< draft-ietf-ipv6-ra-flags-option-01.txt		draft-ietf-ipv6-ra-flags-option-02.txt >
	Network Working Group B. Haberman, Ed.		Network Working Group B. Haberman, Ed.
	Internet-Draft JHU APL		Internet-Draft JHU APL
	Intended status: Standards Track R. Hinden		Intended status: Standards Track R. Hinden
	Expires: December 23, 2007 Nokia		Expires: March 16, 2008 Nokia
	June 21, 2007		September 13, 2007
	IPv6 Router Advertisement Flags Option		IPv6 Router Advertisement Flags Option
	draft-ietf-ipv6-ra-flags-option-01		draft-ietf-ipv6-ra-flags-option-02
	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 35 ¶		skipping to change at page 1, line 35 ¶
	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.
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	This Internet-Draft will expire on December 23, 2007.		This Internet-Draft will expire on March 16, 2008.
	Copyright Notice		Copyright Notice
	Copyright (C) The IETF Trust (2007).		Copyright (C) The IETF Trust (2007).
	Abstract		Abstract
	The IPv6 Neighbor Discovery's Router Advertisement message contains		The IPv6 Neighbor Discovery's Router Advertisement message contains
	an 8-bit field reserved for single-bit flags. Several protocols have		an 8-bit field reserved for single-bit flags. Several protocols have
	reserved flags in this field and others are preparing to reserve a		reserved flags in this field and others are preparing to reserve a
	skipping to change at page 3, line 39 ¶		skipping to change at page 3, line 39 ¶
	+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+
	|M|O|H|Prf|P|R|R|		|M|O|H|Prf|P|R|R|
	+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+
	Figure 1: Router Advertisement Flags		Figure 1: Router Advertisement Flags
	o M - Managed Address Configuration Flag [1]		o M - Managed Address Configuration Flag [1]
	o O - Other Configuration Flag [1]		o O - Other Configuration Flag [1]
	o H - Mobile IPv6 Home Agent Flag [3]		o H - Mobile IPv6 Home Agent Flag [4]
	o Prf - Router Selection Preferences [4]		o Prf - Router Selection Preferences [5]
	o P - Neighbor Discovery Proxy Flag [5]		o P - Neighbor Discovery Proxy Flag [6]
	o R - Reserved		o R - Reserved
	With other protocols in the works (e.g., Detecting Network		With other protocols in the works (e.g., Detecting Network
	Attachment) that are wanting to use flags in the NDP messages, it is		Attachment) that are wanting to use flags in the NDP messages, it is
	necessary to define an expansion capability to support new features.		necessary to define an expansion capability to support new features.
	4. Flags Expansion Option		4. Flags Expansion Option
	The Neighbor Discovery specification [1] contains the capability to		The Neighbor Discovery specification [1] contains the capability to
	skipping to change at page 4, line 24 ¶		skipping to change at page 4, line 24 ¶
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Type | Length | Bit fields available ..		| Type | Length | Bit fields available ..
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	... for assignment |		... for assignment |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Figure 2: Router Advertisement Expanded Flags Option		Figure 2: Router Advertisement Expanded Flags Option
	o Type - TBD (to be assigned by IANA)		o Type - TBD (to be assigned by IANA)
	o Length = 1; The length MUST be checked when processing the option		o Length - The length MUST be checked when processing the option in
	in order to allow for future expansion of this option if the need		order to allow for future expansion of this option. An
	arises.		implementation of this specification MUST set the Length to 1,
			MUST ignore any unrecognized data, and MUST be able to recognize
			the specific length in order to skip over unrecognized bits.
	o Bits - allocated by IANA		o Bits - allocated by IANA
	The definition and usage of these bits is to be found in the document		The definition and usage of these bits is to be found in the document
	requesting their allocation.		requesting their allocation.
	During the construction/transmission, this option:		During the construction/transmission, this option:
	o MUST only occur in Router Advertisement messages		o MUST only occur in Router Advertisement messages
	o MUST be the first option immediately following the Router		o MUST occur prior to any additional options associated with any
	Advertisement message header		flags set in this option
	o MUST only occur once in the Router Advertisement message.		o MUST only occur once in the Router Advertisement message
			o MUST NOT be added to a Router Advertisement message if no flags in
			the option are set
			o MUST set all unused flags to zero.
	Upon reception, a receiver processing NDP messages containing this		Upon reception, a receiver processing NDP messages containing this
	option:		option:
	o MUST ignore the option if it occurs in a message other than a		o MUST ignore the option if it occurs in a message other than a
	Router Advertisement		Router Advertisement
	o MUST ignore the option if it is not the first option in the Router
	Advertisement
	o MUST ignore all instances of the option except the first one		o MUST ignore all instances of the option except the first one
	encountered in the Router Advertisement message		encountered in the Router Advertisement message
			o MUST ignore the option if the Length is less than 1
			o MUST ignore any unknown flag bits.
	The bit fields within the option are numbered from left to right from		The bit fields within the option are numbered from left to right from
	8 to 55 and follow the numbering of the flag bits in the RA option		8 to 55 (starting as bit offset 16 in the option) and follow the
	described in Figure 1. Flag bits 0 to 7 are found in the Router		numbering of the flag bits in the RA option described in Figure 1.
