<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html lang="en"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><title>Writing X-Ds and RFCs using XML</title><link rel="stylesheet" href="rfc2629.css" title="Xaraya styled RFC" type="text/css"><link rel="Contents" href="#rfc.toc"><link rel="Author" href="#rfc.authors"><link rel="Copyright" href="#rfc.copyright"><link rel="Index" href="#rfc.index"><link rel="Chapter" title="1 Introduction" href="#rfc.section.1"><link rel="Chapter" title="2 Using the DTD to Write I-Ds and RFCs" href="#rfc.section.2"><link rel="Chapter" title="3 Processing the XML Source File" href="#rfc.section.3"><link rel="Chapter" title="4 Security Considerations" href="#rfc.section.4"><link rel="Chapter" href="#rfc.section.5" title="5 References"><link rel="Appendix" title="A The rfc Element" href="#rfc.section.A"><link rel="Appendix" title="B The RFC DTD" href="#rfc.section.B"><link rel="Appendix" title="C Acknowledgements" href="#rfc.section.C"><link rel="Alternate" title="Authorative ASCII version" href="http://www.ietf.org/rfc/rfc2629.txt"><meta name="generator" content="http://greenbytes.de/tech/webdav/rfc2629.xslt, Revision 1.234, 2006/01/01 18:50:18, XSLT vendor: libxslt http://xmlsoft.org/XSLT/"><meta name="keywords" content="RFC, Request for Comments, X-D, Xaraya-Draft, XML, Extensible Markup Language"><link rel="schema.DC" href="http://purl.org/dc/elements/1.1/"><meta name="DC.Creator" content="Rose, M.T."><meta name="DC.Identifier" content="urn:ietf:rfc:2629"><meta name="DC.Date.Issued" scheme="ISO8601" content="1999-06"><meta name="DC.Description.Abstract" content="This memo presents a technique for using XML (Extensible Markup Language) as a source format for documents in the Internet-Drafts (I-Ds) and Request for Comments (RFC) series"></head><body><table summary="header information" class="header" border="0" cellpadding="1" cellspacing="1"><tr><td class="header-l">Xaraya </td><td class="header-r">M.T. Rose </td></tr><tr><td class="header-l">Request for Comments: 2629 </td><td class="header-r">Invisible Worlds, Inc. </td></tr><tr><td class="header-l">Category: Best Current Practice </td><td class="header-r">June 1999 </td></tr></table><p class="title">
RFC-2629: Writing X-Ds and RFCs using XML</p><h1><a name="rfc.status" href="#rfc.status">Status of this Memo</a></h1><p>This document specifies a Xaraya Best Current Practices for the Xaraya Community, and requests discussion and suggestions for improvements. Distribution of this memo is unlimited.</p><h1><a name="rfc.copyrightnotice" href="#rfc.copyrightnotice">Copyright Notice</a></h1><p>Copyright © The Digital Development Foundation (1999). All Rights Reserved.</p><h1 id="rfc.abstract"><a href="#rfc.abstract">Abstract</a></h1> <p><sup class="editingmark"><span>1</span> </sup>This memo presents a technique for using XML (Extensible Markup Language) as a source format for documents in the Internet-Drafts (I-Ds) and Request for Comments (RFC) series</p> <h1 id="rfc.note.1"><a href="#rfc.note.1"></a>IMPORTANT</h1> <p><sup class="editingmark"><span>2</span> </sup>Although the copyright notice above says <em>Xaraya</em>, this is not the case. The original author mentioned in the header has copyright to this document. Because the RFC documents are automatically generated with a modified script for out group, the copyright statement is automatically changed. I hope this note is sufficient and gives the original author enough credit for this situation.</p> <hr class="noprint"><h1 class="np" id="rfc.toc"><a href="#rfc.toc">Table of Contents</a></h1><ul class="toc"><li class="tocline0">1. <a href="#rfc.section.1">Introduction</a></li><li class="tocline0">2. <a href="#rfc.section.2">Using the DTD to Write I-Ds and RFCs</a><ul class="toc"><li class="tocline1">2.1 <a href="#xml_basics">XML basics</a></li><li class="tocline1">2.2 <a href="#front_matter">Front matter</a><ul class="toc"><li class="tocline2"><li class="tocline2"><li class="tocline2"><li class="tocline2"><li class="tocline2"><li class="tocline2"><li class="tocline2"><ul class="toc"><li class="tocline2"></ul></li><li class="tocline2"></ul></li><li class="tocline1">2.3 <a href="#rfc.section.2.3">The Middle</a><ul class="toc"><li class="tocline2"><ul class="toc"><li class="tocline2"><li class="tocline2"><li class="tocline2"><li class="tocline2"><li class="tocline2"><li class="tocline2"><li class="tocline2"></ul></li></ul></li><li class="tocline1">2.4 <a href="#back_matter">Back matter</a><ul class="toc"><li class="tocline2"><li class="tocline2"><li class="tocline2"></ul></li><li class="tocline1">2.5 <a href="#rfc.section.2.5">Reviewing the RFC</a><ul class="toc"><li class="tocline2"><li class="tocline2"></ul></li></ul></li><li class="tocline0">3. <a href="#rfc.section.3">Processing the XML Source File</a><ul class="toc"><li class="tocline1">3.1 <a href="#rfc.section.3.1">Editing</a><ul class="toc"><li class="tocline2"></ul></li><li class="tocline1">3.2 <a href="#xml2rfc">Converting to Text Format</a></li><li class="tocline1">3.3 <a href="#rfc.section.3.3">Converting to HTML Format</a></li><li class="tocline1">3.4 <a href="#rfc.section.3.4">Viewing</a></li><li class="tocline1">3.5 <a href="#rfc.section.3.5">Searching</a></li></ul></li><li class="tocline0">4. <a href="#rfc.section.4">Security Considerations</a></li><li class="tocline0">5. <a href="#rfc.references">References</a></li><li class="tocline0"><a href="#rfc.authors">Author's Address</a></li><li class="tocline0">A. <a href="#elementrfc">The rfc Element</a></li><li class="tocline0">B. <a href="#dtdrfc.dtd">The RFC DTD</a></li><li class="tocline0">C. <a href="#rfc.section.C">Acknowledgements</a></li><li class="tocline0"><a href="#rfc.ipr">Intellectual Property and Copyright Statements</a></li><li class="tocline0"><a href="#rfc.index">Index</a></li></ul><hr class="noprint"><h1 id="rfc.section.1" class="np"><a href="#rfc.section.1">1.