Network Working Group M. Cotton Internet-Draft ICANN Intended status: Best Current D. Meyer Practice February 5, 2008 Expires: August 8, 2008 IANA Guidelines for IPv4 Multicast Address Assignments draft-cotton-v4mcast-guidelines-00 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of 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 August 8, 2008. Copyright Notice Copyright (C) The IETF Trust (2008). Abstract This memo provides guidance for the Internet Assigned Numbers Authority (IANA) in assigning IPv4 multicast addresses. Cotton & Meyer Expires August 8, 2008 [Page 1] Internet-Draft IPv4 Multicast Guidelines February 2008 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 . . . . . . . . . . . . . . . . . . 4 5. Internetwork Control Block (224.0.1/24) . . . . . . . . . . . 4 5.1. Assignment Guidelines . . . . . . . . . . . . . . . . . . 5 6. AD-HOC Blocks (including 224.0.2.0/24 - 224.0.255.0/24) . . . 5 6.1. Assignment Guidelines . . . . . . . . . . . . . . . . . . 5 7. SDP/SAP Block (224.2/16) . . . . . . . . . . . . . . . . . . . 5 7.1. Assignment Guidelines . . . . . . . . . . . . . . . . . . 5 8. Source Specific Multicast Block (232/8) . . . . . . . . . . . 5 8.1. Assignment Guidelines . . . . . . . . . . . . . . . . . . 6 9. GLOP Block (233/8) . . . . . . . . . . . . . . . . . . . . . . 6 9.1. Assignment Guidelines . . . . . . . . . . . . . . . . . . 6 9.2. Extended AD-HOC . . . . . . . . . . . . . . . . . . . . . 6 10. Administratively Scoped Address Block (239/8) . . . . . . . . 6 10.1. Assignment Guidelines . . . . . . . . . . . . . . . . . . 7 11. Application Form . . . . . . . . . . . . . . . . . . . . . . . 7 11.1. Size of assignments of IPv4 Multicast Addresses . . . . . 7 12. Annual Review . . . . . . . . . . . . . . . . . . . . . . . . 7 12.1. Address Reclamation . . . . . . . . . . . . . . . . . . . 8 12.2. Positive renewal . . . . . . . . . . . . . . . . . . . . . 8 13. Use of IANA Reserved Addresses . . . . . . . . . . . . . . . . 8 14. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 15. Security Considerations . . . . . . . . . . . . . . . . . . . 8 16. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 8 17. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 17.1. Normative References . . . . . . . . . . . . . . . . . . . 9 17.2. Informative References . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10 Intellectual Property and Copyright Statements . . . . . . . . . . 11 Cotton & Meyer Expires August 8, 2008 [Page 2] Internet-Draft IPv4 Multicast Guidelines February 2008 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. The terms "Specification Required", "Expert Review", "IESG Approval", "IETF Consensus", and "Standards Action", are used in this memo to refer to the processes described in [RFC2434]. The keywords MUST, MUST NOT, MAY, OPTIONAL, REQUIRED, RECOMMENDED, SHALL, SHALL NOT, SHOULD, SHOULD NOT are to be interpreted as defined in [RFC2119]. 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 . 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]. 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 groups appear as follows [IANA]: Cotton & Meyer Expires August 8, 2008 [Page 3] Internet-Draft IPv4 Multicast Guidelines February 2008 224.0.0.0 - 224.0.0.255 224.0.0/24 Local Network Control Block 224.0.1.0 - 224.0.1.255 224.0.1/24 Internetwork Control Block 224.0.2.0 - 224.0.255.0 64769 AD-HOC Block 224.1.0.0 - 224.1.255.255 224.1/16 RESERVED 224.2.0.0 - 224.2.255.255 224.2/16 SDP/SAP Block 224.252.0.0 - 224.255.255.255 224.252/14 RESERVED 225.0.0.0 - 231.255.255.255 7 /8s RESERVED 232.0.0.0 - 232.255.255.255 232/8 Source Specific Multicast Block 233.0.0.0 - 233.255.255.255 16515072 GLOP Block 233.252.0.0 - 233.255.255.255 233.252/14 AD-HOC Block 234.0.0.0 - 238.255.255.255 5 /8s RESERVED 239.0.0.0 - 239.255.255.255 239/8 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]. 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 Cotton & Meyer Expires August 8, 2008 [Page 4] Internet-Draft IPv4 Multicast Guidelines February 2008 control that must 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 224.0.2.0/24 - 224.0.255.0/24) Addresses in the AD-HOC blocks have traditionally been assigned for those applications that don't fit in either the Local or Internetwork Control blocks. These addresses are globally routed and are typically used by applications that require small blocks of addressing (e.g., less than a /24 ). 