<?xml version='1.0' encoding='utf-8'?>
<rfc xmlns:xi="http://www.w3.org/2001/XInclude" version="3" category="std" ipr="trust200902" tocInclude="true" indexInclude="true" obsoletes="" consensus="true" submissionType="IETF" xml:lang="en" updates="8928" docName="draft-ietf-6lo-updating-rfc-8928-05" number="9927" symRefs="true" sortRefs="true" prepTime="2026-02-11T09:07:21" scripts="Common,Latin" tocDepth="3">
  <link href="https://datatracker.ietf.org/doc/draft-ietf-6lo-updating-rfc-8928-05" rel="prev"/>
  <link href="https://dx.doi.org/10.17487/rfc9927" rel="alternate"/>
  <link href="urn:issn:2070-1721" rel="alternate"/>
  <front>
    <title abbrev="Fix of RFC 8928">Fixing the C-Flag in the Extended Address Registration Option (EARO)</title>
    <seriesInfo name="RFC" value="9927" stream="IETF"/>
    <author initials="P" surname="Thubert" fullname="Pascal Thubert">
      <address>
        <postal>
          <city>Roquefort-les-Pins</city>
          <code>06330</code>
          <country>France</country>
        </postal>
        <email>pascal.thubert@gmail.com</email>
      </address>
    </author>
    <author initials="A" surname="Rashid" fullname="Adnan Rashid">
      <organization abbrev="Politecnico di Bari" showOnFrontPage="true">Politecnico di Bari</organization>
      <address>
        <postal>
          <street>Via Edoardo Orabona 4</street>
          <city>Bari</city>
          <code>70126</code>
          <country>Italy</country>
        </postal>
        <email>adnan.rashid@poliba.it</email>
      </address>
    </author>
    <date month="02" year="2026"/>
    <area>INT</area>
    <workgroup>6lo</workgroup>
    <abstract pn="section-abstract">
      <t indent="0" pn="section-abstract-1">This document updates "Address-Protected Neighbor Discovery for
   Low-Power and Lossy Networks" (RFC 8928) by changing the position of the
   C-flag in the Extended Address Registration Option (EARO) and registering
   it with IANA.</t>
    </abstract>
    <boilerplate>
      <section anchor="status-of-memo" numbered="false" removeInRFC="false" toc="exclude" pn="section-boilerplate.1">
        <name slugifiedName="name-status-of-this-memo">Status of This Memo</name>
        <t indent="0" pn="section-boilerplate.1-1">
            This is an Internet Standards Track document.
        </t>
        <t indent="0" pn="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.
        </t>
        <t indent="0" pn="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
            <eref target="https://www.rfc-editor.org/info/rfc9927" brackets="none"/>.
        </t>
      </section>
      <section anchor="copyright" numbered="false" removeInRFC="false" toc="exclude" pn="section-boilerplate.2">
        <name slugifiedName="name-copyright-notice">Copyright Notice</name>
        <t indent="0" pn="section-boilerplate.2-1">
            Copyright (c) 2026 IETF Trust and the persons identified as the
            document authors. All rights reserved.
        </t>
        <t indent="0" pn="section-boilerplate.2-2">
            This document is subject to BCP 78 and the IETF Trust's Legal
            Provisions Relating to IETF Documents
            (<eref target="https://trustee.ietf.org/license-info" brackets="none"/>) 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 Revised BSD License text as described in
            Section 4.e of the Trust Legal Provisions and are provided without
            warranty as described in the Revised BSD License.
