draft-ietf-6man-uri-zoneid-01.txt		draft-ietf-6man-uri-zoneid-02.txt
	6MAN B. Carpenter		6MAN B. Carpenter
	Internet-Draft Univ. of Auckland		Internet-Draft Univ. of Auckland
	Updates: 3986, 4007 (if approved) R. Hinden		Updates: 3986, 4007 (if approved) R. Hinden
	Intended status: Standards Track Check Point		Intended status: Standards Track Check Point
	Expires: November 30, 2012 May 29, 2012		Expires: January 12, 2013 July 11, 2012
	Representing IPv6 Zone Identifiers in Uniform Resource Identifiers		Representing IPv6 Zone Identifiers in Address Literals and Uniform
	draft-ietf-6man-uri-zoneid-01		Resource Identifiers
			draft-ietf-6man-uri-zoneid-02
	Abstract		Abstract
	This document describes how the Zone Identifier of an IPv6 scoped		This document describes how the Zone Identifier of an IPv6 scoped
	address can be represented in a Uniform Resource Identifier that		address can be represented in a a literal IPv6 address and in a
	includes a literal IPv6 address. It updates RFC 3986 and RFC 4007.		Uniform Resource Identifier that includes such a literal address. It
			updates RFC 3986 and RFC 4007 accordingly.
	Status of this Memo		Status of this Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at http://datatracker.ietf.org/drafts/current/.		Drafts is at http://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	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."
	This Internet-Draft will expire on November 30, 2012.		This Internet-Draft will expire on January 12, 2013.
	Copyright Notice		Copyright Notice
	Copyright (c) 2012 IETF Trust and the persons identified as the		Copyright (c) 2012 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 2, line 10		skipping to change at page 2, line 11
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
	2. Specification . . . . . . . . . . . . . . . . . . . . . . . . . 4		2. Specification . . . . . . . . . . . . . . . . . . . . . . . . . 4
	3. Web Browsers . . . . . . . . . . . . . . . . . . . . . . . . . 5		3. Web Browsers . . . . . . . . . . . . . . . . . . . . . . . . . 5
	4. Security Considerations . . . . . . . . . . . . . . . . . . . . 5		4. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
	5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6		5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
	6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6		6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6
	7. Change log [RFC Editor: Please remove] . . . . . . . . . . . . 6		7. Change log [RFC Editor: Please remove] . . . . . . . . . . . . 7
	8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7		8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
	8.1. Normative References . . . . . . . . . . . . . . . . . . . 7		8.1. Normative References . . . . . . . . . . . . . . . . . . . 7
	8.2. Informative References . . . . . . . . . . . . . . . . . . 7		8.2. Informative References . . . . . . . . . . . . . . . . . . 8
	Appendix A. Alternatives Considered . . . . . . . . . . . . . . . 7		Appendix A. Alternatives Considered . . . . . . . . . . . . . . . 8
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9
	1. Introduction		1. Introduction
	[RFC3986] defined how a literal IPv6 address can be represented in		[RFC3986] defined how a literal IPv6 address can be represented in
	the "host" part of a Uniform Resource Identifier (URI).		the "host" part of a Uniform Resource Identifier (URI).
	Subsequently, [RFC4007] extended the text representation of limited-		Subsequently, [RFC4007] extended the text representation of limited-
	scope IPv6 addresses such that a zone identifier may be concatenated		scope IPv6 addresses such that a zone identifier may be concatenated
	to an address, for purposes described in that RFC. Zone identifiers		to a literal address, for purposes described in that RFC. Zone
	are especially useful in contexts where literal addresses are		identifiers are especially useful in contexts where literal addresses
	typically used, for example during fault diagnosis, when it may be		are typically used, for example during fault diagnosis, when it may
	essential to specify which interface is used for sending to a link		be essential to specify which interface is used for sending to a link
	local address. It should be noted that zone identifiers have purely		local address. It should be noted that zone identifiers have purely
	local meaning within the host where they are defined, and they are		local meaning within the host where they are defined, and they are
	completely meaningless for any other host. Today, they are only		completely meaningless for any other host. Today, they are only
	meaningful when attached to addresses with link local scope, but it		meaningful when attached to addresses with less than global scope,
	is possible that other uses might be defined in the future.		but it is possible that other uses might be defined in the future.
