Autonomic IPv6 Edge Prefix Management in Large-scale Networks
draft-ietf-anima-prefix-management-00

ANIMA WG                                                   S. Jiang, Ed.
Internet-Draft                                                     Z. Du
Intended status: Informational              Huawei Technologies Co., Ltd
Expires: July 14, 2016                                      B. Carpenter
                                                       Univ. of Auckland
                                                                  Q. Sun
                                                           China Telecom
                                                        January 11, 2016

     Autonomic IPv6 Edge Prefix Management in Large-scale Networks
                 draft-ietf-anima-prefix-management-00

Abstract

   This document describes an autonomic solution for IPv6 prefix
   management at the edge of large-scale ISP networks.  An important
   purpose of the document is to use it for validation of the design of
   various components of the autonomic networking infrastructure.

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 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 July 14, 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

Jiang, et al.             Expires July 14, 2016                 [Page 1]
Internet-Draft         Auto IPv6 Prefix Management          January 2016

   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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Problem Statement . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  Intended User and Administrator Experience  . . . . . . .   4
     3.2.  Analysis of Parameters and Information Involved . . . . .   4
       3.2.1.  Parameters each device can decide for itself  . . . .   5
       3.2.2.  Information needed from policy intent . . . . . . . .   5
       3.2.3.  Comparison with current solutions . . . . . . . . . .   5
     3.3.  Interaction with other devices  . . . . . . . . . . . . .   6
       3.3.1.  Information needed from other devices . . . . . . . .   6
       3.3.2.  Monitoring, diagnostics and reporting . . . . . . . .   6
   4.  Autonomic Edge Prefix Management Solution . . . . . . . . . .   7
     4.1.  Behaviors on prefix requesting device . . . . . . . . . .   7
     4.2.  Behaviors on prefix providing device  . . . . . . . . . .   8
     4.3.  Behavior after Successful Negotiation . . . . . . . . . .   9
     4.4.  Prefix logging  . . . . . . . . . . . . . . . . . . . . .   9
   5.  Autonomic Prefix Management Options . . . . . . . . . . . . .   9
     5.1.  Edge Prefix Objective Option  . . . . . . . . . . . . . .   9
   6.  Prefix Management Intent  . . . . . . . . . . . . . . . . . .  10
     6.1.  Example of Prefix Management Intent . . . . . . . . . . .  10
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  12
   10. Change log [RFC Editor: Please remove]  . . . . . . . . . . .  12
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  12
     11.2.  Informative References . . . . . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   This document proposes an autonomic solution for IPv6 prefix
   management in large-scale networks.  The background to Autonomic
   Networking (AN) is described in [RFC7575] and [RFC7576].  A generic
   autonomic signaling protocol (GRASP) is specified by
   [I-D.ietf-anima-grasp] and would be used by the proposed autonomic
   prefix management solution.  An important purpose of the present
   document is to use it for validation of the design of GRASP and other
   components of the autonomic networking infrastructure described in
   [I-D.behringer-anima-reference-model].

Jiang, et al.             Expires July 14, 2016                 [Page 2]
Internet-Draft         Auto IPv6 Prefix Management          January 2016

   This document is not intended to solve all cases of IPv6 prefix
   management.  In fact, it assumes that the network's main
   infrastructure elements already have addresses and prefixes.  The
   document is dedicated to how to make IPv6 prefix management at the
   edges of large-scale networks as autonomic as possible.  It is
   specifically written for service provider (ISP) networks.  Although
   there are similarities between ISPs and large enterprise networks,
   the requirements for the two use cases differ.

   However, the solution is designed in a general way.  Its use for a
   broader scope than edge prefixes, including some or all
   infrastructure prefixes, is left for future discussion.

   Note in draft: This version is preliminary.  In particular, many
   design details may be subject to change until the Anima
   specifications become agreed.

2.  Terminology

   TBD

3.  Problem Statement

   The autonomic networking use case considered here is autonomic IPv6
   prefix management at the edge of large-scale ISP networks.

