draft-ietf-6man-reserved-iids-02.txt   draft-ietf-6man-reserved-iids-03.txt 
Network Working Group S. Krishnan Network Working Group S. Krishnan
Internet-Draft Ericsson Internet-Draft Ericsson
Intended status: Standards Track December 2, 2008 Intended status: Standards Track December 3, 2008
Expires: June 5, 2009 Expires: June 6, 2009
Reserved IPv6 Interface Identifiers Reserved IPv6 Interface Identifiers
draft-ietf-6man-reserved-iids-02 draft-ietf-6man-reserved-iids-03
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
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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."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on June 5, 2009. This Internet-Draft will expire on June 6, 2009.
Abstract Abstract
Interface Identifiers in IPv6 unicast addresses are used to identify Interface Identifiers in IPv6 unicast addresses are used to identify
interfaces on a link. They are required to be unique within a interfaces on a link. They are required to be unique within a
subnet. Several RFCs have specified interface identifiers or subnet. Several RFCs have specified interface identifiers or
identifier ranges that have a special meaning attached to them. An identifier ranges that have a special meaning attached to them. An
IPv6 node autoconfiguring an interface identifier in these ranges IPv6 node autoconfiguring an interface identifier in these ranges
will encounter unexpected consequences. Since there is no will encounter unexpected consequences. Since there is no
centralized repository for such reserved identifiers, this document centralized repository for such reserved identifiers, this document
aims to create one. aims to create one.
Table of Contents Table of Contents
1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Applicability . . . . . . . . . . . . . . . . . . . . . . 4
3. Issues with reusing reserved Interface Identifiers . . . . . . 5 3. Issues with reusing reserved Interface Identifiers . . . . . . 5
3.1. Possible solutions . . . . . . . . . . . . . . . . . . . . 5 3.1. Possible solutions . . . . . . . . . . . . . . . . . . . . 5
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . 8 6. Security Considerations . . . . . . . . . . . . . . . . . . . 8
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9
7.1. Normative References . . . . . . . . . . . . . . . . . . . 9 7.1. Normative References . . . . . . . . . . . . . . . . . . . 9
7.2. Informative References . . . . . . . . . . . . . . . . . . 9 7.2. Informative References . . . . . . . . . . . . . . . . . . 9
Appendix A. List of potentially affected RFCs . . . . . . . . . . 10 Appendix A. List of potentially affected RFCs . . . . . . . . . . 10
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 11 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 11
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| n bits | 128-n bits | | n bits | 128-n bits |
+-------------------------------+---------------------------------+ +-------------------------------+---------------------------------+
| subnet prefix | interface ID | | subnet prefix | interface ID |
+-------------------------------+---------------------------------+ +-------------------------------+---------------------------------+
Figure 1: IPv6 Unicast Address Format Figure 1: IPv6 Unicast Address Format
For all unicast addresses, except those that start with the binary For all unicast addresses, except those that start with the binary
value 000, Interface IDs are required to be 64 bits long and to be value 000, Interface IDs are required to be 64 bits long and to be
constructed in Modified EUI-64 format. If the interface identifiers constructed in Modified EUI-64 format. Examples of mechanisms that
are generated from an unique token like an ethernet MAC address, they generate interface identifiers without an unique token include
need to set bit 6 of the first octet to one. If they are not Cryptographically Generated Addresses [RFC3972], Privacy Addresses
generated from an unique token they need to set bit 6 to zero. [RFC4941], Hash Based Addresses [HBA] etc. Non-unique interface
Examples of mechanisms that generate interface identifiers without an identifiers can also be allocated using managed address assignment
unique token include Cryptographically Generated Addresses [RFC3972], mechanisms like DHCPv6 [RFC3315].
Privacy Addresses [RFC4941], Hash Based Addresses [HBA] etc. Non-
unique interface identifiers can also be allocated using managed 2.1. Applicability
address assignment mechanisms like DHCPv6 [RFC3315].
This document applies only to interface identifiers that are formed
in the modified EUI-64 format as defined in Appendix A of [RFC4291].
All other types of interface identifiers are out of scope.