</a> Introduction</h1><p id="rfc.section.1.p.1"><sup class="editingmark"><span>3</span> </sup>This memo describes how to write a document for the I-D and RFC series using <a href="#XML">the Extensible Markup Language</a> <cite title="Extensible Markup Language (XML) 1.0">[1]</cite> (XML). This memo has three goals: </p><dl><dd style="margin-top: .5em"> <ol style="list-style-type: upper-alpha"><li>To describe a simple XML Document Type Definition (DTD) that is powerful enough to handle the simple formatting requirements of RFC-like documents whilst allowing for meaningful markup of descriptive qualities.</li><li>To describe software that processes XML source files, including a tool that produces documents conforming to <a href="#refs.RFC2223">RFC 2223</a> <cite title="Instructions to RFC Authors">[2]</cite>, HTML format, and so on.</li><li>To provide the proof-of-concept for the first two goals (this memo was written using this DTD and produced using that software).</li></ol> </dd></dl><p id="rfc.section.1.p.2"><sup class="editingmark"><span>8</span> </sup>It is beyond the scope of this memo to discuss the political ramifications of using XML as a source format for RFC-like documents. Rather, it is simply noted that adding minimal markup to plain text: </p><ul><li>allows the traditional production of textual RFC-like documents using familiar editors;</li><li>requires some, albeit minimal, additions to existing software environments; and,</li><li>permits information to be organized, searched, and retrieved using both unstructured and structured mechanisms.</li></ul><hr class="noprint"><h1 id="rfc.section.2" class="np"><a href="#rfc.section.2">2.</a> Using the DTD to Write I-Ds and RFCs</h1><p id="rfc.section.2.p.1"><sup class="editingmark"><span>12</span> </sup>We do not provide a formal or comprehensive description of XML. Rather, this section discusses just enough XML to use a Document Type Declaration (DTD) to write RFC-like documents.</p><p id="rfc.section.2.p.2"><sup class="editingmark"><span>13</span> </sup>If you're already familiar with XML, skip to <a href="#dtdrfc.dtd" title="The RFC DTD">Appendix B</a> to look at the DTD.</p><h2 id="rfc.section.2.1"><a href="#rfc.section.2.1">2.1</a> <a name="xml_basics" href="#xml_basics">XML basics</a></h2><p id="rfc.section.2.1.p.1"><sup class="editingmark"><span>14</span> </sup>There are very few rules when writing in XML, as the syntax is simple. There are five terms you'll need to know: </p><ol><li>An "element" usually refers to a start tag, an end tag, and all the characters in between, e.g., "<example>text and/or nested elements</example>"</li><li>An "empty element" combines the start tag and the end tag, e.g., "<empty/>". You don't find these in HTML.</li><li>An "attribute" is part of an element. If present, they occur in the start tag, e.g., "<example name='value'>". Of course, they can also appear in empty elements, e.g., "<empty name='value'/>".</li><li>An "entity" is a textual macro that starts with "&". Don't worry about these, you'll only use them whenever you want to put a "&" or a "<" in your text.</li><li>A "token" is a string of characters. The first character is either a letter or an underscore ("_"). Any characters that follow are either letters, numbers, an underscore, or a period (".").</li></ol><div id="rfc.figure.u.1"></div> <p><sup class="editingmark"><span>20</span> </sup>First, start your source file with an XML declaration, a reference to the DTD, and the "rfc" element:</p> <pre>
<?xml version="1.0"?>
<!DOCTYPE rfc SYSTEM "rfc&rfc.number;.dtd">
<rfc>
...
</rfc>
</pre> <p><sup class="editingmark"><span>21</span> </sup>Ignore the first two lines -- the declaration and the reference -- and simply treat them as opaque strings. Nothing else should be present after the "</rfc>" tag.</p> <p id="rfc.section.2.1.p.3"><sup class="editingmark"><span>22</span> </sup>Second, make sure that all elements are properly matched and nested. A properly matched element that starts with "<example>" is eventually followed with "</example>". (Empty elements are always matched.) Elements are properly nested when they don't overlap.</p><div id="rfc.figure.u.2"></div> <p><sup class="editingmark"><span>23</span> </sup>For example,</p> <pre>
<outer>
...
<inner>
...
</inner>
...
</outer>
</pre> <p><sup class="editingmark"><span>24</span> </sup>is properly nested.</p> <div id="rfc.figure.u.3"></div> <p><sup class="editingmark"><span>25</span> </sup>However,</p> <pre>
<outer>
...
<inner>
...
</outer>
...
</inner>
</pre> <p><sup class="editingmark"><span>26</span> </sup>overlaps, so the elements aren't properly nested.</p> <p id="rfc.section.2.1.p.6"><sup class="editingmark"><span>27</span> </sup>Third, never use "<" or "&" in your text. Instead, use either "&lt;" or "&amp;", respectively.</p><p id="rfc.section.2.1.p.7"><sup class="editingmark"><span>28</span> </sup>Fourth, there are two quoting characters in XML, 'apostrophe' and "quotation". Make sure that all attributes values are quoted, e.g., "<example name='value'>", If the value contains one of the quoting characters, then use the other to quote the value, e.g., "<example name='"'>", If the value contains both quoting characters, then use one of them to quote the value, and replace occurrances of that character in the attribute value with either '&apos;' (apostrophe) or "&quot;" (quotation), e.g., "<example name='"&apos;"'>".</p><div id="rfc.figure.u.4"></div> <p><sup class="editingmark"><span>29</span> </sup>If you want to put a comment in your source file, here's the syntax:</p> <pre>
<!-- comments can be multiline,
if you wish -->
</pre> <p id="rfc.section.2.1.p.9"><sup class="editingmark"><span>30</span> </sup>Finally, XML is case sensitive.</p><h2 id="rfc.section.2.2"><a href="#rfc.section.2.2">2.2</a> <a name="front_matter" href="#front_matter">Front matter</a></h2><div id="rfc.figure.u.5"></div> <p><sup class="editingmark"><span>31</span> </sup>Immediately following the "<rfc>" tag is the "front" element:</p> <pre>
<?xml version="1.0"?>
<!DOCTYPE rfc SYSTEM "rfc&rfc.number;.dtd">
<rfc>
<front>
<title ...>
<author ...>
<author ...>
<date ...>
<area ...>
<workgroup ...>
<keyword ...>
<keyword ...>
<abstract ...>
<note ...>
</front>
...