        </t>
      </section>
    </boilerplate>
    <toc>
      <section anchor="toc" numbered="false" removeInRFC="false" toc="exclude" pn="section-toc.1">
        <name slugifiedName="name-table-of-contents">Table of Contents</name>
        <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1">
          <li pn="section-toc.1-1.1">
            <t indent="0" keepWithNext="true" pn="section-toc.1-1.1.1"><xref derivedContent="1" format="counter" sectionFormat="of" target="section-1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-introduction">Introduction</xref></t>
          </li>
          <li pn="section-toc.1-1.2">
            <t indent="0" pn="section-toc.1-1.2.1"><xref derivedContent="2" format="counter" sectionFormat="of" target="section-2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-terminology">Terminology</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.2.2">
              <li pn="section-toc.1-1.2.2.1">
                <t indent="0" keepWithNext="true" pn="section-toc.1-1.2.2.1.1"><xref derivedContent="2.1" format="counter" sectionFormat="of" target="section-2.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-requirements-language">Requirements Language</xref></t>
              </li>
              <li pn="section-toc.1-1.2.2.2">
                <t indent="0" keepWithNext="true" pn="section-toc.1-1.2.2.2.1"><xref derivedContent="2.2" format="counter" sectionFormat="of" target="section-2.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-related-documents">Related Documents</xref></t>
              </li>
              <li pn="section-toc.1-1.2.2.3">
                <t indent="0" pn="section-toc.1-1.2.2.3.1"><xref derivedContent="2.3" format="counter" sectionFormat="of" target="section-2.3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-acronyms">Acronyms</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.3">
            <t indent="0" pn="section-toc.1-1.3.1"><xref derivedContent="3" format="counter" sectionFormat="of" target="section-3"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-updating-rfc-8928">Updating RFC 8928</xref></t>
          </li>
          <li pn="section-toc.1-1.4">
            <t indent="0" pn="section-toc.1-1.4.1"><xref derivedContent="4" format="counter" sectionFormat="of" target="section-4"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-security-considerations">Security Considerations</xref></t>
          </li>
          <li pn="section-toc.1-1.5">
            <t indent="0" pn="section-toc.1-1.5.1"><xref derivedContent="5" format="counter" sectionFormat="of" target="section-5"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-operational-considerations">Operational Considerations</xref></t>
          </li>
          <li pn="section-toc.1-1.6">
            <t indent="0" pn="section-toc.1-1.6.1"><xref derivedContent="6" format="counter" sectionFormat="of" target="section-6"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-iana-considerations">IANA Considerations</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.6.2">
              <li pn="section-toc.1-1.6.2.1">
                <t indent="0" pn="section-toc.1-1.6.2.1.1"><xref derivedContent="6.1" format="counter" sectionFormat="of" target="section-6.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-bit-position-of-the-c-flag">Bit Position of the C-flag</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.7">
            <t indent="0" pn="section-toc.1-1.7.1"><xref derivedContent="7" format="counter" sectionFormat="of" target="section-7"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-references">References</xref></t>
            <ul bare="true" empty="true" indent="2" spacing="compact" pn="section-toc.1-1.7.2">
              <li pn="section-toc.1-1.7.2.1">
                <t indent="0" pn="section-toc.1-1.7.2.1.1"><xref derivedContent="7.1" format="counter" sectionFormat="of" target="section-7.1"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-normative-references">Normative References</xref></t>
              </li>
              <li pn="section-toc.1-1.7.2.2">
                <t indent="0" pn="section-toc.1-1.7.2.2.1"><xref derivedContent="7.2" format="counter" sectionFormat="of" target="section-7.2"/>.  <xref derivedContent="" format="title" sectionFormat="of" target="name-informative-references">Informative References</xref></t>
              </li>
            </ul>
          </li>
          <li pn="section-toc.1-1.8">
            <t indent="0" pn="section-toc.1-1.8.1"><xref derivedContent="" format="none" sectionFormat="of" target="section-appendix.a"/><xref derivedContent="" format="title" sectionFormat="of" target="name-authors-addresses">Authors' Addresses</xref></t>
          </li>
        </ul>
      </section>
    </toc>
  </front>
  <middle>
    <section anchor="introduction" numbered="true" removeInRFC="false" toc="include" pn="section-1">
      <name slugifiedName="name-introduction">Introduction</name>
      <t indent="0" pn="section-1-1">The <xref target="RFC8928" format="default" sectionFormat="of" derivedContent="RFC8928"> Address-Protected Neighbor Discovery 
   for Low-Power and Lossy Networks (AP-ND)</xref> defined the C-flag in EARO. It is used to indicate that the Registration Ownership Verifier (ROVR) field contains
   a Crypto-ID and that the 6LoWPAN Node (6LN) may be challenged for ownership of the registered address. Initially, <xref target="RFC8928" format="default" sectionFormat="of" derivedContent="RFC8928"/> defined the C-flag in the EARO in bit position 3; later, <xref target="RFC9685" format="default" sectionFormat="of" derivedContent="RFC9685"/> defined the P-Field in bits 2 and 3 of the 
   EARO flags field with proper IANA registration, causing an overlap with  Figure 1 of <xref target="RFC8928" format="default" sectionFormat="of" derivedContent="RFC8928"/>, which depicts the location of the C-flag.</t>
      <t indent="0" pn="section-1-2">This specification updates <xref target="RFC8928" format="default" sectionFormat="of" derivedContent="RFC8928"/> by repositioning the C-flag as bit 1 of the EARO flags field, thereby preventing conflicts.</t>
    </section>
    <section numbered="true" removeInRFC="false" toc="include" pn="section-2">
      <name slugifiedName="name-terminology">Terminology</name>
      <section anchor="bcp" numbered="true" removeInRFC="false" toc="include" pn="section-2.1">
        <name slugifiedName="name-requirements-language">Requirements Language</name>
        <t indent="0" pn="section-2.1-1">
    The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>",
    "<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL NOT</bcp14>",
    "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>",
    "<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>",
    "<bcp14>MAY</bcp14>", and "<bcp14>OPTIONAL</bcp14>" in this document are to be
    interpreted as described in BCP 14 <xref target="RFC2119" format="default" sectionFormat="of" derivedContent="RFC2119"/> <xref target="RFC8174" format="default" sectionFormat="of" derivedContent="RFC8174"/> when, and only when, they appear in all capitals, as
    shown here.
