RFC 5771 - IANA Guidelines for IPv4 Multicast Address Assignments

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href="/doc/html/rfc3171" title="IANA Guidelines for IPv4 Multicast Address Assignments">RFC 3171</a>, <a href="/doc/html/rfc3138" title="Extended Assignments in 233/8">RFC 3138</a></div> <div>Updates <a href="/doc/html/rfc2780" title="IANA Allocation Guidelines For Values In the Internet Protocol and Related Headers">RFC 2780</a></div> <div> Was <a href="/doc/draft-ietf-mboned-rfc3171bis/08/">draft-ietf-mboned-rfc3171bis</a> (<a href="/wg/mboned/about/">mboned WG</a>) </div> </td> </tr> <tr> <td></td> <th scope="row">Select version</th> <td class="edit"></td> <td> <ul class="revision-list pagination pagination-sm text-center flex-wrap my-0"> <li class="page-item"> <a class="page-link" href="/doc/html/draft-ietf-mboned-rfc3171bis-08" rel="nofollow"> 08 </a> </li> <li class="page-item rfc active"> <a class="page-link" href="/doc/html/rfc5771"> RFC 5771 </a> </li> </ul> </td> </tr> <tr> <td></td> <th scope="row">Compare versions</th> <td class="edit"></td> <td> <form 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<option value="draft-ietf-mboned-rfc3171bis-01"> draft-ietf-mboned-rfc3171bis-01 </option> <option value="draft-ietf-mboned-rfc3171bis-00"> draft-ietf-mboned-rfc3171bis-00 </option> </select> <select class="form-select form-select-sm mb-1 select2-field" data-max-entries="1" data-width="resolve" data-allow-clear="false" data-minimum-input-length="0" aria-label="To revision" name="url2"> <option value="rfc5771" selected> RFC 5771 </option> <option value="draft-ietf-mboned-rfc3171bis-08"> draft-ietf-mboned-rfc3171bis-08 </option> <option value="draft-ietf-mboned-rfc3171bis-07"> draft-ietf-mboned-rfc3171bis-07 </option> <option value="draft-ietf-mboned-rfc3171bis-06"> draft-ietf-mboned-rfc3171bis-06 </option> <option value="draft-ietf-mboned-rfc3171bis-05"> draft-ietf-mboned-rfc3171bis-05 </option> <option value="draft-ietf-mboned-rfc3171bis-04"> draft-ietf-mboned-rfc3171bis-04 </option> <option value="draft-ietf-mboned-rfc3171bis-03"> draft-ietf-mboned-rfc3171bis-03 </option> <option 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aria-label="Compose email to mcotton@amsl.com" title="Compose email to mcotton@amsl.com"> <i class="bi bi-envelope"></i></a></span>, <span ><a title="Datatracker profile of Leo Vegoda" href="/person/leo.vegoda@icann.org" >Leo Vegoda</a> <a href="mailto:leo.vegoda%40icann.org" aria-label="Compose email to leo.vegoda@icann.org" title="Compose email to leo.vegoda@icann.org"> <i class="bi bi-envelope"></i></a></span> <br> <a class="btn btn-primary btn-sm mt-1" href="mailto:rfc5771@ietf.org?subject=rfc5771" title="Send email to the document authors">Email authors</a> </td> </tr> <tr> <td></td> <th scope="row"> RFC stream </th> <td class="edit"> </td> <td > <img alt="IETF Logo" class="d-lm-none w-25 mt-1" src="https://static.ietf.org/dt/12.28.2/ietf/images/ietf-logo-nor-white.svg" > <img alt="IETF Logo" class="d-dm-none w-25 mt-1" src="https://static.ietf.org/dt/12.28.2/ietf/images/ietf-logo-nor.svg" > </td> </tr> <tr> <td></td> <th scope="row"> Other formats </th> <td class="edit"> </td> <td> <div class="buttonlist"> <a class="btn btn-primary btn-sm" target="_blank" href="https://www.rfc-editor.org/rfc/rfc5771.txt"> <i class="bi bi-file-text"></i> txt </a> <a class="btn btn-primary btn-sm" target="_blank" href="https://www.rfc-editor.org/rfc/rfc5771.html"> <i class="bi bi-file-code"></i> html </a> <a class="btn btn-primary btn-sm" download="rfc5771.pdf" target="_blank" href="https://www.rfc-editor.org/rfc/pdfrfc/rfc5771.txt.pdf"> <i class="bi bi-file-pdf"></i> pdf </a> <a class="btn btn-primary btn-sm" target="_blank" href="/doc/rfc5771/bibtex/"> <i class="bi bi-file-ruled"></i> bibtex </a> </div> </td> </tr> <tr> <td> </td> <th scope="row"> Additional resources </th> <td class="edit"> </td> <td> <a href="https://mailarchive.ietf.org/arch/browse/mboned/?q=rfc5771 OR %22draft-ietf-mboned-rfc3171bis%22"> Mailing list discussion </a> </td> </tr> </tbody> <tr> <th scope="row"></th> <th scope="row"></th> <td class="edit"></td> <td> <a class="btn btn-sm btn-warning mb-3" target="_blank" href="https://github.com/ietf-tools/datatracker/issues/new/choose"> Report a bug <i class="bi bi-bug"></i> </a> </td> </tr> </table> </div> </div> </nav> <div class="row g-0"> <div class="col-md-9 d-flex justify-content-center lh-sm" data-bs-spy="scroll" data-bs-target="#toc-nav" data-bs-smooth-scroll="true" tabindex="0" id="content"> <div class="rfcmarkup"> <br class="noprint">  <div class="rfcmarkup"><pre>Internet Engineering Task Force (IETF) M. Cotton Request for Comments: 5771 L. Vegoda BCP: 51 ICANN Updates: <a href="/doc/html/rfc2780">2780</a> D. Meyer Obsoletes: <a href="/doc/html/rfc3138">3138</a>, <a href="/doc/html/rfc3171">3171</a> March 2010 Category: Best Current Practice ISSN: 2070-1721 <span class="h1">IANA Guidelines for IPv4 Multicast Address Assignments</span> Abstract This document provides guidance for the Internet Assigned Numbers Authority (IANA) in assigning IPv4 multicast addresses. It obsoletes <a href="/doc/html/rfc3171">RFC 3171</a> and <a href="/doc/html/rfc3138">RFC 3138</a> and updates <a href="/doc/html/rfc2780">RFC 2780</a>. Status of This Memo This memo documents an Internet Best Current Practice. 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 BCPs is available in <a href="/doc/html/rfc5741#section-2">Section 2 of RFC 5741</a>. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at <a href="http://www.rfc-editor.org/info/rfc5771">http://www.rfc-editor.org/info/rfc5771</a>. Copyright Notice Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to <a href="/doc/html/bcp78">BCP 78</a> and the IETF Trust's Legal Provisions Relating to IETF Documents (<a href="http://trustee.ietf.org/license-info">http://trustee.ietf.org/license-info</a>) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. <span class="grey">Cotton, et al. Best Current Practice [Page 1]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-2" ></span> <span class="grey"><a href="/doc/html/rfc5771">RFC 5771</a> IPv4 Multicast Guidelines March 2010</span> Table of Contents <a href="#section-1">1</a>. Introduction ....................................................<a href="#page-2">2</a> <a href="#section-2">2</a>. Terminology .....................................................<a href="#page-3">3</a> <a href="#section-3">3</a>. Definition of Current Assignment Practice .......................<a href="#page-3">3</a> <a href="#section-4">4</a>. Local Network Control Block (224.0.0/24) ........................<a href="#page-4">4</a> <a href="#section-4.1">4.1</a>. Assignment Guidelines ......................................<a href="#page-4">4</a> <a href="#section-5">5</a>. Internetwork Control Block (224.0.1/24) .........................<a href="#page-5">5</a> <a href="#section-5.1">5.1</a>. Assignment Guidelines ......................................<a href="#page-5">5</a> <a href="#section-6">6</a>. AD-HOC Blocks (I, II, and III) ..................................<a href="#page-5">5</a> <a href="#section-6.1">6.1</a>. Assignment Guidelines ......................................<a href="#page-5">5</a> <a href="#section-7">7</a>. SDP/SAP Block (224.2/16) ........................................<a href="#page-5">5</a> <a href="#section-7.1">7.1</a>. Assignment Guidelines ......................................<a href="#page-5">5</a> <a href="#section-8">8</a>. Source-Specific Multicast Block (232/8) .........................<a href="#page-6">6</a> <a href="#section-8.1">8.1</a>. Assignment Guidelines ......................................<a href="#page-6">6</a> <a href="#section-9">9</a>. GLOP Block (233/8) ..............................................<a href="#page-6">6</a> <a href="#section-9.1">9.1</a>. Assignment Guidelines ......................................<a href="#page-6">6</a> <a href="#section-9.2">9.2</a>. AD-HOC Block III ...........................................<a href="#page-6">6</a> <a href="#section-10">10</a>. Administratively Scoped Block (239/8) ..........................<a href="#page-7">7</a> <a href="#section-10.1">10.1</a>. Assignment Guidelines .....................................<a href="#page-7">7</a> <a href="#section-10.1.1">10.1.1</a>. Relative Offsets ...................................<a href="#page-7">7</a> <a href="#section-11">11</a>. Application Form ...............................................<a href="#page-7">7</a> <a href="#section-11.1">11.1</a>. Size of Assignments of IPv4 Multicast Addresses ...........<a href="#page-7">7</a> <a href="#section-12">12</a>. Annual Review ..................................................<a href="#page-8">8</a> <a href="#section-12.1">12.1</a>. Address Reclamation .......................................<a href="#page-8">8</a> <a href="#section-12.2">12.2</a>. Positive Renewal ..........................................<a href="#page-8">8</a> <a href="#section-13">13</a>. Use of IANA Reserved Addresses .................................<a href="#page-8">8</a> <a href="#section-14">14</a>. IANA Considerations ............................................<a href="#page-8">8</a> <a href="#section-15">15</a>. Security Considerations ........................................<a href="#page-9">9</a> <a href="#section-16">16</a>. Acknowledgments ................................................<a href="#page-9">9</a> <a href="#section-17">17</a>. References .....................................................<a href="#page-9">9</a> <a href="#section-17.1">17.1</a>. Normative References ......................................<a href="#page-9">9</a> <a href="#section-17.2">17.2</a>. Informative References ....................................<a href="#page-9">9</a> <span class="h2"><a class="selflink" id="section-1" href="#section-1">1</a>. Introduction</span> The Internet Assigned Numbers Authority (IANA) (www.iana.org) is charged with allocating parameter values for fields in protocols that have been designed, created, or are maintained by the Internet Engineering Task Force (IETF). <a href="/doc/html/rfc2780">RFC 2780</a> [<a href="/doc/html/rfc2780" title=""IANA Allocation Guidelines For Values In the Internet Protocol and Related Headers"">RFC2780</a>] provides the IANA guidance in the assignment of parameters for fields in newly developed protocols. This memo expands on <a href="/doc/html/rfc2780#section-4.4.2">section 4.4.2 of RFC 2780</a> and attempts to codify existing IANA practice used in the assignment of IPv4 multicast addresses. <span class="grey">Cotton, et al. Best Current Practice [Page 2]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-3" ></span> <span class="grey"><a href="/doc/html/rfc5771">RFC 5771</a> IPv4 Multicast Guidelines March 2010</span> This document is a revision of <a href="/doc/html/rfc3171">RFC 3171</a> [<a href="/doc/html/rfc3171" title=""IANA Guidelines for IPv4 Multicast Address Assignments"">RFC3171</a>], which it obsoletes. It