   Although DHCPv6 Prefix Delegation [RFC3633] supports automated
   delegation of IPv6 prefixes from one router to another, prefix
   management is still largely depending on human planning.  In other
   words, there is no basic information or policy to support autonomic
   decisions on the prefix length that each router should request or be
   delegated, according to its role in the network.  Roles could be
   locally defined or could be generic (edge router, interior router,
   etc.).  Furthermore, IPv6 prefix management by humans tends to be
   rigid and static after initial planning.

   The problem to be solved by autonomic networking is how to
   dynamically manage IPv6 address space in large-scale networks, so
   that IPv6 addresses can be used efficiently.  Here, we limit the
   problem to assignment of prefixes at the edge of the network, close
   to access routers that support individual fixed-line subscribers,
   mobile customers, and corporate customers.  We assume that the core
   infrastructure of the network has already been established with
   appropriately assigned prefixes.  The AN approach discussed in this
   document is based on the assumption that there is a generic discovery
   and negotiation protocol that enables direct negotiation between
   intelligent IP routers.  GRASP [I-D.ietf-anima-grasp] is intended to
   be such a protocol.

Jiang, et al.             Expires July 14, 2016                 [Page 3]
Internet-Draft         Auto IPv6 Prefix Management          January 2016

3.1.  Intended User and Administrator Experience

   The intended experience is, for the administrator(s) of a large-scale
   network, that the management of IPv6 address space at the edge of the
   network can be run with minimum efforts, as devices at the edge are
   added and removed and as customers of all kinds join and leave the
   network.  In the ideal scenario, the administrator(s) only have to
   specify a single IPv6 prefix for the whole network and the initial
   prefix length for each device role.  As far as users are concerned,
   IPv6 prefix assignment would occur exactly as it does in any other
   network.

   The actual prefix usage needs to be logged for potential offline
   management operations including audit and security incident tracing.

3.2.  Analysis of Parameters and Information Involved

   For specific purposes of address management, a few parameters are
   involved on each edge device (some of them can be pre-configured
   before they are connected).  They include:

   o  Identity, authentication and authorization of this device.  This
      is expected to use the autonomic networking secure bootstrap
      process [I-D.ietf-anima-bootstrapping-keyinfra], following which
      the device could safely take part in autonomic operations.

   o  Role of this device.

   o  An IPv6 prefix length for this device.

   o  An IPv6 prefix that is assigned to this device and its downstream
      devices.

   A few parameters are involved in the network as a whole.  They are:

   o  Identity of a trust anchor, which is a certification authority
      (CA) maintained by the network administrator(s), used during the
      secure bootstrap process.

   o  Total IPv6 address space available for edge devices.  It is one
      (or several) IPv6 prefix(es).

   o  The initial prefix length for each device role.

Jiang, et al.             Expires July 14, 2016                 [Page 4]
Internet-Draft         Auto IPv6 Prefix Management          January 2016

3.2.1.  Parameters each device can decide for itself

   This section identifies those of the above parameters that do not
   need external information in order for the devices concerned to set
   them to a reasonable value after bootstrap or after a network
   disruption.  There are few of these:

   o  Role of this device.

   o  Default IPv6 prefix length for this device.

   o  Identity of this device.

   The device may be shipped from the manufacturer with pre-configured
   role and default prefix length, which could be modified by an
   autonomic mechanism.

3.2.2.  Information needed from policy intent

   This section identifies those parameters that need external
   information about policy intent in order for the devices concerned to
   set them to a non-default value.

   o  Non-default value for the IPv6 prefix length for this device.
      This needs to be decided based on the role of this device.

   o  The initial prefix length for each device role.

   o  Whether to allow the device request more address space.

   o  The policy when to request more address space, for example, if the
      address usage reaches a certain limit or percentage.

3.2.3.  Comparison with current solutions

   This section briefly compares the above use case with current
   solutions.  Currently, the address management is still largely
   dependent on human planning.  It is rigid and static after initial
   planning.  Address requests will fail if the configured address space
   is used up.

