





Internet Engineering Task Force (IETF)                      B. Carpenter
Request for Comments: 6036                             Univ. of Auckland
Category: Informational                                         S. Jiang
ISSN: 2070-1721                             Huawei Technologies Co., Ltd
                                                            October 2010


        Emerging Service Provider Scenarios for IPv6 Deployment

Abstract

   This document describes practices and plans that are emerging among
   Internet Service Providers for the deployment of IPv6 services.  They
   are based on practical experience so far, as well as current plans
   and requirements, reported in a survey of a number of ISPs carried
   out in early 2010.  This document identifies a number of technology
   gaps, but it does not make recommendations.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6036.

Copyright Notice

   Copyright (c) 2010 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
   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.



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Table of Contents

   1. Introduction ....................................................2
   2. Survey of ISP's Experience, Plans, and Requirements .............4
      2.1. Methodology ................................................4
      2.2. General Questions about IP Service .........................4
      2.3. Requirements for IPv6 Service ..............................5
      2.4. Status and Plans for IPv6 Service ..........................5
      2.5. IPv6 Technologies ..........................................5
      2.6. Effect of Size .............................................6
   3. Lessons from Experience and Planning ............................7
   4. Gap Analysis ....................................................8
      4.1. Product Issues .............................................8
      4.2. Protocol Issues ............................................9
      4.3. Documentation and General Issues ..........................10
   5. Security Considerations ........................................11
   6. Acknowledgements ...............................................11
   7. Informative References .........................................12
   Appendix A. Summary of Replies ....................................14
   Appendix B. Questionnaire .........................................19

1.  Introduction

   As is well known, the approaching exhaustion of IPv4 address space
   will bring about a situation in which Internet Service Providers
   (ISPs) are faced with a choice between one or more of three major
   alternatives:

   1.  Squeeze the use of IPv4 addresses even harder than today, using
       smaller and smaller address blocks per enterprise customer, and
       possibly trading address blocks with other ISPs.

   2.  Install multiple layers of Network Address Translation (NAT)
       [CGN] or share IPv4 addresses by other methods such as address-
       plus-port mapping [APLUSP], [PRANGE].

   3.  Deploy IPv6 and operate IPv4-IPv6 coexistence and interworking
       mechanisms.

   This document focuses on alternative (3), while recognizing that many
   ISPs may be obliged by circumstances to prolong the life of IPv4 by
   using (1) or (2) while preparing for (3).

   This document describes IPv6 deployment scenarios already adopted or
   currently planned by a set of ISPs who responded to a technical
   questionnaire.  Thus, it is a factual record of the responses from
   those ISPs.  It makes no recommendations; the best choice of
   scenarios will depend on the circumstances of individual ISPs.



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   We consider various aspects of IPv6 deployment: addressing, routing,
   DNS, management, and IPv4-IPv6 coexistence and interworking.  We do
   not consider application services in detail, but we do cover general
   aspects.

   The reader is assumed to be familiar with IPv6.  The IETF's view of
   core IPv6 requirements is to be found in [RFC4294] (currently being
   updated as [NODEREQ]).  However, this does not give a complete view
   of mechanisms an ISP may need to deploy, since it considers the
   requirements for an individual node, not for a network or service
   infrastructure as a whole.

   [RFC4029] discusses scenarios for introducing IPv6 into ISP networks,
   as the problem was viewed some years ago.  Its end goal is simply a
   dual-stack ISP backbone.  Today's view is that this is insufficient,
   as it does not allow for interworking between IPv6-only and legacy
   (IPv4-only) hosts.  Indeed, the end goal today might be an IPv6-only
   ISP backbone, with some form of legacy IPv4 support.

   [RFC4779] discusses deployment in broadband access networks such as
   Cable Television (CATV), Asymmetric Digital Subscriber Line (ADSL),
   and wireless.  [RFC5181], [RFC5121], and [RFC5692] deal specifically
   with IEEE 802.16 access networks.  MPLS-based ISPs may use the IPv6
   Provider Edge Router (6PE) [RFC4798] mechanism.