	RFC 4007 does not specify how zone identifiers are to be represented		RFC 4007 does not specify how zone identifiers are to be represented
	in URIs. Practical experience has shown that this feature is useful,		in URIs. Practical experience has shown that this feature is useful,
	in particular when using a web browser for debugging with link local		in particular when using a web browser for debugging with link local
	addresses, but as it is undefined, it is not implemented consistently		addresses, but as it is undefined, it is not implemented consistently
	in URI parsers or in browsers.		in URI parsers or in browsers.
	Some versions of some browsers accept the RFC 4007 syntax for scoped		Some versions of some browsers accept the RFC 4007 syntax for scoped
	IPv6 addresses embedded in URIs, i.e., they have been coded to		IPv6 addresses embedded in URIs, i.e., they have been coded to
	interpret the "%" sign according to RFC 4007 instead of RFC 3986.		interpret the "%" sign according to RFC 4007 instead of RFC 3986.
	Clearly this approach is very convenient for users, although it		Clearly this approach is very convenient for users, although it
	formally breaches the syntax rules of RFC 3986. The present document		formally breaches the syntax rules of RFC 3986. The present document
	defines an alternative approach that respects and extends the rules		defines an alternative approach that respects and extends the rules
	of URI syntax.		of URI syntax, and IPv6 literals in general, to be consistent.
	Thus, this document updates [RFC3986] by adding syntax to allow a		Thus, this document updates [RFC3986] by adding syntax to allow a
	zone identifier to be included in a literal IPv6 address within a		zone identifier to be included in a literal IPv6 address within a
	URI. It also clarifies some statements in [RFC4007].		URI. It also updates [RFC4007], in particular by adding a second
			allowed delimiter for zone identifiers.
	It should be noted that in other contexts than a user interface, a		It should be noted that in other contexts than a user interface, a
	zone identifier is mapped into a numeric zone index or interface		zone identifier is mapped into a numeric zone index or interface
	number. The MIB textual convention [RFC4001] and the socket		number. The MIB textual convention [RFC4001] and the socket
	interface [RFC3493] define this as a 32 bit unsigned integer. The		interface [RFC3493] define this as a 32 bit unsigned integer. The
	mapping between the human-readable zone identifier string and the		mapping between the human-readable zone identifier string and the
	numeric value is a host-specific function that varies between		numeric value is a host-specific function that varies between
	operating systems. The present document is concerned only with the		operating systems. The present document is concerned only with the
	human-readable string.		human-readable string.
	skipping to change at page 5, line 11		skipping to change at page 5, line 11
	optionally to any literal address. This allows flexibility for		optionally to any literal address. This allows flexibility for
	unknown future uses. The rule quoted above from RFC 3986 is replaced		unknown future uses. The rule quoted above from RFC 3986 is replaced
	by three rules:		by three rules:
	IP-literal = "[" ( IPv6addrz / IPvFuture ) "]"		IP-literal = "[" ( IPv6addrz / IPvFuture ) "]"
	ZoneID = 1*( unreserved / pct-encoded )		ZoneID = 1*( unreserved / pct-encoded )
	IPv6addrz = IPv6address [ "-" ZoneID ]		IPv6addrz = IPv6address [ "-" ZoneID ]
			Section 11 of RFC 4007 is updated to allow "-" as well as "%" as the
			preceding delimiter of a ZoneID.
	The rules in [RFC5952] SHOULD be applied in producing URIs.		The rules in [RFC5952] SHOULD be applied in producing URIs.
			RFC 3986 states that URIs have a global scope, but that in some cases
			their interpretation depends on the end-user's context. URIs
			including a ZoneID are to be interpreted only in the context of the
			host where they originate, since the ZoneID is of local signifance
			only.
	The 6man WG discussed and rejected an alternative in which the		The 6man WG discussed and rejected an alternative in which the
	existing syntax of IPv6address would be extended by an option to add		existing syntax of IPv6address would be extended by an option to add
	the ZoneID only for the case of link-local addresses. It was felt		the ZoneID only for the case of link-local addresses. It was felt
	that the present solution offers more flexibility for future uses and		that the present solution offers more flexibility for future uses and
	is more straightforward to implement.		is more straightforward to implement.
	RFC 4007 offers guidance on how the ZoneID affects interface/address		RFC 4007 offers guidance on how the ZoneID affects interface/address
	selection inside the IPv6 stack. Note that the behaviour of an IPv6		selection inside the IPv6 stack. Note that the behaviour of an IPv6
	stack if passed a non-zero zone index for an address other than link-		stack if passed a non-zero zone index for an address other than link-
	local is undefined.		local is undefined.
