<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE rfc [
  <!ENTITY nbsp    "&#160;">
  <!ENTITY zwsp   "&#8203;">
  <!ENTITY nbhy   "&#8209;">
  <!ENTITY wj     "&#8288;">
]>
<?xml-stylesheet type="text/xsl" href="rfc2629.xslt" ?>
<!-- generated by https://github.com/cabo/kramdown-rfc version 1.7.29 1.7.30 (Ruby 3.4.4) 2.5.9) -->
<rfc xmlns:xi="http://www.w3.org/2001/XInclude" ipr="trust200902" docName="draft-ietf-dhc-dhcpv4-over-dhcpv6-ra-06" docName="draft-ietf-dhc-dhcpv4-over-dhcpv6-ra" category="std" consensus="true" submissionType="IETF" xml:lang="en" number="9928" tocInclude="true" sortRefs="true" symRefs="true" version="3">
  <!-- xml2rfc v2v3 conversion 3.30.0 3.31.0 -->
  <link href="https://datatracker.ietf.org/doc/draft-ietf-dhc-dhcpv4-over-dhcpv6-ra" rel="prev"/>
  <front>
    <title abbrev="DHCP 4o6 Relay Agent">DHCPv4-over-DHCPv6 Agent">DHCPv4 over DHCPv6 with Relay Agent Support</title>
    <seriesInfo name="Internet-Draft" value="draft-ietf-dhc-dhcpv4-over-dhcpv6-ra-06"/> name="RFC" value="9928"/>
    <author initials="C." surname="Porfiri" fullname="Claudio Porfiri">
      <organization>Ericsson</organization>
      <address>
        <email>claudio.porfiri@ericsson.com</email>
      </address>
    </author>
    <author initials="S." surname="Krishnan" fullname="Suresh Krishnan">
      <organization>Cisco</organization>
      <address>
        <email>suresh.krishnan@gmail.com</email>
      </address>
    </author>
    <author initials="J." surname="Arkko" fullname="Jari Arkko">
      <organization>Ericsson</organization>
      <address>
        <email>jari.arkko@ericsson.com</email>
      </address>
    </author>
    <author initials="M." surname="Kühlewind" fullname="Mirja Kühlewind">
      <organization>Ericsson</organization>
      <address>
        <email>mirja.kuehlewind@ericsson.com</email>
      </address>
    </author>
    <date year="2025" month="August" day="26"/>
    <area>Internet</area>
    <workgroup>Dynamic Host Configuration</workgroup> year="2026" month="February"/>
    <area>INT</area>
    <workgroup>dhc</workgroup>
    <keyword>dhcp</keyword>
    <abstract>
      <?line 59?> 54?>

<t>This document describes a mechanism for networks
with legacy IPv4-only clients to use services provided by
DHCPv4-over-DHCPv6
DHCPv4 over DHCPv6 in a Relay Agent.
RFC7341
RFC 7341 specifies the use of DHCPv4-over-DHCPv6 DHCPv4 over DHCPv6 in the client only.
This document specifies a RFC7341-based an approach based on RFC 7341 that
allows a Relay Agent to implement the DHCP 4o6 DHCPv4-over-DHCPv6 encapsulation and
decapsulation of DHCPv4 messages in DHCPv6 messages on behalf of a
DHCPv4 client.</t>
    </abstract>
    <note removeInRFC="true">
      <name>About This Document</name>
      <t>
        Status information for this document may be found at <eref target="https://datatracker.ietf.org/doc/draft-ietf-dhc-dhcpv4-over-dhcpv6-ra/"/>.
      </t>
      <t>Source for this draft and an issue tracker can be found at
        <eref target="https://github.com/mirjak/draft-dhc-dhcpv4-over-dhcpv6-ra"/>.</t>
    </note>
  </front>
  <middle>
    <?line 71?> 66?>

<section anchor="introduction">
      <name>Introduction</name>
      <t><xref target="RFC7341"/> describes a transport mechanism for carrying DHCPv4 <xref target="RFC2131"/>
messages using DHCPv6 <xref target="draft-ietf-dhc-rfc8415bis"/> target="RFC9915"/> for dynamic provisioning
of IPv4 addresses and other DHCPv4 specific DHCPv4-specific configuration parameters
across IPv6-only networks. The deployment of <xref target="RFC7341"/> requires support in
DHCP clients and at the DHCPv6 server.
However, if a client is embedded in a host that only supports IPv4
and cannot easily be replaced or updated (which could be due to any
number of technical or business reasons), this approach does not
work.</t>
      <t>Similarly, the specifications for DHCPv6 Relay Agents such as Lightweight DHCPv6 Relay Agent (LDRA) specification defined in <xref target="RFC9915"/>,
which also refers to <xref target="RFC6221"/> or for the Lightweight DHCPv6 Relay Agent (L3RA)
<xref target="draft-ietf-dhc-rfc8415bis"/> do
(LDRA) behavior, does not foresee the possibility provide any mechanism to handle legacy DHCPv4,
other than implementing DHCP 4o6 in
except by requiring the client.</t> client to implement the DHCPv4-over-DHCPv6
encapsulation and decapsulation.</t>
      <t>This document specifies an a solution based on <xref target="RFC7341"/> based solution that can be
implemented in intermediate nodes such as switches or routers,
without putting any requirements on clients. No new protocols or extensions are needed;
instead, this document specifies a new use case for <xref target="RFC7341"/> that allows
a Relay Agent to perform the DHCP 4o6 DHCPv4-over-DHCPv6 encapsulation and decapsulation instead of
the client.</t>
      <section anchor="applicability">
        <name>Applicability Scope</name>
        <t>The mechanisms described in this document apply to the configuration phase
of hosts that need to receive an IPv4 address when a DHCP server for IPv4 <xref target="RFC2131"/> is not
reachable directly from the host. Furthermore, the host is unable to implement
a DHCP client conformant to <xref target="RFC7341"/> target="RFC7341"/>, as it is connected to an IPv4-only
network. But However, there is a DHCPv6 server that can provide IPv4 addresses by means of
the mechanisms specified in <xref target="RFC7341"/>.</t>
      </section>
    </section>
    <section anchor="conventions-and-definitions">
      <name>Conventions and Definitions</name>
      <t>The following terms and acronyms abbreviations are used in this document:</t>
      <ul spacing="normal">
        <li>
          <t>DHCP:
If not otherwise specified, DHCP refers
      <dl newline="true">
        <dt>DHCP:</dt>
        <dd>
          <t>Refers to DHCPv4 and/or DHCPv6.</t>
        </li>
        <li>
          <t>DHCPv4:
 DHCP as defined in <xref target="RFC2131"/>.</t>
        </li>
        <li>
          <t>DHCPv4 over DHCPv6 (or 4o6):
 The architecture, the procedures, and the protocols specified in the
 DHCPv4-over-DHCPv6 document <xref target="RFC7341"/>.</t>
        </li>
        <li>
          <t>DHCP if not otherwise specified.</t>
        </dd>
        <dt>DHCP Relay Agent:
 This is Agent:</dt>
        <dd>
          <t>Refers to a common concept in all of the following protocols, although the details differ
between them: BOOTP the Bootstrap Protocol (BOOTP) <xref target="RFC951"/> target="RFC0951"/> <xref target="RFC1542"/>, DHCPv4
<xref target="RFC2131"/> <xref target="RFC2132"/>, and DHCPv6 <xref target="draft-ietf-dhc-rfc8415bis"/>.</t>
        </li>
        <li>