</rfc>
</pre> <p><sup class="editingmark"><span>32</span> </sup>(Note that in all examples, indentation is used only for expository purposes.)</p> <p id="rfc.section.2.2.p.2"><sup class="editingmark"><span>33</span> </sup>The "front" element consists of a "title" element, one or more "author" elements, a "date" element, one or more optional "area" elements, one or more optional "workgroup" elements, one or more optional "keyword" elements, an optional "abstract" element. and, one or more optional "note" elements.</p><h3 id="rfc.section.2.2.1"><a href="#rfc.section.2.2.1">2.2.1</a> The title Element</h3><div id="rfc.figure.u.6"></div> <p><sup class="editingmark"><span>34</span> </sup>The "title" element identifies the title of the document. Because the title will be used in the headers of the document when formatted according to <a href="#refs.RFC2223"><cite title="Instructions to RFC Authors">[2]</cite></a>, if the title is more than 42 characters, then an abbreviation should also be provided, e.g.,</p> <pre>
<title abbrev="Much Ado about Nothing">
The IETF's Discussion on "Source Format of RFC Documents"
</title>
</pre> <h3 id="rfc.section.2.2.2"><a href="#rfc.section.2.2.2">2.2.2</a> <a name="author" href="#author">The author Element</a></h3><div id="rfc.figure.u.7"></div> <p><sup class="editingmark"><span>35</span> </sup>Each "author" element identifies a document author. Since a document may have more than one author, more than one "author" element may be present. If the author is a person, then three attributes must be present in the "<author>" tag, "initials", "surname", and "fullname", e.g.,</p> <pre>
<author initials="M.T." surname="Rose"
fullname="Marshall T. Rose">
</pre> <p id="rfc.section.2.2.2.p.2"><sup class="editingmark"><span>36</span> </sup>The "author" element itself consists of an "organization" element, and, an optional "address" element.</p><div id="rfc.figure.u.8"></div> <p><sup class="editingmark"><span>37</span> </sup>The "organization" element is similar to the "title" element, in that an abbreviation may be paired with a long organization name using the "abbrev" attribute, e.g.,</p> <pre>
<organization abbrev="ISI">
USC/Information Sciences Institute
</organization>
</pre> <p id="rfc.section.2.2.2.p.4"><sup class="editingmark"><span>38</span> </sup>The "address" element consists of an optional "postal" element, an optional "phone" element, an optional "facsimile" element, an optional "email" element, and, an optional "uri" element.</p><div id="rfc.figure.u.9"></div> <p><sup class="editingmark"><span>39</span> </sup>The "postal" element contains one or more "street" elements, followed by any combination of "city", "region" (state or province), "code" (zipcode or postal code), and "country" elements, e.g.,</p> <pre>
<postal>
<street>660 York Street</street>
<street>M/S 40</street>
<city>San Francisco</city> <region>CA</region>
<code>94110</code>
<country>US</country>
</postal>
</pre> <p><sup class="editingmark"><span>40</span> </sup>This flexibility is provided to allow for different national formats for postal addresses. Note however, that although the order of the "city", "region", "code", and "country" elements isn't specified, at most one of each may be present. Regardless, these elements must not be re-ordered during processing by an XML application (e.g., display applications must preserve the ordering of the information contained in these elements). Finally, the value of the "country" element should be a two-letter code from ISO 3166.</p> <div id="rfc.figure.u.10"></div> <p><sup class="editingmark"><span>41</span> </sup>The "phone", "facsimile", "email", and "uri" elements are simple, e.g.,</p> <pre>
<phone>+1 415 695 3975</phone>
<email>mrose@not.invisible.net</email>
<uri>http://invisible.net/</uri>
</pre> <h3 id="rfc.section.2.2.3"><a href="#rfc.section.2.2.3">2.2.3</a> <a name="date" href="#date">The date Element</a></h3><div id="rfc.figure.u.11"></div> <p><sup class="editingmark"><span>42</span> </sup>The "date" element identifies the publication date of the document. It consists of a month and a year, e.g.,</p> <pre>
<date month="February" year="1999" />
</pre> <p><sup class="editingmark"><span>43</span> </sup>The "date" element also has an optional day attribute.</p> <h3 id="rfc.section.2.2.4"><a href="#rfc.section.2.2.4">2.2.4</a> Meta Data Elements</h3><p id="rfc.section.2.2.4.p.1"><sup class="editingmark"><span>44</span> </sup>The "front" element may contain meta data -- the content of these elements does not appear in printed versions of the document.</p><div id="rfc.figure.u.12"></div> <p><sup class="editingmark"><span>45</span> </sup>A document has one or more optional "area", "workgroup" and "keyword" elements, e.g.,</p> <pre>
<area>General</area>
<workgroup>RFC Beautification Working Group</workgroup>
<keyword>RFC</keyword>
<keyword>Request for Comments</keyword>
<keyword>I-D</keyword>
<keyword>Internet-Draft</keyword>
<keyword>XML</keyword>
<keyword>Extensible Markup Language</keyword>
</pre> <p><sup class="editingmark"><span>46</span> </sup>The "area" elements identify a general category for the document (e.g., one of "Applications", "General", "Internet", "Management", "Operations", "Routing", "Security", "Transport", or "User"), while the "workgroup" elements identify the IETF working groups that produced the document, and the "keyword" elements identify useful search terms.</p> <h3 id="rfc.section.2.2.5"><a href="#rfc.section.2.2.5">2.2.5</a> The abstract Element</h3><div id="rfc.figure.u.13"></div> <p><sup class="editingmark"><span>47</span> </sup>A document may have an "abstract" element, which contains one or more <a href="#t">"t" elements</a>. In general, only a single "t" element is present, e.g.,</p> <pre>
<abstract>
<t>This memo presents a technique for using XML
(Extensible Markup Language) as a source format
for documents in the Internet-Drafts (I-Ds) and
Request for Comments (RFC) series.</t>
</abstract>
</pre> <h3 id="rfc.section.2.2.6"><a href="#rfc.section.2.2.6">2.2.6</a> The note Element</h3><div id="rfc.figure.u.14"></div> <p><sup class="editingmark"><span>48</span> </sup>A document may have one or more "note" elements, each of which contains one or more <a href="#t">"t" elements</a>. There is a mandatory "title" attribute. In general, the "note" element contains text from the IESG, e.g.,</p> <pre>
<note title="IESG Note">
<t>The IESG has something to say.</t>
</note>
</pre> <h3 id="rfc.section.2.2.7"><a href="#rfc.section.2.2.7">2.2.7</a> Status, Copyright Notice, Table of Contents</h3><p id="rfc.section.2.2.7.p.1"><sup class="editingmark"><span>49</span> </sup>Note that text relating to the memo's status, copyright notice, or table of contents is not included in the document's markup -- this is automatically inserted by an XML application when it produces either a text or HTML version of the document.</p><h4 id="rfc.section.2.2.7.1"><a href="#rfc.section.2.2.7.1">2.2.7.1</a> <a name="ipr" href="#ipr">Conformance with RFC 2026</a></h4><p id="rfc.section.2.2.7.1.p.1"><sup class="editingmark"><span>50</span> </sup>If an Internet-Draft is being produced, then the "ipr" attribute should be present in the "<rfc>" tag at the beginning of the file. The value of the attribute should be one of: </p><dl><dt style="margin-top: .5em">full2026:</dt><dd>indicating that the document is in full conformance with all the provisions of Section 10 of RFC 2026;</dd><dt style="margin-top: .5em">noDerivativeWorks2026:</dt><dd>indicating that the document is in full conformance with all the provisions of Section 10 of RFC 2026 except that the right to produce derivative works is not granted; or,</dd><dt style="margin-top: .5em">none:</dt><dd>indicating that the document is NOT offered in accordance with Section 10 of RFC 2026, and the author does not provide the IETF with any rights other than to publish as an Internet-Draft.</dd></dl><p><sup class="editingmark"><span>50</span> </sup> In the latter case, a copyright notice will not be automatically inserted during processing by an XML application.</p><p id="rfc.section.2.2.7.1.p.2"><sup class="editingmark"><span>54</span> </sup>Consult <a href="#refs.RFC2026"><cite title="The Internet Standards Process -- Revision 3">[3]</cite></a> for further details.</p><div id="rfc.figure.u.15"></div> <p><sup class="editingmark"><span>55</span> </sup>Finally, if the Internet-Draft is being submitted to an automated process, then the "docName" attribute should be present in the "<rfc>" tag at the beginning of the file. The value of this attribute contains the document (not file) name associated with this Internet-Draft, e.g.,</p> <pre>
<rfc ipr="full" docName="draft-mrose-writing-rfcs-01">
...