3. Issues with reusing reserved Interface Identifiers 3. Issues with reusing reserved Interface Identifiers
Let us assume a node comes up with an interface identifier that has Let us assume a node comes up with an interface identifier that has
been reserved for use in some other capacity. e.g. An IPv6 node that been reserved for use in some other capacity. e.g. An IPv6 node that
uses temporary IPv6 addresses [RFC4941] comes up with an IID of fdff: uses temporary IPv6 addresses [RFC4941] comes up with an IID of fdff:
ffff:ffff:fff . This node will receive requests from all nodes that ffff:ffff:fff . This node will receive requests from all nodes that
are requesting a service from a MobileIPv6 home agent since the above are requesting a service from a MobileIPv6 home agent since the above
mentioned interface identifier has been reserved in [RFC2526] to mentioned interface identifier has been reserved in [RFC2526] to
serve as a MIPv6 home agents anycast address. At best this is an serve as a MIPv6 home agents anycast address. At best this is an
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4. IANA Considerations 4. IANA Considerations
This document requests the creation of an IANA registry for reserved This document requests the creation of an IANA registry for reserved
IPv6 Interface Identifiers. Initial values for the reserved IPv6 IPv6 Interface Identifiers. Initial values for the reserved IPv6
Interface Identifiers are given below. Interface Identifiers are given below.
+-----------------------------------------+-------------------------+ +-----------------------------------------+-------------------------+
| Interface Identifier Range | Description | | Interface Identifier Range | Description |
+-----------------------------------------+-------------------------+ +-----------------------------------------+-------------------------+
| 0000:0000:0000:0000-0000:0000:0000:0000 | Subnet-Router Anycast | | 0000:0000:0000:0000 | Subnet-Router Anycast |
| | [RFC4291] | | | [RFC4291] |
| | | | | |
| FDFF:FFFF:FFFF:FF80-FDFF:FFFF:FFFF:FFFF | Reserved Subnet Anycast | | FDFF:FFFF:FFFF:FF80-FDFF:FFFF:FFFF:FFFF | Reserved Subnet Anycast |
| | Addresses[RFC2526] | | | Addresses[RFC2526] |
+-----------------------------------------+-------------------------+ +-----------------------------------------+-------------------------+
Table 1: Current Assignments Table 1: Current Assignments
It is possible that implementations might predate a specific It is possible that implementations might predate a specific
assignment from this registry and hence not be cognizant of the assignment from this registry and hence not be cognizant of the
reserved nature of the interface identifier. Hence. future reserved nature of the interface identifier. Hence, future
assignments from this registry are discouraged but in exceptional assignments from this registry are discouraged. Future assignments,
circumstances are to be made through Standards Action [RFC5226]. if any, are to be made through Standards Action [RFC5226].
Assignments consist of a single interface identifier or a range of Assignments consist of a single interface identifier or a range of
interface identifiers. interface identifiers.
NOTE: Please note that the address :: (all zeros in the interface NOTE: Please note that the address :: (all zeros in the interface
identifier field) is used as the unspecified address. In addition, identifier field) is used as the unspecified address and ::/0 is used
many IETF protocols and data formats prescribe that the unused bits as a default route indicator, as specified in [RFC5156]. These uses
in prefixes be set to 0. Hence, prefixes with prefix lengths up to do not conflict with the reserved interface identifiers defined here,
64 are usually stored and transmitted with an interface identifier since the reserved identifiers defined in this document are used for
part of all zeros. This includes ::/0, used as a default route avoiding conflicts with stateless address autoconfiguration that
indicator, as specified in [RFC5156]. These uses do not conflict utilizes a 64 bit prefix length.
with the reserved interface identifiers defined here, since the
reserved identifiers defined in this document are used for avoiding
conflicts with stateless address autoconfiguration that utilizes a 64
bit prefix length.
5. Acknowledgements 5. Acknowledgements
The author would like to thank Alain Durand, Alex Petrescu, Bernie The author would like to thank Alain Durand, Alex Petrescu, Bernie
Volz, Bob Hinden, Christian Huitema, Fred Templin, Jordi Palet Volz, Bob Hinden, Christian Huitema, Fred Templin, Jordi Palet
Martinez, Pekka Savola, Remi Denis-Courmount, Tim Enos, Alex Martinez, Pekka Savola, Remi Denis-Courmount, Tim Enos, Alex
Petrescu, Ed Jankiewicz, Brian Carpenter, Alfred Hoenes, Jari Arkko, Petrescu, Ed Jankiewicz, Brian Carpenter, Alfred Hoenes, Jari Arkko,
Pasi Eronen, Tim Polk, Lars Eggert, Derek Atkins and Robert Sparks Pasi Eronen, Tim Polk, Lars Eggert, Derek Atkins and Robert Sparks
for reviewing this document and suggesting changes. for reviewing this document and suggesting changes.
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