also obsoletes <a href="/doc/html/rfc3138">RFC 3138</a> [<a href="/doc/html/rfc3138" title=""Extended Assignments in 233/8"">RFC3138</a>] and updates [<a href="/doc/html/rfc2780" title=""IANA Allocation Guidelines For Values In the Internet Protocol and Related Headers"">RFC2780</a>]. The terms "Specification Required", "Expert Review", "IESG Approval", "IETF Review", and "Standards Action", are used in this memo to refer to the processes described in [<a href="/doc/html/rfc5226" title="">RFC5226</a>]. In general, due to the relatively small size of the IPv4 multicast address space, further assignment of IPv4 multicast address space is recommended only in limited circumstances. Specifically, the IANA should only assign addresses in those cases where: - the dynamic selection Session Description Protocol/Session Announcement Protocol (SDP/SAP); - GLOP (not an acronym); - Source-Specific Multicast (SSM); or - Administratively Scoped address spaces cannot be used. The guidelines described below are reflected in [<a href="#ref-IANA-protocols">IANA-protocols</a>]. Network operators should also be aware of the availability of IPv6 multicast addresses and consider using them where feasible. <span class="h2"><a class="selflink" id="section-2" href="#section-2">2</a>. Terminology</span> The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in <a href="/doc/html/bcp14">BCP 14</a>, <a href="/doc/html/rfc2119">RFC 2119</a> [<a href="/doc/html/rfc2119" title=""Key words for use in RFCs to Indicate Requirement Levels"">RFC2119</a>]. The word "allocation" designates a block of addresses managed by a registry for the purpose of making assignments and allocations. The word "assignment" designates a block of addresses, or a single address, registered to an end-user for use on a specific network or set of networks. <span class="h2"><a class="selflink" id="section-3" href="#section-3">3</a>. Definition of Current Assignment Practice</span> Unlike IPv4 unicast address assignment, where blocks of addresses are delegated to Regional Internet Registries (RIRs), IPv4 multicast addresses are assigned directly by the IANA. Current registration groups appear as follows [<a href="#ref-IANA" title=""IANA Protocol Registries"">IANA</a>]: <span class="grey">Cotton, et al. Best Current Practice [Page 3]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-4" ></span> <span class="grey"><a href="/doc/html/rfc5771">RFC 5771</a> IPv4 Multicast Guidelines March 2010</span> Address Range Size Designation ------------- ---- ----------- <span class="h5"><a class="selflink" id="section-224.0.0.0" href="#section-224.0.0.0">224.0.0.0</a> - 224.0.0.255 </span> (/24) Local Network Control Block <span class="h5"><a class="selflink" id="section-224.0.1.0" href="#section-224.0.1.0">224.0.1.0</a> - 224.0.1.255 </span> (/24) Internetwork Control Block <span class="h5"><a class="selflink" id="section-224.0.2.0" href="#section-224.0.2.0">224.0.2.0</a> - 224.0.255.255 </span> (65024) AD-HOC Block I <span class="h5"><a class="selflink" id="section-224.1.0.0" href="#section-224.1.0.0">224.1.0.0</a> - 224.1.255.255 </span> (/16) RESERVED <span class="h5"><a class="selflink" id="section-224.2.0.0" href="#section-224.2.0.0">224.2.0.0</a> - 224.2.255.255 </span> (/16) SDP/SAP Block <span class="h5"><a class="selflink" id="section-224.3.0.0" href="#section-224.3.0.0">224.3.0.0</a> - 224.4.255.255 </span> (2 /16s) AD-HOC Block II <span class="h5"><a class="selflink" id="section-224.5.0.0" href="#section-224.5.0.0">224.5.0.0</a> - 224.255.255.255 </span> (251 /16s) RESERVED <span class="h5"><a class="selflink" id="section-225.0.0.0" href="#section-225.0.0.0">225.0.0.0</a> - 231.255.255.255 </span> (7 /8s) RESERVED <span class="h5"><a class="selflink" id="section-232.0.0.0" href="#section-232.0.0.0">232.0.0.0</a> - 232.255.255.255 </span> (/8) Source-Specific Multicast Block <span class="h5"><a class="selflink" id="section-233.0.0.0" href="#section-233.0.0.0">233.0.0.0</a> - 233.251.255.255 </span> (16515072) GLOP Block <span class="h5"><a class="selflink" id="section-233.252.0.0" href="#section-233.252.0.0">233.252.0.0</a> - 233.255.255.255 (/14) </span> AD-HOC Block III <span class="h5"><a class="selflink" id="section-234.0.0.0" href="#section-234.0.0.0">234.0.0.0</a> - 238.255.255.255 </span> (5 /8s) RESERVED <span class="h5"><a class="selflink" id="section-239.0.0.0" href="#section-239.0.0.0">239.0.0.0</a> - 239.255.255.255 </span> (/8) Administratively Scoped Block The IANA generally assigns addresses from the Local Network Control, Internetwork Control and AD-HOC blocks. Assignment guidelines for each of these blocks, as well as for the Source-Specific Multicast, GLOP, and Administratively Scoped blocks, are described below. <span class="h2"><a class="selflink" id="section-4" href="#section-4">4</a>. Local Network Control Block (224.0.0/24)</span> Addresses in the Local Network Control Block are used for protocol control traffic that is not forwarded off link. Examples of this type of use include OSPFIGP All Routers (224.0.0.5) [<a href="/doc/html/rfc2328" title=""OSPF Version 2"">RFC2328</a>]. <span class="h3"><a class="selflink" id="section-4.1" href="#section-4.1">4.1</a>. Assignment Guidelines</span> Pursuant to <a href="/doc/html/rfc2780#section-4.4.2">section 4.4.2 of [RFC2780]</a>, assignments from the Local Network Control Block follow an Expert Review, IESG Approval, or Standards Action process. See IANA [<a href="#ref-IANA" title=""IANA Protocol Registries"">IANA</a>] for