draft-ietf-6man-multicast-addr-arch-update-02.txt   draft-ietf-6man-multicast-addr-arch-update-03.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: April 21, 2014 October 18, 2013 Expires: August 17, 2014 February 13, 2014
Updates to the IPv6 Multicast Addressing Architecture Updates to the IPv6 Multicast Addressing Architecture
draft-ietf-6man-multicast-addr-arch-update-02 draft-ietf-6man-multicast-addr-arch-update-03
Abstract Abstract
This document updates the IPv6 multicast addressing architecture by This document updates the IPv6 multicast addressing architecture by
defining the 17-20 reserved bits as generic flag bits. The document defining the 17-20 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.
skipping to change at page 1, line 42 skipping to change at page 1, line 42
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on April 21, 2014. This Internet-Draft will expire on August 17, 2014.
Copyright Notice Copyright Notice
Copyright (c) 2013 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.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Addressing Architecture Update . . . . . . . . . . . . . . . 2 2. Addressing Architecture Update . . . . . . . . . . . . . . . 2
3. Clarifications . . . . . . . . . . . . . . . . . . . . . . . 3 3. Flag Bits: A Recommendation . . . . . . . . . . . . . . . . . 3
3.1. Flag Bits . . . . . . . . . . . . . . . . . . . . . . . . 3
4. RFC Updates . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. RFC Updates . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.1. RFC 3306 . . . . . . . . . . . . . . . . . . . . . . . . 4 4.1. RFC 3306 . . . . . . . . . . . . . . . . . . . . . . . . 4
4.2. RFC 3956 . . . . . . . . . . . . . . . . . . . . . . . . 5 4.2. RFC 3956 . . . . . . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
6. Security Considerations . . . . . . . . . . . . . . . . . . . 8 6. Security Considerations . . . . . . . . . . . . . . . . . . . 8
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
8. Normative References . . . . . . . . . . . . . . . . . . . . 8 8. Normative References . . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction 1. Introduction
This document updates the IPv6 multicast addressing architecture This document updates the IPv6 multicast addressing architecture
[RFC4291] by defining the 17-20 reserved bits as generic flag bits [RFC4291] by defining the 17-20 reserved bits as generic flag bits
(Section 2). The document provides also some clarifications related (Section 2). The document provides also some clarifications related
to the use of these flag bits (Section 3.1). to the use of these flag bits (Section 3).
This document updates [RFC3956], [RFC3306], and [RFC4291]. This document updates [RFC3956], [RFC3306], and [RFC4291]. These
updates are logical consequences of the recommendation on the flag
bits (Section 3).
Textual representation of IPv6 addresses included in the RFC updates
follows the recommendation in [RFC5952].
2. Addressing Architecture Update 2. Addressing Architecture Update
Bits 17-20 of a multicast address are defined in [RFC3956] and Bits 17-20 of a multicast address are defined in [RFC3956] and
[RFC3306] as reserved bits. This document defines these bits as [RFC3306] as reserved bits. This document defines these bits as
generic flag bits so that they apply to any multicast address. generic flag bits so that they apply to any multicast address.
Figure 1 and Figure 2 show the updated structure of the addressing Figure 1 and Figure 2 show the updated structure of the addressing
architecture. The first diagram shows the update of the base IPv6 architecture. The first diagram shows the update of the base IPv6
addressing architecture, and the second shows the update of so-called addressing architecture, and the second shows the update of so-called
Embedded-RP. Embedded-RP.
OLD: OLD:
| 8 | 4 | 4 | 112 bits | | 8 | 4 | 4 | 112 bits |
+--------+----+----+----------------------------------------------+ +--------+----+----+----------------------------------------------+
|11111111|flgs|scop| group ID | |11111111|flgs|scop| group ID |
+--------+----+----+----------------------------------------------+ +--------+----+----+----------------------------------------------+
NEW: NEW:
| 8 | 4 | 4 | 4 | 108 bits | | 8 | 4 | 4 | 4 | 108 bits |
+--------+----+----+----------------------------------------------+ +--------+----+----+----------------------------------------------+
|11111111|flgs|scop|flgs| group ID | |11111111|ff1 |scop|ff2 | group ID |
+--------+----+----+----+-----------------------------------------+ +--------+----+----+----+-----------------------------------------+
* ff1 refers to "flag field 1"
* ff2 refers to "flag field 2"
* flag bits denote both ff1 and ff2.
