Internet DRAFT - draft-perreault-softwire-lw4over6-pcp

draft-perreault-softwire-lw4over6-pcp







Network Working Group                                             C. Xie
Internet-Draft                                             China Telecom
Intended status: Standards Track                            S. Perreault
Expires: December 05, 2013                                      Viagenie
                                                                 C. Zhou
                                                     Huawei Technologies
                                                           June 03, 2013


 Provisioning Lightweight 4over6 (lw4o6) with the Port Control Protocol
                                 (PCP)
                draft-perreault-softwire-lw4over6-pcp-00

Abstract

   This memo defines the procedures that a Lightweight B4 uses for
   provisioning its parameters with the Port Control Protocol.

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
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   This Internet-Draft will expire on December 05, 2013.

Copyright Notice

   Copyright (c) 2013 IETF Trust and the persons identified as the
   document authors.  All rights reserved.












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   This document is subject to BCP 78 and the IETF Trust's Legal
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   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Lightweight B4 Provisioning with PCP  . . . . . . . . . . . .   3
     3.1.  Setting Up the Tunnel . . . . . . . . . . . . . . . . . .   3
     3.2.  Configuration of the NAT44  . . . . . . . . . . . . . . .   4
     3.3.  PCP Proxy . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.4.  Failover Mechanism  . . . . . . . . . . . . . . . . . . .   4
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   5
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   Lightweight 4over6 (lw4o6) [I-D.ietf-softwire-lw4over6] defines a
   model for providing IPv4 access over an IPv6 network in which the
   Network Address Translation (NAT) function is performed by the
   Customer-Premises Equipment (CPE) instead of being centralized on a
   Carrier-Grade NAT (CGN).

   Separately, the Port Control Protocol [RFC6887] is used to manipulate
   port mappings in a NAT, firewall, port range router, or similar
   equipment.  It is extended in [I-D.ietf-pcp-port-set] with the
   ability to manipulate sets of ports instead of individual ports.

   This document describes how PCP is used to provision a Lightweight B4
   (lwB4) with its port set and how to establish a tunnel to the
   Lightweight AFTR (lwAFTR).

2.  Terminology






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   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

   Terminology defined in [I-D.ietf-softwire-lw4over6] is used
   extensively in this document.

3.  Lightweight B4 Provisioning with PCP

   The elements that are needed for lwB4 provisioning are listed in
   Section 5.1 of [I-D.ietf-softwire-lw4over6].

      Note (to be removed before publication): These elements can be
      provisioned with plain mode or encapsulation mode.

      In the plain mode, PCP port-set request is sent using native IPv6
      packet, while in the encapsulation mode, PCP Port-set request is
      sent using ip-in-ip tunnel.  In this draft, encapsulation mode is
      recommended to guarantee that the same lwAFTR/PCP server would be
      selected for PCP requests and subsequent ip-in-ip traffic.

3.1.  Setting Up the Tunnel

   The lwB4 initiates the provisioning procedure by requesting the
   OPTION_AFTR_NAME DHCPv6 option as indicated in [RFC6334].  This
   option provides the IPv6 address for the lwAFTR.

   Once this address is known, the lwB4 sets up an IPv4-in-IPv6 tunnel
   with the following characteristics:

   IPv6 destination:  value of OPTION_AFTR_NAME, after resolution of the
      name

   IPv6 source:  derived from the IPv6 destination by applying Default
      Address Selection [RFC3484]

   IPv4 source:  192.0.0.2

   IPv4 destination:  192.0.0.1

   The IPv4 addresses correspond to the well-known B4 and AFTR addresses
   defined in Section 5.7 of [RFC6333].









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3.2.  Configuration of the NAT44

   Once the tunnel is up, the lwB4 sends a PCP MAP request with a
   PORT_SET option.  The request is sent inside the tunnel to 192.0.0.1.
   The source is accordingly set to 192.0.0.2.

   The MAP request's Internal Port is set to 1 and the PORT_SET option's
   Port Set Size field is set to 65535, indicating that the lwB4 is
   prepared to accept a maximal size port set.  Practically, the server
   will reply with a port set size corresponding to its configuration.

   Note:  Since there is no NAT in the lwAFTR, the internal port is
      always equal to the external port.  The PCP server cannot change
      the internal port that the client sends.  How can we overcome
      this?  Add an offset parameter in the PORT_SET option?

   The PORT_SET option's P bit is set to 0.

