draft-ietf-6man-reserved-iids-00.txt   draft-ietf-6man-reserved-iids-01.txt 
Network Working Group S. Krishnan Network Working Group S. Krishnan
Internet-Draft Ericsson Internet-Draft Ericsson
Intended status: Standards Track February 8, 2008 Intended status: Standards Track July 14, 2008
Expires: August 11, 2008 Expires: January 15, 2009
Reserved IPv6 Interface Identifiers Reserved IPv6 Interface Identifiers
draft-ietf-6man-reserved-iids-00 draft-ietf-6man-reserved-iids-01
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
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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
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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
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This Internet-Draft will expire on August 11, 2008. This Internet-Draft will expire on January 15, 2009.
Copyright Notice
Copyright (C) The IETF Trust (2008).
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
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Intellectual Property and Copyright Statements . . . . . . . . . . 11 Intellectual Property and Copyright Statements . . . . . . . . . . 11
1. Requirements notation 1. Requirements notation
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 [RFC2119]. document are to be interpreted as described in [RFC2119].
2. Introduction 2. Introduction
An IPv6 unicast address is composed of two parts. A subnet prefix An IPv6 unicast address is composed of two parts : A subnet prefix
and an interface identifier (IID) that identifies an unique interface and an interface identifier (IID) that identifies an unique interface
within the subnet prefix. The structure of an IPv6 unicast address within the subnet prefix. The structure of an IPv6 unicast address
is depicted in the IPv6 Addressing Architecture [RFC4291] and is is depicted in the IPv6 Addressing Architecture [RFC4291] and is
replicated here for clarity. replicated here for clarity.
| 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 binary value For all unicast addresses, except those that start with binary value
000, Interface identifiers are required to be 64 bits long (i.e. 000, interface identifiers are required to be 64 bits long (i.e.
n==64) . If the interface identifiers are generated from an unique n==64) . If the interface identifiers are generated from an unique
token like an ethernet MAC address, they need to set bit 6 of the token like an ethernet MAC address, they need to set bit 6 of the
first octet to one. If they are not generated from an unique token first octet to one. If they are not generated from an unique token
they need to set bit 6 to zero. Examples of mechanisms that generate they need to set bit 6 to zero. Examples of mechanisms that generate
interface identifiers without an unique token include interface identifiers without an unique token include
Cryptographically Generated Addresses [RFC3972], Privacy Addresses Cryptographically Generated Addresses [RFC3972], Privacy Addresses
[PRIVACY], Hash Based Addresses [HBA] etc. Non-unique interface [RFC4941], Hash Based Addresses [HBA] etc. Non-unique interface
identifiers can also be allocated using managed address assignment identifiers can also be allocated using managed address assignment
mechanisms like DHCPv6 [RFC3315]. mechanisms like DHCPv6 [RFC3315].
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 [PRIVACY] comes up with an IID of fdff: uses temporary IPv6 addresses [RFC4941] comes up with an IID of fdff:
ffff:ffff:fffe . 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. At best this are requesting a service from a MobileIPv6 home agent since the above
is an annoyance to the node that came up with this address. In the mentioned interface identifier has been reserved in [RFC2526] to
worst case scenario another node on the link would be denied service serve as a MIPv6 home agents anycast address. At best this is an
and may not look for other methods of acquiring a home agent. Thus, annoyance to the node that came up with this address. In the worst
such reserved interface identifiers MUST NOT be used for autonomous case scenario another node on the link would be denied service and
auto-configuration or for managed address configuration. may not look for other methods of acquiring a home agent. Thus, such
reserved interface identifiers MUST NOT be used for autonomous auto-
configuration or for managed address configuration.
