draft-ietf-v6ops-addr-select-ps-08.txt		draft-ietf-v6ops-addr-select-ps-09.txt
	IPv6 Operations Working Group A. Matsumoto		IPv6 Operations Working Group A. Matsumoto
	Internet-Draft T. Fujisaki		Internet-Draft T. Fujisaki
	Intended status: Informational NTT		Intended status: Informational NTT
	Expires: December 14, 2008 R. Hiromi		Expires: December 19, 2008 R. Hiromi
	Intec Netcore		Intec Netcore
	K. Kanayama		K. Kanayama
	INTEC Systems		INTEC Systems
	June 12, 2008		June 17, 2008
	Problem Statement of Default Address Selection in Multi-prefix		Problem Statement of Default Address Selection in Multi-prefix
	Environment: Operational Issues of RFC3484 Default Rules		Environment: Operational Issues of RFC3484 Default Rules
	draft-ietf-v6ops-addr-select-ps-08.txt		draft-ietf-v6ops-addr-select-ps-09.txt
	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
	skipping to change at page 1, line 39		skipping to change at page 1, line 39
	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 December 14, 2008.		This Internet-Draft will expire on December 19, 2008.
	Copyright Notice
	Copyright (C) The IETF Trust (2008).
	Abstract		Abstract
	A single physical link can have multiple prefixes assigned to it. In		A single physical link can have multiple prefixes assigned to it. In
	that environment, end hosts might have multiple IP addresses and be		that environment, end hosts might have multiple IP addresses and be
	required to use them selectively. RFC 3484 defines default source		required to use them selectively. RFC 3484 defines default source
	and destination address selection rules and is implemented in a		and destination address selection rules and is implemented in a
	variety of OS's. But, it has been too difficult to use operationally		variety of OS's. But, it has been too difficult to use operationally
	for several reasons. In some environment where multiple prefixes are		for several reasons. In some environment where multiple prefixes are
	assigned on a single physical link, the host using the default		assigned on a single physical link, the host using the default
	skipping to change at page 2, line 36		skipping to change at page 2, line 32
	2.2.1. IPv4 or IPv6 prioritization . . . . . . . . . . . . . 10		2.2.1. IPv4 or IPv6 prioritization . . . . . . . . . . . . . 10
	2.2.2. ULA and IPv4 dual-stack environment . . . . . . . . . 11		2.2.2. ULA and IPv4 dual-stack environment . . . . . . . . . 11
	2.2.3. ULA or Global Prioritization . . . . . . . . . . . . . 12		2.2.3. ULA or Global Prioritization . . . . . . . . . . . . . 12
	3. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . 13		3. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . 13
	4. Security Considerations . . . . . . . . . . . . . . . . . . . 14		4. Security Considerations . . . . . . . . . . . . . . . . . . . 14
	5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14		5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
	6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14		6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
	6.1. Normative References . . . . . . . . . . . . . . . . . . . 14		6.1. Normative References . . . . . . . . . . . . . . . . . . . 14
	6.2. Informative References . . . . . . . . . . . . . . . . . . 15		6.2. Informative References . . . . . . . . . . . . . . . . . . 15
	Appendix A. Appendix. Revision History . . . . . . . . . . . . . 15		Appendix A. Appendix. Revision History . . . . . . . . . . . . . 15
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
	Intellectual Property and Copyright Statements . . . . . . . . . . 17		Intellectual Property and Copyright Statements . . . . . . . . . . 17
	1. Introduction		1. Introduction
	In IPv6, a single physical link can have multiple prefixes assigned		In IPv6, a single physical link can have multiple prefixes assigned
	to it. In such cases, an end-host may have multiple IP addresses		to it. In such cases, an end-host may have multiple IP addresses
	assigned to an interface on that link. In the IPv4-IPv6 dual stack		assigned to an interface on that link. In the IPv4-IPv6 dual stack
	environment or in a site connected to both a ULA [RFC4193] and		environment or in a site connected to both a ULA [RFC4193] and
	Globally routable networks, an end-host typically has multiple IP		Globally routable networks, an end-host typically has multiple IP
	addresses. These are examples of the networks that we focus on in		addresses. These are examples of the networks that we focus on in
	this document. In such an environment, an end-host may encounter		this document. In such an environment, an end-host may encounter
	some communication troubles.		some communication troubles.
	Inappropriate source address selection at the end-host causes		Inappropriate source address selection at the end-host causes
	unexpected asymmetric routing, filtering by a router or discarding of		unexpected asymmetric routing, filtering by a router or discarding of
	packets bacause there is no route to the host.		packets because there is no route to the host.