   When a success response is received from the PCP server, the lwB4
   extracts the external IPv4 address and port set from the response and
   uses them to configure its NAT44 function as described in
   [I-D.ietf-softwire-lw4over6].  The lwB4 is now provisioned.

   The lwB4 needs to periodically refresh the port set it obtained with
   PCP as described in [RFC6887] section 15 for as long as the lw4over6
   tunnel is to be operational.

3.3.  PCP Proxy

   The lwB4 SHOULD implement a back-to-back PCP server-client.  The PCP
   port-set client in lwB4 would get a public address and port-set from
   the PCP port-set server, and then the PCP server in the lwB4 will
   setup the mapping for the host behind the lwB4 and response with PCP
   client.

   The lwB4 MAY also implement a PCP proxy in case the host initiates a
   port-set request directly.  It would forward the port-set request to
   PCP server to get a new port-set mapping or refresh an existing
   mapping.

3.4.  Failover Mechanism

   This document considers two failover mechanisms: ICMP and PCP
   ANNOUNCE.  In the ICMP case, when the lwB4 receives an ICMP error
   message from the lwAFTR, the lwB4 MAY re-initiate the dynamic port-
   restricted provisioning process.  The detailed ICMP processing is
   introduced in [I-D.ietf-softwire-lw4over6].




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   In the PCP case, when the lwAFTR receives traffic it doesn't have
   before, lwAFTR MAY send back a PCP unicast ANNOUNCE message.  The
   lwB4 then will re-initiate the PCP Port-set request after receiving
   the ANNOUNCE message.  In the case when there are large amount of
   lwB4s, an optimization of this mechanism MAY be needed to achieve
   fast failure recovery.  Since it is layer 2 network between lwB4 and
   BNG, A BNG device MAY act a PCP proxy to receive unicast ANNOUNCE
   message from lwAFTR.  It will then replace the unicast address of
   itself with the lwb4's multicast address and sends multicast ANNOUNCE
   message to the lwB4s.

4.  Security Considerations

   TO BE COMPLETED

5.  IANA Considerations

   This document has no IANA actions.

6.  Acknowledgements

   Special thanks to Qiong Sun for her many contributions to this
   document.

   The authors would like to thank the following individuals who have
   participated in the drafting, review, and discussion of this memo:
   Jean-Philippe Dionne, Marc Blanchet, and Tina Tsou.

7.  References

7.1.  Normative References

   [I-D.ietf-pcp-port-set]
              Sun, Q., Boucadair, M., Sivakumar, S., Zhou, C., Tsou, T.,
              and S. Perreault, "Port Control Protocol (PCP) Extension
              for Port Set Allocation", draft-ietf-pcp-port-set-00 (work
              in progress), March 2013.

   [I-D.ietf-softwire-lw4over6]
              Cui, Y., Sun, Q., Boucadair, M., Tsou, T., Lee, Y., and I.
              Farrer, "Lightweight 4over6: An Extension to the DS-Lite
              Architecture", draft-ietf-softwire-lw4over6-00 (work in
              progress), April 2013.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.





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   [RFC3484]  Draves, R., "Default Address Selection for Internet
              Protocol version 6 (IPv6)", RFC 3484, February 2003.

   [RFC6334]  Hankins, D. and T. Mrugalski, "Dynamic Host Configuration
              Protocol for IPv6 (DHCPv6) Option for Dual-Stack Lite",
              RFC 6334, August 2011.

   [RFC6887]  Wing, D., Cheshire, S., Boucadair, M., Penno, R., and P.
              Selkirk, "Port Control Protocol (PCP)", RFC 6887, April
              2013.

7.2.  Informative References

   [RFC6333]  Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual-
              Stack Lite Broadband Deployments Following IPv4
              Exhaustion", RFC 6333, August 2011.

Authors' Addresses

   Chongfeng Xie
   China Telecom
   Room 708 No.118, Xizhimenneidajie
   Beijing  100035
   P.R.China

   Email: xiechf@ctbri.com.cn


   Simon Perreault
   Viagenie
   246 Aberdeen
   Quebec, QC  G1R 2E1
   Canada

   Phone: +1 418 656 9254
   Email: simon.perreault@viagenie.ca
   URI:   http://viagenie.ca


   Cathy Zhou
   Huawei Technologies
   Bantian, Longgang District
   Shenzhen  518129
   P.R. China

   Email: cathy.zhou@huawei.com




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