draft-ietf-6man-reserved-iids-03.txt   rfc5453.txt 
Network Working Group S. Krishnan Network Working Group S. Krishnan
Internet-Draft Ericsson Request for Comments: 5453 Ericsson
Intended status: Standards Track December 3, 2008 Category: Standards Track February 2009
Expires: June 6, 2009
Reserved IPv6 Interface Identifiers Reserved IPv6 Interface Identifiers
draft-ietf-6man-reserved-iids-03
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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. Introduction ....................................................2
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Applicability ..............................................2
2.1. Applicability . . . . . . . . . . . . . . . . . . . . . . 4 1.2. Requirements Notation ......................................3
3. Issues with reusing reserved Interface Identifiers . . . . . . 5 2. Issues with Reusing Reserved Interface Identifiers ..............3
3.1. Possible solutions . . . . . . . . . . . . . . . . . . . . 5 2.1. Possible Solutions .........................................3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 3. IANA Considerations .............................................3
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7 4. Acknowledgements ................................................4
6. Security Considerations . . . . . . . . . . . . . . . . . . . 8 5. Security Considerations .........................................4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 6. References ......................................................5
7.1. Normative References . . . . . . . . . . . . . . . . . . . 9 6.1. Normative References .......................................5
7.2. Informative References . . . . . . . . . . . . . . . . . . 9 6.2. Informative References .....................................5
Appendix A. List of potentially affected RFCs . . . . . . . . . . 10 Appendix A. List of Potentially Affected RFCs ......................6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 11
Intellectual Property and Copyright Statements . . . . . . . . . . 12
1. Requirements notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
2. Introduction 1. 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
and an interface identifier (IID) that identifies an unique interface an interface identifier (IID) that identifies a 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 "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 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. Examples of mechanisms that constructed in Modified EUI-64 format [RFC4291]. Examples of
generate interface identifiers without an unique token include mechanisms that generate interface identifiers without a unique token
Cryptographically Generated Addresses [RFC3972], Privacy Addresses include Cryptographically Generated Addresses [RFC3972], Privacy
[RFC4941], Hash Based Addresses [HBA] etc. Non-unique interface Addresses [RFC4941], Hash-Based Addresses [HBA], etc. Non-unique
identifiers can also be allocated using managed address assignment interface identifiers can also be allocated using managed address
mechanisms like DHCPv6 [RFC3315]. assignment mechanisms like DHCPv6 (Dynamic Host Configuration
Protocol for IPv6) [RFC3315].
2.1. Applicability 1.1. Applicability
This document applies only to interface identifiers that are formed This document applies only to interface identifiers that are formed
in the modified EUI-64 format as defined in Appendix A of [RFC4291]. in the modified EUI-64 format as defined in Appendix A of [RFC4291].
All other types of interface identifiers are out of scope. All other types of interface identifiers are out of its scope.
3. Issues with reusing reserved Interface Identifiers 1.2. Requirements Notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
2. 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
ffff:ffff:fff . This node will receive requests from all nodes that fdff:ffff:ffff:ffff. This node will receive requests from all nodes
are requesting a service from a MobileIPv6 home agent since the above that are requesting a service from a Mobile IPv6 home agent since the
mentioned interface identifier has been reserved in [RFC2526] to above-mentioned interface identifier has been reserved in [RFC2526]
serve as a MIPv6 home agents anycast address. At best this is an to serve as a MIPv6 home agent's anycast address. At best, this is
annoyance to the node that came up with this address. In the worst an annoyance to the node that came up with this address. At worst,
case scenario another node on the link would be denied service and another node on the link would be denied service and may not look for
may not look for other methods of acquiring a home agent. Thus, such other methods of acquiring a home agent. Thus, such reserved
reserved interface identifiers MUST NOT be used for autonomous auto- interface identifiers MUST NOT be used for autonomous
configuration or for managed address configuration. autoconfiguration or for managed address configuration.
3.1. Possible solutions 2.1. 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 a
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 would be to create an IANA registry for such
such interface identifiers. There are two disadvantages to the interface identifiers. There are two disadvantages to the normative
normative reference approach. Firstly, this approach does not scale reference approach. Firstly, this approach does not scale well
well. This is because the number of such specifications that need to because the number of such specifications that would need to be
be updated is large. Secondly, the maturity level of the document updated is large. Secondly, the maturity level of the document
reserving the IID might be lower than the one prohibited from using reserving the IID might be lower than the one prohibited from using
it. This will cause a downward reference problem. Therefore the it; this will cause a downward reference problem. Therefore, the
better solution is to create an IANA registry for this purpose. better solution is to create an IANA registry for this purpose.
4. IANA Considerations 3. IANA Considerations
This document requests the creation of an IANA registry for reserved This document creates an IANA registry for reserved IPv6 interface
IPv6 Interface Identifiers. Initial values for the reserved IPv6 identifiers. Initial values for the reserved IPv6 interface
Interface Identifiers are given below. identifiers are given below.