          <t>Lightweight target="RFC9915"/>.</t>
        </dd>
        <dt>DHCPv4:</dt>
        <dd>
          <t>Refers to DHCP as defined in <xref target="RFC2131"/>.</t>
        </dd>
        <dt>DHCPv4 over DHCPv6 (DHCP 4o6):</dt>
        <dd>
          <t>Refers to the architecture, the procedures, and the protocols specified in the
DHCPv4-over-DHCPv6 document <xref target="RFC7341"/>.</t>
        </dd>
        <dt>DHCPv4-over-DHCPv6 Relay Agent (or LDRA):
 This (4o6RA):</dt>
        <dd>
          <t>Refers to a Relay Agent that implements the DHCP 4o6
transport as specified in this document.</t>
        </dd>
        <dt>Layer 3 Relay Agent (L3RA):</dt>
        <dd>
          <t>Refers to a DHCP Relay Agent as specified in <xref target="RFC9915"/> that is not a LDRA.</t>
        </dd>
        <dt>Lightweight DHCPv6 Relay Agent (LDRA):</dt>
        <dd>
          <t>Refers to an extension of the original DHCPv6 Relay Agent specification, to allow
 layer-2-only
Layer 2 (L2) only devices to perform a Relay Agent function <xref target="RFC6221"/>.</t>
        </li>
        <li>
          <t>DHCPv4 over DHCPv6 Relay Agent (or 4o6RA):
 Refers to a Relay Agent that implements the 4o6
 transport as specified in this document.</t>
        </li>
      </ul>
        </dd>
      </dl>
      <t>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"/> <xref target="RFC8174"/> when, and only when, they
appear in all capitals, as shown here.</t>
      <?line -18?>

</section>
    <section anchor="dhcpv4-over-dhcpv6-relay-agent-4o6ra">
      <name>DHCPv4 over DHCPv6
      <name>DHCPv4-over-DHCPv6 Relay Agent (4o6RA)</name>
      <t>This document assumes a network, network where IPv4-only hosts are connected
to a network that supports IPv6 and limited IPv4 services.</t>
      <t>To address such a network setup, this document extends
DHCPv6 Relay Agents with DHCPv4-over-DHCPv6, DHCPv4 over DHCPv6, as shown in <xref target="fig_4o6RA"/>.</t>
      <figure anchor="fig_4o6RA">
        <name>Architecture Example with Legacy DHCP Client</name>
        <artset>
          <artwork type="svg" align="center"><svg xmlns="http://www.w3.org/2000/svg" version="1.1" height="208" width="480" viewBox="0 0 480 208" class="diagram" text-anchor="middle" font-family="monospace" font-size="13px" stroke-linecap="round">
              <path d="M 8,64 L 8,128" fill="none" stroke="black"/>
              <path d="M 80,48 L 80,64" fill="none" stroke="black"/>
              <path d="M 80,128 L 80,144" fill="none" stroke="black"/>
              <path d="M 96,64 L 96,128" fill="none" stroke="black"/>
              <path d="M 176,64 L 176,128" fill="none" stroke="black"/>
              <path d="M 192,48 L 192,64" fill="none" stroke="black"/>
              <path d="M 192,128 L 192,144" fill="none" stroke="black"/>
              <path d="M 288,48 L 288,64" fill="none" stroke="black"/>
              <path d="M 288,128 L 288,144" fill="none" stroke="black"/>
              <path d="M 304,64 L 304,128" fill="none" stroke="black"/>
              <path d="M 384,64 L 384,128" fill="none" stroke="black"/>
              <path d="M 400,48 L 400,64" fill="none" stroke="black"/>
              <path d="M 400,128 L 400,144" fill="none" stroke="black"/>
              <path d="M 472,64 L 472,128" fill="none" stroke="black"/>
              <path d="M 96,32 L 176,32" fill="none" stroke="black"/>
              <path d="M 304,32 L 384,32" fill="none" stroke="black"/>
              <path d="M 8,64 L 96,64" fill="none" stroke="black"/>
              <path d="M 176,64 L 304,64" fill="none" stroke="black"/>
              <path d="M 384,64 L 472,64" fill="none" stroke="black"/>
              <path d="M 96,96 L 176,96" fill="none" stroke="black"/>
              <path d="M 304,96 L 384,96" fill="none" stroke="black"/>
              <path d="M 8,128 L 96,128" fill="none" stroke="black"/>
              <path d="M 176,128 L 304,128" fill="none" stroke="black"/>
              <path d="M 384,128 L 472,128" fill="none" stroke="black"/>
              <path d="M 96,160 L 176,160" fill="none" stroke="black"/>
              <path d="M 304,160 L 384,160" fill="none" stroke="black"/>
              <path d="M 96,32 C 87.16936,32 80,39.16936 80,48" fill="none" stroke="black"/>
              <path d="M 176,32 C 184.83064,32 192,39.16936 192,48" fill="none" stroke="black"/>
              <path d="M 304,32 C 295.16936,32 288,39.16936 288,48" fill="none" stroke="black"/>
              <path d="M 384,32 C 392.83064,32 400,39.16936 400,48" fill="none" stroke="black"/>
              <path d="M 96,160 C 87.16936,160 80,152.83064 80,144" fill="none" stroke="black"/>
              <path d="M 176,160 C 184.83064,160 192,152.83064 192,144" fill="none" stroke="black"/>
              <path d="M 304,160 C 295.16936,160 288,152.83064 288,144" fill="none" stroke="black"/>
              <path d="M 384,160 C 392.83064,160 400,152.83064 400,144" fill="none" stroke="black"/>
              <g class="text">
                <text x="140" y="68">L2</text>
                <text x="340" y="68">IPv6</text>
                <text x="52" y="84">DHCPv4</text>
                <text x="136" y="84">Network</text>
                <text x="236" y="84">DHCPv6</text>
                <text x="344" y="84">Network</text>
                <text x="412" y="84">DHCP</text>
                <text x="448" y="84">4o6</text>
                <text x="52" y="100">Client</text>
                <text x="216" y="100">Relay</text>
                <text x="264" y="100">Agent</text>
                <text x="428" y="100">Server</text>
                <text x="220" y="116">with</text>
                <text x="264" y="116">4o6RA</text>
              </g>
            </svg>
          </artwork>
          <artwork type="ascii-art" align="center"><![CDATA[
           .-----------.             .-----------.
          |             |           |             |
 +--------+-+    L2   +-+-----------+-+  IPv6   +-+--------+
 |  DHCPv4  | Network |    DHCPv6     | Network | DHCP 4o6 |
 |  Client  +---------+  Relay Agent  +---------+  Server  |
 |          |         |   with 4o6RA  |         |          |
 +--------+-+         +-+-----------+-+         +-+--------+
          |             |           |             |
           '-----------'             '-----------'

]]></artwork>
        </artset>
      </figure>
      <t>This document specifies the encapsulation
and decapsulation specified in <xref target="RFC7341"/> to be performed in the Relay Agent
without requiring any changes on the DHCPv4 client.
In this case case, it is up to the Relay Agent to provide the full DHCP
4o6 support support, and the legacy DHCPv4 client is not aware that it is being served
via a DHCP 4o6 service.