        </t>
      </section>
      <section anchor="lo" numbered="true" removeInRFC="false" toc="include" pn="section-2.2">
        <name slugifiedName="name-related-documents">Related Documents</name>
        <t indent="0" pn="section-2.2-1">
	This document uses terms and concepts that are discussed in IPv6 Neighbor Discovery (ND)
   <xref target="RFC4861" format="default" sectionFormat="of" derivedContent="RFC4861"/>, <xref target="RFC4862" format="default" sectionFormat="of" derivedContent="RFC4862"/>, as well as 6LoWPAN-ND 
   <xref target="RFC6775" format="default" sectionFormat="of" derivedContent="RFC6775"/>, <xref target="RFC8505" format="default" sectionFormat="of" derivedContent="RFC8505"/>, 
   <xref target="RFC8928" format="default" sectionFormat="of" derivedContent="RFC8928"/>, <xref target="RFC8929" format="default" sectionFormat="of" derivedContent="RFC8929"/>, 
   <xref target="RFC9685" format="default" sectionFormat="of" derivedContent="RFC9685"/>, and <xref target="RFC9926" format="default" sectionFormat="of" derivedContent="RFC9926"/>.
        </t>
      </section>
      <section anchor="acronyms" numbered="true" removeInRFC="false" toc="include" pn="section-2.3">
        <name slugifiedName="name-acronyms">Acronyms</name>
        <t indent="0" pn="section-2.3-1">This document uses the following abbreviations:</t>
        <dl spacing="normal" newline="false" indent="3" pn="section-2.3-2">
          <dt pn="section-2.3-2.1">6LN:</dt>
          <dd pn="section-2.3-2.2">6LoWPAN Node</dd>
          <dt pn="section-2.3-2.3">EARO:</dt>
          <dd pn="section-2.3-2.4">Extended Address Registration Option</dd>
          <dt pn="section-2.3-2.5">ND:</dt>
          <dd pn="section-2.3-2.6">Neighbor Discovery</dd>
          <dt pn="section-2.3-2.7">RATInd:</dt>
          <dd pn="section-2.3-2.8">Registered Address Type Indicator</dd>
          <dt pn="section-2.3-2.9">ROVR:</dt>
          <dd pn="section-2.3-2.10">Registration Ownership Verifier</dd>
        </dl>
      </section>
    </section>
    <section anchor="updating" numbered="true" removeInRFC="false" toc="include" pn="section-3">
      <name slugifiedName="name-updating-rfc-8928">Updating RFC 8928</name>
      <t indent="0" pn="section-3-1">
 	
  <xref target="RFC8928" format="default" sectionFormat="of" derivedContent="RFC8928"/> incorrectly refers to the Extended Address Registration Option (EARO) as the Enhanced Address Registration Option.
  This specification corrects this terminology throughout the document.
</t>
      <t indent="0" pn="section-3-2">
  In <xref target="RFC8928" format="default" sectionFormat="of" derivedContent="RFC8928"/>, the C-flag is specified in the EARO flags field at bit position 3 (as depicted in Figure 1 of <xref target="RFC8928" format="default" sectionFormat="of" derivedContent="RFC8928"/>); 
  however, <xref target="RFC8928" format="default" sectionFormat="of" derivedContent="RFC8928"/> fails to register its position with IANA. Later, <xref target="RFC9685" format="default" sectionFormat="of" derivedContent="RFC9685"/> defined the P-Field 
  in bits 2 and 3 of the EARO flags field and obtained proper IANA registration, but this introduced an overlap with the 
  representation in <xref target="RFC8928" format="default" sectionFormat="of" derivedContent="RFC8928"/>. To resolve the conflict, this specification updates <xref target="RFC8928" format="default" sectionFormat="of" derivedContent="RFC8928"/> by repositioning 
  the C-flag to bit 1 of the EARO flags field, ensuring there are no overlapping definitions.