+-----------------------------------------+-------------------------+ +-----------------------------------------+-------------------------+
| Interface Identifier Range | Description | | Interface Identifier Range | Description |
+-----------------------------------------+-------------------------+ +-----------------------------------------+-------------------------+
| 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] |
+-----------------------------------------+-------------------------+ +-----------------------------------------+-------------------------+
skipping to change at page 6, line 31 skipping to change at page 4, line 25
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. Future assignments, assignments from this registry are discouraged. Future assignments,
if any, 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: The address :: (all zeros in the interface identifier field) is
identifier field) is used as the unspecified address and ::/0 is used used as the unspecified address and ::/0 is used as a default route
as a default route indicator, as specified in [RFC5156]. These uses indicator, as specified in [RFC5156]. These uses do not conflict
do not conflict with the reserved interface identifiers defined here, with the reserved interface identifiers defined here, since the
since the reserved identifiers defined in this document are used for reserved identifiers defined in this document are used for avoiding
avoiding conflicts with stateless address autoconfiguration that conflicts with stateless address autoconfiguration that utilizes a
utilizes a 64 bit prefix length. 64-bit prefix length.
5. Acknowledgements 4. 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, Ed
Petrescu, Ed Jankiewicz, Brian Carpenter, Alfred Hoenes, Jari Arkko, Jankiewicz, Brian Carpenter, Alfred Hoenes, Jari Arkko, Pasi Eronen,
Pasi Eronen, Tim Polk, Lars Eggert, Derek Atkins and Robert Sparks Tim Polk, Lars Eggert, Derek Atkins, and Robert Sparks for reviewing
for reviewing this document and suggesting changes. this document and suggesting changes.
6. Security Considerations 5. Security Considerations
By utilizing one of the reserved interface identifiers, an IPv6 node By utilizing one of the reserved interface identifiers, an IPv6 node
might receive requests that it is not authorized to receive. might receive requests that it is not authorized to receive.
Information that creates or updates a registration in this registry Information that creates or updates a registration in this registry
needs to be authenticated and authorized by the IANA based on the needs to be authenticated and authorized by the IANA based on the
instructions set forth by [RFC5226]. instructions set forth by [RFC5226].
7. References 6. References
7.1. Normative References 6.1. 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.
[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 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226, IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008. May 2008.
7.2. Informative References 6.2. Informative References
[HBA] Bagnulo, M., "Hash Based Addresses (HBA)", [HBA] Bagnulo, M., "Hash Based Addresses (HBA)", Work in
draft-ietf-shim6-hba-05 (work in progress), October 2006. Progress, October 2006.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., [RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins,
and M. Carney, "Dynamic Host Configuration Protocol for C., and M. Carney, "Dynamic Host Configuration Protocol
IPv6 (DHCPv6)", RFC 3315, July 2003. for 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 [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy
Extensions for Stateless Address Autoconfiguration in Extensions for Stateless Address Autoconfiguration in
IPv6", RFC 4941, September 2007. IPv6", RFC 4941, September 2007.
[RFC5156] Blanchet, M., "Special-Use IPv6 Addresses", RFC 5156, [RFC5156] Blanchet, M., "Special-Use IPv6 Addresses", RFC 5156,
April 2008. April 2008.
Appendix A. List of potentially affected RFCs Appendix A. List of Potentially Affected RFCs
The following RFCs that generate interface identifiers need to be Implementations of the following RFCs need to be aware of the
updated if they wish to avoid conflicts with the reserved interface reserved interface identifier ranges when they allocate new
identifier ranges. addresses. Future revisions of these RFCs should ensure that this is
either already sufficiently clear or that the text is amended to take
this into account.
o RFC2590 - Transmission of IPv6 Packets over Frame Relay Networks o RFC2590 - Transmission of IPv6 Packets over Frame Relay Networks
Specification
o RFC3315 - Dynamic Host Configuration Protocol for IPv6 (DHCPv6) o RFC3315 - Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
o RFC3972 - Cryptographically Generated Addresses (CGA) o RFC3972 - Cryptographically Generated Addresses (CGA)
o RFC4489 - A Method for Generating Link-Scoped IPv6 Multicast o RFC4489 - A Method for Generating Link-Scoped IPv6 Multicast
Addresses Addresses
o RFC4862 - IPv6 Stateless Address Autoconfiguration o RFC4862 - IPv6 Stateless Address Autoconfiguration
o RFC4941 - Privacy Extensions for Stateless Address o RFC4941 - Privacy Extensions for Stateless Address
Autoconfiguration in IPv6 Autoconfiguration in IPv6
o RFC5072 - IP Version 6 over PPP o RFC 4982 - Support for Multiple Hash Algorithms in
Cryptographically Generated Addresses (CGAs)
o RFC4982 - Support for Multiple Hash Algorithms in CGAs o RFC 5072 - IP Version 6 over PPP
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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