Network Working Group M. Cotton Internet-Draft L. Vegoda Obsoletes: 3171, 3138 ICANN (if approved) D. Meyer Intended status: BCP April 15, 2009 Expires: October 17, 2009 IANA Guidelines for IPv4 Multicast Address Assignments draft-ietf-mboned-rfc3171bis-07 Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on October 17, 2009. Copyright Notice Copyright (c) 2009 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Abstract This document provides guidance for the Internet Assigned Numbers Cotton, et al. Expires October 17, 2009 [Page 1] Internet-Draft IPv4 Multicast Guidelines April 2009 Authority (IANA) in assigning IPv4 multicast addresses. It obsoletes RFC 3171 and RFC 3138. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Definition of Current Assignment Practice . . . . . . . . . . 3 4. Local Network Control Block (224.0.0/24) . . . . . . . . . . . 4 4.1. Assignment Guidelines . . . . . . . . . . . . . . . . . . 5 5. Internetwork Control Block (224.0.1/24) . . . . . . . . . . . 5 5.1. Assignment Guidelines . . . . . . . . . . . . . . . . . . 5 6. 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) . . . . . . . . . . . . . . . . . . . . . . . 5 6.1. Assignment Guidelines . . . . . . . . . . . . . . . . . . 5 7. SDP/SAP Block (224.2/16) . . . . . . . . . . . . . . . . . . . 5 7.1. Assignment Guidelines . . . . . . . . . . . . . . . . . . 6 8. Source Specific Multicast Block (232/8) . . . . . . . . . . . 6 8.1. Assignment Guidelines . . . . . . . . . . . . . . . . . . 6 9. GLOP Block (233/8) . . . . . . . . . . . . . . . . . . . . . . 6 9.1. Assignment Guidelines . . . . . . . . . . . . . . . . . . 6 9.2. AD-HOC Block III . . . . . . . . . . . . . . . . . . . . . 7 10. Administratively Scoped Address Block (239/8) . . . . . . . . 7 10.1. Assignment Guidelines . . . . . . . . . . . . . . . . . . 7 11. Application Form . . . . . . . . . . . . . . . . . . . . . . . 7 11.1. Size of assignments of IPv4 Multicast Addresses . . . . . 8 12. Annual Review . . . . . . . . . . . . . . . . . . . . . . . . 8 12.1. Address Reclamation . . . . . . . . . . . . . . . . . . . 8 12.2. Positive renewal . . . . . . . . . . . . . . . . . . . . . 8 13. Use of IANA Reserved Addresses . . . . . . . . . . . . . . . . 9 14. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 15. Security Considerations . . . . . . . . . . . . . . . . . . . 9 16. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9 17. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 17.1. Normative References . . . . . . . . . . . . . . . . . . . 9 17.2. Informative References . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11 Cotton, et al. Expires October 17, 2009 [Page 2] Internet-Draft IPv4 Multicast Guidelines April 2009 1. Introduction The Internet Assigned Numbers Authority (IANA) (www.iana.org) is charged with allocating parameter values for fields in protocols which have been designed, created or are maintained by the Internet Engineering Task Force (IETF). RFC 2780 [RFC2780] provides the IANA guidance in the assignment of parameters for fields in newly developed protocols. This memo expands on section 4.4.2 of RFC 2780 and attempts to codify existing IANA practice used in the assignment IPv4 multicast addresses. This document is a revision of RFC 3171 [RFC3171], which it obsoletes. It also obsoletes RFC 3138 [RFC3138]. 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 [RFC5226]. 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 (SDP/SAP), GLOP, SSM or Administratively Scoped address spaces cannot be used. The guidelines described below are reflected in . Network operators should also be aware of the availability of IPv6 multicast addresses and consider using them where feasible. 2. Terminology 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 BCP 14, RFC 2119 [RFC2119]. 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. 3. Definition of Current Assignment Practice 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 Cotton, et al. Expires October 17, 2009 [Page 3] Internet-Draft IPv4 Multicast Guidelines April 2009 groups appear as follows [IANA]: Address Range Size Designation ------------- ---- ----------- 224.0.0.0 - 224.0.0.255 (/24) Local Network Control Block 224.0.1.0 - 224.0.1.255 (/24) Internetwork Control Block 224.0.2.0 - 224.0.255.255 (65024) AD-HOC Block I 224.1.0.0 - 224.1.255.255 (/16) RESERVED 224.2.0.0 - 224.2.255.255 (/16) SDP/SAP Block 224.3.0.0 - 224.4.255.255 (2 /16s) AD-HOC Block II 224.5.0.0 - 224.255.255.255 (251 /16s) RESERVED 225.0.0.0 - 231.255.255.255 (7 /8s) RESERVED 232.0.0.0 - 232.255.255.255 (/8) Source Specific Multicast Block 233.0.0.0 - 233.251.255.255 (16515072) GLOP Block 233.252.0.0 - 233.255.255.255 (/14) AD-HOC Block III 234.0.0.0 - 238.255.255.255 (5 /8s) RESERVED 239.0.0.0 - 239.255.255.255 (/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. 