   Some autonomic and dynamic address management functions may be
   achievable by extending the existing protocols, for example,
   extending DHCPv6-PD to request IPv6 prefixes according to the device
   role.  However, defining uniform device roles may not be a practical
   task.  Some functions are not suitable to be achieved by any existing
   protocols.

Jiang, et al.             Expires July 14, 2016                 [Page 5]
Internet-Draft         Auto IPv6 Prefix Management          January 2016

   Using a generic autonomic discovery and negotiation protocol instead
   of specific solutions has the advantage that additional parameters
   can be included in the autonomic solution without creating new
   mechanisms.  This is the principal argument for a generic approach.

3.3.  Interaction with other devices

3.3.1.  Information needed from other devices

   This section identifies those of the above parameters that need
   external information from neighbor devices (including the upstream
   devices).  In many cases, two-way dialogue with neighbor devices is
   needed to set or optimize them.

   o  Identity of a trust anchor.

   o  The device will need to discover a device, from which it can
      acquire IPv6 address space.

   o  The initial prefix length for each device role, particularly for
      its own downstream devices.

   o  The default value of the IPv6 prefix length may be overridden by a
      non-default value.

   o  The device will need to request and acquire IPv6 prefix that is
      assigned to this device and its downstream devices.

   o  The device may respond to prefix delegation request from its
      downstream devices.

   o  The device may require to be assigned more IPv6 address space, if
      it used up its assigned IPv6 address space.

3.3.2.  Monitoring, diagnostics and reporting

   This section discusses what role devices should play in monitoring,
   fault diagnosis, and reporting.

   o  The actual address assignments need to be logged for the potential
      offline management operations.

   o  In general, the usage situation of address space should be
      reported to the network administrators, in an abstract way, for
      example, statistics or visualized report.

   o  A forecast of address exhaustion should be reported.

Jiang, et al.             Expires July 14, 2016                 [Page 6]
Internet-Draft         Auto IPv6 Prefix Management          January 2016

4.  Autonomic Edge Prefix Management Solution

   This section introduces an autonomic edge prefix management solution.
   It uses the generic discovery and negotiation protocol defined by
   [I-D.ietf-anima-grasp].  The relevant options are defined in
   Section 5.

   The procedures described below are carried out by an Autonomic
   Service Agent (ASA) in each device that participates in the solution.
   We will refer to this as the PrefixManager ASA.

4.1.  Behaviors on prefix requesting device

   If the device containing an PrefixManager ASA has used up its address
   pool, it can request more space according to its requirements.  It
   should decide the length of the requested prefix by the intent-based
   mechanism, described in Section 6.

   An PrefixManager ASA that needs additional address space should
   firstly discover peers that may be able to provide extra address
   space.  The ASA should send out a GRASP Discovery message that
   contains an PrefixManager Objective option Section 5.1 in order to
   discover peers also supporting that option.  Then it should choose
   one such peer, most likely the first to respond.

   If the GRASP discovery Response message carries a divert option
   pointing to an off-link PrefixManager ASA, the requesting ASA may
   initiate negotiation with that ASA diverted device to find out
   whether it can provide the requested length prefix.

   In any case, the requesting ASA will act as a GRASP negotiation
   initiator by sending a GRASP Request message with an PrefixManager
   Objective option.  The ASA indicates in this option both the length
   of the requested prefix and whether the ASA supports the DHCPv6
   Prefix Delegation (PD) function [RFC3633].  This starts a GRASP
   negotiation process.

   During the subsequent negotiation, the ASA will decide at each step
   whether to accept the offered prefix.  That decision, and the
   decision to end negotiation, is an implementation choice.

   The ASA could alternatively initiate rapid mode GRASP discovery with
   an embedded negotiation request, if it is implemented.