As the 4o6RA acts as a DHCP 4o6 client, all prerequisites and configuration configurations
that apply to the DHCP client in <xref section="5" sectionFormat="of" target="RFC7341"/> are also applied to the 4o6RA.</t>
      <t>As the 4o6RA takes the role of the client in respect to <xref target="RFC7341"/>,
it is responsible for determining a suitable interface where it acts as a
DHCPv6 client, and it is responsible for locating a suitable DHCPv6
server or relay agent Relay Agent and obtain obtaining the necessary IPv6 configuration.. configuration.
As specified in <xref target="RFC7341"/>, the 4o6RA, acting as DHCP 4o6 client, therefore has to request
the DHCP 4o6 Server Address option from the server by sending the
Option Request option as described in <xref target="draft-ietf-dhc-rfc8415bis"/> target="RFC9915"/>
before it can use the DHCP 4o6 transport.</t>
      <t>To maintain interoperability with existing DHCPv6 relays and servers,
the message format is unchanged from <xref target="draft-ietf-dhc-rfc8415bis"/>. target="RFC9915"/>. The 4o6RA implements
the same message types as a DHCPv6 Relay Agent (see <xref section="6" sectionFormat="of" target="RFC7341"/>.</t> target="RFC7341"/>).</t>
      <t>However, in this specification, the 4o6RA, instead of the client, creates the DHCPV4-QUERY Message message
and encapsulates the DHCP request message received from the legacy DHCPv4 client.</t>
      <t>When the DHCPV4-RESPONSE Message message is received by the DHCP 4o6 Relay Agent,
it looks for the DHCPv4 Message message option within this message.
If this option is not found or the DHCPv4-RESPONSE message is not well-formed,
it <bcp14>MUST</bcp14> be discarded.
If the DHCPv4 Message message option is present and correct, the 4o6RA <bcp14>MUST</bcp14> extract the DHCPv4
message and forward the encapsulated DHCPv4-response DHCPv4-RESPONSE to the requesting DHCPv4
client, given that the encapsulated DHCPv4-response DHCPv4-RESPONSE is correct and can be
actually forwarded.</t>
      <t>Layer-2
      <t>Layer 2 (L2) Relay Agents receiving DHCPV4-QUERY or DHCPV4-RESPONSE messages
<bcp14>MUST</bcp14> handle them as specified in <xref section="6" sectionFormat="of" target="RFC6221"/>.</t>
      <t>In any given environment, DHCPv6 servers to which DHCPV4-QUERY
requests are routed are expected to be compliant with DHCP 4o6 according
to <xref target="RFC7341"/>.  No additional requirements on DHCPv6 servers are set
by this specification.</t>
      <section anchor="intermediate-relays">
        <name>Intermediate relays</name> Relays</name>
        <t>Intermediate relays shall behave according to section 10 of <xref section="10" sectionFormat="of" target="RFC7341"/>.</t>
      </section>
      <section anchor="topology_considerations">
        <name>4o6RA and Topology Discovery</name>
        <t>In some networks, the configuration of a host may depend on the topology.
However, when a new host attaches to a network, it may be unaware
of the topology and, consequently, how it has to be configured.</t>
        <t>DHCPv4 <xref target="RFC2131"/> and DHCPv6 <xref target="draft-ietf-dhc-rfc8415bis"/> target="RFC9915"/> specifications
describe how addresses can typically be allocated to clients based on network
topology information provided by a DHCP relay, typically.</t> relay.</t>
        <t>Address/prefix allocation decisions are integral to the allocation of
addresses and prefixes in DHCP, as described in detail
in <xref target="RFC7969"/>. This specification aims to guarantee that the 4o6RA does not
break any legacy capability when used for topology discovery.</t>
        <t>Topology discovery as described in <xref target="RFC7969"/> differs between
IPv4 and IPv6:</t> IPv6 as follows:</t>
        <ul spacing="normal">
          <li>
            <t>IPv4:
when When using DHCP on IPv4 IPv4, only the first Relay Agent <bcp14>SHOULD</bcp14>
set the giaddr field (section 3.1 of <xref (<xref section="3.1" sectionFormat="of" target="RFC7969"/>). Thus, in a
network that has more than one Relay Agent Agent, only part of the topology
is transported via DHCPv4.</t>
          </li>
          <li>
            <t>IPv6:
when When using DHCPv6, all Relay Agents <bcp14>SHOULD</bcp14> send
link-address and Interface-ID options, options that provide
information about the complete path
between the DHCPv6 client and the DHCPv6 server to the DHCPv6 server.</t>
          </li>
        </ul>
        <t>In Layer-2 Layer 2 networks, Lightweight DHCPv6 Relay Agents (LDRAs) <xref target="RFC6221"/>
can be used.</t>
        <t>When provided, the topology information is available at the DHCPv6
server in the form of a sequence of the link-address field and Interface-ID option.</t>
        <t>Then, topology information for the given IP address
can be obtained from the DHCPv6 server and used for configuration
or other purposes.</t>
        <t><xref target="RFC7341"/> enables the client to use DHCPv6 for topology discovery
even within a DHCPv4 context, as the DHCPv6 Relay Agent knows
the interface where the encapsulated DHCP request is received.
As
However, as shown in <xref target="fig_4o6RA_RA"/>, however, the introduction of DHCP 4o6 at
the edge of the IPv6 network hides the Layer-2 Layer 2 network from the DHCPv6 RA.
As such, moving DHCP 4o6 to a an intermediate node rather than performing it at the client breaks
the topology propagation, as 4o6RA-only solutions does do not provide any interface
information in the encapsulated message.</t>
        <figure anchor="fig_4o6RA_RA">
          <name>Broken topology information</name> Topology Information</name>
          <artset>
            <artwork type="svg" align="center"><svg xmlns="http://www.w3.org/2000/svg" version="1.1" height="208" width="576" viewBox="0 0 576 208" class="diagram" text-anchor="middle" font-family="monospace" font-size="13px" stroke-linecap="round">
                <path d="M 8,64 L 8,128" fill="none" stroke="black"/>
                <path d="M 80,48 L 80,64" fill="none" stroke="black"/>
                <path d="M 80,128 L 80,144" fill="none" stroke="black"/>
                <path d="M 96,64 L 96,128" fill="none" stroke="black"/>
                <path d="M 120,64 L 120,128" fill="none" stroke="black"/>
                <path d="M 200,64 L 200,128" fill="none" stroke="black"/>
                <path d="M 224,64 L 224,128" fill="none" stroke="black"/>
                <path d="M 240,48 L 240,64" fill="none" stroke="black"/>
                <path d="M 240,128 L 240,144" fill="none" stroke="black"/>
                <path d="M 272,48 L 272,64" fill="none" stroke="black"/>
                <path d="M 272,128 L 272,144" fill="none" stroke="black"/>
                <path d="M 304,64 L 304,128" fill="none" stroke="black"/>
                <path d="M 344,64 L 344,128" fill="none" stroke="black"/>
                <path d="M 416,64 L 416,128" fill="none" stroke="black"/>
                <path d="M 480,64 L 480,128" fill="none" stroke="black"/>
                <path d="M 496,48 L 496,64" fill="none" stroke="black"/>
                <path d="M 496,128 L 496,144" fill="none" stroke="black"/>
                <path d="M 568,64 L 568,128" fill="none" stroke="black"/>
                <path d="M 96,32 L 224,32" fill="none" stroke="black"/>
                <path d="M 288,32 L 480,32" fill="none" stroke="black"/>
                <path d="M 8,64 L 96,64" fill="none" stroke="black"/>
                <path d="M 120,64 L 200,64" fill="none" stroke="black"/>
                <path d="M 224,64 L 304,64" fill="none" stroke="black"/>
                <path d="M 344,64 L 416,64" fill="none" stroke="black"/>
                <path d="M 480,64 L 568,64" fill="none" stroke="black"/>
                <path d="M 96,96 L 120,96" fill="none" stroke="black"/>
                <path d="M 200,96 L 224,96" fill="none" stroke="black"/>
                <path d="M 304,96 L 344,96" fill="none" stroke="black"/>
                <path d="M 416,96 L 480,96" fill="none" stroke="black"/>
                <path d="M 8,128 L 96,128" fill="none" stroke="black"/>
                <path d="M 120,128 L 200,128" fill="none" stroke="black"/>
                <path d="M 224,128 L 304,128" fill="none" stroke="black"/>
                <path d="M 344,128 L 416,128" fill="none" stroke="black"/>
                <path d="M 480,128 L 568,128" fill="none" stroke="black"/>
                <path d="M 96,160 L 224,160" fill="none" stroke="black"/>
