SNAC Router Flag in ICMPv6 Router Advertisement Messages
draft-ietf-6man-snac-router-ra-flag-02

Internet Engineering Task Force                                   J. Hui
Internet-Draft                                                Google LLC
Intended status: Standards Track                          8 October 2024
Expires: 11 April 2025

        SNAC Router Flag in ICMPv6 Router Advertisement Messages
                 draft-ietf-6man-snac-router-ra-flag-02

Abstract

   This document defines a new flag, the SNAC Router flag, in the Router
   Advertisement message that can be used to distinguish configuration
   information sent by SNAC routers from information sent by
   infrastructure routers.  This flag is used only by SNAC routers and
   is ignored by all other devices.

Status of This Memo

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   This Internet-Draft will expire on 11 April 2025.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  SNAC Router Flag  . . . . . . . . . . . . . . . . . . . . . .   2
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   6.  Normative References  . . . . . . . . . . . . . . . . . . . .   3
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   4

1.  Introduction

   A Stub Network Auto-Configuring Router (SNAC) router is an
   autonomously-configuring router that provides IP connectivity between
   one or more stub networks and one or more infrastructure networks.  A
   common SNAC router example is a device that attaches a 6LoWPAN-based
   network to a home network, automatically providing IPv6 forwarding
   between the two networks without explicit operator configuration.
   SNAC routers are described in [I-D.ietf-snac-simple].  This document
   defines a new IPv6 ND Router Advertisement (RA) flag, the "SNAC
   router" flag, which SNAC routers use to identify RAs sent by other
   SNAC routers.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  SNAC Router Flag

   The "SNAC Router" flag is router advertisement flag bit TBD.

   The SNAC router flag is to be used by SNAC routers.  The use of this
   flag is documented in [I-D.ietf-snac-simple].  Devices that do not
   operate as SNAC routers [I-D.ietf-snac-simple] MUST NOT set the SNAC
   router flag, and MUST silently ignore the SNAC router flag.  This
   means that the presence or absence of the flag should not change the
   behavior of such devices in any way (other than that it is of course
   permissible to log and cache the value of the flag as part of normal
   router advertisement processing, where applicable).

   In environments that implement RA guard in a way that filters RAs
   sent by SNAC routers, devices on the infrastructure network should
   never receive an RA with the SNAC router flag set.

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4.  IANA Considerations

   IANA is requested to allocate a flag from the "Internet Control
   Message Protocol version 6 (ICMPv6) Parameters", "IPv6 ND Router
   Advertisement flags" registry [IANA-RA-FLAGS] as specified below:

         +---------------+----------------------+---------------+
         | RA Option Bit | Description          | Reference     |
         +---------------+----------------------+---------------+
         | TBD           | S - SNAC Router Flag | This Document |
         +---------------+----------------------+---------------+

                                 Table 1

5.  Security Considerations

   The security considerations of IPv6 ND are documented in the
   "Security Considerations" section of [RFC4861].  The addition of the
   SNAC router flag does not changes these considerations.

6.  Normative References

   [I-D.ietf-snac-simple]
              Lemon, T. and J. Hui, "Automatically Connecting Stub
              Networks to Unmanaged Infrastructure", Work in Progress,
              Internet-Draft, draft-ietf-snac-simple-05, 8 July 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-snac-
              simple-05>.

   [IANA-RA-FLAGS]
              IANA, "IPv6 ND Router Advertisement flags",
              <https://www.iana.org/assignments/icmpv6-parameters/
              icmpv6-parameters.xhtml#icmpv6-parameters-11>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [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>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

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Author's Address

   Jonathan Hui
   Google LLC
   1600 Amphitheatre Parkway
   Mountain View, California 940432
   United States of America
   Email: jonhui@google.com

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