--- 1/draft-ietf-mboned-iana-ipv4-mcast-guidelines-01.txt 2006-02-05 00:19:45.000000000 +0100 +++ 2/draft-ietf-mboned-iana-ipv4-mcast-guidelines-02.txt 2006-02-05 00:19:45.000000000 +0100 @@ -2,22 +2,22 @@ INTERNET DRAFT Juniper Networks Kevin Almeroth UCSB David Meyer Cisco Systems Michelle Schipper IANA Category Best Current Practices April, 2001 - IANA Guidelines for IPv4 Multicast Address Allocation - + IANA Guidelines for IPv4 Multicast Address Assignments + 1. Status of this Memo This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. Distribution of this memo is unlimited. This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC 2026. @@ -57,167 +57,161 @@ 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 RFC 2119 [RFC2119]. In general, due to the relatively small size of the IPv4 multicast - addresses space, further allocation of IPv4 multicast address space - is not recommended. 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 http://www.iana.org. + addresses 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 http://www.iana.org/assignments/multicast-addresses. 5. Definition of Current Assignment Practice Unlike IPv4 unicast address assignment, where blocks of addresses are delegated to regional registries, IPv4 multicast addresses are - assigned directly by the IANA. Current allocations appear as follows + assigned directly by the IANA. Current assignments appear as follows [IANA]: 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 AD-HOC Block 224.1.0.0 - 224.1.255.255 (224.1/16) ST Multicast Groups 224.2.0.0 - 224.2.255.255 (224.2/16) SDP/SAP Block 224.252.0.0 - 224.255.255.255 DIS Transient Block 225.0.0.0 - 225.255.255.255 (225/8) MALLOC Block 226.0.0.0 - 231.255.255.255 RESERVED 232.0.0.0 - 232.255.255.255 (232/8) Source Specific Multicast Block 233.0.0.0 - 233.255.255.255 (233/8) GLOP Block 234.0.0.0 - 238.255.255.255 RESERVED 239.0.0.0 - 239.255.255.255 (239/8) Administratively Scoped Block - The IANA generally allocates addresses from the Local Network - Control, Internetwork Control, and AD-HOC blocks. Allocation - guidelines for each of these blocks, as well as for the MALLOC, - Source Specific Multicast, GLOP and Administratively Scoped Blocks, - are described below. - - Note that while some applications may informally use arbitrary parts - of the IPv4 multicast address space (e.g., 229/8), an application - MUST NOT use address space that is not allocated as described in this - memo. + 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 MALLOC, Source Specific + Multicast, GLOP and Administratively Scoped Blocks, are described + below. 6. 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]. -6.1. Allocation Guidelines +6.1. Assignment Guidelines - Allocation of addresses in the Local Network Configuration Block + Assignment of addresses in the Local Network Configuration Block SHOULD BE be accompanied by a specification ("Specification Required"). This specification will typically take the form of an internet draft or RFC. -Internet Draf-draft-ietf-mboned-iana-IPv4-mcast-guidelines-01.txt April, 2001 - 7. Internetwork Control Block (224.0.1/24) Addresses in the Internetwork Control block are used for protocol control that must be forwarded through the Internet. Examples include 224.0.1.1 (NTP [RFC2030]) and 224.0.1.68 (mdhcpdisover [RFC2730]). -7.1. Allocation Guidelines +7.1. Assignment Guidelines - Allocation of addresses in the Internetwork Control block SHOULD BE + Assignment of addresses in the Internetwork Control block SHOULD BE accompanied by a specification ("Specification Required"). This specification will typically take the form of an internet draft or RFC. 8. AD-HOC Block (224.0.2.0/24 - 224.0.255.0/24) - Addresses in the AD-HOC block have traditionally been allocated for + Addresses in the AD-HOC block 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). -8.1. Allocation Guidelines +8.1. Assignment Guidelines - Allocation of addresses in the AD-HOC Block SHOULD BE accompanied by - a specification ("Specification Required").This specification will - typically take the form of an internet draft or RFC. In general, the - IANA SHOULD NOT assign addressing in the AD-HOC Block. + IANA SHOULD NOT assign addressing in the AD-HOC Block unless it is a + special circumstance accompanied by a specification ("Specification + Required"). This specification will typically take the form of an + Internet-Draft or RFC. 9. 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]). -9.1. Allocation Guidelines +9.1. Assignment Guidelines Since addresses in the SDP/SAP block are chosen randomly from the - range of addresses not already in use [RFC2974], no IANA allocation - policy is required. Note that while no additional IANA allocation is + 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. 