draft-ietf-6man-why64-06.txt   draft-ietf-6man-why64-07.txt 
6MAN B. Carpenter, Ed. 6MAN B. Carpenter, Ed.
Internet-Draft Univ. of Auckland Internet-Draft Univ. of Auckland
Intended status: Informational T. Chown Intended status: Informational T. Chown
Expires: April 5, 2015 Univ. of Southampton Expires: April 23, 2015 Univ. of Southampton
F. Gont F. Gont
SI6 Networks / UTN-FRH SI6 Networks / UTN-FRH
S. Jiang S. Jiang
Huawei Technologies Co., Ltd Huawei Technologies Co., Ltd
A. Petrescu A. Petrescu
CEA, LIST CEA, LIST
A. Yourtchenko A. Yourtchenko
cisco cisco
October 2, 2014 October 20, 2014
Analysis of the 64-bit Boundary in IPv6 Addressing Analysis of the 64-bit Boundary in IPv6 Addressing
draft-ietf-6man-why64-06 draft-ietf-6man-why64-07
Abstract Abstract
The IPv6 unicast addressing format includes a separation between the The IPv6 unicast addressing format includes a separation between the
prefix used to route packets to a subnet and the interface identifier prefix used to route packets to a subnet and the interface identifier
used to specify a given interface connected to that subnet. used to specify a given interface connected to that subnet.
Currently the interface identifier is defined as 64 bits long for Currently the interface identifier is defined as 64 bits long for
almost every case, leaving 64 bits for the subnet prefix. This almost every case, leaving 64 bits for the subnet prefix. This
document describes the advantages of this fixed boundary and analyses document describes the advantages of this fixed boundary and analyses
the issues that would be involved in treating it as a variable the issues that would be involved in treating it as a variable
skipping to change at page 1, line 46 skipping to change at page 1, line 46
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 April 5, 2015. This Internet-Draft will expire on April 23, 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
skipping to change at page 2, line 35 skipping to change at page 2, line 35
3.1. Insufficient address space delegated . . . . . . . . . . 5 3.1. Insufficient address space delegated . . . . . . . . . . 5
3.2. Hierarchical addressing . . . . . . . . . . . . . . . . . 6 3.2. Hierarchical addressing . . . . . . . . . . . . . . . . . 6
3.3. Audit requirement . . . . . . . . . . . . . . . . . . . . 6 3.3. Audit requirement . . . . . . . . . . . . . . . . . . . . 6
3.4. Concerns over ND cache exhaustion . . . . . . . . . . . . 7 3.4. Concerns over ND cache exhaustion . . . . . . . . . . . . 7
4. Effects of varying the interface identifier length . . . . . 7 4. Effects of varying the interface identifier length . . . . . 7
4.1. Interaction with IPv6 specifications . . . . . . . . . . 7 4.1. Interaction with IPv6 specifications . . . . . . . . . . 7
4.2. Possible failure modes . . . . . . . . . . . . . . . . . 9 4.2. Possible failure modes . . . . . . . . . . . . . . . . . 9
4.3. Experimental observations . . . . . . . . . . . . . . . . 11 4.3. Experimental observations . . . . . . . . . . . . . . . . 11
4.3.1. Survey of the processing of Neighbor Discovery 4.3.1. Survey of the processing of Neighbor Discovery
options with prefixes other than /64 . . . . . . . . 11 options with prefixes other than /64 . . . . . . . . 11
4.3.2. Other Observations . . . . . . . . . . . . . . . . . 13 4.3.2. Other Observations . . . . . . . . . . . . . . . . . 14
4.4. Implementation and deployment issues . . . . . . . . . . 14 4.4. Implementation and deployment issues . . . . . . . . . . 14
4.5. Privacy issues . . . . . . . . . . . . . . . . . . . . . 15 4.5. Privacy issues . . . . . . . . . . . . . . . . . . . . . 16
5. Security Considerations . . . . . . . . . . . . . . . . . . . 16 5. Security Considerations . . . . . . . . . . . . . . . . . . . 16
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 17 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 17
8. Change log [RFC Editor: Please remove] . . . . . . . . . . . 17 8. Change log [RFC Editor: Please remove] . . . . . . . . . . . 17
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 17 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
9.1. Normative References . . . . . . . . . . . . . . . . . . 18 9.1. Normative References . . . . . . . . . . . . . . . . . . 18
9.2. Informative References . . . . . . . . . . . . . . . . . 21 9.2. Informative References . . . . . . . . . . . . . . . . . 21
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23
1. Introduction 1. Introduction
Rather than simply overcoming the IPv4 address shortage by doubling Rather than simply overcoming the IPv4 address shortage by doubling
the address size to 64 bits, IPv6 addresses were originally chosen to the address size to 64 bits, IPv6 addresses were originally chosen to
be 128 bits long to provide flexibility and new possibilities. In be 128 bits long to provide flexibility and new possibilities. In
particular, the notion of a well-defined interface identifier was particular, the notion of a well-defined interface identifier was
skipping to change at page 3, line 18 skipping to change at page 3, line 18
be treated as an opaque value [RFC7136]. Also, since IPv6 routing is be treated as an opaque value [RFC7136]. Also, since IPv6 routing is
entirely based on variable length prefixes (also known as variable entirely based on variable length prefixes (also known as variable
length subnet masks), there is no basic architectural assumption that length subnet masks), there is no basic architectural assumption that
n has any particular fixed value. All IPv6 routing protocols support n has any particular fixed value. All IPv6 routing protocols support
prefixes of any length up to /128. prefixes of any length up to /128.