the current set of assignments. <span class="grey">Cotton, et al. Best Current Practice [Page 4]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-5" ></span> <span class="grey"><a href="/doc/html/rfc5771">RFC 5771</a> IPv4 Multicast Guidelines March 2010</span> <span class="h2"><a class="selflink" id="section-5" href="#section-5">5</a>. Internetwork Control Block (224.0.1/24)</span> Addresses in the Internetwork Control Block are used for protocol control traffic that MAY be forwarded through the Internet. Examples include 224.0.1.1 (Network Time Protocol (NTP) [<a href="/doc/html/rfc4330" title=""Simple Network Time Protocol (SNTP) Version 4 for IPv4, IPv6 and OSI"">RFC4330</a>]) and 224.0.1.68 (mdhcpdiscover [<a href="/doc/html/rfc2730" title=""Multicast Address Dynamic Client Allocation Protocol (MADCAP)"">RFC2730</a>]). <span class="h3"><a class="selflink" id="section-5.1" href="#section-5.1">5.1</a>. Assignment Guidelines</span> Pursuant to <a href="/doc/html/rfc2780#section-4.4.2">section 4.4.2 of [RFC2780]</a>, assignments from the Internetwork Control Block follow an Expert Review, IESG Approval, or Standards Action process. See IANA [<a href="#ref-IANA" title=""IANA Protocol Registries"">IANA</a>] for the current set of assignments. <span class="h2"><a class="selflink" id="section-6" href="#section-6">6</a>. AD-HOC Blocks (I, II, and III)</span> Addresses in the AD-HOC blocks (including 224.0.2.0 - 224.0.255.255, 224.3.0.0 - 224.4.255.255, and 233.252.0.0 - 233.255.255.255) were traditionally used for assignments for those applications that don't fit in either the Local or Internetwork Control blocks. These addresses MAY be globally routed and are typically used by applications that require small blocks of addressing (e.g., less than a /24 ). Future assignments of blocks of addresses that do not fit in the Local Network or Internetwork Control blocks will be made in AD-HOC Block III. <span class="h3"><a class="selflink" id="section-6.1" href="#section-6.1">6.1</a>. Assignment Guidelines</span> In general, the IANA SHOULD NOT assign addresses in the AD-HOC blocks. However, the IANA MAY, under special circumstances, assign addresses from these blocks. Pursuant to <a href="/doc/html/rfc2780#section-4.4.2">section 4.4.2 of [RFC2780]</a>, assignments from the AD-HOC blocks follow an Expert Review, IESG Approval, or Standards Action process. See [<a href="#ref-IANA" title=""IANA Protocol Registries"">IANA</a>] for the current set of assignments. <span class="h2"><a class="selflink" id="section-7" href="#section-7">7</a>. SDP/SAP Block (224.2/16)</span> Addresses in the SDP/SAP Block are used by applications that receive addresses through the Session Announcement Protocol [<a href="/doc/html/rfc2974" title=""Session Announcement Protocol"">RFC2974</a>] for use via applications like the session directory tool (such as [<a href="#ref-SDR" title=""Session Directory Tool"">SDR</a>]). <span class="h3"><a class="selflink" id="section-7.1" href="#section-7.1">7.1</a>. Assignment Guidelines</span> Since addresses in the SDP/SAP Block are chosen randomly from the range of addresses not already in use [<a href="/doc/html/rfc2974" title=""Session Announcement Protocol"">RFC2974</a>], no IANA assignment policy is required. Note that while no additional IANA assignment is required, addresses in the SDP/SAP Block are explicitly for use by SDP/SAP and MUST NOT be used for other purposes. <span class="grey">Cotton, et al. Best Current Practice [Page 5]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-6" ></span> <span class="grey"><a href="/doc/html/rfc5771">RFC 5771</a> IPv4 Multicast Guidelines March 2010</span> <span class="h2"><a class="selflink" id="section-8" href="#section-8">8</a>. Source-Specific Multicast Block (232/8)</span> SSM [<a href="/doc/html/rfc4607" title=""Source-Specific Multicast for IP"">RFC4607</a>] is an extension of IP Multicast in which traffic is forwarded to receivers from only those multicast sources for which the receivers have explicitly expressed interest and is primarily targeted at one-to-many (broadcast) applications. Note that this block was initially assigned to the Versatile Message Transaction Protocol (VMTP) transient groups [<a href="#ref-IANA" title=""IANA Protocol Registries"">IANA</a>]. <span class="h3"><a class="selflink" id="section-8.1" href="#section-8.1">8.1</a>. Assignment Guidelines</span> Because the SSM model essentially makes the entire multicast address space local to the host, no IANA assignment policy is required. Note, however, that while no additional IANA assignment is required, addresses in the Source-Specific Multicast Block are explicitly for use by SSM and MUST NOT be used for other purposes. <span class="h2"><a class="selflink" id="section-9" href="#section-9">9</a>. GLOP Block (233/8)</span> Addresses in the GLOP Block are globally-scoped, statically-assigned addresses. The assignment is made, for a domain with a 16-bit Autonomous System Number (ASN), by mapping a domain's autonomous system number, expressed in octets as X.Y, into the middle two octets of the GLOP Block, yielding an assignment of 233.X.Y.0/24. The mapping and assignment is defined in [<a href="/doc/html/rfc3180" title=""GLOP Addressing in 233/8"">RFC3180</a>]. Domains with a 32-bit ASN MAY apply for space in AD-HOC Block III, or consider using IPv6 multicast addresses. <span class="h3"><a class="selflink" id="section-9.1" href="#section-9.1">9.1</a>. Assignment Guidelines</span> Because addresses in the