	3. Web Browsers		3. Web Browsers
			Due to the lack of a standard in this area, web browsers have been
			inconsistent in providing for ZoneIDs. Many have no support, but
			there are examples of ad hoc support. For example, older versions of
			Firefox allowed the use of a ZoneID preceded by an unescaped "%"
			character, but this was removed for consistency with RFC 3986. As
			another example, recent versions of Internet Explorer allow use of a
			ZoneID preceded by a "%" character escaped as "%25", still beyond the
			syntax allowed by RFC 3986. This syntax extension is in fact used
			internally in the Windows operating system and some of its APIs.
	In recent years, web browsers have evolved considerably and now		In recent years, web browsers have evolved considerably and now
	accept and parse many forms of input that are not a formal URI.		accept and parse many forms of input that are not a formal URI.
	Examples of this include host names, search items, bookmarks, search		Examples of this include host names, search items, bookmarks, search
	history, etc. For example the Google Chrome browser now calls the		history, etc. For example the Google Chrome browser now calls the
	"address bar" the "omnibox" [chrome]. The authors believe it is		"address bar" the "omnibox" [chrome]. The authors believe it is
	feasible, and very convenient for users, if browsers also allow (in		feasible, and very convenient for users, if browsers also allow (in
	addition to the formal URI syntax defined in this document) a		addition to the formal URI syntax defined in this document) a syntax
	syntax that will enable cut and paste. For example:		that will enable cut and paste. For example:
	http://[fe80::a%en1]		http://[fe80::a%en1]
	It seems that modern browsers can be adapted to parse this because it		It seems that modern browsers can be adapted to parse this because it
	is inside of the "[" "]"'s. This would permit the output of commands		is inside of the "[" "]"'s. This would permit the output of commands
	like ping6 -w ff02::1%en1 to be "cut and pasted" into a browser		like ping6 -w ff02::1%en1 to be "cut and pasted" into a browser
	address bar. Consequently this document recommends that browsers		address bar. Consequently this document recommends that browsers
	support this syntax in addition to the formal URI syntax defined		support this syntax in addition to the formal URI syntax defined
	above.		above.
	skipping to change at page 6, line 13		skipping to change at page 6, line 31
	is intended only for debugging purposes, but of course this intention		is intended only for debugging purposes, but of course this intention
	does not prevent misuse.		does not prevent misuse.
	To limit this risk, implementations SHOULD NOT allow use of this		To limit this risk, implementations SHOULD NOT allow use of this
	format except for well-defined usages such as sending to link local		format except for well-defined usages such as sending to link local
	addresses under prefix fe80::/10.		addresses under prefix fe80::/10.
	An HTTP server or proxy MUST ignore any ZoneID attached to an		An HTTP server or proxy MUST ignore any ZoneID attached to an
	incoming URI, as it only has local significance at the sending host.		incoming URI, as it only has local significance at the sending host.
			The addition of a choice between "%" and "-" as the delimiter
			preceding a ZoneID slightly complicates the string comparison issue
			discussed in [I-D.iab-identifier-comparison].
	5. IANA Considerations		5. IANA Considerations
	This document requests no action by IANA.		This document requests no action by IANA.
	6. Acknowledgements		6. Acknowledgements
	The lack of this format was first pointed out by Margaret Wasserman		The lack of this format was first pointed out by Margaret Wasserman
	some years ago, and more recently by Kerry Lynn. A previous draft		some years ago, and more recently by Kerry Lynn. A previous draft
	document by Martin Duerst and Bill Fenner [I-D.fenner-literal-zone]		document by Martin Duerst and Bill Fenner [I-D.fenner-literal-zone]
	discussed this topic but was not finalised.		discussed this topic but was not finalised.
	Valuable comments and contributions were made by Karl Auer, Carsten		Valuable comments and contributions were made by Karl Auer, Carsten
	Bormann, Brian Haberman, Tatuya Jinmei, Tom Petch, Tomoyuki Sahara,		Bormann, Brian Haberman, Tatuya Jinmei, Tom Petch, Tomoyuki Sahara,
	Juergen Schoenwaelder, and Ole Troan.		Juergen Schoenwaelder, Dave Thaler, and Ole Troan.