The IID is of basic importance in the IPv6 stateless address The IID is of basic importance in the IPv6 stateless address
autoconfiguration (SLAAC) process [RFC4862]. However, it is autoconfiguration (SLAAC) process [RFC4862]. However, it is
important to understand that its length is a parameter in the SLAAC important to understand that its length is a parameter in the SLAAC
process, and it is determined in a separate link-type specific process, and it is determined in a separate link-type specific
document (see Section 2 of RFC 4862). The SLAAC protocol does not document (see the definition of "interface identifier" in Section 2
define its length or assume any particular length. Similarly, DHCPv6 of RFC 4862). The SLAAC protocol does not define its length or
[RFC3315] does not include a prefix length in its address assignment. assume any particular length. Similarly, DHCPv6 [RFC3315] does not
include a prefix length in its address assignment.
The notion of a /64 boundary in the address was introduced after the The notion of a /64 boundary in the address was introduced after the
initial design of IPv6, following a period when it was expected to be initial design of IPv6, following a period when it was expected to be
at /80. There were two motivations for setting it at /64. One was at /80. There were two motivations for setting it at /64. One was
the original "8+8" proposal [DRAFT-odell] that eventually led to ILNP the original "8+8" proposal [DRAFT-odell] that eventually led to ILNP
[RFC6741], which required a fixed point for the split between local [RFC6741], which required a fixed point for the split between local
and wide-area parts of the address. The other was the expectation and wide-area parts of the address. The other was the expectation
that EUI-64 MAC addresses would become widespread in place of 48-bit that EUI-64 MAC addresses would become widespread in place of 48-bit
addresses, coupled with the plan at that time that auto-configured addresses, coupled with the plan at that time that auto-configured
addresses would normally be based on interface identifiers derived addresses would normally be based on interface identifiers derived
skipping to change at page 12, line 25 skipping to change at page 12, line 25
In the tables below, the following notation is used: In the tables below, the following notation is used:
NOT-SUP: NOT-SUP:
This option is not supported (i.e., it is ignored no matter the This option is not supported (i.e., it is ignored no matter the
prefix length used). prefix length used).
LOCAL: LOCAL:
The corresponding prefix is considered "on-link". The corresponding prefix is considered "on-link".
ROUTE ROUTE:
The corresponding route is added to the IPv6 routing table. The corresponding route is added to the IPv6 routing table.
NOT-DEF:
The default configuration is NOT-SUP, but there is an option to
enable ROUTE.
IGNORE: IGNORE:
The Option is ignored as an error. The Option is ignored as an error.