                <path d="M 288,160 L 480,160" fill="none" stroke="black"/>
                <path d="M 96,32 C 87.16936,32 80,39.16936 80,48" fill="none" stroke="black"/>
                <path d="M 224,32 C 232.83064,32 240,39.16936 240,48" fill="none" stroke="black"/>
                <path d="M 288,32 C 279.16936,32 272,39.16936 272,48" fill="none" stroke="black"/>
                <path d="M 480,32 C 488.83064,32 496,39.16936 496,48" fill="none" stroke="black"/>
                <path d="M 96,160 C 87.16936,160 80,152.83064 80,144" fill="none" stroke="black"/>
                <path d="M 224,160 C 232.83064,160 240,152.83064 240,144" fill="none" stroke="black"/>
                <path d="M 288,160 C 279.16936,160 272,152.83064 272,144" fill="none" stroke="black"/>
                <path d="M 480,160 C 488.83064,160 496,152.83064 496,144" fill="none" stroke="black"/>
                <g class="text">
                  <text x="124" y="52">L2</text>
                  <text x="168" y="52">Network</text>
                  <text x="356" y="52">IPv6</text>
                  <text x="408" y="52">Network</text>
                  <text x="52" y="84">DHCPv4</text>
                  <text x="156" y="84">L2</text>
                  <text x="256" y="84">4o6</text>
                  <text x="380" y="84">DHCPv6</text>
                  <text x="508" y="84">DHCP</text>
                  <text x="544" y="84">4o6</text>
                  <text x="52" y="100">Client</text>
                  <text x="156" y="100">Switch</text>
                  <text x="264" y="100">Relay</text>
                  <text x="376" y="100">Relay</text>
                  <text x="524" y="100">Server</text>
                  <text x="264" y="116">Agent</text>
                  <text x="376" y="116">Agent</text>
                </g>
              </svg>
            </artwork>
            <artwork type="ascii-art" align="center"><![CDATA[
           .-----------------.     .-------------------------.
          |    L2 Network     |   |        IPv6 Network       |
 +--------+-+  +---------+  +-+---+---+    +--------+       +-+--------+
 |  DHCPv4  |  |   L2    |  |  4o6    |    | DHCPv6 |       | DHCP 4o6 |
 |  Client  +--+ Switch  +--+  Relay  +----+ Relay  +-------+  Server  |
 |          |  |         |  |  Agent  |    | Agent  |       |          |
 +--------+-+  +---------+  +-+---+---+    +--------+       +-+--------+
          |                   |   |                           |
           '-----------------'     '-------------------------'

]]></artwork>
          </artset>
        </figure>
        <t>In order to provide full topology information, it is <bcp14>RECOMMENDED</bcp14> that
any implementation of 4o6RA be combined
with an LDRA implementation <xref target="RFC6221"/> in a back-to-back structure, structure and that the
LDRA implementation includes a mechanism to obtain interface information that
can be used to provide the Interface-ID option to outgoing
DHCPV4-QUERY messages, as specified in Section 5.3.2 of <xref section="5.3.2" sectionFormat="of" target="RFC6221"/>.</t>
        <t>The internal mechanisms to exchange interface information,
their format format, and whether the interface information contains an indication that a 4o6RA
is involved involved, are out of the scope for this document.</t>
        <t>The resulting architecture is shown in <xref target="fig_4o6LDRA"/> where
the Relay Agent is implementing 4o6RA and LDRA, LDRA and has an internal interface to
propagate topology information from 4o6RA to LDRA.</t>
        <figure anchor="fig_4o6LDRA">
          <name>Topology information preserved Information Preserved with LDRA</name>
          <artset>
            <artwork type="svg" align="center"><svg xmlns="http://www.w3.org/2000/svg" version="1.1" height="224" width="528" viewBox="0 0 528 224" class="diagram" text-anchor="middle" font-family="monospace" font-size="13px" stroke-linecap="round">
                <path d="M 8,80 L 8,144" fill="none" stroke="black"/>
                <path d="M 80,48 L 80,80" fill="none" stroke="black"/>
                <path d="M 80,144 L 80,160" fill="none" stroke="black"/>
                <path d="M 96,80 L 96,144" fill="none" stroke="black"/>
                <path d="M 120,80 L 120,144" fill="none" stroke="black"/>
                <path d="M 200,80 L 200,144" fill="none" stroke="black"/>
                <path d="M 224,80 L 224,144" fill="none" stroke="black"/>
                <path d="M 240,48 L 240,80" fill="none" stroke="black"/>
                <path d="M 240,144 L 240,160" fill="none" stroke="black"/>
                <path d="M 272,48 L 272,80" fill="none" stroke="black"/>
                <path d="M 272,144 L 272,160" fill="none" stroke="black"/>
                <path d="M 296,80 L 296,144" fill="none" stroke="black"/>
                <path d="M 376,80 L 376,144" fill="none" stroke="black"/>
                <path d="M 432,80 L 432,144" fill="none" stroke="black"/>
                <path d="M 488,48 L 488,80" fill="none" stroke="black"/>
                <path d="M 488,144 L 488,160" fill="none" stroke="black"/>
                <path d="M 520,80 L 520,144" fill="none" stroke="black"/>
                <path d="M 96,32 L 224,32" fill="none" stroke="black"/>
                <path d="M 288,32 L 472,32" fill="none" stroke="black"/>
                <path d="M 8,80 L 96,80" fill="none" stroke="black"/>
                <path d="M 120,80 L 200,80" fill="none" stroke="black"/>
                <path d="M 224,80 L 376,80" fill="none" stroke="black"/>
                <path d="M 432,80 L 520,80" fill="none" stroke="black"/>
                <path d="M 96,112 L 120,112" fill="none" stroke="black"/>
                <path d="M 200,112 L 224,112" fill="none" stroke="black"/>
                <path d="M 376,112 L 432,112" fill="none" stroke="black"/>
                <path d="M 8,144 L 96,144" fill="none" stroke="black"/>
                <path d="M 120,144 L 200,144" fill="none" stroke="black"/>
                <path d="M 224,144 L 376,144" fill="none" stroke="black"/>
                <path d="M 432,144 L 520,144" fill="none" stroke="black"/>
                <path d="M 96,176 L 224,176" fill="none" stroke="black"/>
                <path d="M 288,176 L 472,176" fill="none" stroke="black"/>
                <path d="M 96,32 C 87.16936,32 80,39.16936 80,48" fill="none" stroke="black"/>
                <path d="M 224,32 C 232.83064,32 240,39.16936 240,48" fill="none" stroke="black"/>
                <path d="M 288,32 C 279.16936,32 272,39.16936 272,48" fill="none" stroke="black"/>
                <path d="M 472,32 C 480.83064,32 488,39.16936 488,48" fill="none" stroke="black"/>
                <path d="M 96,176 C 87.16936,176 80,168.83064 80,160" fill="none" stroke="black"/>
                <path d="M 224,176 C 232.83064,176 240,168.83064 240,160" fill="none" stroke="black"/>
                <path d="M 288,176 C 279.16936,176 272,168.83064 272,160" fill="none" stroke="black"/>
                <path d="M 472,176 C 480.83064,176 488,168.83064 488,160" fill="none" stroke="black"/>
                <g class="text">
                  <text x="108" y="52">L2</text>
                  <text x="152" y="52">Network</text>
                  <text x="196" y="52">or</text>
                  <text x="348" y="52">IPv6</text>
                  <text x="400" y="52">Network</text>
                  <text x="136" y="68">IPv6-only</text> y="68">IPv6-Only</text>
                  <text x="196" y="68">link</text> y="68">Link</text>
                  <text x="52" y="100">DHCPv4</text>
                  <text x="156" y="100">L2</text>
                  <text x="256" y="100">4o6</text>
                  <text x="332" y="100">LDRA</text>
                  <text x="460" y="100">DHCP</text>
                  <text x="496" y="100">4o6</text>
                  <text x="52" y="116">Client</text>
                  <text x="156" y="116">Switch</text>
                  <text x="264" y="116">Relay</text>
                  <text x="336" y="116">RFC6221</text> x="320" y="116">RFC</text>
                  <text x="356" y="116">6221</text>
                  <text x="476" y="116">Server</text>
                  <text x="264" y="132">Agent</text>
                </g>
              </svg>
            </artwork>
            <artwork type="ascii-art" align="center"><![CDATA[
           .-----------------.     .------------------------.