GLOP Block are algorithmically pre-assigned, no IANA assignment policy is required. <span class="h3"><a class="selflink" id="section-9.2" href="#section-9.2">9.2</a>. AD-HOC Block III</span> [<a id="ref-RFC3138">RFC3138</a>] delegated to the RIRs the assignment of the GLOP sub-block (233.252.0.0 - 233.255.255.255) mapped by the private Autonomous System (AS) space (64512-65534) and the IANA reserved ASN 65535 [<a href="/doc/html/rfc1930" title=""Guidelines for creation, selection, and registration of an Autonomous System (AS)"">RFC1930</a>]. This space was known as Extended GLOP (EGLOP). <a href="/doc/html/rfc3138">RFC 3138</a> should not have asked the RIRs to develop policies for the EGLOP space because [<a href="/doc/html/rfc2860" title=""Memorandum of Understanding Concerning the Technical Work of the Internet Assigned Numbers Authority"">RFC2860</a>] reserves that to the IETF. It is important to make this space available for use by network operators, and it is therefore appropriate to obsolete <a href="/doc/html/rfc3138">RFC 3138</a> and classify this address range as available for AD-HOC assignment as per the guidelines in <a href="#section-6">section 6</a>. <span class="grey">Cotton, et al. Best Current Practice [Page 6]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-7" ></span> <span class="grey"><a href="/doc/html/rfc5771">RFC 5771</a> IPv4 Multicast Guidelines March 2010</span> The first /24 in this range, 233.252.0.0/24, is assigned as "MCAST- TEST-NET" for use in documentation and example code. 233.252.0.0/24 SHOULD be used in conjunction with the [<a href="/doc/html/rfc2606" title=""Reserved Top Level DNS Names"">RFC2606</a>] domain names example.com or example.net in vendor and protocol documentation. Addresses within 233.252.0.0/24 MUST NOT appear on the public Internet. <span class="h2"><a class="selflink" id="section-10" href="#section-10">10</a>. Administratively Scoped Block (239/8)</span> Addresses in the Administratively Scoped Block are for local use within a domain and are described in [<a href="/doc/html/rfc2365" title=""Administratively Scoped IP Multicast"">RFC2365</a>]. <span class="h3"><a class="selflink" id="section-10.1" href="#section-10.1">10.1</a>. Assignment Guidelines</span> Since addresses in this block are local to a domain, no IANA assignment policy is required. <span class="h4"><a class="selflink" id="section-10.1.1" href="#section-10.1.1">10.1.1</a>. Relative Offsets</span> The relative offsets [<a href="/doc/html/rfc2365" title=""Administratively Scoped IP Multicast"">RFC2365</a>] are used to ensure that a service can be located independent of the extent of the enclosing scope (see [<a href="/doc/html/rfc3180" title=""GLOP Addressing in 233/8"">RFC3180</a>] for details). Since there are only 256 such offsets, the IANA should only assign a relative offset to a protocol that provides an infrastructure supporting service. Examples of such services include the Session Announcement Protocol [<a href="/doc/html/rfc2974" title=""Session Announcement Protocol"">RFC2974</a>]. Pursuant to <a href="/doc/html/rfc2780#section-4.4.2">section 4.4.2 of [RFC2780]</a>, assignments of relative offsets follow an Expert Review, IESG Approval, or Standards Action process. See [<a href="#ref-IANA" title=""IANA Protocol Registries"">IANA</a>] for the current set of assignments. <span class="h2"><a class="selflink" id="section-11" href="#section-11">11</a>. Application Form</span> Requests for multicast address assignments can be submitted through the application form on the IANA web site at [<a href="#ref-IANA-registration">IANA-registration</a>]. It is important to submit sufficient detail to allow the IESG designated expert to review the application. If the details given in the request are not clear, or further information is needed, the IESG designated expert may request additional information before assigning an address. <span class="h3"><a class="selflink" id="section-11.1" href="#section-11.1">11.1</a>. Size of Assignments of IPv4 Multicast Addresses</span> Occasionally, more than one multicast address is required. In these cases, multiple addresses are available in AD-HOC Block III. Where there is a requirement for a very large number of addresses, the assignment will be staged. The additional stages will only be made after the complete use of the initial assignment(s). <span class="grey">Cotton, et al. Best Current Practice [Page 7]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-8" ></span> <span class="grey"><a href="/doc/html/rfc5771">RFC 5771</a> IPv4 Multicast Guidelines March 2010</span> A separate document describing the policy governing assignment of addresses in the AD-HOC blocks I, II, and III will be developed and published. The format, location, and content has not yet been decided and so these will be documented in a future version of this document. <span class="h2"><a class="selflink" id="section-12" href="#section-12">12</a>. Annual Review</span> Given the dynamic nature of IPv4 multicast and its associated infrastructure, and the previously undocumented IPv4 multicast address assignment guidelines, the IANA should conduct an annual review of currently assigned addresses. <span class="h3"><a class="selflink" id="section-12.1" href="#section-12.1">12.1</a>. Address Reclamation</span> During the review described above, addresses that were mis-assigned should, where possible, be reclaimed or reassigned. The IANA should also review assignments in the AD-HOC, "DIS Transient Groups", and