10. MALLOC Block (225/8) - Addresses in the MALLOC block are dynamically allocated by the MALLOC + Addresses in the MALLOC block are dynamically assigned by the MALLOC suite of protocols [RFC2908]. This assignment is temporary and MUST BE reviewed annually. -10.1. Allocation Guidelines +10.1. Assignment Guidelines Since addresses in the MALLOC block are chosen by elements of the - MALLOC architecture, no IANA allocation policy is required. Note that - while no additional IANA allocation is required, addresses in the - MALLOC block are explicitly for allocation by MALLOC servers and MUST + MALLOC architecture, no IANA assignment policy is required. Note that + while no additional IANA assignment is required, addresses in the + MALLOC block are explicitly for assignment by MALLOC servers and MUST NOT be used for other purposes. 11. 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. -11.1. Allocation Guidelines +11.1. Assignment Guidelines Because the SSM model essentially makes the entire multicast address - space local to the host, no IANA allocation policy is required. Note, - however, that while no additional IANA allocation is required, + 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. 12. GLOP Block (233/8) Addresses in the GLOP block are globally scoped statically assigned addresses. The assignment is made by mapping a domain's autonomous system number into the middle two octets of 233.X.Y.0/24. The mapping - and allocation is defined in [RFC2770]. + and assignment is defined in [RFC2770]. -12.1. Allocation Guidelines +12.1. Assignment Guidelines Because addresses in the GLOP block are algorithmically preassigned, - no IANA allocation policy is required. Note that while no additional - IANA allocation is required, addresses in the GLOP block are - allocated for use as defined in RFC 2770 and MUST NOT be used for - other purposes. + no IANA assignment policy is required. Note that while no additional + IANA assignment is required, addresses in the GLOP block are assigned + for use as defined in RFC 2770 and MUST NOT be used for other + purposes. 13. 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]. -13.1. Allocation Guidelines +13.1. Assignment Guidelines Since addresses in this block are local to a domain, no IANA - allocation policy is required. + assignment policy is required. 13.1.1. 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 RFC 2770 for details). Since there are only 256 such offsets, the IANA should only assign a relative offset to a protocol that provides an infra-structure supporting service. Examples of such services include the Session Announcement Protocol [RFC2974]. See [IANA] for the current set of assignments. @@ -225,45 +219,40 @@ 14. 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. 14.1. Address Reclamation During the review described above, addresses that were mis-assigned - should, where possible, be reclaimed or reassigned. An example of an - address block that might be reclaimed is 224.1.0/24 [RFC1190], as - this was an experimental allocation and is not in use. In addition, - those allocations in 224.0.1/24 that are not used for Internet-wide - protocol control messages (as described above) above might be - reclaimed. + 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). 15. Use of IANA Reserved Addresses Applications MUST NOT use addressing in the IANA reserved blocks. 16. Appeals Process Appleals of this process are to be handled in accordance with Section 6.5 of RFC 2026 [RFC2026]. 17. Security Considerations - The allocation guidelines described in this document do not alter the + The assignment guidelines described in this document do not alter the security properties of either the Any Source or Source Specific multicast service models. 18. Acknowledgments The authors would like to thank Joe St. Sauver, John Meylor, and Randy Bush for their constructive feedback and comments. 19. Author's Address: @@ -282,21 +271,21 @@ 170 Tasman Drive San Jose, CA, 95134 Email: dmm@cisco.com Michelle Schipper IANA Administrator iana@iana.org 20. References - [IANA] http://www.iana.org + [IANA] http://www.iana.org/assignments/multicast-addresses [RFC1190] C. Topolcic, "Experimental Internet Stream Protocol, Version 2 (ST-II)", RFC 1190, October, 1990. [RFC2026] S. Bradner, "The Internet Standards Process -- Revision 3", RFC2026, October 1996. [RFC2030] Mills, D., Simple Network Time Protocol (SNTP) Version 4 for IPv4, IPv6 and OSI", D. Mills, October 1996.