          |  L2 Network or    |   |       IPv6 Network       |
          |  IPv6-only link  IPv6-Only Link   |   |                          |
 +--------+-+  +---------+  +-+---+--+---------+      +------+---+
 |  DHCPv4  |  |   L2    |  |  4o6   |  LDRA   |      | DHCP 4o6 |
 |  Client  +--+ Switch  +--+  Relay + RFC6221 +------+ RFC 6221+------+  Server  |
 |          |  |         |  |  Agent |         |      |          |
 +--------+-+  +---------+  +-+---+--+---------+      +------+---+
          |                   |   |                          |
           '-----------------'     '------------------------'

]]></artwork>
          </artset>
        </figure>
        <t>In a simple case, where the same node hosts the 4o6RA and the DHCP4o6 DHCP 4o6 server,
it might be enough to only use 4o6RA, as shown in <xref target="fig_4o6RAserver"/>.</t> target="fig_4o6RAserver"/>, where
CPE stands for "Customer Premises Equipment".</t>
        <figure anchor="fig_4o6RAserver">
          <name>Topology information preserved Information Preserved by 4o6 Relay Agent in DHCP server</name> Server</name>
          <artset>
            <artwork type="svg" align="center"><svg xmlns="http://www.w3.org/2000/svg" version="1.1" height="208" width="344" viewBox="0 0 344 208" class="diagram" text-anchor="middle" font-family="monospace" font-size="13px" stroke-linecap="round">
                <path d="M 8,64 L 8,128" fill="none" stroke="black"/>
                <path d="M 80,48 L 80,64" fill="none" stroke="black"/>
                <path d="M 80,128 L 80,144" fill="none" stroke="black"/>
                <path d="M 96,64 L 96,128" fill="none" stroke="black"/>
                <path d="M 176,64 L 176,128" fill="none" stroke="black"/>
                <path d="M 192,48 L 192,64" fill="none" stroke="black"/>
                <path d="M 192,128 L 192,144" fill="none" stroke="black"/>
                <path d="M 248,64 L 248,128" fill="none" stroke="black"/>
                <path d="M 336,64 L 336,128" fill="none" stroke="black"/>
                <path d="M 96,32 L 176,32" fill="none" stroke="black"/>
                <path d="M 8,64 L 96,64" fill="none" stroke="black"/>
                <path d="M 176,64 L 336,64" fill="none" stroke="black"/>
                <path d="M 96,96 L 176,96" fill="none" stroke="black"/>
                <path d="M 8,128 L 96,128" fill="none" stroke="black"/>
                <path d="M 176,128 L 336,128" fill="none" stroke="black"/>
                <path d="M 96,160 L 176,160" fill="none" stroke="black"/>
                <path d="M 96,32 C 87.16936,32 80,39.16936 80,48" fill="none" stroke="black"/>
                <path d="M 176,32 C 184.83064,32 192,39.16936 192,48" fill="none" stroke="black"/>
                <path d="M 96,160 C 87.16936,160 80,152.83064 80,144" fill="none" stroke="black"/>
                <path d="M 176,160 C 184.83064,160 192,152.83064 192,144" fill="none" stroke="black"/>
                <g class="text">
                  <text x="100" y="52">L2</text>
                  <text x="144" y="52">Network</text>
                  <text x="52" y="84">DHCP</text>
                  <text x="208" y="84">4o6</text>
                  <text x="276" y="84">DHCP</text>
                  <text x="312" y="84">4o6</text>
                  <text x="52" y="100">Client</text>
                  <text x="216" y="100">Relay</text>
                  <text x="292" y="100">Server</text>
                  <text x="36" y="116">on</text>
                  <text x="64" y="116">CPE</text>
                  <text x="216" y="116">Agent</text>
                </g>
              </svg>
            </artwork>
            <artwork type="ascii-art" align="center"><![CDATA[
           .-----------.
          | L2 Network  |
 +--------+-+         +-+------+----------+
 |   DHCP   |         |  4o6   | DHCP 4o6 |
 |  Client  +---------+  Relay +  Server  |
 |  on CPE  |         |  Agent |          |
 +--------+-+         +-+------+----------+
          |             |
           '-----------'

]]></artwork>
          </artset>
        </figure>
      </section>
    </section>
    <section anchor="deployment-considerations">
      <name>Deployment Considerations</name>
      <t>As clients are unaware of the presence of 4o6RA, the network
deployment needs to ensure that all DHCPv4 broadcast and unicast messages to and
from clients are steered via a 4o6RA.
This can be achieved by placing the 4o6RA in a central position
that can intercept all traffic from the clients or by using Network Address
Translation (NAT) with the 4o6RA address for unicast messages.</t>
    </section>
    <section anchor="seccons">
      <name>Security Considerations</name>
      <t>This document specifies the applicability of 4o6 DHCP 4o6 in a scenario where legacy IPv4 clients are
connected to 4o6 DHCP 4o6 Relay Agents that perform the encapsulation and decapsulation.
This document does not change anything else in the 4o6 DHCP 4o6 specification and therefore <xref target="RFC7341"/>;
therefore, the security considerations of <xref target="RFC7341"/> that document still apply.
Specifically, since the legacy IPv4 client is not aware of the encapsulation and decapsulation,
it is
4o6RA has to provide the protections that are specficed specified in the security
considerations in <xref section="12" sectionFormat="of" target="RFC7341"/>.</t>
      <t>The mechanisms defined here differ from <xref target="RFC7341"/> as they allow the DHCP client
to send and receive DHCPv4 messages, whereas in <xref target="RFC7341"/> target="RFC7341"/>, the client
only sends DHCPv6 messages. This makes it possible that in improperly configured
networks where the client is located on the same Layer-2 Layer 2 scope of a DHCPv4 server,
DHCPv4 messages could reach a DHCPv4 server without using the 4o6RA.