      </t>
      <t indent="0" pn="section-3-3">
  <xref target="EARO" format="default" sectionFormat="of" derivedContent="Figure 1"/> replaces Figure 1 in <xref target="RFC8928" format="default" sectionFormat="of" derivedContent="RFC8928"/> in the case of an EARO used in an NS message.  
      </t>
      <figure anchor="EARO" align="left" suppress-title="false" pn="figure-1">
        <name slugifiedName="name-extended-address-registrati">Extended Address Registration Option (EARO) Format for Use in NS Messages</name>
        <artwork align="center" pn="section-3-4.1">
   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |     Type      |     Length    |F|Prefix Length|    Opaque     |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |r|C| P | I |R|T|     TID       |     Registration Lifetime     |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |                                                               |
 ...            Registration Ownership Verifier (ROVR)           ...
  |                  (64, 128, 192, or 256 bits)                  |
  |                                                               |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+</artwork>
      </figure>
      <t indent="0" pn="section-3-5">
<xref target="EARO2" format="default" sectionFormat="of" derivedContent="Figure 2"/> replaces Figure 1 in <xref target="RFC8928" format="default" sectionFormat="of" derivedContent="RFC8928"/> in the case of an EARO used in an NA message. The difference between the two formats is in the usage of bits 16 to 23.
</t>
      <figure anchor="EARO2" align="left" suppress-title="false" pn="figure-2">
        <name slugifiedName="name-extended-address-registratio">Extended Address Registration Option (EARO) Format for Use in NA Messages</name>
        <artwork align="center" pn="section-3-6.1">
   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |     Type      |     Length    | r |  Status   |    Opaque     |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |r|C| P | I |R|T|     TID       |     Registration Lifetime     |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |                                                               |
 ...            Registration Ownership Verifier (ROVR)           ...
  |                  (64, 128, 192, or 256 bits)                  |
  |                                                               |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+</artwork>
      </figure>
      <t indent="0" pn="section-3-7">Option fields of interest for this specification:</t>
      <dl spacing="normal" newline="false" indent="3" pn="section-3-8">
        <dt pn="section-3-8.1">Type:</dt>
        <dd pn="section-3-8.2">33</dd>
        <dt pn="section-3-8.3">Length:</dt>
        <dd pn="section-3-8.4">Defined in <xref target="RFC8505" format="default" sectionFormat="of" derivedContent="RFC8505"/></dd>
        <dt pn="section-3-8.5">F:</dt>
        <dd pn="section-3-8.6">Defined in <xref target="RFC9926" format="default" sectionFormat="of" derivedContent="RFC9926"/></dd>
        <dt pn="section-3-8.7">Prefix Length</dt>
        <dd pn="section-3-8.8">Defined in <xref target="RFC9926" format="default" sectionFormat="of" derivedContent="RFC9926"/></dd>
        <dt pn="section-3-8.9">Status:</dt>
        <dd pn="section-3-8.10"> 6-bit unsigned integer. 
      This field is used in NA(EARO) response messages only to indicate the status of a registration.
      This field is defined in <xref target="RFC8505" format="default" sectionFormat="of" derivedContent="RFC8505"/> and resized by <xref target="RFC9010" format="default" sectionFormat="of" derivedContent="RFC9010"/>.
      The values for the Status field are available in <xref target="IANA.ICMP.ARO.STAT" format="default" sectionFormat="of" derivedContent="IANA.ICMP.ARO.STAT"/>.
      This field <bcp14>MUST</bcp14> be set to 0 in NS(EARO) messages unless the registration is for a prefix,
      in which case the F-flag is set and the prefix length is provided. 
   </dd>
        <dt pn="section-3-8.11">Opaque:</dt>
        <dd pn="section-3-8.12">Defined in <xref target="RFC8505" format="default" sectionFormat="of" derivedContent="RFC8505"/></dd>
        <dt pn="section-3-8.13">r (reserved):</dt>
        <dd pn="section-3-8.14">1-bit reserved field in NS(EARO) and NA(EARO) as depicted in <xref target="EARO" format="default" sectionFormat="of" derivedContent="Figure 1"/> and <xref target="EARO2" format="default" sectionFormat="of" derivedContent="Figure 2"/>.
       2-bit reserved field (most significant bits of Status filed) in NA(EARO) as depicted in <xref target="EARO2" format="default" sectionFormat="of" derivedContent="Figure 2"/>. 
