464XLAT/MAT-T Optimization
draft-ietf-v6ops-464xlat-optimization-03

Document Type Active Internet-Draft (v6ops WG)
Last updated 2020-07-28
Replaces draft-palet-v6ops-464xlat-opt-cdn-caches
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v6ops                                                  J. Palet Martinez
Internet-Draft                                          The IPv6 Company
Intended status: Informational                               A. D'Egidio
Expires: January 29, 2021                                     Telecentro
                                                           July 28, 2020

                       464XLAT/MAT-T Optimization
                draft-ietf-v6ops-464xlat-optimization-03

Abstract

   IP/ICMP Translation Algorithm (SIIT) can be used to provide access
   for IPv4-only hosts or applications to IPv4-only or dual-stack
   destinations over IPv6-only infrastructure.  In that case, the
   traffic flows are translated twice: first from IPv4 to IPv6
   (stateless NAT46 at the ingress point to the IPv6-only
   infrastructure) and then from IPv6 back to IPv4 (stateful NAT64, at
   the egress point).  When the destination is IPv6-enabled, the second
   translation might be avoided.  This document describes a possible
   optimization to 464XLAT and MAP-T to avoid translating IPv6 flows
   back to IPv4 if the destination is reachable over IPv6.  The proposed
   solution would significantly reduce the NAT64 utilization in the
   operator's network, increasing the performance.

Status of This Memo

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

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   This Internet-Draft will expire on January 29, 2021.

Copyright Notice

   Copyright (c) 2020 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

Palet Martinez & D'EgidiExpires January 29, 2021                [Page 1]
Internet-Draft         464XLAT/MAP-T Optimization              July 2020

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   3
   3.  Possible Optimization . . . . . . . . . . . . . . . . . . . .   3
   4.  Problem Statement Summary . . . . . . . . . . . . . . . . . .   6
   5.  Solution Approaches . . . . . . . . . . . . . . . . . . . . .   8
     5.1.  Approach 1: DNS/Routing-based Solution  . . . . . . . . .   8
     5.2.  Approach 2: NAT46/CLAT/DNS-proxy-EAM-based Solution . . .   9
       5.2.1.  Optimization enabling . . . . . . . . . . . . . . . .   9
       5.2.2.  Detection of IPv4-only hosts  . . . . . . . . . . . .   9
       5.2.3.  Detection of IPv6-enabled service . . . . . . . . . .  10
       5.2.4.  CE DNS proxy responses  . . . . . . . . . . . . . . .  10
       5.2.5.  Creation of EAMT entries  . . . . . . . . . . . . . .  11
       5.2.6.  Forwarding path via stateful NAT for existing EAMT
               entries . . . . . . . . . . . . . . . . . . . . . . .  13
       5.2.7.  Maintenance of the EAMT entries . . . . . . . . . . .  13
       5.2.8.  Usage example . . . . . . . . . . . . . . . . . . . .  14
       5.2.9.  Behavior in case of multiple A/AAAA RRs . . . . . . .  14
       5.2.10. Behavior in presence/absence of DNS64 . . . . . . . .  14
       5.2.11. Behavior when using literal addresses or non
               IPv6-compliant APIs . . . . . . . . . . . . . . . . .  15
       5.2.12. Behavior in case of Foreign DNS . . . . . . . . . . .  15
       5.2.13. False detection of a dual-stack host as IPv4-only . .  16
       5.2.14. Behavior in presence of Happy Eyeballs  . . . . . . .  16
       5.2.15. Troubleshooting Implications  . . . . . . . . . . . .  18
     5.3.  Approach 3: NAT46/CLAT-provider-EAM-based Solution  . . .  18
   6.  IPv6-only Services become accessible to IPv4-only
       devices/apps  . . . . . . . . . . . . . . . . . . . . . . . .  19
   7.  Conclusions . . . . . . . . . . . . . . . . . . . . . . . . .  20
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  20
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  20
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