draft-ietf-mboned-iana-ipv4-mcast-guidelines-01.txt   draft-ietf-mboned-iana-ipv4-mcast-guidelines-02.txt 
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INTERNET DRAFT Juniper Networks INTERNET DRAFT Juniper Networks
Kevin Almeroth Kevin Almeroth
UCSB UCSB
David Meyer David Meyer
Cisco Systems Cisco Systems
Michelle Schipper Michelle Schipper
IANA IANA
Category Best Current Practices Category Best Current Practices
April, 2001 April, 2001
IANA Guidelines for IPv4 Multicast Address Allocation IANA Guidelines for IPv4 Multicast Address Assignments
<draft-ietf-mboned-iana-ipv4-mcast-guidelines-01.txt> <draft-ietf-mboned-iana-ipv4-mcast-guidelines-02.txt>
1. Status of this Memo 1. Status of this Memo
This document specifies an Internet Best Current Practices for the This document specifies an Internet Best Current Practices for the
Internet Community, and requests discussion and suggestions for Internet Community, and requests discussion and suggestions for
improvements. Distribution of this memo is unlimited. improvements. Distribution of this memo is unlimited.
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC 2026. all provisions of Section 10 of RFC 2026.
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IPv4 multicast addresses. IPv4 multicast addresses.
The terms "Specification Required", "Expert Review", "IESG Approval", The terms "Specification Required", "Expert Review", "IESG Approval",
"IETF Consensus", and "Standards Action", are used in this memo to "IETF Consensus", and "Standards Action", are used in this memo to
refer to the processes described in [RFC2434]. The keywords MUST, refer to the processes described in [RFC2434]. The keywords MUST,
MUST NOT, MAY, OPTIONAL, REQUIRED, RECOMMENDED, SHALL, SHALL NOT, MUST NOT, MAY, OPTIONAL, REQUIRED, RECOMMENDED, SHALL, SHALL NOT,
SHOULD, SHOULD NOT are to be interpreted as defined in RFC 2119 SHOULD, SHOULD NOT are to be interpreted as defined in RFC 2119
[RFC2119]. [RFC2119].
In general, due to the relatively small size of the IPv4 multicast In general, due to the relatively small size of the IPv4 multicast
addresses space, further allocation of IPv4 multicast address space addresses space, further assignment of IPv4 multicast address space
is not recommended. Specifically, the IANA should only assign is recommended only in limited circumstances. Specifically, the IANA
addresses in those cases where the dynamic selection (SDP/SAP), GLOP, should only assign addresses in those cases where the dynamic
SSM or Administratively Scoped address spaces cannot be used. The selection (SDP/SAP), GLOP, SSM or Administratively Scoped address
guidelines described below are reflected in http://www.iana.org. spaces cannot be used. The guidelines described below are reflected
in http://www.iana.org/assignments/multicast-addresses.
5. Definition of Current Assignment Practice 5. Definition of Current Assignment Practice
Unlike IPv4 unicast address assignment, where blocks of addresses are Unlike IPv4 unicast address assignment, where blocks of addresses are
delegated to regional registries, IPv4 multicast 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]: [IANA]:
224.0.0.0 - 224.0.0.255 (224.0.0/24) Local Network Control Block 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 224.0.1.0 - 224.0.1.255 (224.0.1/24) Internetwork Control Block
224.0.2.0 - 224.0.255.0 AD-HOC Block 224.0.2.0 - 224.0.255.0 AD-HOC Block
224.1.0.0 - 224.1.255.255 (224.1/16) ST Multicast Groups 224.1.0.0 - 224.1.255.255 (224.1/16) ST Multicast Groups
224.2.0.0 - 224.2.255.255 (224.2/16) SDP/SAP Block 224.2.0.0 - 224.2.255.255 (224.2/16) SDP/SAP Block
224.252.0.0 - 224.255.255.255 DIS Transient Block 224.252.0.0 - 224.255.255.255 DIS Transient Block
225.0.0.0 - 225.255.255.255 (225/8) MALLOC Block 225.0.0.0 - 225.255.255.255 (225/8) MALLOC Block
226.0.0.0 - 231.255.255.255 RESERVED 226.0.0.0 - 231.255.255.255 RESERVED
232.0.0.0 - 232.255.255.255 (232/8) Source Specific Multicast Block 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 233.0.0.0 - 233.255.255.255 (233/8) GLOP Block
234.0.0.0 - 238.255.255.255 RESERVED 234.0.0.0 - 238.255.255.255 RESERVED
239.0.0.0 - 239.255.255.255 (239/8) Administratively Scoped Block 239.0.0.0 - 239.255.255.255 (239/8) Administratively Scoped Block
The IANA generally allocates addresses from the Local Network The IANA generally assigns addresses from the Local Network Control,
Control, Internetwork Control, and AD-HOC blocks. Allocation Internetwork Control, and AD-HOC blocks. Assignment guidelines for
guidelines for each of these blocks, as well as for the MALLOC, each of these blocks, as well as for the MALLOC, Source Specific
Source Specific Multicast, GLOP and Administratively Scoped Blocks, Multicast, GLOP and Administratively Scoped Blocks, are described
are described below. 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.
