Enterprise Multihoming using Provider-Assigned IPv6 Addresses without Network Prefix Translation: Requirements and Solutions
draft-ietf-rtgwg-enterprise-pa-multihoming-12

Document Type Active Internet-Draft (rtgwg WG)
Last updated 2019-08-01
Replaces draft-bowbakova-rtgwg-enterprise-pa-multihoming
Stream IETF
Intended RFC status Informational
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Stream WG state Submitted to IESG for Publication
Document shepherd Ron Bonica
Shepherd write-up Show (last changed 2018-05-11)
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Has enough positions to pass.
Responsible AD Martin Vigoureux
Send notices to Ron Bonica <rbonica@juniper.net>
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Routing Working Group                                           F. Baker
Internet-Draft
Intended status: Informational                                 C. Bowers
Expires: February 1, 2020                               Juniper Networks
                                                              J. Linkova
                                                                  Google
                                                           July 31, 2019

 Enterprise Multihoming using Provider-Assigned IPv6 Addresses without
         Network Prefix Translation: Requirements and Solutions
             draft-ietf-rtgwg-enterprise-pa-multihoming-12

Abstract

   Connecting an enterprise site to multiple ISPs over IPv6 using
   provider-assigned addresses is difficult without the use of some form
   of Network Address Translation (NAT).  Much has been written on this
   topic over the last 10 to 15 years, but it still remains a problem
   without a clearly defined or widely implemented solution.  Any
   multihoming solution without NAT requires hosts at the site to have
   addresses from each ISP and to select the egress ISP by selecting a
   source address for outgoing packets.  It also requires routers at the
   site to take into account those source addresses when forwarding
   packets out towards the ISPs.

   This document examines currently available mechanisms for providing a
   solution to this problem for a broad range of enterprise topologies.
   It covers the behavior of routers to forward traffic taking into
   account source address, and it covers the behavior of hosts to select
   appropriate default source addresses.  It also covers any possible
   role that routers might play in providing information to hosts to
   help them select appropriate source addresses.  In the process of
   exploring potential solutions, this document also makes explicit
   requirements for how the solution would be expected to behave from
   the perspective of an enterprise site network administrator.

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
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

Baker, et al.           Expires February 1, 2020                [Page 1]
Internet-Draft          Enterprise PA Multihoming              July 2019

   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."

   This Internet-Draft will expire on February 1, 2020.

Copyright Notice

   Copyright (c) 2019 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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   6
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   6
   4.  Enterprise Multihoming Use Cases  . . . . . . . . . . . . . .   8
     4.1.  Simple ISP Connectivity with Connected SERs . . . . . . .   8
     4.2.  Simple ISP Connectivity Where SERs Are Not Directly
           Connected . . . . . . . . . . . . . . . . . . . . . . . .  10
     4.3.  Enterprise Network Operator Expectations  . . . . . . . .  12
     4.4.  More complex ISP connectivity . . . . . . . . . . . . . .  14
     4.5.  ISPs and Provider-Assigned Prefixes . . . . . . . . . . .  16
     4.6.  Simplified Topologies . . . . . . . . . . . . . . . . . .  17
   5.  Generating  Source-Prefix-Scoped Forwarding Tables  . . . . .  17
   6.  Mechanisms For Hosts To Choose Good Default Source Addresses
       In A Multihomed Site  . . . . . . . . . . . . . . . . . . . .  24
     6.1.  Default Source Address Selection Algorithm on Hosts . . .  26
     6.2.  Selecting Default Source Address When Both Uplinks Are
           Working . . . . . . . . . . . . . . . . . . . . . . . . .  29
       6.2.1.  Distributing Default Address Selection Policy Table
               with DHCPv6 . . . . . . . . . . . . . . . . . . . . .  29
       6.2.2.  Controlling Default Source Address Selection With
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