draft-ietf-6man-multicast-addr-arch-update-07.txt   draft-ietf-6man-multicast-addr-arch-update-08.txt 
6man Working Group M. Boucadair 6man Working Group M. Boucadair
Internet-Draft France Telecom Internet-Draft France Telecom
Updates: 3306,3956,4291 (if approved) S. Venaas Updates: 3306,3956,4291 (if approved) S. Venaas
Intended status: Standards Track Cisco Intended status: Standards Track Cisco
Expires: January 8, 2015 July 07, 2014 Expires: February 12, 2015 August 11, 2014
Updates to the IPv6 Multicast Addressing Architecture Updates to the IPv6 Multicast Addressing Architecture
draft-ietf-6man-multicast-addr-arch-update-07 draft-ietf-6man-multicast-addr-arch-update-08
Abstract Abstract
This document updates the IPv6 multicast addressing architecture by This document updates the IPv6 multicast addressing architecture by
re-defining the reserved bits as generic flag bits. The document re-defining the reserved bits as generic flag bits. The document
provides also some clarifications related to the use of these flag provides also some clarifications related to the use of these flag
bits. bits.
This document updates RFC 3956, RFC 3306 and RFC 4291. This document updates RFC 3956, RFC 3306 and RFC 4291.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
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time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 8, 2015. This Internet-Draft will expire on February 12, 2015.
Copyright Notice Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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the copyright in such materials, this document may not be modified the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other it for publication as an RFC or to translate it into languages other
than English. than English.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Addressing Architecture Update . . . . . . . . . . . . . . . 3 2. Addressing Architecture Update . . . . . . . . . . . . . . . 3
3. Flag Bits: A Recommendation . . . . . . . . . . . . . . . . . 3 3. Flag Bits: New Processing Rules . . . . . . . . . . . . . . . 3
4. RFC Updates . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. RFC Updates . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.1. RFC 3306 . . . . . . . . . . . . . . . . . . . . . . . . 4 4.1. RFC 3306 . . . . . . . . . . . . . . . . . . . . . . . . 4
4.1.1. Update #1 . . . . . . . . . . . . . . . . . . . . . . 4 4.1.1. Update #1 . . . . . . . . . . . . . . . . . . . . . . 4
4.1.2. Update #2 . . . . . . . . . . . . . . . . . . . . . . 5 4.1.2. Update #2 . . . . . . . . . . . . . . . . . . . . . . 5
4.2. RFC 3956 . . . . . . . . . . . . . . . . . . . . . . . . 6 4.2. RFC 3956 . . . . . . . . . . . . . . . . . . . . . . . . 6
4.2.1. Update #1 . . . . . . . . . . . . . . . . . . . . . . 6 4.2.1. Update #1 . . . . . . . . . . . . . . . . . . . . . . 6
4.2.2. Update #2 . . . . . . . . . . . . . . . . . . . . . . 7 4.2.2. Update #2 . . . . . . . . . . . . . . . . . . . . . . 7
4.2.3. Update #3 . . . . . . . . . . . . . . . . . . . . . . 8 4.2.3. Update #3 . . . . . . . . . . . . . . . . . . . . . . 8
4.2.4. Update #4 . . . . . . . . . . . . . . . . . . . . . . 8 4.2.4. Update #4 . . . . . . . . . . . . . . . . . . . . . . 8
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
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Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction 1. Introduction
This document updates the IPv6 addressing architecture [RFC4291] by This document updates the IPv6 addressing architecture [RFC4291] by
re-defining reserved bits as generic flag bits (Section 2). The re-defining reserved bits as generic flag bits (Section 2). The
document provides also some clarifications related to the use of document provides also some clarifications related to the use of
these flag bits (Section 3). these flag bits (Section 3).
This document updates [RFC3956], [RFC3306], and [RFC4291]. These This document updates [RFC3956], [RFC3306], and [RFC4291]. These
updates are logical consequences of the recommendation on the flag updates are logical consequences of the new processing rules in
bits (Section 3). Section 3.
Textual representation of IPv6 addresses included in the RFC updates Textual representation of IPv6 addresses included in the RFC updates
follows the recommendation in [RFC5952]. follows the recommendation in [RFC5952].
2. Addressing Architecture Update 2. Addressing Architecture Update
Bits 17-20 of a multicast address, where bit 1 is the most Bits 17-20 of a multicast address, where bit 1 is the most
significant bit, are defined in [RFC3956] and [RFC3306] as reserved significant bit, are defined in [RFC3956] and [RFC3306] as reserved
bits. This document defines these bits as generic flag bits so that bits. This document defines these bits as generic flag bits so that
they apply to any multicast address. These bits are referred to as they apply to any multicast address. These bits are referred to as
ff2 (flag field 2) while the flgs bits in [RFC4291][RFC3956] are ff2 (flag field 2) while the flgs bits in [RFC4291][RFC3956] are
renamed to ff1 (flag field 1). renamed to ff1 (flag field 1).
Within this document, flag bits denote both ff1 and ff2. Within this document, flag bits denote both ff1 and ff2.