4. Local Network Control Block (224.0.0/24) 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) [RFC2328]. Cotton, et al. Expires October 17, 2009 [Page 4] Internet-Draft IPv4 Multicast Guidelines April 2009 4.1. Assignment Guidelines Pursuant to section 4.4.2 of [RFC2780], assignments from the Local Network Control block follow an Expert Review, IESG Approval or Standards Action process. See IANA [IANA] for the current set of assignments. 5. Internetwork Control Block (224.0.1/24) 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 (NTP [RFC2030]) and 224.0.1.68 (mdhcpdiscover [RFC2730]). 5.1. Assignment Guidelines Pursuant to section 4.4.2 of [RFC2780], assignments from the Internetwork Control block follow an Expert Review, IESG Approval or Standards Action process. See IANA [IANA] for the current set of assignments. 6. 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) Addresses in the AD-HOC blocks 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 or Internetwork block will be made in the Ad-Hoc Block III. 6.1. Assignment Guidelines In general, the IANA SHOULD NOT assign addressing in the AD-HOC Blocks. However, the IANA MAY under special circumstances, assign addresses from these blocks. Pursuant to section 4.4.2 of [RFC2780], assignments from the AD-HOC blocks follow an Expert Review, IESG Approval or Standards Action process. See [IANA] for the current set of assignments. 7. SDP/SAP Block (224.2/16) Addresses in the SDP/SAP block are used by applications that receive addresses through the Session Announcement Protocol [RFC2974] for use Cotton, et al. Expires October 17, 2009 [Page 5] Internet-Draft IPv4 Multicast Guidelines April 2009 via applications like the session directory tool (such as SDR [SDR]). 7.1. Assignment Guidelines Since addresses in the SDP/SAP block are chosen randomly from the range of addresses not already in use [RFC2974], 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. 8. Source Specific Multicast Block (232/8) The Source Specific Multicast (SSM) 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 VMTP transient groups [IANA]. 8.1. Assignment Guidelines 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 SSM block are explicitly for use by SSM and MUST NOT be used for other purposes. 9. GLOP Block (233/8) Addresses in the GLOP block are globally scoped statically assigned addresses. The assignment is made, for a domain with 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 [RFC3180]. Domains with 32 bit ASN should apply for space in AD-HOC Block III, or consider using IPv6 multicast addresses. 9.1. Assignment Guidelines Because addresses in the GLOP block are algorithmically pre-assigned, no IANA assignment policy is required. Cotton, et al. Expires October 17, 2009 [Page 6] Internet-Draft IPv4 Multicast Guidelines April 2009 9.2. AD-HOC Block III [RFC3138] delegated to the RIRs the assignment of the GLOP sub-block (233.252.0.0 - 233.255.255.255) mapped by the private AS space (64512-65534) and the IANA reserved ASN 65535 [RFC1930]. This space was known as eGLOP. RFC 3138 should not have asked the RIRs to develop policies for the EGLOP space because [RFC2860] 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 RFC 3138 and classify this address range as available for AD-HOC assignment as per the guidelines in section 6. 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 [RFC2606] 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. 10. Administratively Scoped Address Block (239/8) Addresses in the Administratively Scoped Address block are for local use within a domain and are described in [RFC2365]. 10.1. Assignment Guidelines Since addresses in this block are local to a domain, no IANA assignment policy is required. 10.1.1. Relative Offsets The relative offsets [RFC2365] are used to ensure that a service can be located independent of the extent of the enclosing scope (see [RFC3180] 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 [RFC2974]. Pursuant to section 4.4.2 of [RFC2780], assignments of Relative Offsets follow an Expert Review, IESG Approval or Standards Action process. See [IANA] for the current set of assignments. 