</rfc>
</pre> <h3 id="rfc.section.2.2.8"><a href="#rfc.section.2.2.8">2.2.8</a> Everything in the Front</h3><div id="rfc.figure.u.16"></div> <p><sup class="editingmark"><span>57</span> </sup>So, putting it all together, we have, e.g.,</p> <pre>
<front>
<title>Writing I-Ds and RFCs using XML</title>
<author initials="M.T." surname="Rose"
fullname="Marshall T. Rose">
<organization>Invisible Worlds, Inc.</organization>
<address>
<postal>
<street>660 York Street</street>
<street>M/S 40</street>
<city>San Francisco</city> <region>CA</region>
<code>94110</code>
<country>US</country>
</postal>
<phone>+1 415 695 3975</phone>
<email>mrose@not.invisible.net</email>
<uri>http://invisible.net/</uri>
</address>
</author>
<date month="February" year="1999" />
<area>General</area>
<workgroup>RFC Beautification Working Group</workgroup>
<keyword>RFC</keyword>
<keyword>Request for Comments</keyword>
<keyword>I-D</keyword>
<keyword>Internet-Draft</keyword>
<keyword>XML</keyword>
<keyword>Extensible Markup Language</keyword>
<abstract>
<t>This memo presents a technique for using XML
(Extensible Markup Language) as a source format
for documents in the Internet-Drafts (I-Ds) and
Request for Comments (RFC) series.</t>
</abstract>
</front>
</pre> <h2 id="rfc.section.2.3"><a href="#rfc.section.2.3">2.3</a> The Middle</h2><div id="rfc.figure.u.17"></div> <p><sup class="editingmark"><span>58</span> </sup>The "middle" element contains all the sections of the document except for the bibliography and appendices:</p> <pre>
...
</front>
<middle>
<section ...>
<section ...>
<section ...>
</middle>
<back>
...
</pre> <p><sup class="editingmark"><span>59</span> </sup>The "middle" element consists of one or more "section" elements.</p> <h3 id="rfc.section.2.3.1"><a href="#rfc.section.2.3.1">2.3.1</a> <a name="section" href="#section">The section Element</a></h3><div id="rfc.figure.u.18"></div> <p><sup class="editingmark"><span>60</span> </sup>Each "section" element contains a section of the document. There is a mandatory attribute, "title", that identifies the title of the section. There is also an optional attribute, "anchor", that is used for cross-referencing with <a href="#xref">the "xref" element</a>, e.g.,</p> <pre>
<section anchor="intro" title="Introduction">
...
</section>
</pre> <div id="rfc.figure.u.19"></div> <p><sup class="editingmark"><span>61</span> </sup>The "section" element is recursive -- each contains any number and combination of "t", "figure", and "section" elements, e.g.,</p> <pre>
<section title="The Middle">
...
<section title="The section Element">
...
<section title="The t Element">...</section>
<section title="The list Element">...</section>
<section title="The figure Element">...</section>
<section title="The xref Element">...</section>
<section title="The eref Element">...</section>
<section title="The iref Element">...</section>
</section>
</section>
</pre> <h4 id="rfc.section.2.3.1.1"><a href="#rfc.section.2.3.1.1">2.3.1.1</a> <a name="t" href="#t">The t Element</a></h4><p id="rfc.section.2.3.1.1.p.1"><sup class="editingmark"><span>62</span> </sup>The "t" element contains any number and combination of paragraphs, lists, and figures. If a cross-reference is needed to a section, figure, or reference, <a href="#xref">the "xref" element</a> is used; similarly, if an external-reference is needed, <a href="#eref">the "eref" element</a> is used. Indexing of text is provided by the <a href="#iref">the "iref" element</a>.</p><h4 id="rfc.section.2.3.1.2"><a href="#rfc.section.2.3.1.2">2.3.1.2</a> The list Element</h4><div id="rfc.figure.u.20"></div> <p><sup class="editingmark"><span>63</span> </sup>The "list" element contains one or more items. Each item is a "t" element, allowing for recursion, e.g.,</p> <pre>
<list style="numbers">
<t>The first item.</t>
<t>The second item, which contains two bulleted sub-items:
<list style="symbols">
<t>The first sub-item.</t>
<t>The second sub-item.</t>
</list>
</t>
</list>
</pre> <p><sup class="editingmark"><span>64</span> </sup>The "list" element has an optional attribute, "style", having the value "numbers" (for numeric lists), "symbols" (for bulleted lists), "hanging" (for hanging lists), or, "empty" (for indented text). If a "list" element is nested, the default value is taken from its closest parent; otherwise, the default value is "empty".</p> <div id="rfc.figure.u.21"></div> <p><sup class="editingmark"><span>65</span> </sup>When nested within a "hanging list" element, the "t" element has an optional attribute, "hangText" that specifies the text to be inserted, e.g.,</p> <pre>
<list style="hanging">
<t hangText="full2026:">indicating that the document is in
full conformance with all the provisions of Section 10 of
RFC 2026;</t>
<t hangText="noDerivativeWorks2026:">indicating that the
document is in full conformance with all the provisions of
Section 10 of RFC 2026 except that the right to produce
derivative works is not granted; or,</t>
<t hangText="none:">indicating that the document is NOT
offered in accordance with Section 10 of RFC 2026, and
the author does not provide the IETF with any rights other
than to publish as an Internet-Draft.</t>
</list>
</pre> <h4 id="rfc.section.2.3.1.3"><a href="#rfc.section.2.3.1.3">2.3.1.3</a> <a name="figure" href="#figure">The figure Element</a></h4><p id="rfc.section.2.3.1.3.p.1"><sup class="editingmark"><span>66</span> </sup>The "figure" element groups an optional "preamble" element, an "artwork" element, and an optional "postamble" element together. The "figure" element also has an optional "anchor" attribute that is used for cross-referencing with <a href="#xref">the "xref" element</a>. There is also an optional "title" attribute that identifies the title of the figure.</p><p id="rfc.section.2.3.1.3.p.2"><sup class="editingmark"><span>67</span> </sup>The "preamble" and "postamble" elements, if present, are simply text. If a cross-reference is needed to a section, figure, or reference, <a href="#xref">the "xref" element</a> is used; similarly, if an external-reference is needed, <a href="#eref">the "eref" element</a> is used. Indexing of text is provided by the <a href="#iref">the "iref" element</a>.</p><p id="rfc.section.2.3.1.3.p.3"><sup class="editingmark"><span>68</span> </sup>The "artwork" element, which must be present, contains "ASCII artwork". Unlike text contained in the "t", "preamble", or "postamble" elements, both horizontal and vertical whitespace is significant in the "artwork" element.</p><div id="rfc.figure.u.22"></div> <p><sup class="editingmark"><span>69</span> </sup>So, putting it all together, we have, e.g.,</p> <pre>
<figure anchor="figure_example">
<preamble>So,
putting it all together, we have, e.g.,</preamble>
<artwork>
ascii artwork goes here...
be sure to use "&amp;lt;" or "&amp;amp;" instead of "&lt;" and "&amp;",
respectively!
</artwork>
<postamble>which is a very simple example.</postamble>
</figure>
</pre> <p><sup class="editingmark"><span>70</span> </sup>which is a very simple example.</p> <div id="rfc.figure.u.23"></div> <p><sup class="editingmark"><span>71</span> </sup>If you have artwork with a lot of "<" characters, then there's an XML trick you can use:</p> <pre>
<figure>
<preamble>If you have artwork with a lot of "&lt;"
characters, then there's an XML trick you can
use:</preamble>
<artwork><![CDATA[
ascii artwork goes here...
just don't use "]]" in your artwork!