6. Local Network Control Block (224.0.0/24) 6. Local Network Control Block (224.0.0/24)
Addresses in the Local Network Control block are used for protocol Addresses in the Local Network Control block are used for protocol
control traffic that is not forwarded off link. Examples of this type control traffic that is not forwarded off link. Examples of this type
of use include OSPFIGP All Routers (224.0.0.5) [RFC2328]. 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 SHOULD BE be accompanied by a specification ("Specification
Required"). This specification will typically take the form of an Required"). This specification will typically take the form of an
internet draft or RFC. 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) 7. Internetwork Control Block (224.0.1/24)
Addresses in the Internetwork Control block are used for protocol Addresses in the Internetwork Control block are used for protocol
control that must be forwarded through the Internet. Examples include control that must be forwarded through the Internet. Examples include
224.0.1.1 (NTP [RFC2030]) and 224.0.1.68 (mdhcpdisover [RFC2730]). 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 accompanied by a specification ("Specification Required"). This
specification will typically take the form of an internet draft or specification will typically take the form of an internet draft or
RFC. RFC.
8. AD-HOC Block (224.0.2.0/24 - 224.0.255.0/24) 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 those applications that don't fit in either the Local or Internetwork
Control blocks. These addresses are globally routed and are typically Control blocks. These addresses are globally routed and are typically
used by applications that require small blocks of addressing (e.g., used by applications that require small blocks of addressing (e.g.,
less than a /24). less than a /24).
8.1. Allocation Guidelines 8.1. Assignment Guidelines
Allocation of addresses in the AD-HOC Block SHOULD BE accompanied by IANA SHOULD NOT assign addressing in the AD-HOC Block unless it is a
a specification ("Specification Required").This specification will special circumstance accompanied by a specification ("Specification
typically take the form of an internet draft or RFC. In general, the Required"). This specification will typically take the form of an
IANA SHOULD NOT assign addressing in the AD-HOC Block. Internet-Draft or RFC.
9. SDP/SAP Block (224.2/16) 9. SDP/SAP Block (224.2/16)
Addresses in the SDP/SAP block are used by applications that receive Addresses in the SDP/SAP block are used by applications that receive
addresses through the Session Announcement Protocol [RFC2974] for use addresses through the Session Announcement Protocol [RFC2974] for use
via applications like the session directory tool (such as SDR [SDR]). 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 Since addresses in the SDP/SAP block are chosen randomly from the
range of addresses not already in use [RFC2974], no IANA allocation range of addresses not already in use [RFC2974], no IANA assignment
policy is required. Note that while no additional IANA allocation is policy is required. Note that while no additional IANA assignment is
required, addresses in the SDP/SAP block are explicitly for use by required, addresses in the SDP/SAP block are explicitly for use by
SDP/SAP and MUST NOT be used for other purposes. SDP/SAP and MUST NOT be used for other purposes.
10. MALLOC Block (225/8) 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 suite of protocols [RFC2908]. This assignment is temporary and MUST
BE reviewed annually. BE reviewed annually.
10.1. Allocation Guidelines 10.1. Assignment Guidelines
Since addresses in the MALLOC block are chosen by elements of the Since addresses in the MALLOC block are chosen by elements of the
MALLOC architecture, no IANA allocation policy is required. Note that MALLOC architecture, no IANA assignment policy is required. Note that
while no additional IANA allocation is required, addresses in the while no additional IANA assignment is required, addresses in the
MALLOC block are explicitly for allocation by MALLOC servers and MUST MALLOC block are explicitly for assignment by MALLOC servers and MUST
NOT be used for other purposes. NOT be used for other purposes.
11. Source Specific Multicast Block (232/8) 11. Source Specific Multicast Block (232/8)
The Source Specific Multicast (SSM) is an extension of IP Multicast The Source Specific Multicast (SSM) is an extension of IP Multicast
in which traffic is forwarded to receivers from only those multicast in which traffic is forwarded to receivers from only those multicast
sources for which the receivers have explicitly expressed interest, sources for which the receivers have explicitly expressed interest,
and is primarily targeted at one-to-many (broadcast) applications. 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 Because the SSM model essentially makes the entire multicast address
space local to the host, no IANA allocation policy is required. Note, space local to the host, no IANA assignment policy is required. Note,
however, that while no additional IANA allocation is required, however, that while no additional IANA assignment is required,
addresses in the SSM block are explicitly for use by SSM and MUST NOT addresses in the SSM block are explicitly for use by SSM and MUST NOT
be used for other purposes. be used for other purposes.