ST Multicast Groups [<a href="/doc/html/rfc1819" title=""Internet Stream Protocol Version 2 (ST2) Protocol Specification - Version ST2+"">RFC1819</a>] blocks and reclaim those addresses that are not in use on the global Internet (i.e., those applications that can use SSM, GLOP, or Administratively Scoped addressing, or are not globally routed). <span class="h3"><a class="selflink" id="section-12.2" href="#section-12.2">12.2</a>. Positive Renewal</span> It is occasionally appropriate to make temporary assignments that can be renewed as necessary. In cases where this happens the registrant needs to positively request an extension to the temporary assignment or the addresses assigned. When the IANA has not received a request to renew the registration of a temporary assignment within 30 days of the expiry of the assignment, it MUST be removed from the multicast registry. Addresses returned to the IANA when a temporary assignment ends MUST NOT be assigned to anyone other than the last registrant for at least one calendar year. <span class="h2"><a class="selflink" id="section-13" href="#section-13">13</a>. Use of IANA Reserved Addresses</span> Applications MUST NOT use addressing in the IANA reserved blocks. <span class="h2"><a class="selflink" id="section-14" href="#section-14">14</a>. IANA Considerations</span> IANA has updated its IPv4 multicast request and assignment procedures to reflect this document. <span class="grey">Cotton, et al. Best Current Practice [Page 8]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-9" ></span> <span class="grey"><a href="/doc/html/rfc5771">RFC 5771</a> IPv4 Multicast Guidelines March 2010</span> <span class="h2"><a class="selflink" id="section-15" href="#section-15">15</a>. Security Considerations</span> The assignment guidelines described in this document do not alter the security properties of either the Any Source or Source-Specific Multicast service models. <span class="h2"><a class="selflink" id="section-16" href="#section-16">16</a>. Acknowledgments</span> The authors would like to thank Joe St. Sauver, John Meylor, Randy Bush, Thomas Narten, Marshall Eubanks, Zaid Albanna (co-author of <a href="/doc/html/rfc3171">RFC</a> <a href="/doc/html/rfc3171">3171</a>), Kevin Almeroth (co-author of <a href="/doc/html/rfc3171">RFC 3171</a>), Pekka Savola, and Alfred Hoenes for their constructive feedback and comments. <span class="h2"><a class="selflink" id="section-17" href="#section-17">17</a>. References</span> <span class="h3"><a class="selflink" id="section-17.1" href="#section-17.1">17.1</a>. Normative References</span> [<a id="ref-RFC2119">RFC2119</a>] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", <a href="/doc/html/bcp14">BCP 14</a>, <a href="/doc/html/rfc2119">RFC 2119</a>, March 1997. [<a id="ref-RFC5226">RFC5226</a>] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", <a href="/doc/html/bcp26">BCP 26</a>, <a href="/doc/html/rfc5226">RFC 5226</a>, May 2008. <span class="h3"><a class="selflink" id="section-17.2" href="#section-17.2">17.2</a>. Informative References</span> [<a id="ref-IANA">IANA</a>] IANA, "IANA Protocol Registries", <<a href="http://www.iana.org/">http://www.iana.org/</a>>. [<a id="ref-IANA-protocols">IANA-protocols</a>] IANA, "IANA Protocol Registries", <<a href="http://www.iana.org/protocols">http://www.iana.org/protocols</a>>. [<a id="ref-IANA-registration">IANA-registration</a>] IANA, "IANA Protocol Registration Forms", <<a href="http://www.iana.org/protocols/apply">http://www.iana.org/protocols/apply</a>>. [<a id="ref-RFC1819">RFC1819</a>] Delgrossi, L., Ed., and L. Berger, Ed., "Internet Stream Protocol Version 2 (ST2) Protocol Specification - Version ST2+", <a href="/doc/html/rfc1819">RFC 1819</a>, August 1995. [<a id="ref-RFC1930">RFC1930</a>] Hawkinson, J. and T. Bates, "Guidelines for creation, selection, and registration of an Autonomous System (AS)", <a href="/doc/html/bcp6">BCP 6</a>, <a href="/doc/html/rfc1930">RFC 1930</a>, March 1996. [<a id="ref-RFC2328">RFC2328</a>] Moy, J., "OSPF Version 2", STD 54, <a href="/doc/html/rfc2328">RFC 2328</a>, April 1998. [<a id="ref-RFC2365">RFC2365</a>] Meyer, D., "Administratively Scoped IP Multicast", <a href="/doc/html/bcp23">BCP 23</a>, <a href="/doc/html/rfc2365">RFC 2365</a>, July 1998. <span class="grey">Cotton, et al. Best Current Practice [Page 9]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-10" ></span> <span class="grey"><a href="/doc/html/rfc5771">RFC 5771</a> IPv4 Multicast Guidelines March 2010</span> [<a id="ref-RFC2606">RFC2606</a>] Eastlake 3rd, D. and A. Panitz, "Reserved Top Level DNS Names", <a href="/doc/html/bcp32">BCP 32</a>, <a href="/doc/html/rfc2606">RFC 2606</a>, June 1999. [<a id="ref-RFC2730">RFC2730</a>] Hanna, S., Patel, B., and M. Shah, "Multicast Address Dynamic Client Allocation Protocol (MADCAP)", <a href="/doc/html/rfc2730">RFC 2730</a>, December 1999. [<a id="ref-RFC2780">RFC2780</a>] Bradner, S. and V. Paxson, "IANA Allocation Guidelines For Values In the Internet Protocol and Related Headers", <a href="/doc/html/bcp37">BCP</a> <a href="/doc/html/bcp37">37</a>, <a href="/doc/html/rfc2780">RFC 2780</a>, March 2000. [<a id="ref-RFC2860">RFC2860</a>] Carpenter, B., Baker, F., and M. Roberts, "Memorandum of Understanding Concerning the Technical Work of the Internet Assigned Numbers Authority", <a href="/doc/html/rfc2860">RFC 2860</a>, June 2000. [<a id="ref-RFC2974">RFC2974</a>] Handley, M., Perkins, C., and E. Whelan, "Session Announcement Protocol", <a href="/doc/html/rfc2974">RFC 