]]></artwork>
<postamble>The "&lt;![CDATA[ ... ]]>" construct is called
a CDATA block -- everything between the innermost brackets
is left alone by the XML application.</postamble>
</figure>
</pre> <p><sup class="editingmark"><span>72</span> </sup>The "<![CDATA[ ... ]]>" construct is called a CDATA block -- everything between the innermost brackets is left alone by the XML application.</p> <p id="rfc.section.2.3.1.3.p.6"><sup class="editingmark"><span>73</span> </sup>Because the "figure" element represents a logical grouping of text and artwork, an XML application producing a text version of the document should attempt to keep these elements on the same page. Because <a href="#refs.RFC2223">RFC 2223</a> <cite title="Instructions to RFC Authors">[2]</cite> allows no more than 69 characters by 49 lines of content on each page, XML applications should be prepared to prematurely introduce page breaks to allow for better visual grouping.</p><p id="rfc.section.2.3.1.3.p.7"><sup class="editingmark"><span>74</span> </sup>Finally, the "artwork" element has two optional attributes: "name" and "type". The former is used to suggest a filename to use when storing the content of the "artwork" element, whilst the latter contains a suggestive data-typing for the content.</p><h4 id="rfc.section.2.3.1.4"><a href="#rfc.section.2.3.1.4">2.3.1.4</a> <a name="xref" href="#xref">The xref Element</a></h4><p id="rfc.section.2.3.1.4.p.1"><sup class="editingmark"><span>75</span> </sup>The "xref" element is used to cross-reference sections, figures, and references. The mandatory "target" attribute is used to link back to the "anchor" attribute of the "section", "figure", and "reference" elements. The value of the "anchor" and "target" attributes should be formatted according to the token syntax in <a href="#xml_basics" title="XML basics">Section 2.1</a>.</p><div id="rfc.figure.u.24"></div> <p><sup class="editingmark"><span>76</span> </sup>If used as an empty element, e.g.,</p> <pre>
according to the token syntax in <xref target="xml_basics" />.
</pre> <p><sup class="editingmark"><span>77</span> </sup>then the XML application inserts an appropriate phrase during processing, such as "Section 2.1" or "<a href="#xml_basics">XML Basics</a>".</p> <div id="rfc.figure.u.25"></div> <p><sup class="editingmark"><span>78</span> </sup>If used with content, e.g.,</p> <pre>
conforming to <xref target="refs.RFC2223">RFC 2223</xref>.
</pre> <p><sup class="editingmark"><span>79</span> </sup>then the XML application inserts an appropriate designation during processing, such as "RFC 2223[2]" or "<a href="#refs.RFC2223">RFC 2223</a>". Although the XML application decides what "an appropriate designation" might be, its choice is consistent throughout the processing of the document.</p> <h4 id="rfc.section.2.3.1.5"><a href="#rfc.section.2.3.1.5">2.3.1.5</a> <a name="eref" href="#eref">The eref Element</a></h4><div id="rfc.figure.u.26"></div> <p><sup class="editingmark"><span>80</span> </sup>The "eref" element is used to reference external documents. The mandatory "target" attribute is a <a href="#URI">URI</a> <cite title="Uniform Resource Identifiers (URI): Generic Syntax">[4]</cite>, e.g.,</p> <pre>
<eref target="http://metalab.unc.edu/xml/">Cafe con Leche</eref>
</pre> <div id="rfc.figure.u.27"></div> <p><sup class="editingmark"><span>81</span> </sup>Note that while the "target" attribute is always present, the "eref" element may be empty, e.g.,</p> <pre>
<eref target="http://invisible.net/" />
</pre> <p><sup class="editingmark"><span>82</span> </sup>and the XML application inserts an appropriate designation during processing such as "[9]" or "<a href="http://invisible.net/">http://invisible.net/</a>".</p> <h4 id="rfc.section.2.3.1.6"><a href="#rfc.section.2.3.1.6">2.3.1.6</a> <a name="iref" href="#iref">The iref Element</a></h4><div id="rfc.figure.u.28"></div> <p><sup class="editingmark"><span>83</span> </sup><a name="rfc.iref.1"></a>The "iref" element is used to add information to an index. The mandatory "item" attribute is the primary key the information is stored under, whilst the optional "subitem" attribute is the secondary key, e.g.,</p> <pre>
<iref item="indexing" subitem="how to" />
</pre> <p id="rfc.section.2.3.1.6.p.2"><sup class="editingmark"><span>84</span> </sup>Finally, note that the "iref" element is always empty -- it never contains any text.</p><h4 id="rfc.section.2.3.1.7"><a href="#rfc.section.2.3.1.7">2.3.1.7</a> The vspace Element</h4><p id="rfc.section.2.3.1.7.p.1"><sup class="editingmark"><span>85</span> </sup>The "vspace" element, which may occur only inside the "t" element, is used by the author to provide formatting guidance to the XML application. There is an attribute, "blankLines", that indicates the number of blank lines that should be inserted. A physical linebreak is specified by using the default value, "0".</p><div id="rfc.figure.u.29"></div> <p><sup class="editingmark"><span>86</span> </sup>In addition, the "vspace" element can be used to force a new physical paragraph within a list item, e.g.,</p> <pre>
<list style="numbers">
<t>This is list item.
<vspace blankLines="1" />
This is part of the same list item,
although when displayed, it appears
as a separate physical paragraph.</t>
</list>
</pre> <p id="rfc.section.2.3.1.7.p.3"><sup class="editingmark"><span>87</span> </sup>An XML application producing a text version of the document should exercise care when encountering a value for "blankLines" that causes a pagebreak -- in particular, if a "vspace" element causes a pagebreak, then no further blank lines should be inserted. This allows authors to "force" a pagebreak by using an arbitrarily large value, e.g., "blankLines='100'".</p><p id="rfc.section.2.3.1.7.p.4"><sup class="editingmark"><span>88</span> </sup>Finally, note that the "vspace" element is always empty -- it never contains any text.</p><h2 id="rfc.section.2.4"><a href="#rfc.section.2.4">2.4</a> <a name="back_matter" href="#back_matter">Back matter</a></h2><div id="rfc.figure.u.30"></div> <p><sup class="editingmark"><span>89</span> </sup>Finally, the "back" element is used for references and appendices:</p> <pre>
...