11. Application Form Requests for multicast address assignments can be submitted through the application form on the IANA web site at: Cotton, et al. Expires October 17, 2009 [Page 7] Internet-Draft IPv4 Multicast Guidelines April 2009 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. 11.1. Size of assignments of IPv4 Multicast Addresses 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). 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. 12. Annual Review 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. 12.1. Address Reclamation 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 [RFC1190] blocks and reclaim those addresses that are not in use on the global Internet (i.e, those applications which can use SSM, GLOP, or Administratively Scoped addressing, or are not globally routed). 12.2. Positive renewal 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 Cotton, et al. Expires October 17, 2009 [Page 8] Internet-Draft IPv4 Multicast Guidelines April 2009 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. 13. Use of IANA Reserved Addresses Applications MUST NOT use addressing in the IANA reserved blocks. 14. IANA Considerations IANA is requested to update its IPv4 multicast request and assignment procedures to reflect this document. 15. Security Considerations The assignment guidelines described in this document do not alter the security properties of either the Any Source or Source Specific multicast service models. 16. Acknowledgments The authors would like to thank Joe St. Sauver, John Meylor, Randy Bush, Thomas Narten, Marshall Eubanks, Zaid Albanna (co-author of RFC3171), Kevin Almeroth (co-author of RFC3171) Pekka Savola and Alfred Hoenes for their constructive feedback and comments. 17. References 17.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 17.2. Informative References [IANA] IANA, "IANA Matrix for Protocol Parameter Assignment/ Registration Procedures", . [RFC1190] Casner, S., Lynn, C., Park, P., Schroder, K., and C. Topolcic, "Experimental Internet Stream Protocol: Version Cotton, et al. Expires October 17, 2009 [Page 9] Internet-Draft IPv4 Multicast Guidelines April 2009 2 (ST-II)", RFC 1190, October 1990. [RFC1930] Hawkinson, J. and T. Bates, "Guidelines for creation, selection, and registration of an Autonomous System (AS)", BCP 6, RFC 1930, March 1996. [RFC2030] Mills, D., "Simple Network Time Protocol (SNTP) Version 4 for IPv4, IPv6 and OSI", RFC 2030, October 1996. [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998. [RFC2365] Meyer, D., "Administratively Scoped IP Multicast", BCP 23, RFC 2365, July 1998. [RFC2606] Eastlake, D. and A. Panitz, "Reserved Top Level DNS Names", BCP 32, RFC 2606, June 1999. [RFC2730] Hanna, S., Patel, B., and M. Shah, "Multicast Address Dynamic Client Allocation Protocol (MADCAP)", RFC 2730, December 1999. [RFC2780] Bradner, S. and V. Paxson, "IANA Allocation Guidelines For Values In the Internet Protocol and Related Headers", BCP 37, RFC 2780, March 2000. [RFC2860] Carpenter, B., Baker, F., and M. Roberts, "Memorandum of Understanding Concerning the Technical Work of the Internet Assigned Numbers Authority", RFC 2860, June 2000. [RFC2974] Handley, M., Perkins, C., and E. Whelan, "Session Announcement Protocol", RFC 2974, October 2000. [RFC3138] Meyer, D., "Extended Assignments in 233/8", RFC 3138, June 2001. [RFC3171] Albanna, Z., Almeroth, K., Meyer, D., and M. Schipper, "IANA Guidelines for IPv4 Multicast Address Assignments", BCP 51, RFC 3171, August 2001. [RFC3180] Meyer, D. and P. Lothberg, "GLOP Addressing in 233/8", BCP 53, RFC 3180, September 2001. [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. Cotton, et al. Expires October 17, 2009 [Page 10] Internet-Draft IPv4 Multicast Guidelines April 2009 Authors' Addresses Michelle Cotton Internet Corporation for Assigned Names and Numbers 4676 Admiralty Way, Suite 330 Marina del Rey 90292 United States Phone: +310-823-9358 Email: michelle.cotton@icann.org URI: http://www.iana.org/ Leo Vegoda Internet Corporation for Assigned Names and Numbers 4676 Admiralty Way, Suite 330 Marina del Rey 90292 United States Phone: +310-823-9358 Email: leo.vegoda@icann.org URI: http://www.iana.org/ David Meyer Email: dmm@1-4-5.net Cotton, et al. Expires October 17, 2009 [Page 11]