draft-ietf-6man-text-addr-representation-02.txt		draft-ietf-6man-text-addr-representation-03.txt
	IPv6 Maintenance Working Group S. Kawamura		IPv6 Maintenance Working Group S. Kawamura
	Internet-Draft NEC BIGLOBE, Ltd.		Internet-Draft NEC BIGLOBE, Ltd.
	Intended status: Standards Track M. Kawashima		Intended status: Standards Track M. Kawashima
	Expires: May 14, 2010 NEC AccessTechnica, Ltd.		Expires: May 29, 2010 NEC AccessTechnica, Ltd.
	November 10, 2009		November 25, 2009
	A Recommendation for IPv6 Address Text Representation		A Recommendation for IPv6 Address Text Representation
	draft-ietf-6man-text-addr-representation-02		draft-ietf-6man-text-addr-representation-03
	Abstract		Abstract
	As IPv6 network grows, there will be more engineers and also non-		As IPv6 network grows, there will be more engineers and also non-
	engineers who will have the need to use an IPv6 address in text.		engineers who will have the need to use an IPv6 address in text.
	While the IPv6 address architecture RFC 4291 section 2.2 depicts a		While the IPv6 address architecture RFC 4291 section 2.2 depicts a
	flexible model for text representation of an IPv6 address, this		flexible model for text representation of an IPv6 address, this
	flexibility has been causing problems for operators, system		flexibility has been causing problems for operators, system
	engineers, and users. This document will describe the problems that		engineers, and users. This document will describe the problems that
	a flexible text representation has been causing. This document also		a flexible text representation has been causing. This document also
	skipping to change at page 1, line 48		skipping to change at page 1, line 48
	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 May 14, 2010.		This Internet-Draft will expire on May 29, 2010.
	Copyright Notice		Copyright Notice
	Copyright (c) 2009 IETF Trust and the persons identified as the		Copyright (c) 2009 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 3, line 10		skipping to change at page 3, line 10
	3.4.3. Legibility . . . . . . . . . . . . . . . . . . . . . . 9		3.4.3. Legibility . . . . . . . . . . . . . . . . . . . . . . 9
	4. A Recommendation for IPv6 Text Representation . . . . . . . . 10		4. A Recommendation for IPv6 Text Representation . . . . . . . . 10
	4.1. Handling Leading Zeros in a 16 Bit Field . . . . . . . . . 10		4.1. Handling Leading Zeros in a 16 Bit Field . . . . . . . . . 10
	4.2. "::" Usage . . . . . . . . . . . . . . . . . . . . . . . . 10		4.2. "::" Usage . . . . . . . . . . . . . . . . . . . . . . . . 10
	4.2.1. Shorten As Much As Possible . . . . . . . . . . . . . 10		4.2.1. Shorten As Much As Possible . . . . . . . . . . . . . 10
	4.2.2. Handling One 16 Bit 0 Field . . . . . . . . . . . . . 10		4.2.2. Handling One 16 Bit 0 Field . . . . . . . . . . . . . 10
	4.2.3. Choice in Placement of "::" . . . . . . . . . . . . . 10		4.2.3. Choice in Placement of "::" . . . . . . . . . . . . . 10
	4.3. Lower Case . . . . . . . . . . . . . . . . . . . . . . . . 10		4.3. Lower Case . . . . . . . . . . . . . . . . . . . . . . . . 10
	5. Text Representation of Special Addresses . . . . . . . . . . . 11		5. Text Representation of Special Addresses . . . . . . . . . . . 11
	6. Notes on Combining IPv6 Addresses with Port Numbers . . . . . 11		6. Notes on Combining IPv6 Addresses with Port Numbers . . . . . 11
	7. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . 11		7. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . 12
	8. Security Considerations . . . . . . . . . . . . . . . . . . . 12		8. Security Considerations . . . . . . . . . . . . . . . . . . . 12
	9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12		9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
	10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12		10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12
	11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12		11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
	11.1. Normative References . . . . . . . . . . . . . . . . . . . 12		11.1. Normative References . . . . . . . . . . . . . . . . . . . 13
	11.2. Informative References . . . . . . . . . . . . . . . . . . 13		11.2. Informative References . . . . . . . . . . . . . . . . . . 13
	Appendix A. For Developers . . . . . . . . . . . . . . . . . . . 13		Appendix A. For Developers . . . . . . . . . . . . . . . . . . . 13
	Appendix B. Prefix Issues . . . . . . . . . . . . . . . . . . . . 13		Appendix B. Prefix Issues . . . . . . . . . . . . . . . . . . . . 13
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14
	1. Introduction		1. Introduction
	A single IPv6 address can be text represented in many ways. Examples		A single IPv6 address can be text represented in many ways. Examples
	are shown below.		are shown below.
	2001:db8:0:0:1:0:0:1		2001:db8:0:0:1:0:0:1
	2001:0db8:0:0:1:0:0:1		2001:0db8:0:0:1:0:0:1
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	4.3. Lower Case		4.3. Lower Case
	Recent implementations tend to represent IPv6 address as lower case.		Recent implementations tend to represent IPv6 address as lower case.
	It is better to use lower case to avoid problems such as described in		It is better to use lower case to avoid problems such as described in
	section 3.3.3 and 3.4.3.		section 3.3.3 and 3.4.3.