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
| Operating System | PIO-A | PIO-L | PIO-AL | RIO | | Operating System | PIO-A | PIO-L | PIO-AL | RIO |
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
| FreeBSD 9.0 | IGNORE | LOCAL | LOCAL | NOT-SUP | | FreeBSD 9.0 | IGNORE | LOCAL | LOCAL | NOT-SUP |
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
| Linux 3.0.0-15 | IGNORE | LOCAL | LOCAL | NOT-SUP | | Linux 3.0.0-15 | IGNORE | LOCAL | LOCAL | NOT-DEF |
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
| Linux-current | IGNORE | LOCAL | LOCAL | NOT-SUP | | Linux-current | IGNORE | LOCAL | LOCAL | NOT-DEF |
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
| NetBSD 5.1 | IGNORE | LOCAL | LOCAL | NOT-SUP | | NetBSD 5.1 | IGNORE | LOCAL | LOCAL | NOT-SUP |
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
| OpenBSD-current | IGNORE | LOCAL | LOCAL | NOT-SUP | | OpenBSD-current | IGNORE | LOCAL | LOCAL | NOT-SUP |
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
| Win XP SP2 | IGNORE | LOCAL | LOCAL | ROUTE | | Win XP SP2 | IGNORE | LOCAL | LOCAL | ROUTE |
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
| Win 7 Home Premium | IGNORE | LOCAL | LOCAL | ROUTE | | Win 7 Home Premium | IGNORE | LOCAL | LOCAL | ROUTE |
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
skipping to change at page 13, line 4 skipping to change at page 13, line 24
| NetBSD 5.1 | IGNORE | LOCAL | LOCAL | NOT-SUP | | NetBSD 5.1 | IGNORE | LOCAL | LOCAL | NOT-SUP |
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
| OpenBSD-current | IGNORE | LOCAL | LOCAL | NOT-SUP | | OpenBSD-current | IGNORE | LOCAL | LOCAL | NOT-SUP |
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
| Win XP SP2 | IGNORE | LOCAL | LOCAL | ROUTE | | Win XP SP2 | IGNORE | LOCAL | LOCAL | ROUTE |
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
| Win 7 Home Premium | IGNORE | LOCAL | LOCAL | ROUTE | | Win 7 Home Premium | IGNORE | LOCAL | LOCAL | ROUTE |
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
Table 1: Processing of ND options with prefixes longer than /64 Table 1: Processing of ND options with prefixes longer than /64
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
| Operating System | PIO-A | PIO-L | PIO-AL | RIO | | Operating System | PIO-A | PIO-L | PIO-AL | RIO |
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
| FreeBSD 9.0 | IGNORE | LOCAL | LOCAL | NOT-SUP | | FreeBSD 9.0 | IGNORE | LOCAL | LOCAL | NOT-SUP |
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
| Linux 3.0.0-15 | IGNORE | LOCAL | LOCAL | NOT-SUP | | Linux 3.0.0-15 | IGNORE | LOCAL | LOCAL | NOT-DEF |
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
| Linux-current | IGNORE | LOCAL | LOCAL | NOT-SUP | | Linux-current | IGNORE | LOCAL | LOCAL | NOT-DEF |
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
| NetBSD 5.1 | IGNORE | LOCAL | LOCAL | NOT-SUP | | NetBSD 5.1 | IGNORE | LOCAL | LOCAL | NOT-SUP |
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
| OpenBSD-current | IGNORE | LOCAL | LOCAL | NOT-SUP | | OpenBSD-current | IGNORE | LOCAL | LOCAL | NOT-SUP |
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
| Win XP SP2 | IGNORE | LOCAL | LOCAL | ROUTE | | Win XP SP2 | IGNORE | LOCAL | LOCAL | ROUTE |
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
| Win 7 Home Premium | IGNORE | LOCAL | LOCAL | ROUTE | | Win 7 Home Premium | IGNORE | LOCAL | LOCAL | ROUTE |
+--------------------+--------+-------+--------+---------+ +--------------------+--------+-------+--------+---------+
skipping to change at page 13, line 37 skipping to change at page 14, line 10
the prefix length is 64. At least for the case where the IID the prefix length is 64. At least for the case where the IID
length is defined to be 64 bits in the corresponding link-type- length is defined to be 64 bits in the corresponding link-type-
specific document, which is the case for all currently published specific document, which is the case for all currently published
such documents, this is consistent with [RFC4862], which defines such documents, this is consistent with [RFC4862], which defines
the case where the sum of the advertised prefix length and the IID the case where the sum of the advertised prefix length and the IID
length does not equal 128 as an error condition. length does not equal 128 as an error condition.
o the "L" bit in the Prefix Information Options is honored for any o the "L" bit in the Prefix Information Options is honored for any
arbitrary prefix length (whether shorter or longer than /64). arbitrary prefix length (whether shorter or longer than /64).
o nodes that support the Route Information Option, allow such routes o nodes that support the Route Information Option allow such routes
to be specified with prefixes of any arbitrary length (whether to be specified with prefixes of any arbitrary length (whether
shorter or longer than /64) shorter or longer than /64)
4.3.2. Other Observations 4.3.2. Other Observations
Participants in the V6OPS working group have indicated that some Participants in the V6OPS working group have indicated that some
forwarding devices have been shown to work correctly with long forwarding devices have been shown to work correctly with long
prefixes such as /80 or /96. Indeed, it is to be expected that prefixes such as /80 or /96. Indeed, it is to be expected that
longest prefix match based forwarding will work for any prefix longest prefix match based forwarding will work for any prefix
length, and no reports of this completely failing have been noted. length, and no reports of this completely failing have been noted.
skipping to change at page 17, line 24 skipping to change at page 17, line 46
Blake, Lorenzo Colitti, David Farmer, Bill Fenner, Ray Hunter, Blake, Lorenzo Colitti, David Farmer, Bill Fenner, Ray Hunter,
Paraskevi Iliadou, Jen Linkova, Philip Matthews, Matthew Petach, Paraskevi Iliadou, Jen Linkova, Philip Matthews, Matthew Petach,
Scott Schmit, Tatuya Jinmei, Fred Templin, Ole Troan, Stig Venaas, Scott Schmit, Tatuya Jinmei, Fred Templin, Ole Troan, Stig Venaas,
and numerous other participants in the 6MAN working group. An and numerous other participants in the 6MAN working group. An
extremely detailed review by Mark Smith was especially helpful. extremely detailed review by Mark Smith was especially helpful.