Figure 1: Updated IPv6 Multicast Addressing Architecture Figure 1: Updated IPv6 Multicast Addressing Architecture
OLD (RFC 3956): OLD (RFC 3956):
| 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 |
+--------+----+----+----+----+--------+----------------+----------+ +--------+----+----+----+----+--------+----------------+----------+
NEW: NEW:
| 8 | 4 | 4 | 4 | 4 | 8 | 64 | 32 | | 8 | 4 | 4 | 4 | 4 | 8 | 64 | 32 |
+--------+----+----+----+----+--------+----------------+----------+ +--------+----+----+----+----+--------+----------------+----------+
|11111111|flgs|scop|flgs|RIID| plen | network prefix | group ID | |11111111|ff1 |scop|ff2 |RIID| plen | network prefix | group ID |
+--------+----+----+----+----+--------+----------------+----------+ +--------+----+----+----+----+--------+----------------+----------+
Figure 2: Embedded-RP with Updated IPv6 Multicast Address Arch. Figure 2: Embedded-RP with Updated IPv6 Multicast Address Arch.
Further specification documents may define a meaning for these flag Further specification documents may define a meaning for these flag
bits. Defining the bits 17-20 as flags for all IPv6 multicast bits. Defining the bits 17-20 as flags for all IPv6 multicast
addresses allows addresses to be treated in a more uniform and addresses allows addresses to be treated in a more uniform and
generic way, and allows for these bits to be defined in the future generic way, and allows for these bits to be defined in the future
for different purposes, irrespective of the specific type of for different purposes, irrespective of the specific type of
multicast address. multicast address.
3. Clarifications 3. Flag Bits: A Recommendation
3.1. Flag Bits
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 SSM IPv6 prefix block. the only allowed SSM IPv6 prefix block.
skipping to change at page 4, line 18 skipping to change at page 4, line 25
Implementations MUST treat flag bits as separate bits. Implementations MUST treat flag bits as separate bits.
4. RFC Updates 4. RFC Updates
4.1. RFC 3306 4.1. RFC 3306
This document changes Section 4 of [RFC3306] as follows: This document changes Section 4 of [RFC3306] as follows:
OLD: OLD:
| 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 |
+--------+----+----+--------+--------+----------------+----------+ +--------+----+----+--------+--------+----------------+----------+
+-+-+-+-+ +-+-+-+-+
flgs is a set of 4 flags: |0|0|P|T| flgs is a set of 4 flags: |0|0|P|T|
+-+-+-+-+ +-+-+-+-+
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 [ADDRARCH]. address as defined in [ADDRARCH].
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 [ADDRARCH]. bit is defined in Section 2.7 of [ADDRARCH].
The reserved field MUST be zero. The reserved field MUST be zero.
NEW: NEW:
| 8 | 4 | 4 | 8 | 8 | 64 | 32 | | 8 | 4 | 4 | 4 | 4 | 8 | 64 | 32 |
+--------+----+----+--------+--------+----------------+----------+ +--------+----+----+----+----+--------+----------------+----------+
|11111111|flgs|scop|reserved| plen | network prefix | group ID | |11111111|ff1 |scop|ff2 |rsvd| plen | network prefix | group ID |
+--------+----+----+--------+--------+----------------+----------+ +--------+----+----+----+----+--------+----------------+----------+
+-+-+-+-+ +-+-+-+-+
flgs 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.
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 [ADDRARCH]. 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 [ADDRARCH]. bit is defined in Section 2.7 of [RFC4291].
