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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