Adaptive IPv4 Address Space
draft-chen-ati-adaptive-ipv4-address-space-14

Softwire                                                          Y. Lee
Internet-Draft                                                  Comcast
Intended status: Informational                              R. Maglione
Expires: March 3, 2013                                    Telecom Italia
                                                            C. Williams
                                                              MCSR Labs
                                                            C. Jacquenet
                                                            M. Boucadair
                                                          France Telecom
                                                        August 30, 2012

            Deployment Considerations for Dual-Stack Lite
                draft-ietf-softwire-dslite-deployment-06

Abstract

  This document discusses the deployment issues and describes
  requirements for the deployment and operation of Dual-Stack Lite.
  This document describes the various deployment considerations and
  applicability of the Dual-Stack Lite architecture.

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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  Drafts is at http://datatracker.ietf.org/drafts/current/.

  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 March 3, 2013.

Copyright Notice

  Copyright (c) 2012 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

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Internet-Draft    Deployment Considerations for DS-Lite      August 2012

  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.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  3
  2.  AFTR Deployment Considerations . . . . . . . . . . . . . . . .  3
    2.1.  Interface Consideration  . . . . . . . . . . . . . . . . .  3
    2.2.  MTU Considerations . . . . . . . . . . . . . . . . . . . .  3
    2.3.  Fragmentation  . . . . . . . . . . . . . . . . . . . . . .  3
    2.4.  Lawful Intercept Considerations  . . . . . . . . . . . . .  4
    2.5.  Logging at the AFTR  . . . . . . . . . . . . . . . . . . .  4
    2.6.  Blacklisting a Shared IPv4 Address . . . . . . . . . . . .  5
    2.7.  AFTR's Policies  . . . . . . . . . . . . . . . . . . . . .  5
    2.8.  AFTR Impacts on Accounting Process . . . . . . . . . . . .  6
    2.9.  Reliability Considerations of AFTR . . . . . . . . . . . .  7
    2.10. Strategic Placement of AFTR  . . . . . . . . . . . . . . .  7
    2.11. AFTR Considerations for Geographically Aware Services  . .  8
    2.12. Impacts on QoS . . . . . . . . . . . . . . . . . . . . . .  8
    2.13. Port Forwarding Considerations . . . . . . . . . . . . . .  9
    2.14. DS-Lite Tunnel Security  . . . . . . . . . . . . . . . . .  9
    2.15. IPv6-only Network Considerations . . . . . . . . . . . . .  9
  3.  B4 Deployment Considerations . . . . . . . . . . . . . . . . . 10
    3.1.  DNS deployment Considerations  . . . . . . . . . . . . . . 10
    3.2.  IPv4 Service Monitoring  . . . . . . . . . . . . . . . . . 10
      3.2.1.  B4 Remote Management . . . . . . . . . . . . . . . . . 10
      3.2.2.  IPv4 Connectivity Check  . . . . . . . . . . . . . . . 10
  4.  Security Considerations  . . . . . . . . . . . . . . . . . . . 11
  5.  Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . 11
  6.  Acknowledgement  . . . . . . . . . . . . . . . . . . . . . . . 11
  7.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 12
  8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
    8.1.  Normative References . . . . . . . . . . . . . . . . . . . 12
    8.2.  Informative References . . . . . . . . . . . . . . . . . . 12
  Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13

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1.  Overview

  Dual-stack Lite (DS-Lite) [RFC6333] is a transition technique that
  enable operators to multiplex public IPv4 addresses while
  provisioning only IPv6 to users.  DS-Lite is designed to continue
  offering IPv4 services while operators upgrading their network
  incrementally to IPv6.  DS-Lite combines IPv4-in-IPv6 [RFC2473]
  softwire and NAT44 [RFC3022] to enable more than one user to share a
  public IPv4 address.  This document discusses various DS-Lite
  deployment considerations for operators.

2.  AFTR Deployment Considerations

2.1.  Interface Consideration

  Address Family Transition Router (AFTR) is a network element that
  deployed inside the operator's network.  AFTR can be a standalone
  device or embedded into a router.  AFTR is the IPv4-in-IPv6 tunnel
  termination point and the NAT44 device.  It is deployed at the IPv4-
  IPv6 network border where the tunnel interface is IPv6 and the
  external NAT44 interface is IPv4.  Although an operator can configure
  a dual-stack interface for both functions, we recommend to configure
  two individual interfaces (i.e. one dedicated for IPv4 and one
  dedicated for IPv6) to segregate the functions.

2.2.  MTU Considerations

  DS-Lite is part tunneling protocol.  Tunneling introduces overhead to
  the packet and decreases the effective MTU size after encapsulation.
  The DS-lite users may experience problems with applications such as
  not being able to download Internet pages or transfer large file.  To
  mitigate the tunnel overhead, the access network may increase the MTU
  size to account the necessary tunnel overhead.  If simple IPv4-in-
  IPv6 softwire [RFC2473] is used, the overhead is the size of an IPv6
  header.  If the access network MTU size is fixed and cannot be
  changed, the B4 element and the AFTR must support fragmentation
  defined in [RFC6333].

2.3.  Fragmentation

  The IPv4-in-IPv6 tunnel is established between B4 and AFTR.  When a
  host behind the B4 element communicates with a remote peer, both end
  nodes are not aware of the tunnel.  For example, the peers may use
  the MTU size associated with their connected interfaces.  In fact,
  the IPv4 packet isn't over-sized, it is the IPv6 encapsulation that
  may cause the oversize of the encapsulating packets.  So the tunnel
  endpoints are responsible for handling the fragmentation.  In

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