   [RFC4942] covers IPv6 security issues, especially those that are
   specific to transition and IPv4-IPv6 coexistence scenarios.
   [RFC4864] discusses "Local Network Protection", i.e., how the
   internal structure of an IPv6 site network can be protected.  This
   affects how well an ISP's customers are protected after they deploy
   IPv6.

   Although the basic IPv6 standards have long been stable, it should be
   noted that considerable work continues in the IETF, particularly to
   resolve the issue of highly scalable multihoming support for IPv6
   sites, and to resolve the problem of IP layer interworking between
   IPv6-only and IPv4-only hosts.  IPv6/IPv4 interworking at the
   application layers is handled within the original dual-stack model of
   IPv6 deployment: either one end of an application session will have
   dual-stack connectivity, or a dual-stack intermediary such as an HTTP
   proxy or SMTP server will interface to both IPv4-only and IPv6-only
   hosts or applications.

   [RFC5211] describes an independent view of a possible sequence of
   events for IPv6 adoption in the Internet as a whole, with direct
   implications for ISPs.  Its main point, perhaps, is that by the year
   2012, it will be appropriate to regard IPv4 networks as the legacy
   solution.



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2.  Survey of ISP's Experience, Plans, and Requirements

2.1.  Methodology

   To obtain a view of the IPv6 experience, plans, and requirements of
   ISPs, a questionnaire was issued by the authors in December 2009 and
   announced widely to the operational community.  We promised to keep
   the replies strictly confidential and to publish only combined
   results, without identifying information about individual ISPs in any
   published results.  The raw technical questions are shown in
   Appendix B, and a detailed summary of the replies is in Appendix A.
   Note that although the questionnaire was widely announced, those who
   chose to reply were self-selected and we can make no claim of
   statistical significance or freedom from bias in the results.  In
   particular, we assume that ISPs with a pre-existing interest in IPv6
   are more likely to have replied than others.  The results should
   therefore be interpreted with some care.

2.2.  General Questions about IP Service

   Thirty-one ISPs replied before the cutoff date for this analysis. 65%
   of responses were from European ISPs but large operators in North
   America and Asian/Pacific regions are included.  Commercial ISPs
   operating nationally predominate, with a vast range of size (from 30
   customers up to 40 million).  Note that some providers chose not to
   answer about the exact number of customers.  Nevertheless, it can be
   stated that 6 providers each had millions of customers, the next 10
   each had more than 10,000 customers, and the remaining 15 each had
   fewer than 10,000 customers.

   80% of the respondents offer both transit and origin-only service;
   29% offer IP multicast service; 80% have multihomed customers.

   A very wide variety of access technologies is used: xDSL, Data Over
   Cable Service Interface Specification (DOCSIS), leased line (X.25,
   Time Division Multiplexer / Plesiochronous Digital Hierarchy (TDM/
   PDH), Synchronous Digital Hierarchy (SDH)), ATM, frame relay, dialup,
   microwave, Fiber To The Premises (FTTP), CDMA, Universal Mobile
   Telecommunications System (UMTS), Long Term Evolution (LTE),
   Worldwide Interoperability for Microwave Access (WiMAX), Broadband
   Wireless Access (BWA), WiFi, Ethernet (100M-10G), Ethernet/SDH,
   MetroEthernet/MPLS.  Most ISPs provide Customer Premises Equipment
   (CPE) to some or all of their customers, but these CPE are often
   unable to support IPv6.

   Estimates of when ISPs will run out of public IPv4 address space for
   internal use vary widely, between "now" and "never".  Public IPv4
   address space for customers is mainly expected to run out between



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   2010 and 2015, but four or five ISPs suggested it will never happen,
   or at least not in the foreseeable future.  About 19% of ISPs offer
   RFC 1918 space to customers, and about 39% use such addresses
   internally.