While this can cause erroneous state in both clients and servers
and potentially even lead to misconfigurations that impact reachability,
this is seen as a deployment error rather than a security concern.
Further, even though this mechanism may be used for attacks from within the network,
this is not a new concern introduced by this specification.</t>
      <t>More generally, legacy IPv4 clients are not aware of this mechanism, mechanism; however, even
when DHCP 4o6 is used, the client does not have any control about the
information provided by the Relay agent. Agent.
As such such, this change does not raise any additional security concerns.</t>
    </section>
    <section anchor="iana-considerations">
      <name>IANA Considerations</name>
      <t>This document has no IANA actions.</t>
    </section>
  </middle>
  <back>
    <references anchor="sec-combined-references">
      <name>References</name>
      <references anchor="sec-normative-references">
        <name>Normative References</name>
        <reference anchor="RFC6221">
          <front>
            <title>Lightweight DHCPv6 Relay Agent</title>
            <author fullname="D. Miles" initials="D." role="editor" surname="Miles"/>
            <author fullname="S. Ooghe" initials="S." surname="Ooghe"/>
            <author fullname="W. Dec" initials="W." surname="Dec"/>
            <author fullname="S. Krishnan" initials="S." surname="Krishnan"/>
            <author fullname="A. Kavanagh" initials="A." surname="Kavanagh"/>
            <date month="May" year="2011"/>
            <abstract>
              <t>This document proposes a Lightweight DHCPv6 Relay Agent (LDRA) that is used to insert relay agent options in DHCPv6 message exchanges identifying client-facing interfaces. The LDRA can be implemented in existing access nodes (such as Digital Subscriber Link Access Multiplexers (DSLAMs) and Ethernet switches) that do not support IPv6 control or routing functions. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6221"/>
          <seriesInfo name="DOI" value="10.17487/RFC6221"/>
        </reference>
        <reference anchor="RFC7341">
          <front>
            <title>DHCPv4-over-DHCPv6 (DHCP 4o6) Transport</title>
            <author fullname="Q. Sun" initials="Q." surname="Sun"/>
            <author fullname="Y. Cui" initials="Y." surname="Cui"/>
            <author fullname="M. Siodelski" initials="M." surname="Siodelski"/>
            <author fullname="S. Krishnan" initials="S." surname="Krishnan"/>
            <author fullname="I. Farrer" initials="I." surname="Farrer"/>
            <date month="August" year="2014"/>
            <abstract>
              <t>IPv4 connectivity is still needed as networks migrate towards IPv6. Users require IPv4 configuration even if the uplink to their service provider supports IPv6 only. This document describes a mechanism for obtaining IPv4 configuration information dynamically in IPv6 networks by carrying DHCPv4 messages over DHCPv6 transport. Two new DHCPv6 messages and two new DHCPv6 options are defined for this purpose.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="7341"/>
          <seriesInfo name="DOI" value="10.17487/RFC7341"/>
        </reference>
        <reference anchor="draft-ietf-dhc-rfc8415bis" target="https://datatracker.ietf.org/doc/draft-ietf-dhc-rfc8415bis/">
          <front>
            <title>Dynamic Host Configuration Protocol for IPv6 (DHCPv6)</title>
            <author>
              <organization/>
            </author>
            <date year="2025" month="June"/>
          </front>
        </reference>
        <reference anchor="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>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="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>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>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.6221.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.7341.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9915.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.2119.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8174.xml"/>
      </references>
      <references anchor="sec-informative-references">
        <name>Informative References</name>
        <reference anchor="RFC951">
          <front>
            <title>Bootstrap Protocol</title>
            <author fullname="W.J. Croft" initials="W.J." surname="Croft"/>
            <author fullname="J. Gilmore" initials="J." surname="Gilmore"/>
            <date month="September" year="1985"/>
            <abstract>
              <t>This RFC describes an IP/UDP bootstrap protocol (BOOTP) which allows a diskless client machine to discover its own IP address, the address of a server host, and the name of a file to be loaded into memory and executed. The bootstrap operation can be thought of as consisting of TWO PHASES. This RFC describes the first phase, which could be labeled `address determination and bootfile selection'. After this address and filename information is obtained, control passes to the second phase of the bootstrap where a file transfer occurs. The file transfer will typically use the TFTP protocol, since it is intended that both phases reside in PROM on the client. However BOOTP could also work with other protocols such as SFTP or FTP. This RFC suggests a proposed protocol for the ARPA-Internet community, and requests discussion and suggestions for improvements.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="951"/>
          <seriesInfo name="DOI" value="10.17487/RFC0951"/>
        </reference>
        <reference anchor="RFC1542">
          <front>
            <title>Clarifications and Extensions for the Bootstrap Protocol</title>
            <author fullname="W. Wimer" initials="W." surname="Wimer"/>
            <date month="October" year="1993"/>
            <abstract>
              <t>Some aspects of the BOOTP protocol were rather loosely defined in its original specification. In particular, only a general description was provided for the behavior of "BOOTP relay agents" (originally called "BOOTP forwarding agents"). The client behavior description also suffered in certain ways. This memo attempts to clarify and strengthen the specification in these areas. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="1542"/>
          <seriesInfo name="DOI" value="10.17487/RFC1542"/>
        </reference>
        <reference anchor="RFC2131">
          <front>
            <title>Dynamic Host Configuration Protocol</title>
            <author fullname="R. Droms" initials="R." surname="Droms"/>
            <date month="March" year="1997"/>
            <abstract>
              <t>The Dynamic Host Configuration Protocol (DHCP) provides a framework for passing configuration information to hosts on a TCPIP network. DHCP is based on the Bootstrap Protocol (BOOTP), adding the capability of automatic allocation of reusable network addresses and additional configuration options. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="2131"/>
          <seriesInfo name="DOI" value="10.17487/RFC2131"/>
        </reference>
        <reference anchor="RFC2132">
          <front>
            <title>DHCP Options and BOOTP Vendor Extensions</title>
            <author fullname="S. Alexander" initials="S." surname="Alexander"/>
            <author fullname="R. Droms" initials="R." surname="Droms"/>
            <date month="March" year="1997"/>
            <abstract>
              <t>This document specifies the current set of DHCP options. Future options will be specified in separate RFCs. The current list of valid options is also available in ftp://ftp.isi.edu/in-notes/iana/assignments. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="2132"/>
          <seriesInfo name="DOI" value="10.17487/RFC2132"/>
        </reference>
        <reference anchor="RFC7969">
          <front>
            <title>Customizing DHCP Configuration on the Basis of Network Topology</title>
            <author fullname="T. Lemon" initials="T." surname="Lemon"/>
            <author fullname="T. Mrugalski" initials="T." surname="Mrugalski"/>
            <date month="October" year="2016"/>
            <abstract>
              <t>DHCP servers have evolved over the years to provide significant functionality beyond that described in the DHCP base specifications. One aspect of this functionality is support for context-specific configuration information. This memo describes some such features and explains their operation.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="7969"/>
          <seriesInfo name="DOI" value="10.17487/RFC7969"/>
        </reference>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.0951.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.1542.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.2131.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.2132.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.7969.xml"/>
      </references>
    </references>
    <?line 379?> 376?>

<section anchor="usecase">
      <name>Example Use Case: Topology Discovery for IPv4-only IPv4-Only Radio Unit in 3GPP RAN with Switched Fronthaul</name>
      <t>In 3GPP mobile network architecture, the User Equipments Equipment (UE) are is
connected via a Radio Access Network (RAN).  RAN is built up with
Baseband Units (BB) (BBUs) and Radio Units (RU). Radio (RUs). A radio Fronthaul Network (FH) network
connects RU RUs and BB, each of BBUs.  Each RU and BB BBU is an IP host, and they may
support IPv4 only, IPv6 only only, or both both, depending on the vendor and the
model.