       All reserved field <bcp14>MUST</bcp14> be set to zero by the sender and <bcp14>MUST</bcp14> be ignored by the receiver.</dd>
        <dt pn="section-3-8.15">C:</dt>
        <dd pn="section-3-8.16">1-bit flag, moved from its position in Figure 1 of <xref target="RFC8928" format="default" sectionFormat="of" derivedContent="RFC8928"/>. It is set to indicate that the ROVR field contains a Crypto-ID and that the 6LN <bcp14>MAY</bcp14> be challenged for ownership.</dd>
        <dt pn="section-3-8.17">P:</dt>
        <dd pn="section-3-8.18">2-bit field for Registered Address Type Indicator (RATInd). Indicates whether the registered address is unicast, multicast, anycast, or derived from the registered unicast prefix.
   Used to transport the RATInd in different protocols. The values for the RATInd field are available in <xref target="IANA.ICMP.ARO.P-FIELD" format="default" sectionFormat="of" derivedContent="IANA.ICMP.ARO.P-FIELD"/>.</dd>
        <dt pn="section-3-8.19">I:</dt>
        <dd pn="section-3-8.20">Defined in <xref target="RFC8505" format="default" sectionFormat="of" derivedContent="RFC8505"/></dd>
        <dt pn="section-3-8.21">R:</dt>
        <dd pn="section-3-8.22">Defined in <xref target="RFC8505" format="default" sectionFormat="of" derivedContent="RFC8505"/></dd>
        <dt pn="section-3-8.23">T:</dt>
        <dd pn="section-3-8.24">Defined in <xref target="RFC8505" format="default" sectionFormat="of" derivedContent="RFC8505"/></dd>
        <dt pn="section-3-8.25">TID (Transaction ID):</dt>
        <dd pn="section-3-8.26">Defined in <xref target="RFC8505" format="default" sectionFormat="of" derivedContent="RFC8505"/></dd>
        <dt pn="section-3-8.27">Registration Lifetime:</dt>
        <dd pn="section-3-8.28">Defined in <xref target="RFC8505" format="default" sectionFormat="of" derivedContent="RFC8505"/></dd>
        <dt pn="section-3-8.29">Registration Ownership Verifier (ROVR):</dt>
        <dd pn="section-3-8.30">Defined in <xref target="RFC8505" format="default" sectionFormat="of" derivedContent="RFC8505"/>. Variable-length field used to verify who "owns" a registered IPv6 address. 
   When the C-flag is set, this field contains a Crypto-ID <xref target="RFC8928" format="default" sectionFormat="of" derivedContent="RFC8928"/>.</dd>
      </dl>
    </section>
    <section numbered="true" removeInRFC="false" toc="include" pn="section-4">
      <name slugifiedName="name-security-considerations">Security Considerations</name>
      <t indent="0" pn="section-4-1">This specification does not introduce any new security considerations beyond those already discussed in <xref target="RFC8928" format="default" sectionFormat="of" derivedContent="RFC8928"/> and <xref target="RFC8505" format="default" sectionFormat="of" derivedContent="RFC8505"/>.</t>
    </section>
    <section numbered="true" removeInRFC="false" toc="include" pn="section-5">
      <name slugifiedName="name-operational-considerations">Operational Considerations</name>
      <t indent="0" pn="section-5-1">
The updates introduced in this document are not backward compatible. However, given that there are no known implementations or deployments of <xref target="RFC8928" format="default" sectionFormat="of" derivedContent="RFC8928"/>, 
this document does not require any transition plan.