3.1. Possible solutions 3.1. Possible solutions
There are two possible ways to go about avoiding usage of these There are two possible ways to go about avoiding usage of these
reserved interface identifiers. One of them would be to add reserved interface identifiers. One of them would be to add
normative reference to each specification that reserves an interface normative reference to each specification that reserves an interface
identifier. The other one would be to create an IANA registry for identifier. The other one would be to create an IANA registry for
such interface identifiers. There are two disadvantages to the such interface identifiers. There are two disadvantages to the
normative reference approach. Firstly, this approach does not scale normative reference approach. Firstly, this approach does not scale
well. This is because the number of such specifications can need to well. This is because the number of such specifications can need to
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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 | | 0000:0000:0000:0000-0000:0000:0000:0000 | Subnet-Router Anycast |
| | [RFC4291] | | | [RFC4291] |
| | | | | |
| fdff:ffff:ffff:ff80-fdff:ffff:ffff:fffd | Reserved Subnet Anycast | | fdff:ffff:ffff:ff80-fdff:ffff:ffff:fffd | Reserved Subnet Anycast |
| | [RFC2526] | | | [RFC2526] |
| | | | | |
| fdff:ffff:ffff:fffe-fdff:ffff:ffff:fffe | MobileIPv6 Home Agents | | fdff:ffff:ffff:fffe-fdff:ffff:ffff:fffe | MobileIPv6 Home Agents |
| | Anycast [RFC2526] | | | Anycast [RFC2526] |
| | | | | |
| fdff:ffff:ffff:ffff-fdff:ffff:ffff:ffff | Reserved Subnet Anycast | | fdff:ffff:ffff:ffff-fdff:ffff:ffff:ffff | Reserved Subnet Anycast |
| | [RFC2526] | | | [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 but in exceptional
circumstances are to be made through Standards Action [IANABIS]. circumstances 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 ::/128 (all zeros in the interface
identifier field) is used as an unspecified address and ::/0 (again
all zeros in the interface identifier field) is used as a default
route indicator as specified in [RFC5156]. These do not necessarily
conflict 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 uses
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 and Tim Enos for Martinez, Pekka Savola, Remi Denis-Courmount, Tim Enos, Alex
reviewing this document and suggesting changes. Petrescu, Ed Jankiewicz and Brian Carpenter for reviewing this
document and suggesting changes.
6. Security Considerations 6. Security Considerations
Information that creates or updates a registration needs to be Information that creates or updates a registration needs to be
authenticated and authorized. By utilizing one of the reserved authenticated and authorized. By utilizing one of the reserved
interface identifiers an IPv6 node might receive requests that it is interface identifiers an IPv6 node might receive requests that it is
not authorized to receive. not authorized to receive.
7. References 7. References
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[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.
[RFC2526] Johnson, D. and S. Deering, "Reserved IPv6 Subnet Anycast [RFC2526] Johnson, D. and S. Deering, "Reserved IPv6 Subnet Anycast
Addresses", RFC 2526, March 1999. Addresses", RFC 2526, March 1999.
[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.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
7.2. Informative References 7.2. Informative References
[HBA] Bagnulo, M., "Hash Based Addresses (HBA)", [HBA] Bagnulo, M., "Hash Based Addresses (HBA)",
draft-ietf-shim6-hba-02 (work in progress), October 2006. draft-ietf-shim6-hba-02 (work in progress), October 2006.
[IANABIS] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs",
draft-narten-iana-considerations-rfc2434bis-05 (work in
progress), September 2006.
[PRIVACY] Narten, T., Draves, R., and S. Krishnan, "Privacy
Extensions for Stateless Address Autoconfiguration in
IPv6", draft-ietf-ipv6-privacy-addrs-v2-05 (work in
progress), October 2006.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
and M. Carney, "Dynamic Host Configuration Protocol for and M. Carney, "Dynamic Host Configuration Protocol for
IPv6 (DHCPv6)", RFC 3315, July 2003. IPv6 (DHCPv6)", RFC 3315, July 2003.
[RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)", [RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)",
RFC 3972, March 2005. RFC 3972, March 2005.
[RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy
Extensions for Stateless Address Autoconfiguration in
IPv6", RFC 4941, September 2007.
[RFC5156] Blanchet, M., "Special-Use IPv6 Addresses", RFC 5156,
April 2008.
Author's Address Author's Address
Suresh Krishnan Suresh Krishnan
Ericsson Ericsson
8400 Decarie Blvd. 8400 Decarie Blvd.
Town of Mount Royal, QC Town of Mount Royal, QC
Canada Canada
Phone: +1 514 345 7900 x42871 Phone: +1 514 345 7900 x42871
Email: suresh.krishnan@ericsson.com Email: suresh.krishnan@ericsson.com
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attempt made to obtain a general license or permission for the use of attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr. http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at this standard. Please address the information to the IETF at
ietf-ipr@ietf.org. ietf-ipr@ietf.org.
Acknowledgment
Funding for the RFC Editor function is provided by the IETF
Administrative Support Activity (IASA).
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