Each RU is unique as it is tied to a set of antennas, and each antenna
is serving a specific Cell and Sector.
Each RU is configured by the BB BBU depending on the Cell and Sectors it serves.
However, that dependency is only specified by the cabling between RU RUs and antennas.
BB
BBUs can be cabled to RU RUs directly or via a Layer-2 Layer 2 switched network.</t>
      <figure anchor="bb_connected_to_ru">
        <name>3GPP RAN where RU are cabled directly Where RUs Are Cabled Directly to BB</name> BBUs</name>
        <artset>
          <artwork type="svg" align="center"><svg xmlns="http://www.w3.org/2000/svg" version="1.1" height="368" width="256" viewBox="0 0 256 368" class="diagram" text-anchor="middle" font-family="monospace" font-size="13px" stroke-linecap="round">
              <path d="M 8,32 L 8,80" fill="none" stroke="black"/>
              <path d="M 8,112 L 8,160" fill="none" stroke="black"/>
              <path d="M 8,208 L 8,256" fill="none" stroke="black"/>
              <path d="M 8,288 L 8,336" fill="none" stroke="black"/>
              <path d="M 80,32 L 80,80" fill="none" stroke="black"/>
              <path d="M 80,112 L 80,160" fill="none" stroke="black"/>
              <path d="M 80,208 L 80,256" fill="none" stroke="black"/>
              <path d="M 80,288 L 80,336" fill="none" stroke="black"/>
              <path d="M 104,144 L 104,176" fill="none" stroke="black"/>
              <path d="M 104,208 L 104,224" fill="none" stroke="black"/>
              <path d="M 128,48 L 128,160" fill="none" stroke="black"/>
              <path d="M 128,224 L 128,304" fill="none" stroke="black"/>
              <path d="M 152,144 L 152,240" fill="none" stroke="black"/>
              <path d="M 248,144 L 248,240" fill="none" stroke="black"/>
              <path d="M 8,32 L 80,32" fill="none" stroke="black"/>
              <path d="M 80,48 L 128,48" fill="none" stroke="black"/>
              <path d="M 8,80 L 80,80" fill="none" stroke="black"/>
              <path d="M 8,112 L 80,112" fill="none" stroke="black"/>
              <path d="M 80,144 L 104,144" fill="none" stroke="black"/>
              <path d="M 152,144 L 248,144" fill="none" stroke="black"/>
              <path d="M 8,160 L 80,160" fill="none" stroke="black"/>
              <path d="M 128,160 L 144,160" fill="none" stroke="black"/>
              <path d="M 104,176 L 144,176" fill="none" stroke="black"/>
              <path d="M 8,208 L 80,208" fill="none" stroke="black"/>
              <path d="M 104,208 L 144,208" fill="none" stroke="black"/>
              <path d="M 80,224 L 104,224" fill="none" stroke="black"/>
              <path d="M 128,224 L 144,224" fill="none" stroke="black"/>
              <path d="M 152,240 L 248,240" fill="none" stroke="black"/>
              <path d="M 8,256 L 80,256" fill="none" stroke="black"/>
              <path d="M 8,288 L 80,288" fill="none" stroke="black"/>
              <path d="M 80,304 L 128,304" fill="none" stroke="black"/>
              <path d="M 8,336 L 80,336" fill="none" stroke="black"/>
              <g class="text">
                <text x="40" y="52">RU2</text>
                <text x="40" y="132">RU3</text>
                <text x="196" y="180">Baseband</text>
                <text x="196" y="212">Unit</text>
                <text x="40" y="228">RU4</text>
                <text x="40" y="308">RU2</text>
              </g>
            </svg>
          </artwork>
          <artwork type="ascii-art" align="center"><![CDATA[
     +--------+
     |  RU2   +-----+
     |        |     |
     +--------+     |
                    |
     +--------+     |
     |  RU3   |     |
     |        +--+  |  +-----------+
     +--------+  |  +--|           |
                 +-----| Baseband  |
                       |           |
     +--------+  +-----|   Unit    |
     |  RU4   +--+  +--|           |
     |        |     |  +-----------+
     +--------+     |
                    |
     +--------+     |
     |  RU2   +-----+
     |        |
     +--------+
]]></artwork>
        </artset>
      </figure>
      <t>In <xref target="bb_connected_to_ru"/> BB target="bb_connected_to_ru"/>, the BBU is directly cabled to a set of RUs, and the
BB
BBU can recognize the relationship between RUs and Cell/Sectors
based on the cabling between the RUs and antennas.</t>
      <t>When BBs BBUs and RUs are connected via a Layer-2 Layer 2 switched network,
the added level of complexity requires the BBs BBUs to have a deeper
knowledge of the topology in order to properly configure the RUs,
involving knowledge of all the cabling in the switched network.</t>
      <t>Examples for switched networks are shown in section 3 of <xref section="3" sectionFormat="of" target="RFC7969"/>
and demonstrate the different levels of complexity.