	Considering a multi-prefix environment, destination address selection		Considering a multi-prefix environment, destination address selection
	is also important for correct or better communication establishment.		is also important for correct or better communication establishment.
	RFC 3484 [RFC3484] defines default source and destination address		RFC 3484 [RFC3484] defines default source and destination address
	selection algorithms and is implemented in a variety of OS's. But,		selection algorithms and is implemented in a variety of OS's. But,
	it has been too difficult to use operationally for several reasons,		it has been too difficult to use operationally for several reasons,
	such as lack of autoconfiguration method. There are some problematic		such as lack of autoconfiguration method. There are some problematic
	cases where the hosts using the default address selection rules		cases where the hosts using the default address selection rules
	encounter communication troubles.		encounter communication troubles.
	skipping to change at page 3, line 40		skipping to change at page 3, line 40
	This document describes such possibilities of incorrect address		This document describes such possibilities of incorrect address
	selection which leads to dropping packets and communication failure.		selection which leads to dropping packets and communication failure.
	1.1. Scope of this document		1.1. Scope of this document
	As other mechanisms already exist, the multi-homing techniques for		As other mechanisms already exist, the multi-homing techniques for
	achieving redundancy are basically out of our scope.		achieving redundancy are basically out of our scope.
	We focus on an end-site network environment and unmanaged hosts in		We focus on an end-site network environment and unmanaged hosts in
	such an environment. This is because address selection behavior at		such an environment. This is because address selection behavior at
	this kind of hosts is difficult to manipulate owing to the users's		this kind of hosts is difficult to manipulate owing to the users'
	lack of knowledge, hosts' location, or massiveness of the hosts.		lack of knowledge, hosts' location, or massiveness of the hosts.
	The scope of this document is to sort out problematic cases related		The scope of this document is to sort out problematic cases related
	to address selection. It includes problems that can be solved in the		to address selection. It includes problems that can be solved in the
	framework of RFC 3484 and problems that cannot. For the latter, RFC		framework of RFC 3484 and problems that cannot. For the latter, RFC
	3484 might be modified to meet their needs, or another address		3484 might be modified to meet their needs, or another address
	selection solution might be necessary. For the former, an additional		selection solution might be necessary. For the former, an additional
	mechanism that mitigates the operational difficulty might be		mechanism that mitigates the operational difficulty might be
	necessary.		necessary.
	skipping to change at page 7, line 18		skipping to change at page 7, line 18
	matching algorithm chooses 2001:db8:8000:1::100 for the source		matching algorithm chooses 2001:db8:8000:1::100 for the source
	address. In this case, the packet goes through ISP1 and may be		address. In this case, the packet goes through ISP1 and may be
	filtered by ISP1's ingress filter. Even if the packet is not		filtered by ISP1's ingress filter. Even if the packet is not
	filtered by ISP1, a return packet from Host-C cannot possibly be		filtered by ISP1, a return packet from Host-C cannot possibly be
	delivered to Host-A because the return packet is destined for 2001:		delivered to Host-A because the return packet is destined for 2001:
	db8:8000:1::100, which is closed from the Internet.		db8:8000:1::100, which is closed from the Internet.
	The important point is that each host chooses a correct source		The important point is that each host chooses a correct source
	address for a given destination address. To solve this kind of		address for a given destination address. To solve this kind of
	network policy based address selection problems, it is likely that		network policy based address selection problems, it is likely that
	delivering addtional information to a node fits better than		delivering additional information to a node fits better than
	algorithmic solutions that are local to the node.		algorithmic solutions that are local to the node.
	Solution analysis:		Solution analysis:
	This problem can be solved in the RFC 3484 framework. For		This problem can be solved in the RFC 3484 framework. For
	example, configuring some address selection policies into Host-A's		example, configuring some address selection policies into Host-A's
	RFC 3484 policy table can solve this problem.		RFC 3484 policy table can solve this problem.
	2.1.4. Combined Use of Global and ULA		2.1.4. Combined Use of Global and ULA
	============		============
	skipping to change at page 9, line 27		skipping to change at page 9, line 27
	[Fig. 5]		[Fig. 5]
	Solution analysis:		Solution analysis:
	This problem can be mitigated in the RFC 3484 framework. For		This problem can be mitigated in the RFC 3484 framework. For
	example, configuring some address selection policies into Host's		example, configuring some address selection policies into Host's
	RFC 3484 policy table can solve this problem.		RFC 3484 policy table can solve this problem.