2974</a>, October 2000. [<a id="ref-RFC3138">RFC3138</a>] Meyer, D., "Extended Assignments in 233/8", <a href="/doc/html/rfc3138">RFC 3138</a>, June 2001. [<a id="ref-RFC3171">RFC3171</a>] Albanna, Z., Almeroth, K., Meyer, D., and M. Schipper, "IANA Guidelines for IPv4 Multicast Address Assignments", <a href="/doc/html/bcp51">BCP 51</a>, <a href="/doc/html/rfc3171">RFC 3171</a>, August 2001. [<a id="ref-RFC3180">RFC3180</a>] Meyer, D. and P. Lothberg, "GLOP Addressing in 233/8", <a href="/doc/html/bcp53">BCP</a> <a href="/doc/html/bcp53">53</a>, <a href="/doc/html/rfc3180">RFC 3180</a>, September 2001. [<a id="ref-RFC4330">RFC4330</a>] Mills, D., "Simple Network Time Protocol (SNTP) Version 4 for IPv4, IPv6 and OSI", <a href="/doc/html/rfc4330">RFC 4330</a>, January 2006. [<a id="ref-RFC4607">RFC4607</a>] Holbrook, H. and B. Cain, "Source-Specific Multicast for IP", <a href="/doc/html/rfc4607">RFC 4607</a>, August 2006. [<a id="ref-SDR">SDR</a>] University College London / ISI, "Session Directory Tool", <<a href="http://www-mice.cs.ucl.ac.uk/multimedia/software/sdr/">http://www-mice.cs.ucl.ac.uk/multimedia/software/sdr/</a>>. <span class="grey">Cotton, et al. Best Current Practice [Page 10]</span></pre> <hr class='noprint'/><pre class='newpage'><span id="page-11" ></span> <span class="grey"><a href="/doc/html/rfc5771">RFC 5771</a> IPv4 Multicast Guidelines March 2010</span> Authors' Addresses Michelle Cotton Internet Corporation for Assigned Names and Numbers 4676 Admiralty Way, Suite 330 Marina del Rey, CA 90292 United States of America Phone: +310-823-9358 EMail: michelle.cotton@icann.org URI: <a href="http://www.iana.org/">http://www.iana.org/</a> Leo Vegoda Internet Corporation for Assigned Names and Numbers 4676 Admiralty Way, Suite 330 Marina del Rey, CA 90292 United States of America Phone: +310-823-9358 EMail: leo.vegoda@icann.org URI: <a href="http://www.iana.org/">http://www.iana.org/</a> David Meyer EMail: dmm@1-4-5.net Cotton, et al. Best Current Practice [Page 11] </pre></div> </div> </div> <div class="d-print-none col-md-3 bg-light-subtle collapse show" id="sidebar"> <div class="position-fixed border-start sidebar overflow-scroll overscroll-none no-scrollbar"> <div class="d-flex flex-column vh-100 pt-2 pt-lg-3 ps-3 pl-md-2 pl-lg-3"> <div> <a class="btn btn-primary btn-sm" href="/doc/rfc5771/">Datatracker</a> <p class="fw-bold pt-2"> RFC 5771 <br> <span class="text-success">RFC - Best Current Practice </span> </p> </div> <ul class="nav nav-tabs nav-fill small me-2" role="tablist"> <li class="nav-item" role="presentation" title="Document information"> <button class="nav-link px-2" id="docinfo-tab" data-bs-toggle="tab" data-bs-target="#docinfo-tab-pane" type="button" role="tab" aria-controls="docinfo-tab-pane" aria-selected="true"> <i class="bi bi-info-circle"></i><span class="d-none d-md-block d-xl-inline ms-xl-1">Info</span> </button> </li> <li class="nav-item" role="presentation" title="Table of contents"> <button class="nav-link px-2" id="toc-tab" data-bs-toggle="tab" data-bs-target="#toc-tab-pane" type="button" role="tab" aria-controls="toc-tab-pane" aria-selected="false"> <i class="bi bi-list-ol"></i><span class="d-none d-md-block d-xl-inline ms-xl-1">Contents</span> </button> </li> <li class="nav-item" role="presentation" title="Preferences"> <button class="nav-link px-2" id="pref-tab" data-bs-toggle="tab" data-bs-target="#pref-tab-pane" type="button" role="tab" aria-controls="pref-tab-pane" aria-selected="false"> <i class="bi bi-gear"></i><span class="d-none d-md-block d-xl-inline ms-xl-1">Prefs</span> </button> </li> </ul> <div class="overflow-auto tab-content pt-2 me-2"> <div class="tab-pane" id="docinfo-tab-pane" role="tabpanel" aria-labelledby="docinfo-tab" tabindex="0"> <table class="table table-sm table-borderless"> <tbody class="meta align-top "> <tr> <th scope="row">Document</th> <th scope="row">Document type</th> <td class="edit"></td> <td> <span class="text-success">RFC - Best Current Practice </span> <br>March 2010 <br> <a class="btn btn-primary btn-sm my-1" href="https://www.rfc-editor.org/errata_search.php?rfc=5771" title="Click to view errata." rel="nofollow"> View errata </a> <a class="btn btn-sm btn-warning" title="Click to report an error in the document." href="https://www.rfc-editor.org/errata.php#reportnew" target="_blank"> Report errata </a> <div>Obsoletes <a href="/doc/html/rfc3171" title="IANA Guidelines for IPv4 Multicast Address Assignments">RFC 3171</a>, <a href="/doc/html/rfc3138" title="Extended Assignments in 233/8">RFC 3138</a></div> <div>Updates <a href="/doc/html/rfc2780" title="IANA Allocation Guidelines For Values In the Internet Protocol and Related Headers">RFC 2780</a></div> <div> Was <a href="/doc/draft-ietf-mboned-rfc3171bis/08/">draft-ietf-mboned-rfc3171bis</a> (<a href="/wg/mboned/about/">mboned WG</a>) </div> </td> </tr> <tr> <td></td> <th scope="row">Select version</th> <td class="edit"></td> <td> <ul class="revision-list pagination pagination-sm text-center flex-wrap my-0"> <li class="page-item"> <a class="page-link" href="/doc/html/draft-ietf-mboned-rfc3171bis-08" rel="nofollow"> 08 </a> </li> <li class="page-item rfc active"> <a class="page-link" href="/doc/html/rfc5771"> RFC 5771 </a> </li> </ul> </td> </tr> <tr> <td></td> <th scope="row">Compare versions</th> <td class="edit"></td> <td> <form class="form-horizontal diff-form" action="https://author-tools.ietf.org/iddiff" method="get" target="_blank"> <select class="form-select form-select-sm mb-1 