An example of a FH is depicted in <xref target="l2_switched_fh"/>.</t>
      <figure anchor="l2_switched_fh">
        <name>3GPP RAN with Layer-2 Layer 2 Switched Fronthaul Example</name>
        <artset>
          <artwork type="svg" align="center"><svg xmlns="http://www.w3.org/2000/svg" version="1.1" height="352" width="544" viewBox="0 0 544 352" class="diagram" text-anchor="middle" font-family="monospace" font-size="13px" stroke-linecap="round">
              <path d="M 8,32 L 8,80" fill="none" stroke="black"/>
              <path d="M 8,112 L 8,160" fill="none" stroke="black"/>
              <path d="M 8,192 L 8,240" fill="none" stroke="black"/>
              <path d="M 8,272 L 8,320" fill="none" stroke="black"/>
              <path d="M 80,32 L 80,80" fill="none" stroke="black"/>
              <path d="M 80,112 L 80,160" fill="none" stroke="black"/>
              <path d="M 80,192 L 80,240" fill="none" stroke="black"/>
              <path d="M 80,272 L 80,320" fill="none" stroke="black"/>
              <path d="M 152,48 L 152,144" fill="none" stroke="black"/>
              <path d="M 152,208 L 152,304" fill="none" stroke="black"/>
              <path d="M 168,48 L 168,80" fill="none" stroke="black"/>
              <path d="M 168,208 L 168,240" fill="none" stroke="black"/>
              <path d="M 224,48 L 224,144" fill="none" stroke="black"/>
              <path d="M 224,208 L 224,304" fill="none" stroke="black"/>
              <path d="M 272,48 L 272,320" fill="none" stroke="black"/>
              <path d="M 296,64 L 296,144" fill="none" stroke="black"/>
              <path d="M 296,224 L 296,304" fill="none" stroke="black"/>
              <path d="M 336,64 L 336,96" fill="none" stroke="black"/>
              <path d="M 392,64 L 392,144" fill="none" stroke="black"/>
              <path d="M 392,224 L 392,304" fill="none" stroke="black"/>
              <path d="M 432,48 L 432,320" fill="none" stroke="black"/>
              <path d="M 456,144 L 456,224" fill="none" stroke="black"/>
              <path d="M 536,144 L 536,224" fill="none" stroke="black"/>
              <path d="M 8,32 L 80,32" fill="none" stroke="black"/>
              <path d="M 152,48 L 224,48" fill="none" stroke="black"/>
              <path d="M 80,64 L 144,64" fill="none" stroke="black"/>
              <path d="M 296,64 L 392,64" fill="none" stroke="black"/>
              <path d="M 8,80 L 80,80" fill="none" stroke="black"/>
              <path d="M 168,80 L 224,80" fill="none" stroke="black"/>
              <path d="M 272,96 L 288,96" fill="none" stroke="black"/>
              <path d="M 336,96 L 392,96" fill="none" stroke="black"/>
              <path d="M 8,112 L 80,112" fill="none" stroke="black"/>
              <path d="M 80,128 L 144,128" fill="none" stroke="black"/>
              <path d="M 224,128 L 264,128" fill="none" stroke="black"/>
              <path d="M 392,128 L 424,128" fill="none" stroke="black"/>
              <path d="M 152,144 L 224,144" fill="none" stroke="black"/>
              <path d="M 296,144 L 392,144" fill="none" stroke="black"/>
              <path d="M 456,144 L 536,144" fill="none" stroke="black"/>
              <path d="M 8,160 L 80,160" fill="none" stroke="black"/>
              <path d="M 432,176 L 448,176" fill="none" stroke="black"/>
              <path d="M 8,192 L 80,192" fill="none" stroke="black"/>
              <path d="M 152,208 L 224,208" fill="none" stroke="black"/>
              <path d="M 80,224 L 144,224" fill="none" stroke="black"/>
              <path d="M 296,224 L 392,224" fill="none" stroke="black"/>
              <path d="M 456,224 L 536,224" fill="none" stroke="black"/>
              <path d="M 8,240 L 80,240" fill="none" stroke="black"/>
              <path d="M 168,240 L 224,240" fill="none" stroke="black"/>
              <path d="M 272,256 L 288,256" fill="none" stroke="black"/>
              <path d="M 8,272 L 80,272" fill="none" stroke="black"/>
              <path d="M 80,288 L 144,288" fill="none" stroke="black"/>
              <path d="M 224,288 L 264,288" fill="none" stroke="black"/>
              <path d="M 392,288 L 424,288" fill="none" stroke="black"/>
              <path d="M 152,304 L 224,304" fill="none" stroke="black"/>
              <path d="M 296,304 L 392,304" fill="none" stroke="black"/>
              <path d="M 8,320 L 80,320" fill="none" stroke="black"/>
              <g class="text">
                <text x="40" y="52">RU1</text>
                <text x="132" y="52">P1</text>
                <text x="196" y="68">L2RA</text>
                <text x="364" y="84">L3RA</text>
                <text x="180" y="100">L2</text>
                <text x="132" y="116">P2</text>
                <text x="188" y="116">switch</text> y="116">Switch</text>
                <text x="40" y="132">RU2</text>
                <text x="180" y="132">#1</text>
                <text x="348" y="132">Router</text>
                <text x="484" y="180">DHCP</text>
                <text x="492" y="196">Server</text>
                <text x="40" y="212">RU3</text>
                <text x="132" y="212">P1</text>
                <text x="492" y="212">#1</text>
                <text x="196" y="228">L2RA</text>
                <text x="180" y="260">L2</text>
                <text x="340" y="260">Baseband</text>
                <text x="132" y="276">P2</text>
                <text x="188" y="276">switch</text> y="276">Switch</text>
                <text x="340" y="276">Unit</text>
                <text x="40" y="292">RU4</text>
                <text x="180" y="292">#2</text>
              </g>
            </svg>
          </artwork>
          <artwork type="ascii-art" align="center"><![CDATA[
     +--------+
     |  RU1   |     P1 +-+------+     |                   |
     |        +--------| | L2RA |     |  +----+------+    |
     +--------+        | +------+     |  |    | L3RA |    |
                       |  L2    |     +--|    +------+    |
     +--------+     P2 | switch Switch |     |  |           |    |
     |  RU2   +--------|  #1    +-----|  |   Router  +----|
     |        |        +--------+     |  +-----------+    |  +---------+
     +--------+                       |                   |  |         |
                                      |                   +--| DHCP    |
     +--------+                       |                   |  | Server  |
     |  RU3   |     P1 +-+------+     |                   |  |   #1    |
     |        +--------| | L2RA |     |  +-----------+    |  +---------+
     +--------+        | +------+     |  |           |    |
                       |  L2    |     +--| Baseband  |    |
     +--------+     P2 | switch Switch |     |  |   Unit    |    |
     |  RU4   +--------|  #2    +-----|  |           +----|
     |        |        +--------+     |  +-----------+    |
     +--------+                       |                   |
]]></artwork>
        </artset>
      </figure>
      <t>If IPv6 is used and all RU RUs are capable of DHCPv6 in <xref target="l2_switched_fh"/>,
DHCP topology knowledge can be used for solving the RU configuration problem.
Such solution would use the topology discovery mechanisms described in section 3.2
of <xref section="3.2" sectionFormat="of" target="RFC7969"/>.</t>
      <t>If RU RUs are capable of IPv4 only but implement a DHCP 4o6 client according to <xref target="RFC7341"/>, the same topology discovery mechanisms are applicable.</t>
      <t>If RU RUs are capable of IPV4 IPv4 only and cannot implement a DHCP 4o6 client according to <xref target="RFC7341"/>,
the topology discovery mechanisms described in section 3.2
of <xref section="3.2" sectionFormat="of" target="RFC7969"/> can be used by introducing 4o6RA in the switches as decribed described in this document.</t>
    </section>
    <section numbered="false" anchor="acknowledgments">
      <name>Acknowledgments</name>
      <t>The authors would also like to acknowledge interesting discussions in
this problem space with Sarah Gannon, Ines Ramadza, and Siddharth Sharma <contact fullname="Sarah Gannon"/>, <contact fullname="Ines Ramadza"/>, and <contact fullname="Siddharth Sharma"/>,
as well as reviews and comments provided by Eric Vyncke, Mohamed Boucadair,
David Lamparter, Michael Richardson, Alan DeKok, Dale Worley, Paul Wouters,
Deb Cooley, Erik Kline, Ketan Talaulikar, Mike Bishop and Roman Danyliw.</t> <contact fullname="Éric Vyncke"/>, <contact fullname="Mohamed Boucadair"/>,
<contact fullname="David Lamparter"/>, <contact fullname="Michael Richardson"/>, <contact fullname="Alan DeKok"/>, <contact fullname="Dale Worley"/>, <contact fullname="Paul Wouters"/>,
<contact fullname="Deb Cooley"/>, <contact fullname="Erik Kline"/>, <contact fullname="Ketan Talaulikar"/>, <contact fullname="Mike Bishop"/>, and <contact fullname="Roman Danyliw"/>.</t>
    </section>
  </back>
  <!-- ##markdown-source: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H4sIAOdcn2kAA61cbXMbt7X+zhn+B1z5Q62KYizZUWKlaStLcq1GtlVJrifT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-->

</rfc>