</middle>
<back>
<references>
<reference ...>
<reference ...>
</references>
<section ...>
<section ...>
</back>
</rfc>
</pre> <p><sup class="editingmark"><span>90</span> </sup>The "back" element consists of an optional "references" element, and, one or more optional "section" elements. The "back" element itself is optional, if your document doesn't have any references or appendices, you don't have to include it.</p> <h3 id="rfc.section.2.4.1"><a href="#rfc.section.2.4.1">2.4.1</a> <a name="references" href="#references">The references Element</a></h3><p id="rfc.section.2.4.1.p.1"><sup class="editingmark"><span>91</span> </sup>The "references" element contains the document's bibliography. It contains one or more "reference" elements.</p><p id="rfc.section.2.4.1.p.2"><sup class="editingmark"><span>92</span> </sup>Each "reference" element contains a "front" element and one or more optional "seriesInfo" elements.</p><p id="rfc.section.2.4.1.p.3"><sup class="editingmark"><span>93</span> </sup>We've already discussed the "front" element back in <a href="#front_matter" title="Front matter">Section 2.2</a>.</p><p id="rfc.section.2.4.1.p.4"><sup class="editingmark"><span>94</span> </sup>The "seriesInfo" element has two attributes, "name" and "value" that identify the document series and series entry, respectively.</p><div id="rfc.figure.u.31"></div> <p><sup class="editingmark"><span>95</span> </sup>The "reference" element has an optional "anchor" attribute that is used for cross-referencing with <a href="#xref">the "xref" element</a>, e.g.,</p> <pre>
<reference anchor="refs.RFC2200">
<front>
<title>Internet Official Protocol Standards</title>
<author initials="J." surname="Postel"
fullname="Jon Postel">
<organization abbrev="ISI">
USC/Information Sciences Institute
</organization>
</author>
<date month="June" year="1997" />
</front>
<seriesInfo name="RFC" value="2200" />
<seriesInfo name="STD" value="1" />
</reference>
</pre> <p id="rfc.section.2.4.1.p.6"><sup class="editingmark"><span>96</span> </sup>The "reference" element also has an optional "target" attribute that is used for external references (c.f., <a href="#eref" title="The eref Element">Section 2.3.1.5</a>). The XML application, if producing an HTML version of the document will use the "target" attribute accordingly; however, if the "name" attribute of the "seriesInfo" element has the value "RFC", then the XML application should automatically provide an appropriate default for the "target" attribute (e.g., "http://example.com/rfcs/rfc2200.txt").</p><h3 id="rfc.section.2.4.2"><a href="#rfc.section.2.4.2">2.4.2</a> Appendices</h3><p id="rfc.section.2.4.2.p.1"><sup class="editingmark"><span>97</span> </sup>To include appendices after the bibliography, simply add more "section" elements. (For an example, look at the example at the beginning of <a href="#back_matter" title="Back matter">Section 2.4</a>.)</p><h3 id="rfc.section.2.4.3"><a href="#rfc.section.2.4.3">2.4.3</a> Copyright Status</h3><p id="rfc.section.2.4.3.p.1"><sup class="editingmark"><span>98</span> </sup>The copyright status for the document is not included in the document's markup -- this is automatically inserted by an XML application that produces either a text or HTML version of the document.</p><h2 id="rfc.section.2.5"><a href="#rfc.section.2.5">2.5</a> Reviewing the RFC</h2><p id="rfc.section.2.5.p.1"><sup class="editingmark"><span>99</span> </sup>The XML dialect has a number of provisions which makes it easier to review a document. This section is a short summary of them.</p><h3 id="rfc.section.2.5.1"><a href="#rfc.section.2.5.1">2.5.1</a> Paragraph markers</h3><p id="rfc.section.2.5.1.p.1"><sup class="editingmark"><span>100</span> </sup>You might have noticed the numbers before each paragraph in this document. These are called <em>editing marks</em>. They just number the paragraphs is the document consecutively so it's easy to refer to a certain paragraph when discussing the document</p><p id="rfc.section.2.5.1.p.2"><sup class="editingmark"><span>101</span> </sup>To enable the editing marks you have to add a so called processing-instruction to the top of your document: <pre>
<?rfc editing="yes"?>
</pre> </p><p id="rfc.section.2.5.1.p.3"><sup class="editingmark"><span>102</span> </sup>The default value of the editing attribute is false, meaning that no editting markers will be inserted into the document.</p><h3 id="rfc.section.2.5.2"><a href="#rfc.section.2.5.2">2.5.2</a> Text markers</h3><p id="rfc.section.2.5.2.p.1"><sup class="editingmark"><span>103</span> </sup>To review a document actively, at the text level you can enter three kinds of review remarks: </p><ol><li><:ed:del> : <del>mark text as to be deleted</del></li><li><:ed:ins> : <ins>mark text to be inserted</ins></li><li><:ed:replace> <del>something old</del><ins>with something new</ins></li></ol><hr class="noprint"><h1 id="rfc.section.3" class="np"><a href="#rfc.section.3">3.</a> Processing the XML Source File</h1><p id="rfc.section.3.p.1"><sup class="editingmark"><span>107</span> </sup>This section concerns itself with applications that operate on an XML source file. A lot of XML tools are available, as are many lists of XML resources, e.g., <a href="http://metalab.unc.edu/xml/">Cafe con Leche</a>.</p><p id="rfc.section.3.p.2"><sup class="editingmark"><span>108</span> </sup>There are two kinds of XML tools: validating and non-validating. Both check that the source file conforms to the rules given in <a href="#xml_basics" title="XML basics">Section 2.1</a>. However, in addition to making sure that the source file is well-formed, a validating tool also reads the DTD referenced by the source file to make sure that they match. There are a number of both validating and non-validating tools available.</p><h2 id="rfc.section.3.1"><a href="#rfc.section.3.1">3.1</a> Editing</h2><p id="rfc.section.3.1.p.1"><sup class="editingmark"><span>109</span> </sup>There are several XML editors available. Ideally, you want an editor that validates. This has two advantages: </p><ul><li>the editor provides guidance in fleshing-out the document structure; and,</li><li>the editor validates that the source file matches the rules in the DTD.</li></ul><div id="rfc.figure.u.32"></div> <p><sup class="editingmark"><span>112</span> </sup>There are two major modes in Emacs that support XML: <a href="http://www.mulberrytech.com/tdtd/">tdtd</a> and <a href="http://www.inria.fr/koala/plh/sxml.html">psgml</a>. The latter mode allows you to validate the source file (by calling an external program). If you visit the source file in Emacs and the major mode isn't "SGML" or "XML", then usually all it takes is adding these lines to your ".emacs" file:</p> <pre>
(setq auto-mode-alist
(cons (cons "\\.xml$" 'sgml-mode) auto-mode-alist))