+-+-+-+-+
ff2 (flag field 2) is a set of 4 flags: |r|r|r|r|
+-+-+-+-+
where "rrrr" are for future assignment as additional flag bits.
Flag bits denote both ff1 and ff2.
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
valid scope value). The source address field in the IPv6 header valid scope value). The source address field in the IPv6 header
identifies the owner of the multicast address. identifies the owner of the multicast address.
NEW: NEW:
If the flag bits are set to 0011, these settings create an SSM If the flag bits in ff1 are set to 0011, these settings create an
range of ff3x::/32 (where 'x' is any valid scope value). The SSM range of ff3x::/32 (where 'x' is any valid scope value). The
source address field in the IPv6 header identifies the owner of source address field in the IPv6 header identifies the owner of
the multicast address. ff3x::/32 is not the only allowed SSM the multicast address. ff3x::/32 is not the only allowed SSM
prefix range. For example if the most significant flag bit is prefix range. For example if the most significant flag bit in ff1
set, then we would get the SSM range ffbx::/32. is set, then we would get the SSM range ffbx::/32.
4.2. RFC 3956 4.2. RFC 3956
This document changes Section 2 of [RFC3956] as follows: This document changes Section 2 of [RFC3956] as follows:
OLD: OLD:
As described in [RFC3306], the multicast address format is as As described in [RFC3306], the multicast address format is as
follows: follows:
skipping to change at page 6, line 9 skipping to change at page 6, line 28
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|flgs|scop|flgs|rsvd|plen| network prefix | group ID | |11111111|ff1 |scop|ff2 |rsvd|plen| network prefix | group ID |
+--------+----+----+---------+----+----------------+----------+ +--------+----+----+----+----+----+----------------+----------+
+-+-+-+-+
flgs 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. X may be set to 0 or 1.
+-+-+-+-+
ff2 (flag field 2) is a set of 4 flags: |r|r|r|r|
+-+-+-+-+
where "rrrr" are for future assignment as additional flag bits.
Flag bits denote both ff1 and ff2.
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 |
+--------+----+----+----+----+----+----------------+----------+ +--------+----+----+----+----+----+----------------+----------+
+-+-+-+-+ +-+-+-+-+
flgs is a set of four flags: |0|R|P|T| flgs is a set of four flags: |0|R|P|T|
+-+-+-+-+ +-+-+-+-+
When the highest-order bit is 0, R = 1 indicates a multicast address When the highest-order bit is 0, R = 1 indicates a multicast address
that embeds the address on the RP. Then P MUST be set to 1, and that embeds the address on the RP. Then P MUST be set to 1, and
consequently T MUST be set to 1, as specified in [RFC3306]. In consequently T MUST be set to 1, as specified in [RFC3306]. In
effect, this implies the prefix FF70::/12. In this case, the last 4 effect, this implies the prefix FF70::/12. In this case, the last 4
bits of the previously reserved field are interpreted as embedding bits of the previously reserved field are interpreted as embedding
the RP interface ID, as specified in this memo. the RP interface ID, as specified in this memo.
The behavior is unspecified if P or T is not set to 1, as then the The behavior is unspecified if P or T is not set to 1, as then the
prefix would not be FF70::/12. Likewise, the encoding and the prefix would not be FF70::/12. Likewise, the encoding and the
protocol mode used when the two high-order bits in "flgs" are set to protocol mode used when the two high-order bits in "flgs" are set to
11 ("FFF0::/12") is intentionally unspecified until such time that 11 ("FFF0::/12") is intentionally unspecified until such time that
the highest-order bit is defined. Without further IETF the highest-order bit is defined. Without further IETF
specification, implementations SHOULD NOT treat the FFF0::/12 range specification, implementations SHOULD NOT treat the FFF0::/12 range
as Embedded-RP. as Embedded-RP.