</t>
    </section>
    <section numbered="true" removeInRFC="false" toc="include" pn="section-6">
      <name slugifiedName="name-iana-considerations">IANA Considerations</name>
      <section numbered="true" removeInRFC="false" toc="include" pn="section-6.1">
        <name slugifiedName="name-bit-position-of-the-c-flag">Bit Position of the C-flag</name>
        <t indent="0" pn="section-6.1-1"> 
   
   IANA has updated the "Address Registration Option Flags" <xref target="IANA.ICMP.ARO.FLG" format="default" sectionFormat="of" derivedContent="IANA.ICMP.ARO.FLG"/> registry
   in the "Internet Control Message Protocol version 6 (ICMPv6) Parameters" registry group as specified
   in <xref target="AROflags" format="default" sectionFormat="of" derivedContent="Table 1"/> so this document is referenced in addition to <xref target="RFC8928" format="default" sectionFormat="of" derivedContent="RFC8928"/> for bit number 1:
        </t>
        <table anchor="AROflags" align="center" pn="table-1">
          <name slugifiedName="name-bit-position-of-the-c-flag-2">Bit Position of the C-flag</name>
          <thead>
            <tr>
              <th align="left" colspan="1" rowspan="1">Bit Number</th>
              <th align="left" colspan="1" rowspan="1">Description</th>
              <th align="left" colspan="1" rowspan="1">Reference</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td align="left" colspan="1" rowspan="1">1</td>
              <td align="left" colspan="1" rowspan="1"> C-Flag </td>
              <td align="left" colspan="1" rowspan="1">RFC 9927 and <xref target="RFC8928" format="default" sectionFormat="of" derivedContent="RFC8928"/></td>
            </tr>
          </tbody>
        </table>
      </section>
    </section>
  </middle>
  <back>
    <references pn="section-7">
      <name slugifiedName="name-references">References</name>
      <references pn="section-7.1">
        <name slugifiedName="name-normative-references">Normative References</name>
        <reference anchor="IANA.ICMP.ARO.FLG" target="https://www.iana.org/assignments/icmpv6-parameters" quoteTitle="true" derivedAnchor="IANA.ICMP.ARO.FLG">
          <front>
            <title>Address Registration Option Flags</title>
            <author>
              <organization showOnFrontPage="true">IANA</organization>
            </author>
          </front>
        </reference>
        <reference anchor="IANA.ICMP.ARO.P-FIELD" target="https://www.iana.org/assignments/icmpv6-parameters" quoteTitle="true" derivedAnchor="IANA.ICMP.ARO.P-FIELD">
          <front>
            <title>P-Field Values</title>
            <author>
              <organization showOnFrontPage="true">IANA</organization>
            </author>
          </front>
        </reference>
        <reference anchor="IANA.ICMP.ARO.STAT" target="https://www.iana.org/assignments/icmpv6-parameters" quoteTitle="true" derivedAnchor="IANA.ICMP.ARO.STAT">
          <front>
            <title>Address Registration Option Status Values</title>
            <author>
              <organization showOnFrontPage="true">IANA</organization>
            </author>
          </front>
        </reference>
        <reference anchor="RFC2119" target="https://www.rfc-editor.org/info/rfc2119" quoteTitle="true" derivedAnchor="RFC2119">
          <front>
            <title>Key words for use in RFCs to Indicate Requirement Levels</title>
            <author fullname="S. Bradner" initials="S." surname="Bradner"/>
            <date month="March" year="1997"/>
            <abstract>
              <t indent="0">In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="14"/>
          <seriesInfo name="RFC" value="2119"/>
          <seriesInfo name="DOI" value="10.17487/RFC2119"/>
        </reference>
        <reference anchor="RFC4861" target="https://www.rfc-editor.org/info/rfc4861" quoteTitle="true" derivedAnchor="RFC4861">
          <front>
            <title>Neighbor Discovery for IP version 6 (IPv6)</title>
            <author fullname="T. Narten" initials="T." surname="Narten"/>
            <author fullname="E. Nordmark" initials="E." surname="Nordmark"/>
            <author fullname="W. Simpson" initials="W." surname="Simpson"/>
            <author fullname="H. Soliman" initials="H." surname="Soliman"/>
            <date month="September" year="2007"/>
            <abstract>
              <t indent="0">This document specifies the Neighbor Discovery protocol for IP Version 6. IPv6 nodes on the same link use Neighbor Discovery to discover each other's presence, to determine each other's link-layer addresses, to find routers, and to maintain reachability information about the paths to active neighbors. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4861"/>
          <seriesInfo name="DOI" value="10.17487/RFC4861"/>
        </reference>
        <reference anchor="RFC4862" target="https://www.rfc-editor.org/info/rfc4862" quoteTitle="true" derivedAnchor="RFC4862">
          <front>
            <title>IPv6 Stateless Address Autoconfiguration</title>
            <author fullname="S. Thomson" initials="S." surname="Thomson"/>
            <author fullname="T. Narten" initials="T." surname="Narten"/>
            <author fullname="T. Jinmei" initials="T." surname="Jinmei"/>
            <date month="September" year="2007"/>