Jiang, et al.             Expires July 14, 2016                 [Page 7]
Internet-Draft         Auto IPv6 Prefix Management          January 2016

4.2.  Behaviors on prefix providing device

   A device that receives a Discovery message with an PrefixManager
   Objective option should respond with a GRASP Response message if it
   contains an PrefixManager ASA.  Further details of the discovery
   process are described in [I-D.ietf-anima-grasp].  When this ASA
   receives a subsequent Request message it should conduct a GRASP
   negotiation sequence, using Negotiate, Confirm-waiting, and
   Negotiation-ending messages as appropriate.  The Negotiate messages
   carry an PrefixManager Objective option.  This will indicate whether
   the sending device supports the PD function.  More importantly, it
   will indicate the prefix and its length offered to the requesting
   ASA.  As described in [I-D.ietf-anima-grasp], negotiation will
   continue until either end stops it with a Negotiation-ending message.
   If the negotiation succeeds, the prefix providing ASA will remove the
   negotiated prefix from its pool, and the requesting ASA will add it.
   If the negotiation fails, the party sending the Negotiation-ending
   message may include an error code string.

   During the negotiation, the ASA will decide at each step how large a
   prefix to offer.  That decision, and the decision to end negotiation,
   is an implementation choice.

   The ASA could alternatively negotiate in response to rapid mode GRASP
   discovery, if it is implemented.

   This specification is independent of whether the PrefixManager ASAs
   are all embedded in routers, but that would be a rather natural
   scenario.  A gateway router in a hierarchical network topology
   normally provides prefixes for routers within its subnet, and it is
   likely to contain the first PrefixManager ASA discovered by its
   downstream routers.  However, the GRASP discovery model, including
   its Redirect feature, means that this is not an exclusive scenario,
   and a downstream PrefixManager ASA could negotiate a new prefix with
   a router other than its upstream router.

   A resource shortage may cause the gateway router to request more
   resource in turn from its own upstream device.  This would be another
   independent GRASP discovery and negotiation process.  During the
   processing time, the gateway router should send a Confirm-waiting
   Message to the initial requesting router, to extend its timeout.
   When the new resource becomes available, the gateway router responds
   with a GRASP Negotiate message with a prefix length matching the
   request.

   The algorithm to choose which prefixes to assign on the prefix
   providing devices is an implementation choice.

Jiang, et al.             Expires July 14, 2016                 [Page 8]
Internet-Draft         Auto IPv6 Prefix Management          January 2016

4.3.  Behavior after Successful Negotiation

   Upon receiving a GRASP Negotiation-ending message that indicates that
   an acceptable prefix length is available, the requesting device may
   request the prefix using DHCPv6 PD, if both ASAs have indicated that
   they are within a device that supports PD.  Otherwise, it is
   permissible for the initiating ASA to use the negotiated prefix
   without further messages.

   [Author's note: It is not intended to undermine DHCPv6 PD.  But in
   fact, if PD is not supported and the GRASP negotiation has succeeded,
   there should be no problem with this and it seems consistent as a
   solution.]

4.4.  Prefix logging

   Within the autonomic prefix management, all the prefix assignment is
   done by devices without human intervention.  It is therefore
   important to record all the prefix assignment history.  However, the
   logging and reporting process is out of scope for this specification.

5.  Autonomic Prefix Management Options

   This section defines the GRASP options that are used to support
   autonomic prefix management.

5.1.  Edge Prefix Objective Option

   The PrefixManager Objective option is a GRASP objective option
   conforming to [I-D.ietf-anima-grasp].  Its name is "PrefixManager"
   (see Section 8) and it carries up to three data items as its value:
   the PD support flag, the prefix length, and the actual prefix bits.
   The format of the PrefixManager Objective option is described as
   follows in CBOR data definition language (CDDL)
   [I-D.greevenbosch-appsawg-cbor-cddl]:

     objective = ["PrefixManager", objective-flags, loop-count,
                  PD-support, length, ?prefix]

     loop-count = 0..255         ; as in the GRASP specification
     objective-flags /=          ; as in the GRASP specification
     PD-support = true / false   ; indicates whether sender supports PD
     length = 0..128             ; requested or offered prefix length
     prefix = bytes .size 16     ; offered prefix in binary format

Jiang, et al.             Expires July 14, 2016                 [Page 9]
Internet-Draft         Auto IPv6 Prefix Management          January 2016

6.  Prefix Management Intent

   With in a single administrative domain, the network operator could
   provide intent for all devices with a certain role.  Thus it would be
   possible to apply an intended policy for every device in a simple
   way, without human intervention or configuration files.