	2.1.6. Multicast Source Address Selection		2.1.6. Multicast Source Address Selection
	This case is an example of site-local or global prioritization. When		This case is an example of site-local or global unicast
	you send a multicast packet across site-borders, the source address		prioritization. When you send a multicast packet across site-
	of the multicast packet should be a globally routable address. The		borders, the source address of the multicast packet should be a
	longest matching algorithm, however, selects a ULA if the sending		globally routable address. The longest matching algorithm, however,
	host has both a ULA and a Global Unicast Address.		selects a ULA if the sending host has both a ULA and a Global Unicast
			Address.
	Solution analysis:		Solution analysis:
	This problem can be solved in the RFC 3484 framework. For		This problem can be solved in the RFC 3484 framework. For
	example, configuring some address selection policies into the		example, configuring some address selection policies into the
	sending host's RFC 3484 policy table can solve this problem.		sending host's RFC 3484 policy table can solve this problem.
	2.1.7. Temporary Address Selection		2.1.7. Temporary Address Selection
	RFC 3041 [RFC3041] defines a Temporary Address. The usage of a		RFC 3041 [RFC3041] defines a Temporary Address. The usage of a
	Temporary Address has both pros and cons. That is good for viewing		Temporary Address has both pros and cons. That is good for viewing
	skipping to change at page 10, line 13		skipping to change at page 10, line 13
	IPv6 [RFC3775] network.		IPv6 [RFC3775] network.
	The Future Work section in RFC 3041 discusses that an API extension		The Future Work section in RFC 3041 discusses that an API extension
	might be necessary to achieve a better address selection mechanism		might be necessary to achieve a better address selection mechanism
	with finer granularity.		with finer granularity.
	Solution analysis:		Solution analysis:
	This problem can not be solved in the RFC 3484 framework. A		This problem can not be solved in the RFC 3484 framework. A
	possible solution is to make applications to select desirable		possible solution is to make applications to select desirable
	addresses by using the IPv6 Socket API for Source Address		addresses by using the IPv6 Socket API for Source Address
	Selection defind in RFC 5014 [RFC5014].		Selection defined in RFC 5014 [RFC5014].
	2.2. Destination Address Selection		2.2. Destination Address Selection
	2.2.1. IPv4 or IPv6 prioritization		2.2.1. IPv4 or IPv6 prioritization
	The default policy table gives IPv6 addresses higher precedence than		The default policy table gives IPv6 addresses higher precedence than
	IPv4 addresses. There seem to be many cases, however, where network		IPv4 addresses. There seem to be many cases, however, where network
	administrators want to control the address selection policy of end-		administrators want to control the address selection policy of end-
	hosts the other way around.		hosts the other way around.
	skipping to change at page 15, line 29		skipping to change at page 15, line 29
	[RFC5014] Nordmark, E., Chakrabarti, S., and J. Laganier, "IPv6		[RFC5014] Nordmark, E., Chakrabarti, S., and J. Laganier, "IPv6
	Socket API for Source Address Selection", RFC 5014,		Socket API for Source Address Selection", RFC 5014,
	September 2007.		September 2007.
	6.2. Informative References		6.2. Informative References
	Appendix A. Appendix. Revision History		Appendix A. Appendix. Revision History
	01:		01:
	IP addresse notations changed to documentation address.		IP address notations changed to documentation address.
	Description of solutions deleted.		Description of solutions deleted.
	02:		02:
	Security considerations section rewritten according to comments		Security considerations section rewritten according to comments
	from SECDIR.		from SECDIR.
	03:		03:
	Intended status changed to Informational.		Intended status changed to Informational.
	04:		04:
	This version reflects comments from IESG members.		This version reflects comments from IESG members.
	05:		05:
	This version reflects comments from IESG members and Bob Hinden.		This version reflects comments from IESG members and Bob Hinden.
	06:		06:
	This version reflects comments from Thomas Narten.		This version reflects comments from Thomas Narten.
	07:		07:
	This version reflects comments from Alfred Hoenes.		This version reflects comments from Alfred Hoenes.
	08:		08:
	Solution analysis for the section 2.1.6 was added.		Solution analysis for the section 2.1.6 was added.
			09:
			Typos were fixed, thanks to Jari Arrko.
	Authors' Addresses		Authors' Addresses
	Arifumi Matsumoto		Arifumi Matsumoto
	NTT PF Lab		NTT PF Lab
	Midori-Cho 3-9-11		Midori-Cho 3-9-11
	Musashino-shi, Tokyo 180-8585		Musashino-shi, Tokyo 180-8585
	Japan		Japan
	Phone: +81 422 59 3334		Phone: +81 422 59 3334
	skipping to change at page 17, line 44		skipping to change at line 747
	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).
End of changes. 13 change blocks.
	19 lines changed or deleted		19 lines changed or added
This html diff was produced by rfcdiff 1.35. The latest version is available from http://tools.ietf.org/tools/rfcdiff/