	Advertisement message header defined in [1]		Flag bits 0 to 7 are found in the Router Advertisement message header
			defined in [1]
	5. IANA Considerations		5. IANA Considerations
	The IANA is requested to define a new IPv6 Neighbor Discovery option		The IANA is requested to define a new IPv6 Neighbor Discovery option
	for the option defined in this document of the form:		for the option defined in this document of the form:
	+------+---------------------------+-----------+		+------+---------------------------+-----------+
	| Type | Description | Reference |		| Type | Description | Reference |
	+------+---------------------------+-----------+		+------+---------------------------+-----------+
	| TBA | RA Flags Extension Option | [RFCXXXX] |		| TBA | RA Flags Extension Option | [RFCXXXX] |
	skipping to change at page 5, line 36 ¶		skipping to change at page 5, line 47 ¶
	option and in the extension option defined in this document. It is		option and in the extension option defined in this document. It is
	suggested the new registry be added to the icmpv6-parameters as shown		suggested the new registry be added to the icmpv6-parameters as shown
	above. The format for the registry is:		above. The format for the registry is:
	+---------------+---------------------------------------+-----------+		+---------------+---------------------------------------+-----------+
	| RA Option Bit | Description | Reference |		| RA Option Bit | Description | Reference |
	+---------------+---------------------------------------+-----------+		+---------------+---------------------------------------+-----------+
	| 0 | M - Managed Address Configuration | [1] |		| 0 | M - Managed Address Configuration | [1] |
	| | Flag | |		| | Flag | |
	| 1 | O - Other Configuration Flag | [1] |		| 1 | O - Other Configuration Flag | [1] |
	| 2 | H - Mobile IPv6 Home Agent Flag | [3] |		| 2 | H - Mobile IPv6 Home Agent Flag | [4] |
	| 3 | Prf - Router Selection Preferences | [4] |		| 3 | Prf - Router Selection Preferences | [5] |
	| 4 | Prf - Router Selection Preferences | [4] |		| 4 | Prf - Router Selection Preferences | [5] |
	| 5 | P - Neighbor Discovery Proxy Flag | [5] |		| 5 | P - Neighbor Discovery Proxy Flag | [6] |
	| 6-53 | R - Reserved; Available for | |		| 6-53 | R - Reserved; Available for | |
	| | assignment | |		| | assignment | |
	| 54-55 | Private Experimentation | |		| 54-55 | Private Experimentation | |
	+---------------+---------------------------------------+-----------+		+---------------+---------------------------------------+-----------+
	The assignment of new RA flags in the RA option header and for the		The assignment of new RA flags in the RA option header and for the
	bits defined in the RA extension option defined in this document		bits defined in the RA extension option defined in this document
	require standards action or IESG approval.		require standards action or IESG approval[3].
	6. Security Considerations		6. Security Considerations
	This protocol shares the security issues of NDP that are documented		This protocol shares the security issues of NDP that are documented
	in the "Security Considerations" section of [1].		in the "Security Considerations" section of [1].
	The inclusion of additional optional bit fields provides a potential		The inclusion of additional optional bit fields provides a potential
	covert channel useful for passing information.		covert channel useful for passing information.
	7. References		7. References
	7.1. Normative References		7.1. Normative References
	[1] Narten, T., Nordmark, E., and W. Simpson, "Neighbor Discovery		[1] Narten, T., Nordmark, E., and W. Simpson, "Neighbor Discovery
	for IP Version 6 (IPv6)", RFC 2461, December 1998.		for IP Version 6 (IPv6)", RFC 2461, December 1998.
	[2] Bradner, S., "Key words for use in RFCs to Indicate Requirement		[2] Bradner, S., "Key words for use in RFCs to Indicate Requirement
	Levels", BCP 14, RFC 2119, March 1997.		Levels", BCP 14, RFC 2119, March 1997.
			[3] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
			Considerations Section in RFCs", BCP 26, RFC 2434, October 1998.
	7.2. Informative References		7.2. Informative References
	[3] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in		[4] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in
	IPv6", RFC 3775, June 2004.		IPv6", RFC 3775, June 2004.
	[4] Draves, R. and D. Thaler, "Default Router Preferences and More-		[5] Draves, R. and D. Thaler, "Default Router Preferences and More-
	Specific Routes", RFC 4191, November 2005.		Specific Routes", RFC 4191, November 2005.
	[5] Thaler, D., Talwar, M., and C. Patel, "Neighbor Discovery		[6] Thaler, D., Talwar, M., and C. Patel, "Neighbor Discovery
	Proxies (ND Proxy)", RFC 4389, April 2006.		Proxies (ND Proxy)", RFC 4389, April 2006.
	Authors' Addresses		Authors' Addresses
	Brian Haberman (editor)		Brian Haberman (editor)
	Johns Hopkins University Applied Physics Lab		Johns Hopkins University Applied Physics Lab
	11100 Johns Hopkins Road		11100 Johns Hopkins Road
	Laurel, MD 20723-6099		Laurel, MD 20723-6099
	USA		USA
End of changes. 18 change blocks.
	27 lines changed or deleted		39 lines changed or added
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