Defining the bits 17-20 as flags for all IPv6 multicast addresses Defining the bits 17-20 as flags for all IPv6 multicast addresses
allows addresses to be treated in a more uniform and generic way, and allows addresses to be treated in a more uniform and generic way, and
allows for these bits to be defined in the future for different allows for these bits to be defined in the future for different
purposes, irrespective of the specific type of multicast address. purposes, irrespective of the specific type of multicast address.
For the record, this design choice was initially triggered by For the record, this design choice was initially triggered by the
specification in [I-D.ietf-mboned-64-multicast-address-format] which specification in [I-D.ietf-mboned-64-multicast-address-format] which
proposed for associating a meaning with one of the reserved bits. proposed for associating a meaning with one of the reserved bits.
Moreover, [I-D.ietf-mboned-64-multicast-address-format] considered Moreover, [I-D.ietf-mboned-64-multicast-address-format] considered
also the use of the last remaining flag in ff1 but that approach was also the use of the last remaining flag in ff1 but that approach was
abandoned because it is not clear at this stage whether there is abandoned because it is not clear at this stage whether there is
other usage scenarios of the flag. other usage scenarios of the flag.
Section 4 specifies the updated structure of the addressing Section 4 specifies the updated structure of the addressing
architecture. architecture.
Further specification documents may define a meaning for these flag Further specification documents may define a meaning for these flag
bits. bits.
3. Flag Bits: A Recommendation 3. Flag Bits: New Processing Rules
Some implementations and specification documents do not treat the Some implementations and specification documents do not treat the
flag bits as separate bits but tend to use their combined value as a flag bits as separate bits but tend to use their combined value as a
4-bit integer. This practice is a hurdle for assigning a meaning to 4-bit integer. This practice is a hurdle for assigning a meaning to
the remaining flag bits. Below are listed some examples for the remaining flag bits. Below are listed some examples for
illustration purposes: illustration purposes:
o the reading of [RFC3306] may lead to conclude that ff3x::/32 is o the reading of [RFC3306] may lead to conclude that ff3x::/32 is
the only allowed Source Specific Multicast (SSM) IPv6 prefix the only allowed Source Specific Multicast (SSM) IPv6 prefix
block. block.
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| 8 | 4 | 4 | 4 | 4 | 8 | 64 | 32 | | 8 | 4 | 4 | 4 | 4 | 8 | 64 | 32 |
+--------+----+----+----+----+--------+----------------+----------+ +--------+----+----+----+----+--------+----------------+----------+
|11111111|ff1 |scop|ff2 |rsvd| plen | network prefix | group ID | |11111111|ff1 |scop|ff2 |rsvd| plen | network prefix | group ID |
+--------+----+----+----+----+--------+----------------+----------+ +--------+----+----+----+----+--------+----------------+----------+
+-+-+-+-+ +-+-+-+-+
ff1 (flag field 1) is a set of 4 flags: |X|Y|P|T| ff1 (flag field 1) is a set of 4 flags: |X|Y|P|T|
+-+-+-+-+ +-+-+-+-+
X and Y may each be set to 0 or 1. X and Y may each be set to 0 or 1. Note, X is for future assignment
while a meaning is associated with Y in RFC3956.
o P = 0 indicates a multicast address that is not assigned o P = 0 indicates a multicast address that is not assigned
based on the network prefix. This indicates a multicast based on the network prefix. This indicates a multicast
address as defined in [RFC4291]. address as defined in [RFC4291].
o P = 1 indicates a multicast address that is assigned based o P = 1 indicates a multicast address that is assigned based
on the network prefix. on the network prefix.
o If P = 1, T MUST be set to 1, otherwise the setting of the T o If P = 1, T MUST be set to 1, otherwise the setting of the T
bit is defined in Section 2.7 of [RFC4291]. bit is defined in Section 2.7 of [RFC4291].
+-+-+-+-+ +-+-+-+-+
ff2 (flag field 2) is a set of 4 flags: |r|r|r|r| ff2 (flag field 2) is a set of 4 flags: |r|r|r|r|
+-+-+-+-+ +-+-+-+-+
where "rrrr" are for future assignment as additional flag bits. where "rrrr" are for future assignment as additional flag bits.
r bits MUST each be set to 0. r bits MUST each be sent as zero and MUST be ignored on receipt.
Flag bits denote both ff1 and ff2. Flag bits denote both ff1 and ff2.
4.1.2. Update #2 4.1.2. Update #2
This document changes Section 6 of [RFC3306] as follows: This document changes Section 6 of [RFC3306] as follows:
OLD: OLD:
These settings create an SSM range of FF3x::/32 (where 'x' is any These settings create an SSM range of FF3x::/32 (where 'x' is any
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| 8 | 4 | 4 | 8 | 8 | 64 | 32 | | 8 | 4 | 4 | 8 | 8 | 64 | 32 |
+--------+----+----+--------+----+----------------+----------+ +--------+----+----+--------+----+----------------+----------+
|11111111|flgs|scop|reserved|plen| network prefix | group ID | |11111111|flgs|scop|reserved|plen| network prefix | group ID |
+--------+----+----+--------+----+----------------+----------+ +--------+----+----+--------+----+----------------+----------+
Where flgs are "0011". (The first two bits are as yet undefined, Where flgs are "0011". (The first two bits are as yet undefined,
sent as zero and ignored on receipt.) sent as zero and ignored on receipt.)