   For example, the network operator could define the default prefix
   length for each type of role.  A prefix management intent, which
   contains all mapping information of device roles and their default
   prefix lengths, should be flooded in the network, through the
   Autonomic Control Plane (ACP)
   [I-D.ietf-anima-autonomic-control-plane].  The intent flooding
   mechanism is not yet defined, but one possibility would be define a
   suitable GRASP synchronization objective and flood it through the
   network.  To make this concrete, there could be an objective defined
   as follows:

     objective = ["Intent.PrefixManager", objective-flags, text]

     loop-count = 0..255         ; as in the GRASP specification
     objective-flags /=          ; as in the GRASP specification

     ;The text object would be the relevant intent statements (such
     ;as the example below) transmitted as a single string with all
     ;whitespace and format characters removed.

   This could be flooded to all nodes, and any PrefixManager ASA that
   did not receive it for some reason could obtain a copy using GRASP
   synchronization.  Upon receiving the prefix management intent, every
   device can decide its default prefix length by matching its own role.

6.1.  Example of Prefix Management Intent

   The prefix management intent in this document is used to carry
   mapping information of device roles and their default prefix lengths
   in an autonomic domain.  For example, an IPRAN operator wants to
   configure the prefix length of RNC Site Gateway (RSG) as 34, the
   prefix length of Aggregation Site Gateway (ASG) as 44, and the prefix
   length of Cell Site Gateway (CSG) as 56.  She/he may input the
   following intent into the autonomic network:

Jiang, et al.             Expires July 14, 2016                [Page 10]
Internet-Draft         Auto IPv6 Prefix Management          January 2016

   {"autonomic_intent":
   [
      {"model_version": "1.0"},
      {"intent_type": "Network management"},
      {"autonomic_domain": "Customer_X_intranet"},
      {"intent_name": "Prefix management"},
      {"intent_version": 73},
      {"Timestamp": "20150606 00:00:00"},
      {"Lifetime": "Permanent"},
      {"signature": "XXXXXXXXXXXXXXXXXXX"},
      {"content":
      [
         {"role": [{"role_name": "RSG"},
            {"role_characteristic":
               [{"prefix_length": "34"}]}
            ]},
         {"role": [{"role_name": "ASG"},
            {"role_characteristic":
               [{"prefix_length": "44"}]}
            ]},
         {"role": [{"role_name": "CSG"},
            {"role_characteristic":
               [{"prefix_length": "56"}]}
            ]}
      ]
      }
   ]
   }

7.  Security Considerations

   Relevant security issues are discussed in [I-D.ietf-anima-grasp].
   The preferred security model is that devices are trusted following
   the secure bootstrap procedure
   [I-D.ietf-anima-bootstrapping-keyinfra] and that a secure Autonomic
   Control Plane (ACP) [I-D.ietf-anima-autonomic-control-plane] is in
   place.

   It is RECOMMENDED that DHCPv6 PD, if used, should be operated using
   DHCPv6 authentication or Secure DHCPv6.

8.  IANA Considerations

   This document defines one new GRASP Objective Option name,
   "PrefixManager".  The IANA is requested to add this to the GRASP
   Objective Names Table registry defined by [I-D.ietf-anima-grasp] (if
   approved).

Jiang, et al.             Expires July 14, 2016                [Page 11]
Internet-Draft         Auto IPv6 Prefix Management          January 2016

9.  Acknowledgements

   Valuable comments were received from Michael Behringer, Joel Halpern,
   and Chongfeng Xie.

   This document was produced using the xml2rfc tool [RFC2629].

