draft-ietf-ipv6-ra-flags-option-02.txt   rfc5075.txt 
Network Working Group B. Haberman, Ed. Network Working Group B. Haberman, Ed.
Internet-Draft JHU APL Request for Comments: 5075 JHU APL
Intended status: Standards Track R. Hinden Category: Standards Track R. Hinden
Expires: March 16, 2008 Nokia Nokia
September 13, 2007 November 2007
IPv6 Router Advertisement Flags Option IPv6 Router Advertisement Flags Option
draft-ietf-ipv6-ra-flags-option-02
Status of this Memo
By submitting this Internet-Draft, each author represents that any
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
aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at Status of This Memo
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on March 16, 2008.
Copyright Notice
Copyright (C) The IETF Trust (2007). This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
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
sufficient number of flags to exhaust the field. This document sufficient number of flags to exhaust the field. This document
defines an option to the Router Advertisement message that expands defines an option to the Router Advertisement message that expands
the available number of flag bits available. the available number of flag bits available.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Current Router Advertisement Flags . . . . . . . . . . . . . . 3 3. Current Router Advertisement Flags . . . . . . . . . . . . . . 2
4. Flags Expansion Option . . . . . . . . . . . . . . . . . . . . 4 4. Flags Expansion Option . . . . . . . . . . . . . . . . . . . . 3
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . . 6 7.1. Normative References . . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . . 6 7.2. Informative References . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
Intellectual Property and Copyright Statements . . . . . . . . . . 8
1. Introduction 1. Introduction
The IPv6 Neighbor Discovery Protocol's [1] Router Advertisement The IPv6 Neighbor Discovery Protocol's (NDP) [RFC4861] Router
message contains an 8-bit field reserved for single-bit flags. Advertisement message contains an 8-bit field reserved for single-bit
Several protocols have reserved flags in this field and others are flags. Several protocols have reserved flags in this field and
preparing to reserve a sufficient number of flags to exhaust the others are preparing to reserve a sufficient number of flags to
field. exhaust the field.
This document defines an option for the Router Advertisement message This document defines an option for the Router Advertisement message
that expands the available number of flag bits by adding an that expands the available number of flag bits by adding an
additional 48 flag bits to NDP messages. additional 48 flag bits to NDP messages.
2. Terminology 2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [2]. document are to be interpreted as described in [RFC2119].
3. Current Router Advertisement Flags 3. Current Router Advertisement Flags
Currently, the NDP Router Advertisement message contains the Currently, the NDP Router Advertisement message contains the
following one-bit flags defined in published RFCs: following one-bit flags defined in published RFCs:
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|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 [RFC4861]
o O - Other Configuration Flag [1] o O - Other Configuration Flag [RFC4861]
o H - Mobile IPv6 Home Agent Flag [4] o H - Mobile IPv6 Home Agent Flag [RFC3775]
o Prf - Router Selection Preferences [5] o Prf - Router Selection Preferences [RFC4191]
o P - Neighbor Discovery Proxy Flag [6] o P - Neighbor Discovery Proxy Flag [RFC4389]
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 want 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 [RFC4861] contains the
define NDP options. The following (Figure 2) is the definition of capability to define NDP options. The following (Figure 2) is the
the Expanded Flags Option (EFO) for NDP Router Advertisement definition of the Expanded Flags Option (EFO) for NDP Router
messages. Advertisement messages.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 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
skipping to change at page 4, line 37 skipping to change at page 3, line 37
MUST ignore any unrecognized data, and MUST be able to recognize MUST ignore any unrecognized data, and MUST be able to recognize
the specific length in order to skip over unrecognized bits. 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 occur prior to any additional options associated with any o MUST occur prior to any additional options associated with any
flags set in this option 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 o MUST NOT be added to a Router Advertisement message if no flags in
the option are set the option are set.
o MUST set all unused flags to zero. 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 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 the option if the Length is less than 1.
o MUST ignore any unknown flag bits. 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,
8 to 55 (starting as bit offset 16 in the option) and follow the from 8 to 55 (starting as bit offset 16 in the option) and follow the
numbering of the flag bits in the RA option described in Figure 1. numbering of the flag bits in the RA option described in Figure 1.
Flag bits 0 to 7 are found in the Router Advertisement message header Flag bits 0 to 7 are found in the Router Advertisement message header
defined in [1] defined in [RFC4861].
