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Internet Engineering Task Force (IETF) O. Troan Request for Comments: 8425 Cisco Systems Updates: 4861 July 2018 Category: Standards Track ISSN: 2070-1721

          IANA Considerations for IPv6 Neighbor Discovery
                  Prefix Information Option Flags

Abstract

 The Prefix Information Option (PIO) in the IPv6 Neighbor Discovery
 Router Advertisement message defines an 8-bit flag field; this field
 has two flags defined, and the remaining 6 bits are reserved
 (Reserved1).  RFC 6275 defines a flag from this field without
 creating an IANA registry or updating RFC 4861.  The purpose of this
 document is to create an IANA registry for the PIO flags.  This
 document updates RFC 4861.

Status of This Memo

 This is an Internet Standards Track document.

 This document is a product of the Internet Engineering Task Force
 (IETF).  It represents the consensus of the IETF community.  It has
 received public review and has been approved for publication by the
 Internet Engineering Steering Group (IESG).  Further information on
 Internet Standards is available in Section 2 of RFC 7841.

 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 https://www.rfc-editor.org/info/rfc8425.

Copyright Notice

 Copyright (c) 2018 IETF Trust and the persons identified as the
 document authors.  All rights reserved.

 This document is subject to BCP 78 and the IETF Trust's Legal
 Provisions Relating to IETF Documents
 (https://trustee.ietf.org/license-info) in effect on the date of
 publication of this document.  Please review these documents
 carefully, as they describe your rights and restrictions with respect
 to this document.  Code Components extracted from this document must
 include Simplified BSD License text as described in Section 4.e of
 the Trust Legal Provisions and are provided without warranty as
 described in the Simplified BSD License.

Troan Standards Track [Page 1] RFC 8425 IANA Considerations for PIO Flags July 2018

Table of Contents

 1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
 2.  Current Prefix Information Option Flags . . . . . . . . . . .   2
 3.  Updates to RFC 4861 . . . . . . . . . . . . . . . . . . . . .   3
 4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
 5.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
 6.  Normative References  . . . . . . . . . . . . . . . . . . . .   4
 Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   4

1. Introduction

 The Prefix Information Option (PIO) in the IPv6 Neighbor Discovery
 Router Advertisement message defines an 8-bit flag field; this field
 has two flags defined and the remaining 6 bits are reserved
 (Reserved1).  RFC 6275 defines a flag from this field without
 creating an IANA registry or updating RFC 4861.  The purpose of this
 document is to create a new registry for the PIO flags.

2. Current Prefix Information Option Flags

 Currently, the Neighbor Discovery Protocol Prefix Information Option
 [RFC4861] contains the following one-bit flags defined in published
 RFCs:

                             0 1 2 3 4 5 6 7
                            +-+-+-+-+-+-+-+-+
                            |L|A|R|Reserved1|
                            +-+-+-+-+-+-+-+-+

                          Figure 1: PIO Flags

    L - On-link Flag [RFC4861]

    A - Autonomous Address Configuration Flag [RFC4861]

    R - Router Address Flag [RFC6275]

    Reserved1 - Reserved

Troan Standards Track [Page 2] RFC 8425 IANA Considerations for PIO Flags July 2018

3. Updates to RFC 4861

 This document updates Section 4.6.2 "Prefix Information" of [RFC4861]
 to point to the IANA registry that is created in this document (see
 Section 4).

 Specifically, the current list of flags in the Prefix Information
 Option can be found in the "IPv6 Neighbor Discovery Prefix
 Information Option Flags" registry.

4. IANA Considerations

 IANA has created a new registry for IPv6 Neighbor Discovery Prefix
 Information Option flags.  This registry includes the current flags
 in the PIO.  The initial contents of the registry are as follows:

     +----------------+---------------------------------+-----------+
     | PIO Option Bit | Description                     | Reference |
     +----------------+---------------------------------+-----------+
     | 0              | L - On-link Flag                | [RFC4861] |
     | 1              | A - Autonomous Address          | [RFC4861] |
     |                |     Configuration Flag          |           |
     | 2              | R - Router Address Flag         | [RFC6275] |
     | 3-7            | Reserved                        |           |
     +----------------+---------------------------------+-----------+

   Figure 2: IPv6 Neighbor Discovery Prefix Information Option Flags

 The assignment of new flags in the PIO option header requires
 Standards Action [RFC8126].

 The registry for these flags is available at
 <http://www.iana.org/assignments/icmpv6-parameters>.

5. Security Considerations

 This document has no security considerations.

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6. Normative References

 [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
            "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
            DOI 10.17487/RFC4861, September 2007,
            <https://www.rfc-editor.org/info/rfc4861>.

 [RFC6275]  Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
            Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July
            2011, <https://www.rfc-editor.org/info/rfc6275>.

 [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
            Writing an IANA Considerations Section in RFCs", BCP 26,
            RFC 8126, DOI 10.17487/RFC8126, June 2017,
            <https://www.rfc-editor.org/info/rfc8126>.

Author's Address

 Ole Troan
 Cisco Systems
 Philip Pedersens vei 1
 Lysaker  1366
 Norway

 Email: ot@cisco.com

Troan Standards Track [Page 4]