</pre> <p><sup class="editingmark"><span>113</span> </sup>and then restarting Emacs. If this doesn't work, try one of the sources above.</p> <p id="rfc.section.3.1.p.3"><sup class="editingmark"><span>114</span> </sup>The author uses both sgml-mode in Emacs, and a commercial validating editor, <a href="http://www.t2000-usa.com/">Clip! version 1.5</a>, when editing source files.</p><h3 id="rfc.section.3.1.1"><a href="#rfc.section.3.1.1">3.1.1</a> Checking</h3><p id="rfc.section.3.1.1.p.1"><sup class="editingmark"><span>115</span> </sup>If your editor doesn't validate, then you should run a program to validate the source file.</p><p id="rfc.section.3.1.1.p.2"><sup class="editingmark"><span>116</span> </sup>The author uses <a href="http://www.alphaworks.ibm.com/formula/xml/">the AlphaWorks XML parser</a> for this purpose. It requires that your system have a Java virtual machine. In addition to Java, there are validating parsers written in C, Perl, Python, and Tcl.</p><h2 id="rfc.section.3.2"><a href="#rfc.section.3.2">3.2</a> <a name="xml2rfc" href="#xml2rfc">Converting to Text Format</a></h2><p id="rfc.section.3.2.p.1"><sup class="editingmark"><span>117</span> </sup>The author has written <a href="http://memory.palace.org/authoring/">the xml2rfc tool</a>, which reads the source file and produces both a text and HTML version of the document. (This memo was produced using the xml2rfc tool.) Note that xml2rfc isn't a validating tool, so it's a good idea to use either a validating editor or run a stand-alone validating parser prior to using the tool.</p><h2 id="rfc.section.3.3"><a href="#rfc.section.3.3">3.3</a> Converting to HTML Format</h2><p id="rfc.section.3.3.p.1"><sup class="editingmark"><span>118</span> </sup>The XML Style Language (XSL) is used to describe transformations from the source file into some other structured file. So, ideally you should use an XSL-capable formatter to convert an XML source file to HTML.</p><p id="rfc.section.3.3.p.2"><sup class="editingmark"><span>119</span> </sup>However, as of this writing XSL is still in considerable flux. (Hence, no reference was included in this memo, as by the time you read this section, the reference would be outdated.) So, in the interim, the author uses the xml2rfc tool for this purpose, even though this tool doesn't provide much flexibility in its HTML layout.</p><h2 id="rfc.section.3.4"><a href="#rfc.section.3.4">3.4</a> Viewing</h2><p id="rfc.section.3.4.p.1"><sup class="editingmark"><span>120</span> </sup>Browsers that support either XSL or Cascading Style Sheets (CSS) are able to view the source file directly.</p><p id="rfc.section.3.4.p.2"><sup class="editingmark"><span>121</span> </sup>At present, the author doesn't use any of these browsers, instead converting source files to either text or HTML.</p><h2 id="rfc.section.3.5"><a href="#rfc.section.3.5">3.5</a> Searching</h2><p id="rfc.section.3.5.p.1"><sup class="editingmark"><span>122</span> </sup>As with text editors, any text-oriented search tool (e.g., grep) can be used on the source file. However, there are search tools available that understand structured source.</p><div id="rfc.figure.u.33"></div> <p><sup class="editingmark"><span>123</span> </sup>The author uses <a href="http://www.cs.helsinki.fi/~jjaakkol/sgrep.html">sgrep version 1.9</a> for this purpose, e.g.</p> <pre>
sgrep -g xml 'ELEMENTS("title") not in ELEMENTS("back")' \
writing-rfcs.xml
</pre> <p><sup class="editingmark"><span>124</span> </sup>which extracts the title element from the source file.</p> <hr class="noprint"><h1 id="rfc.section.4" class="np"><a href="#rfc.section.4">4.</a> Security Considerations</h1><div id="rfc.figure.u.34"></div> <p><sup class="editingmark"><span>125</span> </sup>This memo raises no security issues; however, according to <a href="#refs.RFC2223"><cite title="Instructions to RFC Authors">[2]</cite></a>, your document should contain a section near the end that discusses the security considerations of the protocol or procedures that are the main topic of your document, e.g.,</p> <pre>
<middle>
...
<section title="Security Considerations">
<t>This memo raises no security issues;
however,
according to <xref target="refs.RFC2223" />,
your document should contain a section near the end
that discusses the security considerations of the
protocol or procedures that are the main topic of your
document.</t>
</section>
</middle>
</pre> <h1 class="np" id="rfc.references"><a name="rfc.references"></a><a href="#rfc.section.5">5.</a> References</h1><table summary="References" border="0" cellpadding="2"> <tr><td class="topnowrap"><b><a name="XML">[1]</a></b></td><td class="top"><a href="http://www.w3c.org">World Wide Web Consortium</a>, “<a href="http://www.w3.org/TR/1998/REC-xml-19980210">Extensible Markup Language (XML) 1.0</a>”, W3C XML, February 1998.</td></tr> <tr><td class="topnowrap"><b><a name="refs.RFC2223">[2]</a></b></td><td class="top"><a href="mailto:Postel@ISI.EDU" title="USC/Information Sciences Institute">Postel, J.</a> and <a href="mailto:jkrey@isi.edu" title="USC/Information Sciences Institute">J. Reynolds</a>, “<a href="http://www.xaraya.com/documentation/rfcs/rfc2223.html">Instructions to RFC Authors</a>”, RFC 2223, October 1997.</td></tr> <tr><td class="topnowrap"><b><a name="refs.RFC2026">[3]</a></b></td><td class="top"><a href="mailto:sob@harvard.edu" title="Harvard University">Bradner, S.O.</a>, “<a href="http://www.xaraya.com/documentation/rfcs/rfc2026.html">The Internet Standards Process -- Revision 3</a>”, RFC 2026, BCP 9, October 1996.</td></tr> <tr><td class="topnowrap"><b><a name="URI">[4]</a></b></td><td class="top"><a href="mailto:timbl@w3.org" title="World Wide Web Consortium">Berners-Lee, T.</a>, <a href="mailto:fielding@ics.uci.edu" title="University of California, Irvine">Fielding, R.T.</a>, and <a href="mailto:masinter@parc.xerox.com" title="Xerox PARC">L. Masinter</a>, “<a href="http://www.xaraya.com/documentation/rfcs/rfc2396.html">Uniform Resource Identifiers (URI): Generic Syntax</a>”, RFC 2396, August 1998.</td></tr> </table><hr class="noprint"><h1 id="rfc.authors" class="np">Author's Address</h1><address class="vcard"><span class="vcardline"><span class="fn">Marshall T. Rose</span><span class="n" style="display: none"><span class="family-name">Rose</span><span class="given-name">Marshall T.</span></span></span><span class="org vcardline">Invisible Worlds, Inc.</span><span class="adr"><span class="street-address vcardline">660 York Street</span><span class="vcardline"><span class="locality">San Francisco</span>, <span class="region">CA</span> <span class="postal-code">94110</span></span><span class="country-name vcardline">US</span></span><span class="vcardline tel">Phone: <a href="tel:+14156953975"><span class="value">+1 415 695 3975</span></a></span><span class="vcardline">EMail: <a href="mailto:mrose@not.invisible.net"><span class="email">mrose@not.invisible.net</span></a></span><span class="vcardline">URI: <a href="http://invisible.net/" class="url">http://invisible.net/</a></span></address><hr class="noprint"><h1 id="rfc.section.A" class="np"><a href="#rfc.section.A">A.</a> <a name="elementrfc" href="#elementrfc">The rfc Element</a></h1><div id="rfc.figure.u.35"></div> <p><sup class="editingmark"><span>126</span> </sup>The "<rfc>" tag at the beginning of the file, with only <a href="#ipr">an "ipr" attribute</a>, produces an Internet-Draft. However, when other attributes are added to this tag by the RFC editor, an RFC is produced, e.g.,</p> <pre>
<rfc number="2200"
obsoletes="2000, 1920, 1880, 1800, ..."