10.  Change log [RFC Editor: Please remove]

   draft-jiang-anima-prefix-management-00: original version, 2014-10-25.

   draft-jiang-anima-prefix-management-01: add intent example and
   coauthor Zongpeng Du, 2015-05-04.

   draft-jiang-anima-prefix-management-02: update references and the
   format of the prefix management intent, 2015-10-14.

   draft-ietf-anima-prefix-management-00: WG adoption, clarify scope and
   purpose, update text to match latest GRASP spec, 2016-01-11.

11.  References

11.1.  Normative References

   [I-D.greevenbosch-appsawg-cbor-cddl]
              Vigano, C. and H. Birkholz, "CBOR data definition language
              (CDDL): a notational convention to express CBOR data
              structures", draft-greevenbosch-appsawg-cbor-cddl-07 (work
              in progress), October 2015.

   [I-D.ietf-anima-autonomic-control-plane]
              Behringer, M., Bjarnason, S., BL, B., and T. Eckert, "An
              Autonomic Control Plane", draft-ietf-anima-autonomic-
              control-plane-01 (work in progress), October 2015.

   [I-D.ietf-anima-bootstrapping-keyinfra]
              Pritikin, M., Richardson, M., Behringer, M., and S.
              Bjarnason, "Bootstrapping Key Infrastructures", draft-
              ietf-anima-bootstrapping-keyinfra-01 (work in progress),
              October 2015.

   [I-D.ietf-anima-grasp]
              Bormann, C., Carpenter, B., and B. Liu, "A Generic
              Autonomic Signaling Protocol (GRASP)", draft-ietf-anima-
              grasp-01 (work in progress), October 2015.

Jiang, et al.             Expires July 14, 2016                [Page 12]
Internet-Draft         Auto IPv6 Prefix Management          January 2016

   [RFC3633]  Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
              Host Configuration Protocol (DHCP) version 6", RFC 3633,
              DOI 10.17487/RFC3633, December 2003,
              <http://www.rfc-editor.org/info/rfc3633>.

11.2.  Informative References

   [I-D.behringer-anima-reference-model]
              Behringer, M., Carpenter, B., Eckert, T., Ciavaglia, L.,
              Liu, B., Jeff, J., and J. Strassner, "A Reference Model
              for Autonomic Networking", draft-behringer-anima-
              reference-model-04 (work in progress), October 2015.

   [RFC2629]  Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
              DOI 10.17487/RFC2629, June 1999,
              <http://www.rfc-editor.org/info/rfc2629>.

   [RFC7575]  Behringer, M., Pritikin, M., Bjarnason, S., Clemm, A.,
              Carpenter, B., Jiang, S., and L. Ciavaglia, "Autonomic
              Networking: Definitions and Design Goals", RFC 7575,
              DOI 10.17487/RFC7575, June 2015,
              <http://www.rfc-editor.org/info/rfc7575>.

   [RFC7576]  Jiang, S., Carpenter, B., and M. Behringer, "General Gap
              Analysis for Autonomic Networking", RFC 7576,
              DOI 10.17487/RFC7576, June 2015,
              <http://www.rfc-editor.org/info/rfc7576>.

Authors' Addresses

   Sheng Jiang (editor)
   Huawei Technologies Co., Ltd
   Q14, Huawei Campus, No.156 Beiqing Road
   Hai-Dian District, Beijing, 100095
   P.R. China

   Email: jiangsheng@huawei.com

   Zongpeng Du
   Huawei Technologies Co., Ltd
   Q14, Huawei Campus, No.156 Beiqing Road
   Hai-Dian District, Beijing, 100095
   P.R. China

   Email: duzongpeng@huawei.com

Jiang, et al.             Expires July 14, 2016                [Page 13]
Internet-Draft         Auto IPv6 Prefix Management          January 2016

   Brian Carpenter
   Department of Computer Science
   University of Auckland
   PB 92019
   Auckland  1142
   New Zealand

   Email: brian.e.carpenter@gmail.com

   Qiong Sun
   China Telecom
   No.118, Xizhimennei Street
   Beijing  100035
   P. R. China

   Email: sunqiong@ctbri.com.cn

Jiang, et al.             Expires July 14, 2016                [Page 14]