	Brian Carpenter was a visitor at the Computer Laboratory, Cambridge		Brian Carpenter was a visitor at the Computer Laboratory, Cambridge
	University during part of this work.		University during part of this work.
	This document was produced using the xml2rfc tool [RFC2629].		This document was produced using the xml2rfc tool [RFC2629].
	7. Change log [RFC Editor: Please remove]		7. Change log [RFC Editor: Please remove]
			draft-ietf-6man-uri-zoneid-02: additional WG comments, 2012-07-11.
	draft-ietf-6man-uri-zoneid-01: use "-" instead of %25, listed		draft-ietf-6man-uri-zoneid-01: use "-" instead of %25, listed
	alternatives in Appendix, according to WG debate, added suggestion		alternatives in Appendix, according to WG debate, added suggestion
	for browser developers, 2012-05-29.		for browser developers, 2012-05-29.
	draft-ietf-6man-uri-zoneid-00: adopted by WG, fixed syntax to allow		draft-ietf-6man-uri-zoneid-00: adopted by WG, fixed syntax to allow
	for % encoded characters, 2012-02-17.		for % encoded characters, 2012-02-17.
	draft-carpenter-6man-uri-zoneid-01: chose Option 2, removed 15		draft-carpenter-6man-uri-zoneid-01: chose Option 2, removed 15
	character limit, added explanation of ID/number mapping and other		character limit, added explanation of ID/number mapping and other
	clarifications, 2012-02-08.		clarifications, 2012-02-08.
	skipping to change at page 7, line 34		skipping to change at page 8, line 13
	Address Text Representation", RFC 5952, August 2010.		Address Text Representation", RFC 5952, August 2010.
	8.2. Informative References		8.2. Informative References
	[I-D.fenner-literal-zone]		[I-D.fenner-literal-zone]
	Fenner, B. and M. Duerst, "Formats for IPv6 Scope Zone		Fenner, B. and M. Duerst, "Formats for IPv6 Scope Zone
	Identifiers in Literal Address Formats",		Identifiers in Literal Address Formats",
	draft-fenner-literal-zone-02 (work in progress),		draft-fenner-literal-zone-02 (work in progress),
	October 2005.		October 2005.
			[I-D.iab-identifier-comparison]
			Thaler, D., "Issues in Identifier Comparison for Security
			Purposes", draft-iab-identifier-comparison-02 (work in
			progress), May 2012.
	[RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,		[RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
	June 1999.		June 1999.
	[RFC3493] Gilligan, R., Thomson, S., Bound, J., McCann, J., and W.		[RFC3493] Gilligan, R., Thomson, S., Bound, J., McCann, J., and W.
	Stevens, "Basic Socket Interface Extensions for IPv6",		Stevens, "Basic Socket Interface Extensions for IPv6",
	RFC 3493, February 2003.		RFC 3493, February 2003.
	[RFC4001] Daniele, M., Haberman, B., Routhier, S., and J.		[RFC4001] Daniele, M., Haberman, B., Routhier, S., and J.
	Schoenwaelder, "Textual Conventions for Internet Network		Schoenwaelder, "Textual Conventions for Internet Network
	Addresses", RFC 4001, February 2005.		Addresses", RFC 4001, February 2005.
	skipping to change at page 8, line 39		skipping to change at page 9, line 21
	Disadvantage: ugly and confusing, doesn't allow simple cut and		Disadvantage: ugly and confusing, doesn't allow simple cut and
	paste.		paste.
	4. Alternative separator		4. Alternative separator
	http://[fe80::a-en1]		http://[fe80::a-en1]
	Advantage: allows use of browser, simple syntax		Advantage: allows use of browser, simple syntax
	Disadvantage: doesn't allow simple cut and paste.		Disadvantage: Requires all IPv6 address literal parsers and
			generators to be updated in order to allow simple cut and paste.
	Note: the initial proposal for this choice was to use an		Note: the initial proposal for this choice was to use an
	underscore as the separator, but it was noted that this becomes		underscore as the separator, but it was noted that this becomes
	effectively invisible when a user interface automatically		effectively invisible when a user interface automatically
	underlines URLs.		underlines URLs.
	5. With the "IPvFuture" syntax left open in RFC 3986:		5. With the "IPvFuture" syntax left open in RFC 3986:
	http://[v6.fe80::a_en1]		http://[v6.fe80::a_en1]
End of changes. 20 change blocks.
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