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].
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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
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
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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].
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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
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