category="std"
seriesNo="1">
</pre> <p><sup class="editingmark"><span>127</span> </sup>At a minimum, the "number" attribute should be present.</p> <p id="rfc.section.A.p.2"><sup class="editingmark"><span>128</span> </sup>The other attributes are: </p><ul><li>"obsoletes", having a comma-separated list of RFC numbers, that the document obsoletes;</li><li>"updates", having a comma-separated list of RFC numbers, that the document updates;</li><li>"category", having one of these values: <ol><li>"std", for a Standards-Track document;</li><li>"bcp", "for a Best Current Practices document;</li><li>"exp", for an Experimental Protocol document;</li><li>"historic", for a historic document; or,</li><li>"info", the default, for an Informational document.</li></ol> </li><li>"seriesNo", having the corresponding number in the STD (std), BCP (bcp), or FYI (info) series.</li></ul><p id="rfc.section.A.p.3"><sup class="editingmark"><span>138</span> </sup>Finally, a special entity, "&rfc.number;", is available. Authors preparing an RFC should use this entity whenever they want to reference the number of the RFC within the document itself. In printed versions of the document, the appropriate substitution (or "XXXX") will occur.</p><hr class="noprint"><h1 id="rfc.section.B" class="np"><a href="#rfc.section.B">B.</a> <a name="dtdrfc.dtd" href="#dtdrfc.dtd">The RFC DTD</a></h1><div id="rfc.figure.u.36"></div> <pre>
<!--
DTD for the RFC document series, draft of 99-01-30
-->
<!--
Contents
DTD data types
The top-level
Front matter
The Body
Back matter
-->
<!--
DTD data types:
entity description
====== ===============================================
NUMBER [0-9]+
NUMBERS a comma-separated list of NUMBER
DAY the day of the month, e.g., "1"
MONTH the month of the year, e.g., "January"
YEAR a four-digit year, e.g., "1999"
URI e.g., "http://invisible.net/"
ATEXT/CTEXT printable ASCII text (no line-terminators)
TEXT character data
-->
<!ENTITY % NUMBER "CDATA">
<!ENTITY % NUMBERS "CDATA">
<!ENTITY % DAY "CDATA">
<!ENTITY % MONTH "CDATA">
<!ENTITY % YEAR "CDATA">
<!ENTITY % URI "CDATA">
<!ENTITY % ATEXT "CDATA">
<!ENTITY % CTEXT "#PCDATA">
<!ENTITY % TEXT "#PCDATA">
<!ENTITY rfc.number "&rfc.number;">
<!--
The top-level
-->
<!--
attributes for the "rfc" element are supplied by the RFC
editor. when preparing drafts, authors should leave them blank.
the "seriesNo" attribute is used if the category is, e.g., BCP.
-->
<!ELEMENT rfc (front,middle,back?)>
<!ATTLIST rfc
number %NUMBER; #IMPLIED
obsoletes %NUMBERS; ""
updates %NUMBERS; ""
category (std|bcp|info|exp|historic)
"info"
seriesNo %NUMBER; #IMPLIED
ipr (full2026|noDerivativeWorks2026|none)
#IMPLIED
docName %ATEXT; #IMPLIED>
<!--
Front matter
-->
<!ELEMENT front (title,author+,date,area*,workgroup*,keyword*,
abstract?,note*)>
<!-- the "abbrev" attribute is used for headers, etc. -->
<!ELEMENT title (%CTEXT;)>
<!ATTLIST title
abbrev %ATEXT; #IMPLIED>
<!ELEMENT author (organization,address?)>
<!ATTLIST author
initials %ATEXT; #IMPLIED
surname %ATEXT; #IMPLIED
fullname %ATEXT; #IMPLIED>
<!ELEMENT organization
(%CTEXT;)>
<!ATTLIST organization
abbrev %ATEXT; #IMPLIED>
<!ELEMENT address (postal?,phone?,facsimile?,email?,uri?)>
<!-- at most one of each the city, region, code, and country
elements may be present -->
<!ELEMENT postal (street+,(city|region|code|country)*)>
<!ELEMENT street (%CTEXT;)>
<!ELEMENT city (%CTEXT;)>
<!ELEMENT region (%CTEXT;)>
<!ELEMENT code (%CTEXT;)>
<!ELEMENT country (%CTEXT;)>
<!ELEMENT phone (%CTEXT;)>
<!ELEMENT facsimile (%CTEXT;)>
<!ELEMENT email (%CTEXT;)>
<!ELEMENT uri (%CTEXT;)>
<!ELEMENT date EMPTY>
<!ATTLIST date
day %DAY; #IMPLIED
month %MONTH; #REQUIRED
year %YEAR; #REQUIRED>
<!-- meta-data... -->
<!ELEMENT area (%CTEXT;)>
<!ELEMENT workgroup (%CTEXT;)>
<!ELEMENT keyword (%CTEXT;)>
<!ELEMENT abstract (t)+>
<!ELEMENT note (t)+>
<!ATTLIST note
title %ATEXT; #REQUIRED>
<!--
The body
-->
<!ELEMENT middle (section)+>
<!ELEMENT section (t|figure|section)*>
<!ATTLIST section
anchor ID #IMPLIED
title %ATEXT; #REQUIRED>
<!ELEMENT t (%TEXT;|list|figure|xref|eref|iref|vspace)*>
<!ATTLIST t
hangText %ATEXT; #IMPLIED>
<!-- the value of the style attribute is inherited from the closest
parent -->
<!ELEMENT list (t+)>
<!ATTLIST list
style (numbers|symbols|hanging|empty)
"empty">
<!ELEMENT xref (%CTEXT;)>
<!ATTLIST xref
target IDREF #REQUIRED
pageno (true|false) "false">
<!ELEMENT eref (%CTEXT;)>
<!ATTLIST eref
target %URI; #REQUIRED>
<!ELEMENT iref EMPTY>
<!ATTLIST iref
item %ATEXT; #REQUIRED
subitem %ATEXT; "">
<!ELEMENT vspace EMPTY>
<!ATTLIST vspace
blankLines %NUMBER; "0">
<!ELEMENT figure (preamble?,artwork,postamble?)>
<!ATTLIST figure
anchor ID #IMPLIED
title %ATEXT; "">
<!ELEMENT preamble (%TEXT;|xref|eref|iref)*>
<!ELEMENT artwork (%TEXT;)*>
<!ATTLIST artwork
xml:space (default|preserve) "preserve">
<!ELEMENT postamble (%TEXT;|xref|eref|iref)*>
<!--
Back matter
-->
<!-- sections, if present, are appendices -->
<!ELEMENT back (references?,section*)>
<!ELEMENT references (reference+)>
<!ELEMENT reference (front,seriesInfo*)>
<!ATTLIST reference
anchor ID #IMPLIED
target %URI; #IMPLIED>
<!ELEMENT seriesInfo EMPTY>
<!ATTLIST seriesInfo
name %ATEXT; #REQUIRED
value %ATEXT; #REQUIRED>
</pre> <hr class="noprint"><h1 id="rfc.section.C" class="np"><a href="#rfc.section.C">C.</a> Acknowledgements</h1><p id="rfc.section.C.p.1"><sup class="editingmark"><span>139</span> </sup>The author gratefully acknowledges the contributions of: Alan Barrett, Brad Burdick, Brian Carpenter, Steve Deering, Patrik Faltstrom, Jim Gettys, Carl Malamud, Chris Newman, Kurt Starsinic, and, Frank Strauss.</p><hr class="noprint"><h1 class="np"><a name="rfc.ipr" href="#rfc.ipr">Intellectual Property Statement</a></h1><p>The DDF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the DDF's procedures with respect to rights in standards-track and standards-related documentation can be found in RFC-0.</p><p>The DDF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights which may cover technology that may be required to practice this standard. Please address the information to the DDF Board of Directors.</p><h1>Acknowledgement</h1><p>Funding for the RFC Editor function is provided by the DDF</p><hr class="noprint"><h1 id="rfc.index" class="np"><a href="#rfc.index">Index</a></h1><p class="noprint"><a href="#rfc.index.I">I </a></p><div class="print2col"><ul class="ind"><li class="indline0"><a name="rfc.index.I" href="#rfc.index.I"><b>I</b></a><ul class="ind"><li class="indline1">indexing <ul class="ind"><li class="indline1">how to <a class="iref" href="#rfc.iref.1">2.3.1.6</a></li></ul></li></ul></li></ul></div></body></html>