2.3.  Requirements for IPv6 Service

   61% of ISPs report that some big customers are requesting IPv6.
   Predictions for when 10% of customers will require IPv6 range from
   2010 to 2017, and for 50% from 2011 to 2020.  These ISPs require IPv6
   to be a standard service by 2010 to 2015; the most common target date
   is 2011.

2.4.  Status and Plans for IPv6 Service

   42% of ISPs already offer IPv6 as a regular service, although, in
   general, it is used by fewer than 1% of customers.  Another 48% of
   ISPs have IPv6 deployment in progress or planned.  These all plan at
   least beta-test service in 2010.  Planned dates for regular service
   are between 2010 and 2013 (except for one ISP who replied that it
   depends on the marketing department).  When asked when IPv6 will
   reach 50% of total traffic, the most common answer is 2015.

2.5.  IPv6 Technologies

   Turning to technology choices, the overwhelming choice of approach
   (94%) is a dual-stack routing backbone, and the reason given is
   simplicity and cost. 39% run, or plan to run, a 6to4 relay as well,
   and 16% run or plan a Teredo server.  However, 77% of ISPs don't have
   or plan to have any devices dedicated to IPv6.  A different 77% don't
   see IPv6 as an opportunity to restructure their network topology.

   When asked which types of equipment are unable to support IPv6, the
   most common answer was CPE (10 mentions).  Also mentioned: handsets;
   Digital Subscriber Line Access Multiplexers (DSLAMs); routers
   (including several specific models); traffic management boxes; load
   balancers; VPN boxes; some SIP platforms; management interfaces &
   systems; firewalls; billing systems.  When asked if such devices can
   be field-upgraded, the answers were gloomy: 5 yes, 4 partially, 10
   no, and numerous "don't know" or "hopefully".

   84% support or plan DNS Authentication, Authorization, Accounting,
   and Auditing (AAAA) queries over IPv6, and all but one of these
   include reverse DNS lookup for IPv6.

   The ISPs surveyed have prefixes ranging from /19 to /48, and have a
   variety of policies for customer prefixes.  Fifteen ISPs offer more
   than one of /48, /52, /56, /60, or /64.  Two offer /56 only, eight



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   offer /48 only.  Two wired operators offer /64 only.  Mobile
   operators offer /64 in accordance with 3GPP, but at least one would
   like to be allowed to offer /128 or /126.  Also, as many as 30% of
   the operators already have IPv6 customers preferring a PI (provider
   independent) prefix.  The methods chosen for prefix delegation to
   CPEs are manual, DHCPv6[-PD], Stateless Address Autoconfiguration
   (SLAAC), RADIUS, and Point-to-Point Protocol over Ethernet (PPPoE).
   However, in fact, the latter two cannot assign a prefix on their own.

   About 50% of ISPs already operate or plan dual-stack SMTP, Post
   Office Protocol 3 (POP3), IMAP, and HTTP services.  In terms of
   internal services, it seems that firewalls, intrusion detection,
   address management, monitoring, and network management tools are also
   around the 50% mark.  However, accounting and billing software is
   only ready at 23% of ISPs.

   Considering IPv4-IPv6 interworking, 58% of ISPs don't expect to have
   IPv6-only customers (but mobile operators are certain they will have
   millions).  Five ISPs report customers who explicitly refused to
   consider IPv6.  When asked how long customers will run IPv4-only
   applications, the most frequent answer is "more than ten years".
   Only three ISPs state that IPv6-IPv4 interworking at the IP layer is
   not needed.  On the other hand, only three (a different three!) run
   or plan to run NAT-PT (Protocol Translation).  At least 30% plan to
   run some kind of translator (presumably NAT64/DNS64), but only two
   felt that a multicast translator was essential.  Among those who do
   not plan a translator, when asked how they plan to connect IPv6-only
   customers to IPv4-only services, seven rely on dual stack and four
   have no plan (one said, paraphrasing, "it's their problem").

