< draft-ietf-6man-multicast-addr-arch-update-04.txt		draft-ietf-6man-multicast-addr-arch-update-05.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: September 13, 2014 March 12, 2014		Expires: December 20, 2014 June 18, 2014
	Updates to the IPv6 Multicast Addressing Architecture		Updates to the IPv6 Multicast Addressing Architecture
	draft-ietf-6man-multicast-addr-arch-update-04		draft-ietf-6man-multicast-addr-arch-update-05
	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		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.
	Requirements Language		Requirements Language
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in RFC 2119 [RFC2119].		document are to be interpreted as described in RFC 2119 [RFC2119].
	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
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at http://datatracker.ietf.org/drafts/current/.		Drafts is at http://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	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 September 13, 2014.		This Internet-Draft will expire on December 20, 2014.
	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
	skipping to change at page 2, line 20 ¶		skipping to change at page 2, line 20 ¶
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	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. Flag Bits: A Recommendation . . . . . . . . . . . . . . . . . 3		3. Flag Bits: A Recommendation . . . . . . . . . . . . . . . . . 3
	4. RFC Updates . . . . . . . . . . . . . . . . . . . . . . . . . 4		4. RFC Updates . . . . . . . . . . . . . . . . . . . . . . . . . 3
	4.1. RFC 3306 . . . . . . . . . . . . . . . . . . . . . . . . 4		4.1. RFC 3306 . . . . . . . . . . . . . . . . . . . . . . . . 3
	4.2. RFC 3956 . . . . . . . . . . . . . . . . . . . . . . . . 6		4.2. RFC 3956 . . . . . . . . . . . . . . . . . . . . . . . . 6
	5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8		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 . . . . . . . . . . . . . . . . . . . . . . . 9		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
	1. Introduction		1. Introduction
	This document updates the IPv6 multicast addressing architecture		This document updates the IPv6 addressing architecture [RFC4291] by
	[RFC4291] by defining the 17-20 reserved bits as generic flag bits		re-defining reserved bits as generic flag bits (Section 2). The
	(Section 2). The document provides also some clarifications related		document provides also some clarifications related to the use of
	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 recommendation on the flag
	bits (Section 3).		bits (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 are defined in [RFC3956] and		Bits 17-20 of a multicast address, where bit 1 is the most
	[RFC3306] as reserved bits. This document defines these bits as		significant bit, are defined in [RFC3956] and [RFC3306] as reserved
	generic flag bits so that they apply to any multicast address.		bits. This document defines these bits as generic flag bits so that
	Figure 1 and Figure 2 show the updated structure of the addressing		they apply to any multicast address. These bits are referred to as
	architecture. The first diagram shows the update of the base IPv6		ff2 (flag field 2) while the flgs bits in [RFC4291][RFC3956] are
	addressing architecture, and the second shows the update of so-called		renamed to ff1 (flag field 1).
	Embedded-RP.
	OLD:
	| 8 | 4 | 4 | 112 bits |
	+--------+----+----+----------------------------------------------+
	|11111111|flgs|scop| group ID |
	+--------+----+----+----------------------------------------------+
	NEW:
	| 8 | 4 | 4 | 4 | 108 bits |
	+--------+----+----+----------------------------------------------+
	|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
	OLD (RFC 3956):		Within this document, flag bits denote both ff1 and ff2.
	| 8 | 4 | 4 | 4 | 4 | 8 | 64 | 32 |
	+--------+----+----+----+----+--------+----------------+----------+
	|11111111|flgs|scop|rsvd|RIID| plen | network prefix | group ID |
	+--------+----+----+----+----+--------+----------------+----------+
	NEW:		Defining the bits 17-20 as flags for all IPv6 multicast addresses
	| 8 | 4 | 4 | 4 | 4 | 8 | 64 | 32 |		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
	|11111111|ff1 |scop|ff2 |RIID| plen | network prefix | group ID |		purposes, irrespective of the specific type of multicast address.
	+--------+----+----+----+----+--------+----------------+----------+
	Figure 2: Embedded-RP with Updated IPv6 Multicast Address Arch.		Section 4 specifies the updated structure of the addressing
			architecture.
	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.
	addresses 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 purposes, irrespective of the specific type of
	multicast address.
	3. Flag Bits: A Recommendation		3. Flag Bits: A Recommendation
	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.
	o [RFC3956] states only ff70::/12 applies to Embedded-RP.		o [RFC3956] states only ff70::/12 applies to Embedded-RP.
	Particularly, implementations should not treat the fff0::/12 range		Particularly, implementations should not treat the fff0::/12 range
	as Embedded-RP.		as Embedded-RP.
	To avoid such confusion and to unambiguously associate a meaning with		To avoid such confusion and to unambiguously associate a meaning with
	the remaining flags, the following requirement is made		the remaining flags, the following requirement is made:
	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 | 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.
	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].
	skipping to change at page 8, line 40 ¶		skipping to change at page 8, line 40 ¶
	This document does not require any action from IANA.		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
	Special thanks to B. Haberman for the discussions prior to the		Special thanks to Brian 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.		Many thanks to Jouni Korhonen and Tatuya Jinmei their review.
	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
End of changes. 16 change blocks.
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