First-Hop Router Selection by Hosts in a Multi-Prefix Network
RFC 8028

Document Type RFC - Proposed Standard (November 2016; No errata)
Updates RFC 4861
Last updated 2016-11-28
Replaces draft-baker-6man-multi-homed-host
Stream IETF
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Reviews
Stream WG state Submitted to IESG for Publication
Document shepherd Jouni Korhonen
Shepherd write-up Show (last changed 2016-05-05)
IESG IESG state RFC 8028 (Proposed Standard)
Consensus Boilerplate Yes
Telechat date
Responsible AD Suresh Krishnan
Send notices to "Jouni Korhonen" <jouni.nospam@gmail.com>
IANA IANA review state Version Changed - Review Needed
IANA action state No IC
Internet Engineering Task Force (IETF)                          F. Baker
Request for Comments: 8028
Updates: 4861                                               B. Carpenter
Category: Standards Track                              Univ. of Auckland
ISSN: 2070-1721                                            November 2016

     First-Hop Router Selection by Hosts in a Multi-Prefix Network

Abstract

   This document describes expected IPv6 host behavior in a scenario
   that has more than one prefix, each allocated by an upstream network
   that is assumed to implement BCP 38 ingress filtering, when the host
   has multiple routers to choose from.  It also applies to other
   scenarios such as the usage of stateful firewalls that effectively
   act as address-based filters.  Host behavior in choosing a first-hop
   router may interact with source address selection in a given
   implementation.  However, the selection of the source address for a
   packet is done before the first-hop router for that packet is chosen.
   Given that the network or host is, or appears to be, multihomed with
   multiple provider-allocated addresses, that the host has elected to
   use a source address in a given prefix, and that some but not all
   neighboring routers are advertising that prefix in their Router
   Advertisement Prefix Information Options, this document specifies to
   which router a host should present its transmission.  It 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
   http://www.rfc-editor.org/info/rfc8028.

Baker & Carpenter            Standards Track                    [Page 1]
RFC 8028       Router Selection in a Multi-Prefix Network  November 2016

Copyright Notice

   Copyright (c) 2016 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
   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.

Table of Contents

   1.  Introduction and Applicability  . . . . . . . . . . . . . . .   3
     1.1.  Host Model  . . . . . . . . . . . . . . . . . . . . . . .   4
     1.2.  Requirements Language . . . . . . . . . . . . . . . . . .   5
   2.  Sending Context Expected by the Host  . . . . . . . . . . . .   5
     2.1.  Expectations the Host Has of the Network  . . . . . . . .   5
     2.2.  Expectations of Multihomed Networks . . . . . . . . . . .   7
   3.  Reasonable Expectations of the Host . . . . . . . . . . . . .   7
     3.1.  Interpreting Router Advertisements  . . . . . . . . . . .   7
     3.2.  Default Router Selection  . . . . . . . . . . . . . . . .   9
     3.3.  Source Address Selection  . . . . . . . . . . . . . . . .   9
     3.4.  Redirects . . . . . . . . . . . . . . . . . . . . . . . .   9
     3.5.  History . . . . . . . . . . . . . . . . . . . . . . . . .  10
   4.  Residual Issues . . . . . . . . . . . . . . . . . . . . . . .  10
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  10
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  11
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  12
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

Baker & Carpenter            Standards Track                    [Page 2]
RFC 8028       Router Selection in a Multi-Prefix Network  November 2016

1.  Introduction and Applicability

   This document describes the expected behavior of an IPv6 [RFC2460]
   host in a network that has more than one prefix, each allocated by an
   upstream network that is assumed to implement BCP 38 [RFC2827]
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