   Asked about plans for Mobile IPv6 (or Nemo mobile networks), 19% said
   yes, and 71% said no, with the others uncertain.  A detailed analysis
   shows that of the six ISPs who responded positively, three are large
   mobile operators (and a fourth mobile operator said no).  The other
   three who responded positively were broadband ISPs ranging from small
   to very large.

2.6.  Effect of Size

   We examined the data to see whether any other differences would
   emerge between the very large (millions of customers), medium (at
   least 10,000), and small (fewer than 10,000) operators.  However, the
   range of answers seems to be broadly similar in all cases.  The major
   exception is that among the six very large operators, one plans to
   use 6PE and dual-stack lite (DS-lite), and another to use IPv6 on VPN
   to Provider Edge Router (6VPE), instead of a simple dual stack.  The
   other large operators and all the medium and small operators prefer a
   simple dual stack.



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3.  Lessons from Experience and Planning

   This section is assembled and paraphrased from general comments made
   in the various questionnaire responses.  Any inconsistencies or
   contradictions are present in the original data.  Comments related to
   missing features and products have been included in Section 4.

   As noted in the summary above, the ISPs that responded overwhelmingly
   prefer a native dual-stack deployment.  Numerous comments mentioned
   the simplicity of this model and the complexity and sub-optimal
   routing of tunnel-based solutions.  Topology redesign is not
   generally considered desirable, because congruent IPv4 and IPv6
   topology simplifies maintenance and engineering.  Nevertheless, 6to4
   is considered convenient for cable modem (DOCSIS) users and IPv6
   Rapid Deployment (6RD) is considered an attractive model by some.
   Various operators, but by no means all, also see a need for Teredo.
   One very large MPLS-based operator prefers 6PE because it avoids an
   IPv6 IGP and reduces operational costs.  This operator also sees IPv4
   scarcity addressed by DS-lite [DSLITE] and Carrier Grade NAT, also
   acting as a catalyst for IPv6.  Another very large operator with an
   existing NAT44 infrastructure plans to use 6VPE [RFC4659] and
   believes that NAT64 will be similar to NAT44 in support requirements.

   Several ISPs observe that IPv6 deployment is technically not hard.
   The most eloquent statement: "Just do it, bit by bit.  It is very
   much an 'eating the elephant' problem, but at one mouthful at a time,
   it appears to be surprisingly easy."  Other comments paraphrased from
   the replies are:

   o  Despite the known gaps, the tools and toolkits are fairly mature
      at this point.

   o  Managerial commitment and a systematic approach to analyzing
      requirements and readiness are essential.

   o  Evangelization remains a must, as it seems that many ISP and IT
      managers are still unaware of the need for an IPv6 plan, and are
      inclined to dismiss IPv4 depletion as a false alarm, and also seem
      unaware that NATs create expensive support requirements.

   o  Without customers wanting IPv6, getting business backing is very
      hard, and IPv6 security and scale was not a focus for vendors
      until very recently.

   o  Operators lack real experience with customer usage of IPv6, and
      the resulting lack of confidence causes delay.





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   Three further quotations are of interest:

   "We are planning to move all our management addressing from IPv4 to
   IPv6 to free up IPv4 addresses."

   "I am actively pushing our larger customers to start testing IPv6 as
   our development has pretty much stopped as we need some real world
   testing to be done."

   "Customer support needs to be aware that IPv6 is being started in
   your network, or servers.  We experienced many IPv6 blocking
   applications, applications that do not fall back to IPv4, etc.  The
   most difficult part may be to get engineers, sales, customer support
   personnel to like IPv6."

4.  Gap Analysis

   The survey has shown a certain number of desirable features to be
   missing, either in relevant specifications, or in many products.
   This section summarizes those gaps.