NEW: NEW:
| 8 | 4 | 4 | 4 | 4 | 8 | 64 | 32 | | 8 | 4 | 4 | 4 | 4 | 8 | 64 | 32 |
+--------+----+----+----+----+----+----------------+----------+ +--------+----+----+----+----+----+----------------+----------+
|11111111|flgs|scop|flgs|RIID|plen| network prefix | group ID | |11111111|ff1 |scop|ff2 |RIID|plen| network prefix | group ID |
+--------+----+----+----+----+----+----------------+----------+ +--------+----+----+----+----+----+----------------+----------+
+-+-+-+-+ +-+-+-+-+
flgs 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. X may be set to 0 or 1.
R = 1 indicates a multicast address that embeds the address of the RP. R = 1 indicates a multicast address that embeds the address of the RP.
P MUST be set to 1, and consequently T MUST be set to 1, according P MUST be set to 1, and consequently T MUST be set to 1, according
to [RFC3306], as this is a special case of to [RFC3306], as this is a special case of
unicast-prefix based addresses. This implies that for instance prefixes unicast-prefix based addresses. This implies that for instance prefixes
ff70::/12 and fff0::/12 are embedded RP prefixes, but all multicast ff70::/12 and fff0::/12 are embedded RP prefixes.
addresses with the R-bit set to 1 MUST be treated as Embedded RP The behavior is unspecified if P or T is not set to 1. When the
addresses. The behavior is unspecified if P or T is not set to 1. When the R-bit is set, the last 4 bits of the previously reserved field are
R-bit is set, the last 4 bits of the previously reserved field are interpreted as embedding the RP interface ID, as specified in this memo.
interpreted as embedding the RP interface ID, as specified in this memo.
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,
NEW: NEW:
skipping to change at page 8, line 4 skipping to change at page 8, line 30
FF70::/12, the Embedded-RP mapping MUST be considered the longest FF70::/12, the Embedded-RP mapping MUST be considered the longest
possible match and higher priority than any other mechanism. possible match and higher priority than any other mechanism.
NEW: NEW:
To avoid loops and inconsistencies, for addresses with R-bit set To avoid loops and inconsistencies, for addresses with R-bit set
to 1, the Embedded-RP mapping MUST be considered the longest to 1, the Embedded-RP mapping MUST be considered the longest
possible match and higher priority than any other mechanism. possible match and higher priority than any other mechanism.
5. IANA Considerations 5. IANA Considerations
This document may require IANA updates. However, at this point it is
not clear exactly what these updates may be. This document does not require any action from IANA.
6. Security Considerations 6. Security Considerations
Security considerations discussed in [RFC3956], [RFC3306] and Security considerations discussed in [RFC3956], [RFC3306] and
[RFC4291] MUST be taken into account. [RFC4291] MUST be taken into account.
7. Acknowledgements 7. Acknowledgements
Many thanks to B. Haberman for the discussions prior to the Special thanks to B. Haberman for the discussions prior to the
publication of this document. publication of this document.
Many thanks to J. Korhonen and T. Jinmei their comments.
8. Normative References 8. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3306] Haberman, B. and D. Thaler, "Unicast-Prefix-based IPv6 [RFC3306] Haberman, B. and D. Thaler, "Unicast-Prefix-based IPv6
Multicast Addresses", RFC 3306, August 2002. Multicast Addresses", RFC 3306, August 2002.
[RFC3956] Savola, P. and B. Haberman, "Embedding the Rendezvous [RFC3956] Savola, P. and B. Haberman, "Embedding the Rendezvous
Point (RP) Address in an IPv6 Multicast Address", RFC Point (RP) Address in an IPv6 Multicast Address", RFC
3956, November 2004. 3956, November 2004.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, February 2006. Architecture", RFC 4291, February 2006.
[RFC5952] Kawamura, S. and M. Kawashima, "A Recommendation for IPv6
Address Text Representation", RFC 5952, August 2010.
Authors' Addresses Authors' Addresses
Mohamed Boucadair Mohamed Boucadair
France Telecom France Telecom
Rennes 35000 Rennes 35000
France France
Email: mohamed.boucadair@orange.com Email: mohamed.boucadair@orange.com
Stig Venaas Stig Venaas
 End of changes. 40 change blocks. 
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