            <abstract>
              <t indent="0">This document specifies the steps a host takes in deciding how to autoconfigure its interfaces in IP version 6. The autoconfiguration process includes generating a link-local address, generating global addresses via stateless address autoconfiguration, and the Duplicate Address Detection procedure to verify the uniqueness of the addresses on a link. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4862"/>
          <seriesInfo name="DOI" value="10.17487/RFC4862"/>
        </reference>
        <reference anchor="RFC6775" target="https://www.rfc-editor.org/info/rfc6775" quoteTitle="true" derivedAnchor="RFC6775">
          <front>
            <title>Neighbor Discovery Optimization for IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs)</title>
            <author fullname="Z. Shelby" initials="Z." role="editor" surname="Shelby"/>
            <author fullname="S. Chakrabarti" initials="S." surname="Chakrabarti"/>
            <author fullname="E. Nordmark" initials="E." surname="Nordmark"/>
            <author fullname="C. Bormann" initials="C." surname="Bormann"/>
            <date month="November" year="2012"/>
            <abstract>
              <t indent="0">The IETF work in IPv6 over Low-power Wireless Personal Area Network (6LoWPAN) defines 6LoWPANs such as IEEE 802.15.4. This and other similar link technologies have limited or no usage of multicast signaling due to energy conservation. In addition, the wireless network may not strictly follow the traditional concept of IP subnets and IP links. IPv6 Neighbor Discovery was not designed for non- transitive wireless links, as its reliance on the traditional IPv6 link concept and its heavy use of multicast make it inefficient and sometimes impractical in a low-power and lossy network. This document describes simple optimizations to IPv6 Neighbor Discovery, its addressing mechanisms, and duplicate address detection for Low- power Wireless Personal Area Networks and similar networks. The document thus updates RFC 4944 to specify the use of the optimizations defined here. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6775"/>
          <seriesInfo name="DOI" value="10.17487/RFC6775"/>
        </reference>
        <reference anchor="RFC8174" target="https://www.rfc-editor.org/info/rfc8174" quoteTitle="true" derivedAnchor="RFC8174">
          <front>
            <title>Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words</title>
            <author fullname="B. Leiba" initials="B." surname="Leiba"/>
            <date month="May" year="2017"/>
            <abstract>
              <t indent="0">RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="14"/>
          <seriesInfo name="RFC" value="8174"/>
          <seriesInfo name="DOI" value="10.17487/RFC8174"/>
        </reference>
        <reference anchor="RFC8505" target="https://www.rfc-editor.org/info/rfc8505" quoteTitle="true" derivedAnchor="RFC8505">
          <front>
            <title>Registration Extensions for IPv6 over Low-Power Wireless Personal Area Network (6LoWPAN) Neighbor Discovery</title>
            <author fullname="P. Thubert" initials="P." role="editor" surname="Thubert"/>
            <author fullname="E. Nordmark" initials="E." surname="Nordmark"/>
            <author fullname="S. Chakrabarti" initials="S." surname="Chakrabarti"/>
            <author fullname="C. Perkins" initials="C." surname="Perkins"/>
            <date month="November" year="2018"/>
            <abstract>
              <t indent="0">This specification updates RFC 6775 -- the Low-Power Wireless Personal Area Network (6LoWPAN) Neighbor Discovery specification -- to clarify the role of the protocol as a registration technique and simplify the registration operation in 6LoWPAN routers, as well as to provide enhancements to the registration capabilities and mobility detection for different network topologies, including the Routing Registrars performing routing for host routes and/or proxy Neighbor Discovery in a low-power network.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8505"/>
          <seriesInfo name="DOI" value="10.17487/RFC8505"/>
        </reference>
        <reference anchor="RFC8928" target="https://www.rfc-editor.org/info/rfc8928" quoteTitle="true" derivedAnchor="RFC8928">
          <front>
            <title>Address-Protected Neighbor Discovery for Low-Power and Lossy Networks</title>
            <author fullname="P. Thubert" initials="P." role="editor" surname="Thubert"/>
            <author fullname="B. Sarikaya" initials="B." surname="Sarikaya"/>
            <author fullname="M. Sethi" initials="M." surname="Sethi"/>
            <author fullname="R. Struik" initials="R." surname="Struik"/>
            <date month="November" year="2020"/>
            <abstract>
              <t indent="0">This document updates the IPv6 over Low-Power Wireless Personal Area Network (6LoWPAN) Neighbor Discovery (ND) protocol defined in RFCs 6775 and 8505. The new extension is called Address-Protected Neighbor Discovery (AP-ND), and it protects the owner of an address against address theft and impersonation attacks in a Low-Power and Lossy Network (LLN). Nodes supporting this extension compute a cryptographic identifier (Crypto-ID), and use it with one or more of their Registered Addresses. The Crypto-ID identifies the owner of the Registered Address and can be used to provide proof of ownership of the Registered Addresses. Once an address is registered with the Crypto-ID and a proof of ownership is provided, only the owner of that address can modify the registration information, thereby enforcing Source Address Validation.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8928"/>