5. IANA Considerations 5. IANA Considerations
The IANA is requested to define a new IPv6 Neighbor Discovery option IANA has defined a new IPv6 Neighbor Discovery option for the option
for the option defined in this document of the form: defined in this document of the form:
+------+---------------------------+-----------+ +------+---------------------------+-----------+
| Type | Description | Reference | | Type | Description | Reference |
+------+---------------------------+-----------+ +------+---------------------------+-----------+
| TBA | RA Flags Extension Option | [RFCXXXX] | | 26 | RA Flags Extension Option | [RFC5075] |
+------+---------------------------+-----------+ +------+---------------------------+-----------+
The registry for these options can be found at: The registry for these options can be found at:
http://www.iana.org/assignments/icmpv6-parameters http://www.iana.org/assignments/icmpv6-parameters
The IANA is requested to create a new registry for IPv6 ND Router IANA has created a new registry for IPv6 ND Router Advertisement
Advertisement flags. This should include the current flags in the RA flags. This should include the current flags in the RA option and in
option and in the extension option defined in this document. It is the extension option defined in this document. The new registry has
suggested the new registry be added to the icmpv6-parameters as shown been added to the icmpv6-parameters as shown above. The format for
above. The format for the registry is: the registry is:
+---------------+---------------------------------------+-----------+ +---------------+---------------------------------------+-----------+
| RA Option Bit | Description | Reference | | RA Option Bit | Description | Reference |
+---------------+---------------------------------------+-----------+ +---------------+---------------------------------------+-----------+
| 0 | M - Managed Address Configuration | [1] | | 0 | M - Managed Address Configuration | [RFC4861] |
| | Flag | | | | Flag | |
| 1 | O - Other Configuration Flag | [1] | | 1 | O - Other Configuration Flag | [RFC4861] |
| 2 | H - Mobile IPv6 Home Agent Flag | [4] | | 2 | H - Mobile IPv6 Home Agent Flag | [RFC3775] |
| 3 | Prf - Router Selection Preferences | [5] | | 3 | Prf - Router Selection Preferences | [RFC4191] |
| 4 | Prf - Router Selection Preferences | [5] | | 4 | Prf - Router Selection Preferences | [RFC4191] |
| 5 | P - Neighbor Discovery Proxy Flag | [6] | | 5 | P - Neighbor Discovery Proxy Flag | [RFC4389] |
| 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 the bits
bits defined in the RA extension option defined in this document defined in the RA extension option defined in this document require
require standards action or IESG approval[3]. standards action or IESG approval [RFC2434].
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 [RFC4861].
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 that is 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 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
for IP Version 6 (IPv6)", RFC 2461, December 1998. Requirement Levels", BCP 14, RFC 2119, March 1997.
[2] Bradner, S., "Key words for use in RFCs to Indicate Requirement [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
Levels", BCP 14, RFC 2119, March 1997. IANA Considerations Section in RFCs", BCP 26, RFC 2434,
October 1998.
[3] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007.
7.2. Informative References 7.2. Informative References
[4] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in [RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support
IPv6", RFC 3775, June 2004. in IPv6", RFC 3775, June 2004.
[5] Draves, R. and D. Thaler, "Default Router Preferences and More- [RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and
Specific Routes", RFC 4191, November 2005. More-Specific Routes", RFC 4191, November 2005.
[6] Thaler, D., Talwar, M., and C. Patel, "Neighbor Discovery [RFC4389] 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
Phone: +1 443 778 1319 Phone: +1 443 778 1319
Email: brian@innovationslab.net EMail: brian@innovationslab.net
Robert Hinden Robert Hinden
Nokia Nokia
313 Fairchild Drive 313 Fairchild Drive
Mountain View, CA 94043 Mountain View, CA 94043
USA USA
Phone: +1 650 625 2004 Phone: +1 650 625 2004
Email: bob.hinden@nokia.com EMail: bob.hinden@nokia.com
Full Copyright Statement Full Copyright Statement
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2007).
This document is subject to the rights, licenses and restrictions This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors contained in BCP 78, and except as set forth therein, the authors
retain all their rights. retain all their rights.
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
skipping to change at page 8, line 44 skipping to change at line 280
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. 41 change blocks. 
100 lines changed or deleted 78 lines changed or added

This html diff was produced by rfcdiff 1.34. The latest version is available from http://tools.ietf.org/tools/rfcdiff/