	5. Text Representation of Special Addresses		5. Text Representation of Special Addresses
	Addresses such as IPv4-Mapped IPv6 addresses, ISATAP [RFC5214], and		Addresses such as IPv4-Mapped IPv6 addresses, ISATAP [RFC5214], and
	IPv4-translated addresses [RFC2765] have IPv4 addresses embedded in		IPv4-translatable addresses [I-D.ietf-behave-address-format] have
	the low-order 32 bits of the address. These addresses have special		IPv4 addresses embedded in the low-order 32 bits of the address.
	representation that may mix hexadecimal and decimal notations. In		These addresses have special representation that may mix hexadecimal
	cases where there is a choice of whether to express the address as		and decimal notations. The decimal notation may be used only for the
	fully hexadecimal or hexadecimal and decimal mixed, and if the		last 32 bits of the address. For these addresses, mixed notation is
	address type can be distinguished as having IPv4 addresses embedded		recommended if either of the below conditions are met.
	in the lower 32 bits solely from the 128bits of the address field
	itself, mixed notation is the better choice. However, there may be		(1) The address can be distinguished as having IPv4 addresses
	situations where hexadecimal representation is chosen to meet certain		embedded in the lower 32 bits solely from the address field. (e.g.
	needs. Addressing those needs is out of the scope of this document.		Well Known Prefixes)
	The text representation method noted in Section 4 should be applied
	for the leading hexadecimal part (i.e. ::ffff:192.0.2.1 instead of		(2) An external mechanism such as prefix learning or pre-
	0:0:0:0:0:ffff:192.0.2.1).		configuration helps in recognizing the address as having IPv4
			addresses embedded in the lower 32 bits.
			However, there may be situations where full hexadecimal
			representation is chosen to meet certain needs. Addressing those
			needs is out of the scope of this document. The text representation
			method noted in Section 4 should be applied for the leading
			hexadecimal part (i.e. ::ffff:192.0.2.1 instead of 0:0:0:0:0:ffff:
			192.0.2.1).
	6. Notes on Combining IPv6 Addresses with Port Numbers		6. Notes on Combining IPv6 Addresses with Port Numbers
	When IPv6 addresses and port numbers are represented in text combined		When IPv6 addresses and port numbers are represented in text combined
	together, there seems to be many different ways to do so. Examples		together, there seems to be many different ways to do so. Examples
	are shown below.		are shown below.
	o [2001:db8::1]:80		o [2001:db8::1]:80
	o 2001:db8::1:80		o 2001:db8::1:80
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	None.		None.
	10. Acknowledgements		10. Acknowledgements
	The authors would like to thank Jan Zorz, Randy Bush, Yuichi Minami,		The authors would like to thank Jan Zorz, Randy Bush, Yuichi Minami,
	Toshimitsu Matsuura for their generous and helpful comments in kick		Toshimitsu Matsuura for their generous and helpful comments in kick
	starting this document. We also would like to thank Brian Carpenter,		starting this document. We also would like to thank Brian Carpenter,
	Akira Kato, Juergen Schoenwaelder, Antonio Querubin, Dave Thaler,		Akira Kato, Juergen Schoenwaelder, Antonio Querubin, Dave Thaler,
	Brian Haley, Suresh Krishnan, Jerry Huang, Roman Donchenko, Heikki		Brian Haley, Suresh Krishnan, Jerry Huang, Roman Donchenko, Heikki
	Vatiainen for their input. Also a very special thanks to Ron Bonica,		Vatiainen ,Dan Wing for their input. Also a very special thanks to
	Fred Baker, Brian Haberman, Robert Hinden, Jari Arkko, and Kurt		Ron Bonica, Fred Baker, Brian Haberman, Robert Hinden, Jari Arkko,
	Lindqvist for their support in bringing this document to the light of		and Kurt Lindqvist for their support in bringing this document to the
	IETF working groups.		light of IETF working groups.
	11. References		11. References
	11.1. Normative References		11.1. 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.
	[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.
	11.2. Informative References		11.2. Informative References
	[RFC2765] Nordmark, E., "Stateless IP/ICMP Translation Algorithm		[I-D.ietf-behave-address-format]
	(SIIT)", RFC 2765, February 2000.		Huitema, C., Bao, C., Bagnulo, M., Boucadair, M., and X.
			Li, "IPv6 Addressing of IPv4/IPv6 Translators",
			draft-ietf-behave-address-format-01 (work in progress),
			October 2009.
	[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform		[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
	Resource Identifier (URI): Generic Syntax", STD 66,		Resource Identifier (URI): Generic Syntax", STD 66,
	RFC 3986, January 2005.		RFC 3986, January 2005.
	[RFC4038] Shin, M-K., Hong, Y-G., Hagino, J., Savola, P., and E.		[RFC4038] Shin, M-K., Hong, Y-G., Hagino, J., Savola, P., and E.
	Castro, "Application Aspects of IPv6 Transition",		Castro, "Application Aspects of IPv6 Transition",
	RFC 4038, March 2005.		RFC 4038, March 2005.
	[RFC5214] Templin, F., Gleeson, T., and D. Thaler, "Intra-Site		[RFC5214] Templin, F., Gleeson, T., and D. Thaler, "Intra-Site
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