          <seriesInfo name="DOI" value="10.17487/RFC8928"/>
        </reference>
        <reference anchor="RFC9010" target="https://www.rfc-editor.org/info/rfc9010" quoteTitle="true" derivedAnchor="RFC9010">
          <front>
            <title>Routing for RPL (Routing Protocol for Low-Power and Lossy Networks) Leaves</title>
            <author fullname="P. Thubert" initials="P." role="editor" surname="Thubert"/>
            <author fullname="M. Richardson" initials="M." surname="Richardson"/>
            <date month="April" year="2021"/>
            <abstract>
              <t indent="0">This specification provides a mechanism for a host that implements a routing-agnostic interface based on IPv6 over Low-Power Wireless Personal Area Network (6LoWPAN) Neighbor Discovery to obtain reachability services across a network that leverages RFC 6550 for its routing operations. It updates RFCs 6550, 6775, and 8505.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="9010"/>
          <seriesInfo name="DOI" value="10.17487/RFC9010"/>
        </reference>
        <reference anchor="RFC9685" target="https://www.rfc-editor.org/info/rfc9685" quoteTitle="true" derivedAnchor="RFC9685">
          <front>
            <title>Listener Subscription for IPv6 Neighbor Discovery Multicast and Anycast Addresses</title>
            <author fullname="P. Thubert" initials="P." role="editor" surname="Thubert"/>
            <date month="November" year="2024"/>
            <abstract>
              <t indent="0">This document updates the 6LoWPAN extensions to IPv6 Neighbor Discovery (specified in RFCs 4861 and 8505) to enable a listener to subscribe to an IPv6 anycast or multicast address. This document also updates the Routing Protocol for Low-Power and Lossy Networks (RPL) (specified in RFCs 6550 and 6553) to add a new Non-Storing multicast mode and new support for anycast addresses in Storing and Non-Storing modes. This document extends RFC 9010 to enable a 6LoWPAN Router (6LR) to inject the anycast and multicast addresses in RPL.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="9685"/>
          <seriesInfo name="DOI" value="10.17487/RFC9685"/>
        </reference>
        <reference anchor="RFC9926" target="https://www.rfc-editor.org/info/rfc9926" quoteTitle="true" derivedAnchor="RFC9926">
          <front>
            <title>Prefix Registration for IPv6 Neighbor Discovery</title>
            <author initials="P." surname="Thubert" fullname="Pascal Thubert" role="editor">
    </author>
            <date month="February" year="2026"/>
          </front>
          <seriesInfo name="RFC" value="9926"/>
          <seriesInfo name="DOI" value="10.17487/RFC9926"/>
        </reference>
      </references>
      <references pn="section-7.2">
        <name slugifiedName="name-informative-references">Informative References</name>
        <reference anchor="RFC8929" target="https://www.rfc-editor.org/info/rfc8929" quoteTitle="true" derivedAnchor="RFC8929">
          <front>
            <title>IPv6 Backbone Router</title>
            <author fullname="P. Thubert" initials="P." role="editor" surname="Thubert"/>
            <author fullname="C.E. Perkins" initials="C.E." surname="Perkins"/>
            <author fullname="E. Levy-Abegnoli" initials="E." surname="Levy-Abegnoli"/>
            <date month="November" year="2020"/>
            <abstract>
              <t indent="0">This document updates RFCs 6775 and 8505 in order to enable proxy services for IPv6 Neighbor Discovery by Routing Registrars called "Backbone Routers". Backbone Routers are placed along the wireless edge of a backbone and federate multiple wireless links to form a single Multi-Link Subnet (MLSN).</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8929"/>
          <seriesInfo name="DOI" value="10.17487/RFC8929"/>
        </reference>
      </references>
    </references>
    <section anchor="authors-addresses" numbered="false" removeInRFC="false" toc="include" pn="section-appendix.a">
      <name slugifiedName="name-authors-addresses">Authors' Addresses</name>
      <author initials="P" surname="Thubert" fullname="Pascal Thubert">
        <address>
          <postal>
            <city>Roquefort-les-Pins</city>
            <code>06330</code>
            <country>France</country>
          </postal>
          <email>pascal.thubert@gmail.com</email>
        </address>
      </author>
      <author initials="A" surname="Rashid" fullname="Adnan Rashid">
        <organization abbrev="Politecnico di Bari" showOnFrontPage="true">Politecnico di Bari</organization>
        <address>
          <postal>
            <street>Via Edoardo Orabona 4</street>
            <city>Bari</city>
            <code>70126</code>
            <country>Italy</country>
          </postal>
          <email>adnan.rashid@poliba.it</email>
        </address>
      </author>
    </section>
  </back>
</rfc>
