MBONED Working Group David Meyer Internet Draft Sprint E|Solutions Peter Lothberg Sprint E|Solutions Category Best Current Practice GLOP Addressing in 233/8 1. Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC 2026. 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. 2. Abstract This
describes adocument defines the policy for the use of the class D address space using233/8 as thefor statically assigned subset ofmulticast addresses. It is envisioned that the class D address space. Thisprimary use of this space is generally towill be utilized for many to many applications, such as non-broadcastmany-to-many applications. This allocation is in addition to those described on [IANA] (e.g.(e.g., [RFC2365]). The IANA has allocated 223/8 as per RFC 2770 [RFC2770]. This document updates RFC 2770. This memo is a product of the Multicast Deployment Working Group (MBONED) in the Operations and Management Area of the Internet Engineering Task Force. Submit comments to <email@example.com> or the author. 3. Copyright Notice Copyright (C) The Internet Society (2001). All Rights Reserved. 4. Problem Statement Multicast addresses have traditionally been allocated by a dynamic mechanism such as SDR [SAP].[RFC2974]. However, many current multicast deployment models are not amenable to dynamic allocation. For example, many content aggregators require group addresses whichthat are fixed on a time scale whichthat is not amenable to allocation by a mechanism such as described in [SAP].[RFC2974]. Perhaps more seriously, since there isn'tis not general consensus by providers, content aggregators, or application writers as to the allocation mechanism, the Internet is left without a coherent multicast address allocation scheme. The MALLOC working group has created a specific strategy for global multicast address allocation [RFC2730, RFC2909]. However, this approach has not been widely implemented or deployed. This document proposes a solution for a subset of the problem, namely, those cases not covered by Source Specific Multicast [SS]. 5. Address Space The IANA has allocated 223/8 as per RFC 2770 [RFC277].[RFC2770]. RFC 2770 describes the administration of the middle two octetesoctets of 233/8 in a manner similar to that described in RFC1797: 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 233 | 16 bits AS | local bits | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 5.1. Example Consider, for example, AS 5662. Written in binary, left padded with 0s, we get 0001011000011110. Mapping the high order octet to the second octet of the address, and the low order octet to the third octet, we get 233.22.30/24. 6. Allocation As mentioned above, the allocation proposed here follows the RFC1797 (case 1) allocation scheme, modified as follows: the high orderhigh-order octet has the value 233, and the next 16 bits are a previously assigned Autonomous System number (AS), as registered by a network registry and listed in the RWhois database system. This allows a single /24 per AS. As was the case with RFC1797, using the AS number in this way allows automatic assignment of a single /24 to each service provider and does not require aan additional registration step. 6.1. Private AS Space The address spacepart of 233/8 that is mapped to the private AS space [RFC1930] is assigned to the IRRs to assign as per their local policy[RFC3138]. 7. Large AS Numbers It is important to note that this approach will work only for two octet AS numbers. In particular, it does not work for any AS number extension scheme. 8. Security Considerations The approach described here may have the effect of reduced exposure to denial of spacedenial-of-service attacks based on dynamic allocation. Further, since dynamic assignment does not cross domain boundaries, well knownwell-known intra-domain security techniques can be applied. 8.9. IANA Considerations The IANA should assign 233/8 for this purpose. 9.10. Acknowledgments This ideaproposal originated with Peter Lothberg's idea that we use the same allocation (AS based) as described in RFC 1797 in the class D address space.1797. Randy Bush and Mark Handley contributed many insightful comments. 10.comments, and Pete and Natalie Whiting contributed greatly to the readability of this document. 11. References [IANA] http://www.iana.org/numbers.html [RFC1797] IANA, "Class A Subnet Experiment", RFC 1797, April, 1995. [RFC1930] J. Hawkinson, et. al., "Guidelines for creation, selection, and registration of an Autonomous System (AS)", RFC1930,RFC 1930, March, 1996. [RFC2365] David Meyer, "Administratively Scoped IP Multicast", RFC 2365, July, 1998. [RFC2374] R. Hinden, et. al., "An IPv6 Aggregatable Global Unicast Address Format", RFC 2374, July, 1998. [RFC2730] B. Patel, et. al., "Multicast Address Dynamic Client Allocation Protocol (MADCAP)", RFC2730,RFC 2730, December, 1999. [RFC2770] D. Meyer and P. Lothberg, "GLOP Addressing in 233/8", RFC 2770, Feburary, 2000. [RFC2909] D. Estrin, et. al., "The Multicast Address-Set Claim (MASC) Protocol", RFC2909,RFC 2909, September 2000. [RFC2974] M. Handley, et. al., "Session Announcement Protocol", RFC 2974, October 2000. [RFC3138] D. Meyer "Extended Assignmentns in 233/8", RFC 3138, June 2001. [SAP] Handley, Mark, "SAP: Session Announcement Protocol", draft-ietf-mmusic-sap-00.txt, November, 1996.[SS] www.isi.edu/in-notes/iana/assignments/single-source- multicast 11.www.iana.org/assignments/single-source-multicast 12. Author's Address David Meyer Sprint VARESA0104 12502 Sunrise Valley Drive Reston VA, 20196 Email: firstname.lastname@example.org Peter Lothberg Sprint VARESA0104 12502 Sunrise Valley Drive Reston VA, 20196 Email: email@example.com 12.13. Full Copyright Statement Copyright (C) The Internet Society (2001). All Rights Reserved. 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