12. GLOP Block (233/8) 12. GLOP Block (233/8)
Addresses in the GLOP block are globally scoped statically assigned Addresses in the GLOP block are globally scoped statically assigned
addresses. The assignment is made by mapping a domain's autonomous 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 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, Because addresses in the GLOP block are algorithmically preassigned,
no IANA allocation policy is required. Note that while no additional no IANA assignment policy is required. Note that while no additional
IANA allocation is required, addresses in the GLOP block are IANA assignment is required, addresses in the GLOP block are assigned
allocated for use as defined in RFC 2770 and MUST NOT be used for for use as defined in RFC 2770 and MUST NOT be used for other
other purposes. purposes.
13. Administratively Scoped Address Block (239/8) 13. Administratively Scoped Address Block (239/8)
Addresses in the Administratively Scoped Address block are for local Addresses in the Administratively Scoped Address block are for local
use within a domain and are described in [RFC2365]. 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 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 13.1.1. Relative Offsets
The relative offsets [RFC2365] are used to ensure that a service can The relative offsets [RFC2365] are used to ensure that a service can
be located independent of the extent of the enclosing scope (see RFC be located independent of the extent of the enclosing scope (see RFC
2770 for details). Since there are only 256 such offsets, the IANA 2770 for details). Since there are only 256 such offsets, the IANA
should only assign a relative offset to a protocol that provides an should only assign a relative offset to a protocol that provides an
infra-structure supporting service. Examples of such services include infra-structure supporting service. Examples of such services include
the Session Announcement Protocol [RFC2974]. See [IANA] for the the Session Announcement Protocol [RFC2974]. See [IANA] for the
current set of assignments. current set of assignments.
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14. Annual Review 14. Annual Review
Given the dynamic nature of IPv4 multicast and its associated infra- Given the dynamic nature of IPv4 multicast and its associated infra-
structure, and the previously undocumented IPv4 multicast address structure, and the previously undocumented IPv4 multicast address
assignment guidelines, the IANA should conduct an annual review of assignment guidelines, the IANA should conduct an annual review of
currently assigned addresses. currently assigned addresses.
14.1. Address Reclamation 14.1. Address Reclamation
During the review described above, addresses that were mis-assigned During the review described above, addresses that were mis-assigned
should, where possible, be reclaimed or reassigned. An example of an should, where possible, be reclaimed or reassigned.
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.
The IANA should also review assignments in the AD-HOC, DIS Transient The IANA should also review assignments in the AD-HOC, DIS Transient
Groups, and ST Multicast Groups blocks and reclaim those addresses Groups, and ST Multicast Groups blocks and reclaim those addresses
that are not in use on the global Internet (i.e, those applications that are not in use on the global Internet (i.e, those applications
which can use SSM, GLOP, or Administratively Scoped addressing, or which can use SSM, GLOP, or Administratively Scoped addressing, or
are not globally routed). are not globally routed).
15. Use of IANA Reserved Addresses 15. Use of IANA Reserved Addresses
Applications MUST NOT use addressing in the IANA reserved blocks. Applications MUST NOT use addressing in the IANA reserved blocks.
16. Appeals Process 16. Appeals Process
Appleals of this process are to be handled in accordance with Section Appleals of this process are to be handled in accordance with Section
6.5 of RFC 2026 [RFC2026]. 6.5 of RFC 2026 [RFC2026].
17. Security Considerations 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 security properties of either the Any Source or Source Specific
multicast service models. multicast service models.
18. Acknowledgments 18. Acknowledgments
The authors would like to thank Joe St. Sauver, John Meylor, and The authors would like to thank Joe St. Sauver, John Meylor, and
Randy Bush for their constructive feedback and comments. Randy Bush for their constructive feedback and comments.
19. Author's Address: 19. Author's Address:
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170 Tasman Drive 170 Tasman Drive
San Jose, CA, 95134 San Jose, CA, 95134
Email: dmm@cisco.com Email: dmm@cisco.com
Michelle Schipper Michelle Schipper
IANA Administrator IANA Administrator
iana@iana.org iana@iana.org
20. References 20. References
[IANA] http://www.iana.org [IANA] http://www.iana.org/assignments/multicast-addresses
[RFC1190] C. Topolcic, "Experimental Internet Stream [RFC1190] C. Topolcic, "Experimental Internet Stream
Protocol, Version 2 (ST-II)", RFC 1190, October, Protocol, Version 2 (ST-II)", RFC 1190, October,
1990. 1990.
[RFC2026] S. Bradner, "The Internet Standards Process -- [RFC2026] S. Bradner, "The Internet Standards Process --
Revision 3", RFC2026, October 1996. Revision 3", RFC2026, October 1996.
[RFC2030] Mills, D., Simple Network Time Protocol (SNTP) Version 4 [RFC2030] Mills, D., Simple Network Time Protocol (SNTP) Version 4
for IPv4, IPv6 and OSI", D. Mills, October 1996. for IPv4, IPv6 and OSI", D. Mills, October 1996.
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