NEW: NEW:
The multicast address format is as The multicast address format is as follows:
follows:
| 8 | 4 | 4 | 4 | 4 | 8 | 64 | 32 | | 8 | 4 | 4 | 4 | 4 | 8 | 64 | 32 |
+--------+----+----+----+----+----+----------------+----------+ +--------+----+----+----+----+----+----------------+----------+
|11111111|ff1 |scop|ff2 |rsvd|plen| network prefix | group ID | |11111111|ff1 |scop|ff2 |rsvd|plen| network prefix | group ID |
+--------+----+----+----+----+----+----------------+----------+ +--------+----+----+----+----+----+----------------+----------+
+-+-+-+-+ +-+-+-+-+
ff1 (flag field 1) is a set of four flags: |X|R|P|T| ff1 (flag field 1) is a set of four flags: |X|R|P|T|
+-+-+-+-+ +-+-+-+-+
X may be set to 0 or 1. where X is for future assignment as additional flag bit. X may be
set to 0 or 1.
+-+-+-+-+ +-+-+-+-+
ff2 (flag field 2) is a set of 4 flags: |r|r|r|r| ff2 (flag field 2) is a set of 4 flags: |r|r|r|r|
+-+-+-+-+ +-+-+-+-+
where "rrrr" are for future assignment as additional flag bits. where "rrrr" are for future assignment as additional flag bits.
r bits MUST each be set to 0. r bits MUST each be sent as zero and MUST be ignored on receipt.
Flag bits denote both ff1 and ff2. Flag bits denote both ff1 and ff2.
4.2.2. Update #2 4.2.2. Update #2
This document changes Section 3 of [RFC3956] as follows: This document changes Section 3 of [RFC3956] as follows:
OLD: OLD:
| 8 | 4 | 4 | 4 | 4 | 8 | 64 | 32 | | 8 | 4 | 4 | 4 | 4 | 8 | 64 | 32 |
+--------+----+----+----+----+----+----------------+----------+ +--------+----+----+----+----+----+----------------+----------+
|11111111|flgs|scop|rsvd|RIID|plen| network prefix | group ID | |11111111|flgs|scop|rsvd|RIID|plen| network prefix | group ID |
skipping to change at page 8, line 12 skipping to change at page 8, line 12
NEW: NEW:
| 8 | 4 | 4 | 4 | 4 | 8 | 64 | 32 | | 8 | 4 | 4 | 4 | 4 | 8 | 64 | 32 |
+--------+----+----+----+----+----+----------------+----------+ +--------+----+----+----+----+----+----------------+----------+
|11111111|ff1 |scop|ff2 |RIID|plen| network prefix | group ID | |11111111|ff1 |scop|ff2 |RIID|plen| network prefix | group ID |
+--------+----+----+----+----+----+----------------+----------+ +--------+----+----+----+----+----+----------------+----------+
+-+-+-+-+ +-+-+-+-+
ff1 is a set of four flags: |X|R|P|T| ff1 is a set of four flags: |X|R|P|T|
+-+-+-+-+ +-+-+-+-+
X may be set to 0 or 1. where X is for future assignment as additional flag bit. X may be
set to 0 or 1.
R = 1 indicates a multicast address that embeds the address of the R = 1 indicates a multicast address that embeds the address of the
RP. Then P MUST be set to 1, and consequently T MUST be set to 1, RP. Then P MUST be set to 1, and consequently T MUST be set to 1,
according to [RFC3306], as this is a special case of unicast-prefix according to [RFC3306], as this is a special case of unicast-prefix
based addresses. This implies that, for instance, prefixes ff70::/12 based addresses. This implies that, for instance, prefixes ff70::/12
and fff0::/12 are embedded RP prefixes. The behavior is unspecified and fff0::/12 are embedded RP prefixes. When the R-bit is set, the
if P or T is not set to 1. When the R-bit is set, the last 4 bits of last 4 bits of the field that were reserved in [RFC3306] are
the field that were reserved in [RFC3306] are interpreted as interpreted as embedding the RP interface ID, as specified in this
embedding the RP interface ID, as specified in this memo. memo.
4.2.3. Update #3 4.2.3. Update #3
This document changes Section 4 of [RFC3956] as follows: This document changes Section 4 of [RFC3956] as follows:
OLD: OLD:
It MUST be a multicast address with "flgs" set to 0111, that is, It MUST be a multicast address with "flgs" set to 0111, that is,
to be of the prefix FF70::/12, to be of the prefix FF70::/12,
 End of changes. 16 change blocks. 
31 lines changed or deleted 33 lines changed or added

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