6.1. Assignment Guidelines In general, the IANA SHOULD NOT assign addressing in the AD-HOC Block. However, the IANA MAY under special circumstances, assign addresses from this block. Pursuant to section 4.4.2 of [RFC2780], assignments from the AD-HOC block follow an Expert Review, IESG Approval or Standards Action process. See IANA [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 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 Cotton & Meyer Expires August 8, 2008 [Page 5] Internet-Draft IPv4 Multicast Guidelines February 2008 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 as initially assigned to the VMTP transient groups IANA [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 the number, expressed in octets as X.Y, system number into the middle two octets of 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 the Extended AD-HOC block. 9.1. Assignment Guidelines Because addresses in the GLOP block are algorithmically pre-assigned, no IANA assignment policy is required. 9.2. Extended AD-HOC [RFC3138] delegated assignment of the GLOP sub-block mapped by the [RFC1930] private AS space (233.252.0.0 - 233.255.255.255) to the RIRs. This space was known as eGLOP. The RIRs did not develop policies or the mechanisms for the assignment of the eGLOP space and it is important to make this space available for use by network operators. 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 5. 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]. Cotton & Meyer Expires August 8, 2008 [Page 6] Internet-Draft IPv4 Multicast Guidelines February 2008 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 [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: 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. Where are very large number of addresses is required, the assignment will be staged, with additional stages only being made after the complete use of the initial assignment(s). 12. Annual Review Given the dynamic nature of IPv4 multicast and its associated infra- structure, and the previously undocumented IPv4 multicast address assignment guidelines, the IANA should conduct an annual review of currently assigned addresses. Cotton & Meyer Expires August 8, 2008 [Page 7] Internet-Draft IPv4 Multicast Guidelines February 2008 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 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 are can be renewed if appropriate. 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 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 This document is all about IANA Considerations. 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) and Leo Vegoda for their constructive feedback and comments. Cotton & Meyer Expires August 8, 2008 [Page 8] Internet-Draft IPv4 Multicast Guidelines February 2008 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 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. [RFC2026] Bradner, S., "The Internet Standards Process -- Revision 3", BCP 9, RFC 2026, October 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. [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. [RFC2730] Hanna, S., Patel, B., and M. Shah, "Multicast Address Dynamic Client Allocation Protocol (MADCAP)", RFC 2730, December 1999. [RFC2770] Meyer, D. and P. Lothberg, "GLOP Addressing in 233/8", RFC 2770, February 2000. [RFC2780] Bradner, S. and V. Paxson, "IANA Allocation Guidelines For Values In the Internet Protocol and Related Headers", BCP 37, RFC 2780, March 2000. [RFC2908] Thaler, D., Handley, M., and D. Estrin, "The Internet Cotton & Meyer Expires August 8, 2008 [Page 9] Internet-Draft IPv4 Multicast Guidelines February 2008 Multicast Address Allocation Architecture", RFC 2908, September 2000. [RFC2909] Radoslavov, P., Estrin, D., Govindan, R., Handley, M., Kumar, S., and D. Thaler, "The Multicast Address-Set Claim (MASC) Protocol", RFC 2909, September 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. [RFC3180] Meyer, D. and P. Lothberg, "GLOP Addressing in 233/8", BCP 53, RFC 3180, September 2001. 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/ David Meyer Email: dmm@1-4-5.net Cotton & Meyer Expires August 8, 2008 [Page 10] Internet-Draft IPv4 Multicast Guidelines February 2008 Full Copyright Statement Copyright (C) The IETF Trust (2008). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. 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Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Cotton & Meyer Expires August 8, 2008 [Page 11]