select2-field" data-max-entries="1" data-width="resolve" data-allow-clear="false" data-minimum-input-length="0" aria-label="From revision" name="url1"> <option value="rfc5771"> RFC 5771 </option> <option value="draft-ietf-mboned-rfc3171bis-08" selected> draft-ietf-mboned-rfc3171bis-08 </option> <option value="draft-ietf-mboned-rfc3171bis-07"> draft-ietf-mboned-rfc3171bis-07 </option> <option value="draft-ietf-mboned-rfc3171bis-06"> draft-ietf-mboned-rfc3171bis-06 </option> <option value="draft-ietf-mboned-rfc3171bis-05"> draft-ietf-mboned-rfc3171bis-05 </option> <option value="draft-ietf-mboned-rfc3171bis-04"> draft-ietf-mboned-rfc3171bis-04 </option> <option value="draft-ietf-mboned-rfc3171bis-03"> draft-ietf-mboned-rfc3171bis-03 </option> <option value="draft-ietf-mboned-rfc3171bis-02"> draft-ietf-mboned-rfc3171bis-02 </option> <option value="draft-ietf-mboned-rfc3171bis-01"> draft-ietf-mboned-rfc3171bis-01 </option> <option value="draft-ietf-mboned-rfc3171bis-00"> draft-ietf-mboned-rfc3171bis-00 </option> </select> <select class="form-select form-select-sm mb-1 select2-field" data-max-entries="1" data-width="resolve" data-allow-clear="false" data-minimum-input-length="0" aria-label="To revision" name="url2"> <option value="rfc5771" selected> RFC 5771 </option> <option value="draft-ietf-mboned-rfc3171bis-08"> draft-ietf-mboned-rfc3171bis-08 </option> <option value="draft-ietf-mboned-rfc3171bis-07"> draft-ietf-mboned-rfc3171bis-07 </option> <option value="draft-ietf-mboned-rfc3171bis-06"> draft-ietf-mboned-rfc3171bis-06 </option> <option value="draft-ietf-mboned-rfc3171bis-05"> draft-ietf-mboned-rfc3171bis-05 </option> <option value="draft-ietf-mboned-rfc3171bis-04"> draft-ietf-mboned-rfc3171bis-04 </option> <option value="draft-ietf-mboned-rfc3171bis-03"> draft-ietf-mboned-rfc3171bis-03 </option> <option value="draft-ietf-mboned-rfc3171bis-02"> draft-ietf-mboned-rfc3171bis-02 </option> <option value="draft-ietf-mboned-rfc3171bis-01"> draft-ietf-mboned-rfc3171bis-01 </option> <option value="draft-ietf-mboned-rfc3171bis-00"> draft-ietf-mboned-rfc3171bis-00 </option> </select> <button type="submit" class="btn btn-primary btn-sm" value="--html" name="difftype"> Side-by-side </button> <button type="submit" class="btn btn-primary btn-sm" value="--hwdiff" name="difftype"> Inline </button> </form> </td> </tr> <tr> <td></td> <th scope="row">Authors</th> <td class="edit"> </td> <td> <span ><a title="Datatracker profile of David Meyer" href="/person/dmm@1-4-5.net" >David Meyer</a> <a href="mailto:dmm%401-4-5.net" aria-label="Compose email to dmm@1-4-5.net" title="Compose email to dmm@1-4-5.net"> <i class="bi bi-envelope"></i></a></span>, <span ><a title="Datatracker profile of Michelle Cotton" href="/person/mcotton@amsl.com" >Michelle Cotton</a> <a href="mailto:mcotton%40amsl.com" aria-label="Compose email to mcotton@amsl.com" title="Compose email to mcotton@amsl.com"> <i class="bi bi-envelope"></i></a></span>, <span ><a title="Datatracker profile of Leo Vegoda" href="/person/leo.vegoda@icann.org" >Leo Vegoda</a> <a href="mailto:leo.vegoda%40icann.org" aria-label="Compose email to leo.vegoda@icann.org" title="Compose email to leo.vegoda@icann.org"> <i class="bi bi-envelope"></i></a></span> <br> <a class="btn btn-primary btn-sm mt-1" href="mailto:rfc5771@ietf.org?subject=rfc5771" title="Send email to the document authors">Email authors</a> </td> </tr> <tr> <td></td> <th scope="row"> RFC stream </th> <td class="edit"> </td> <td > <img alt="IETF Logo" class="d-lm-none w-25 mt-1" src="https://static.ietf.org/dt/12.28.2/ietf/images/ietf-logo-nor-white.svg" > <img alt="IETF Logo" class="d-dm-none w-25 mt-1" src="https://static.ietf.org/dt/12.28.2/ietf/images/ietf-logo-nor.svg" > </td> </tr> <tr> <td></td> <th scope="row"> Other formats </th> <td class="edit"> </td> <td> <div class="buttonlist"> <a class="btn btn-primary btn-sm" target="_blank" href="https://www.rfc-editor.org/rfc/rfc5771.txt"> <i class="bi bi-file-text"></i> txt </a> <a class="btn btn-primary btn-sm" target="_blank" href="https://www.rfc-editor.org/rfc/rfc5771.html"> <i class="bi bi-file-code"></i> html </a> <a class="btn btn-primary btn-sm" download="rfc5771.pdf" target="_blank" href="https://www.rfc-editor.org/rfc/pdfrfc/rfc5771.txt.pdf"> <i class="bi bi-file-pdf"></i> pdf </a> <a class="btn btn-primary btn-sm" target="_blank" href="/doc/rfc5771/bibtex/"> <i class="bi bi-file-ruled"></i> bibtex </a> </div> </td> </tr> <tr> <td> </td> <th scope="row"> Additional resources </th> <td class="edit"> </td> <td> <a href="https://mailarchive.ietf.org/arch/browse/mboned/?q=rfc5771 OR %22draft-ietf-mboned-rfc3171bis%22"> Mailing list discussion </a> </td> </tr> </tbody> </table> <a class="btn btn-sm btn-warning mb-3" target="_blank" href="https://github.com/ietf-tools/datatracker/issues/new/choose"> Report a datatracker bug <i class="bi bi-bug"></i> </a> </div> <div class="tab-pane mb-5" id="toc-tab-pane" role="tabpanel" aria-labelledby="toc-tab" tabindex="0"> <nav class="nav nav-pills flex-column small" id="toc-nav"> </nav> </div> <div class="tab-pane mb-5 small" id="pref-tab-pane" role="tabpanel" aria-labelledby="pref-tab" tabindex="0"> <label class="form-label fw-bold mb-2">Show sidebar by default</label> <div class="btn-group-vertical btn-group-sm d-flex" role="group"> <input type="radio" class="btn-check" name="sidebar" id="on-radio"> <label class="btn btn-outline-primary" 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RFC 5771 - IANA Guidelines for IPv4 Multicast Address Assignments