uberti, J.</span><span class="refAuthor">, and P. Saint-Andre</span>, <span class="refTitle">"Trickle ICE: Incremental Provisioning of Candidates for the Interactive Connectivity Establishment (ICE) Protocol"</span>, <span class="seriesInfo">RFC 8838</span>, <span class="seriesInfo">DOI 10.17487/RFC8838</span>, <time datetime="2021-01" class="refDate">January 2021</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8838">https://www.rfc-editor.org/info/rfc8838</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="RFC8843">[RFC8843]</dt>
        <dd>
<span class="refAuthor">Holmberg, C.</span><span class="refAuthor">, Alvestrand, H.</span><span class="refAuthor">, and C. Jennings</span>, <span class="refTitle">"Negotiating Media Multiplexing Using the Session Description Protocol (SDP)"</span>, <span class="seriesInfo">RFC 8843</span>, <span class="seriesInfo">DOI 10.17487/RFC8843</span>, <time datetime="2021-01" class="refDate">January 2021</time>, <span>&lt;<a href="https://www.rfc-editor.org/info/rfc8843">https://www.rfc-editor.org/info/rfc8843</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="I-D.ietf-rtcweb-gateways">[WebRTC-Gateways]</dt>
        <dd>
<span class="refAuthor">Alvestrand, H.</span><span class="refAuthor"> and U. Rauschenbach</span>, <span class="refTitle">"WebRTC Gateways"</span>, <span class="refContent">Work in Progress</span>, <span class="seriesInfo">Internet-Draft, draft-ietf-rtcweb-gateways-02</span>, <time datetime="2016-01-21" class="refDate">21 January 2016</time>, <span>&lt;<a href="https://tools.ietf.org/html/draft-ietf-rtcweb-gateways-02">https://tools.ietf.org/html/draft-ietf-rtcweb-gateways-02</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="XEP-0124">[XEP-0124]</dt>
        <dd>
<span class="refAuthor">Paterson, I.</span><span class="refAuthor">, Smith, D.</span><span class="refAuthor">, Saint-Andre, P.</span><span class="refAuthor">, Moffitt, J.</span><span class="refAuthor">, Stout, L.</span><span class="refAuthor">, and W. Tilanus</span>, <span class="refTitle">"Bidirectional-streams Over Synchronous HTTP (BOSH)"</span>, <span class="seriesInfo">XSF XEP 0124</span>, <time datetime="2016-11" class="refDate">November 2016</time>, <span>&lt;<a href="https://xmpp.org/extensions/xep-0124.html">https://xmpp.org/extensions/xep-0124.html</a>&gt;</span>. </dd>
<dd class="break"></dd>
<dt id="XEP-0166">[XEP-0166]</dt>
      <dd>
<span class="refAuthor">Ludwig, S.</span><span class="refAuthor">, Beda, J.</span><span class="refAuthor">, Saint-Andre, P.</span><span class="refAuthor">, McQueen, R.</span><span class="refAuthor">, Egan, S.</span><span class="refAuthor">, and J. Hildebrand</span>, <span class="refTitle">"Jingle"</span>, <span class="seriesInfo">XSF XEP 0166</span>, <time datetime="2018-09" class="refDate">September 2018</time>, <span>&lt;<a href="https://xmpp.org/extensions/xep-0166.html">https://xmpp.org/extensions/xep-0166.html</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">The number of people who have taken part in the discussions
      surrounding this document are too numerous to list, or even to identify.
      The people listed below have made special, identifiable contributions; this does
      not mean that others' contributions are less important.<a href="#section-appendix.a-1" class="pilcrow">¶</a></p>
<p id="section-appendix.a-2">Thanks to <span class="contact-name">Cary Bran</span>, <span class="contact-name">Cullen       Jennings</span>, <span class="contact-name">Colin Perkins</span>, <span class="contact-name">Magnus       Westerlund</span>, and <span class="contact-name">Jörg Ott</span>, who offered technical contributions to various
      draft versions of this document.<a href="#section-appendix.a-2" class="pilcrow">¶</a></p>
<p id="section-appendix.a-3">Thanks to <span class="contact-name">Jonathan Rosenberg</span>, <span class="contact-name">Matthew Kaufman</span>, and others at Skype for
      the ASCII drawings in <a href="#arch-func-grps" class="xref">Section 3</a>.<a href="#section-appendix.a-3" class="pilcrow">¶</a></p>
<p id="section-appendix.a-4">Thanks to <span class="contact-name">Alissa Cooper</span>, <span class="contact-name">Björn Höhrmann</span>, <span class="contact-name">Colin Perkins</span>,
      <span class="contact-name">Colton Shields</span>, <span class="contact-name">Eric       Rescorla</span>, <span class="contact-name">Heath Matlock</span>, <span class="contact-name">Henry Sinnreich</span>,
      <span class="contact-name">Justin Uberti</span>, <span class="contact-name">Keith Drage</span>,
      <span class="contact-name">Magnus Westerlund</span>, <span class="contact-name">Olle E. Johansson</span>,
      <span class="contact-name">Sean Turner</span>, and <span class="contact-name">Simon Leinen</span> for document review.<a href="#section-appendix.a-4" 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">Harald T. Alvestrand</span></div>
<div dir="auto" class="left"><span class="org">Google</span></div>
<div dir="auto" class="left"><span class="street-address">Kungsbron 2</span></div>
<div dir="auto" class="left">SE-<span class="postal-code">11122</span> <span class="locality">Stockholm</span>
</div>
<div dir="auto" class="left"><span class="country-name">Sweden</span></div>
<div class="email">
<span>Email:</span>
<a href="mailto:harald@alvestrand.no" class="email">harald@alvestrand.no</a>
</div>
</address>
</section>
</div>
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