This document was produced using the xml2rfc tool [RFC2629]. This document was produced using the xml2rfc tool [RFC2629].
8. Change log [RFC Editor: Please remove] 8. Change log [RFC Editor: Please remove]
draft-ietf-6man-why64-07: correction to Linux NOT-SUP status,
2014-10-20.
draft-ietf-6man-why64-06: minor IETF Last Call comments, 2014-10-02. draft-ietf-6man-why64-06: minor IETF Last Call comments, 2014-10-02.
draft-ietf-6man-why64-05: Area Director review comments, 2014-09-16. draft-ietf-6man-why64-05: Area Director review comments, 2014-09-16.
draft-ietf-6man-why64-04: fixed reference error, 2014-09-10. draft-ietf-6man-why64-04: fixed reference error, 2014-09-10.
draft-ietf-6man-why64-03: fixed nits, 2014-08-27. draft-ietf-6man-why64-03: fixed nits, 2014-08-27.
draft-ietf-6man-why64-02: responded to WGLC reviews and comments, draft-ietf-6man-why64-02: responded to WGLC reviews and comments,
2014-08-16. 2014-08-16.
skipping to change at page 21, line 44 skipping to change at page 22, line 24
(work in progress), February 2013. (work in progress), February 2013.
[I-D.ietf-6man-6lobac] [I-D.ietf-6man-6lobac]
Lynn, K., Martocci, J., Neilson, C., and S. Donaldson, Lynn, K., Martocci, J., Neilson, C., and S. Donaldson,
"Transmission of IPv6 over MS/TP Networks", draft-ietf- "Transmission of IPv6 over MS/TP Networks", draft-ietf-
6man-6lobac-01 (work in progress), March 2012. 6man-6lobac-01 (work in progress), March 2012.
[I-D.ietf-6man-ipv6-address-generation-privacy] [I-D.ietf-6man-ipv6-address-generation-privacy]
Cooper, A., Gont, F., and D. Thaler, "Privacy Cooper, A., Gont, F., and D. Thaler, "Privacy
Considerations for IPv6 Address Generation Mechanisms", Considerations for IPv6 Address Generation Mechanisms",
draft-ietf-6man-ipv6-address-generation-privacy-01 (work draft-ietf-6man-ipv6-address-generation-privacy-02 (work
in progress), February 2014. in progress), October 2014.
[I-D.ietf-homenet-arch] [I-D.ietf-homenet-arch]
Chown, T., Arkko, J., Brandt, A., Troan, O., and J. Weil, Chown, T., Arkko, J., Brandt, A., Troan, O., and J. Weil,
"IPv6 Home Networking Architecture Principles", draft- "IPv6 Home Networking Architecture Principles", draft-
ietf-homenet-arch-17 (work in progress), July 2014. ietf-homenet-arch-17 (work in progress), July 2014.
[I-D.ietf-opsec-ipv6-host-scanning] [I-D.ietf-opsec-ipv6-host-scanning]
Gont, F. and T. Chown, "Network Reconnaissance in IPv6 Gont, F. and T. Chown, "Network Reconnaissance in IPv6
Networks", draft-ietf-opsec-ipv6-host-scanning-04 (work in Networks", draft-ietf-opsec-ipv6-host-scanning-04 (work in
progress), June 2014. progress), June 2014.
[I-D.templin-aerolink] [I-D.templin-aerolink]
Templin, F., "Transmission of IP Packets over AERO Links", Templin, F., "Transmission of IP Packets over AERO Links",
draft-templin-aerolink-40 (work in progress), September draft-templin-aerolink-44 (work in progress), October
2014. 2014.
[IEEE802] IEEE, "IEEE Standard for Local and Metropolitan Area [IEEE802] IEEE, "IEEE Standard for Local and Metropolitan Area
Networks: Overview and Architecture", IEEE Std 802-2001 Networks: Overview and Architecture", IEEE Std 802-2001
(R2007), 2007. (R2007), 2007.
[RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629, [RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
June 1999. June 1999.
[RFC3756] Nikander, P., Kempf, J., and E. Nordmark, "IPv6 Neighbor [RFC3756] Nikander, P., Kempf, J., and E. Nordmark, "IPv6 Neighbor
 End of changes. 19 change blocks. 
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