IPv6 Router Advertisement IPv6-Only Flag
draft-ietf-6man-ipv6only-flag-03

Document Type Active Internet-Draft (6man WG)
Last updated 2018-10-16
Replaces draft-hinden-ipv4flag
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Network Working Group                                          R. Hinden
Internet-Draft                                      Check Point Software
Updates: 5175 (if approved)                                 B. Carpenter
Intended status: Standards Track                       Univ. of Auckland
Expires: April 19, 2019                                 October 16, 2018

                IPv6 Router Advertisement IPv6-Only Flag
                    draft-ietf-6man-ipv6only-flag-03

Abstract

   This document specifies a Router Advertisement Flag to indicate to
   hosts that the administrator has configured the router to advertise
   that the link is IPv6-Only.  This document updates RFC5175.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   This Internet-Draft will expire on April 19, 2019.

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
   (http://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
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   4
   3.  Applicability Statements  . . . . . . . . . . . . . . . . . .   4
   4.  IPv6-Only Definition  . . . . . . . . . . . . . . . . . . . .   4
   5.  IPv6-Only Flag  . . . . . . . . . . . . . . . . . . . . . . .   5
   6.  Router and Operational Considerations . . . . . . . . . . . .   6
   7.  Host Behavior Considerations  . . . . . . . . . . . . . . . .   6
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   8
   11. Change log [RFC Editor: Please remove]  . . . . . . . . . . .   8
   12. References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     12.1.  Normative References . . . . . . . . . . . . . . . . . .  10
     12.2.  Informative References . . . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12

1.  Introduction

   This document specifies a Router Advertisement Flag to indicate to
   hosts that the administrator has configured the router to advertise
   that the link is IPv6-Only.  The flag does not apply to non-default
   IPv6 routers.

   Hosts that support IPv4 and IPv6, usually called dual stack hosts,
   need to also work efficiently on IPv6 only links.  That is, a link
   where there are no IPv4 routers and/or IPv4 services.  Dual stack is
   the default configuration for most current host operating systems
   such as Windows 10, IOS, Android, Linux, and BSD, as well as devices
   such as printers.  Monitoring of an IPv6-only link, for example at
   the IETF 100 meeting in Singapore, shows that current dual stack
   hosts will create local auto-configured IPv4 addresses and attempt to
   reach IPv4 services, even though they cannot configure a normal
   address using DHCP.  This may be a problem for several reasons,
   depending on the equipment in use and its configuration, especially
   on large wireless networks:

   o  It may result in an undesirable level of wasted Layer 2 broadcast
      traffic.

   o  In particular, this may overload switches in multi-segment
      wireless networks if the switches create IPv4 state for every dual
      stack host.

   o  Such traffic may drain battery power on wireless hosts that have
      no interest in link-local IPv4, ARP, and DHCPv4 relay traffic, but

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      receive unwanted IPv4 packets.  [RFC7772] indicates how this risk
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