4.1.  Product Issues

   As noted above, numerous models of various types of product still do
   not support IPv6:

   o  CPE

   o  Handsets

   o  DSLAMs

   o  Routers

   o  Traffic management boxes

   o  Load balancers

   o  VPN boxes

   o  SIP and other appliances

   o  Management interfaces and systems

   o  Firewalls

   o  Even where they support IPv6, customer-side firewalls and routers
      need to operate at 25-100 Mbit/s



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   o  Intrusion detection systems

   o  Accounting and billing systems

   It is not the purpose of this document to name and shame vendors, but
   today it is becoming urgent for all products to avoid becoming part
   of the IPv4 legacy.  ISPs stated that they want consistent feature-
   equivalent support for IPv4 and IPv6 in all equipment and software at
   reasonable or no extra cost.  The problems can be quite subtle: for
   example, one CPE with "full" IPv6 support does not support IPv6
   traffic shaping, so the ISP cannot cap IPv6 traffic to contractual
   limits.

   Numerous ISPs want a scalable NAT64/DNS64 product.

   The need for IPv6 support in "all the best open source tools" was
   also mentioned.

   Several ISPs also noted that much commercial applications software
   does not correctly support IPv6 and that this will cause customer
   problems.  Also, some operating systems are still shipped with IPv6
   disabled by default or with features such as IPv4-mapped addresses
   disabled by default.

4.2.  Protocol Issues

   Various needs and issues related mainly to protocols were mentioned:

   o  A specific CPE need is an intelligent prefix sub-delegation
      mechanism (ease of use issue).

   o  "Getting it right" so that a dual-stack client doesn't end up
      trying to use the wrong transport to reach a site.

   o  "User-side port allocation mechanisms.  UPnP IGD and NAT-PMP can
      be used for IPv4, but nothing exists for IPv6 (yet)."  UPnP IGD
      refers to the Universal Plug and Play Forum's Internet Gateway
      Device.  NAT-PMP is the NAT Port Mapping Protocol.

      Editor's comment:  even though port mapping is in principle
         unnecessary for IPv6, a method of opening ports through
         firewalls on demand seems necessary.

   o  Full Router Advertisement (RA) support on LAN side of ADSL CPE.







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   o  PPPoE and RADIUS support.  Specifically, global unicast address
      assignment for Layer 2 Tunneling Protocol (L2TP) / PPPoE.
      Currently, the PPPoE client will be assigned a link-local address,
      requiring a second step (DHCPv6 or SLAAC).

   o  Simple automatic distribution of DNS server details is essential;
      a DNS server option in RA [RFC5006] is wanted.

   o  ISPs need fully featured DHCPv6, especially since SLAAC does not
      allow settings to be pushed out (except for RFC 5006).

   o  Firewall systems should not use separate IPv4 and IPv6 rules.

   o  Gaps in infrastructure security for IPv6 management.

   o  Gaps in routers' treatment of header options.

   o  RA-Guard in switches.

   o  Virtual Router Redundancy Protocol (VRRP) support.

   o  PE-CE routing protocols (OSPF and IS-IS).

   o  Problems using a single BGP session to exchange routes for both
      IPv4 and IPv6.

   o  Consistent IPv6 address display format in outputs and
      configuration input.  Inconsistency breaks a lot of existing
      tools.

4.3.  Documentation and General Issues

   We also note areas where there was clearly confusion among the ISPs
   responding, which may denote weaknesses of existing documentation:

   o  Perhaps due to poor phrasing in the survey questions, some ISPs
      indicated that they would use PPPoE or RADIUS to assign prefixes
      to CPEs.  In fact, IPv6 PPP only negotiates 64-bit interface
      identifiers; a full address has to be assigned by another method,
      and even this does not delegate a prefix to a CPE router.  RADIUS
      alone is also insufficient, as it needs to be combined with
      another method for full address assignment.

   o  Although most ISPs see a need for IPv4-IPv6 interworking at the
      network layer, many of them do not see a need for an ISP to
      operate the resulting translator.  Yet, their customers, whether
      subscribers or content providers, will be the first to suffer when
      IPv6-only clients cannot reach IPv4-only services.



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   o  Most ISPs seemed to misunderstand the nature of a tunnel broker,
      even though this is a service that any ISP could consider offering
      to its subscribers.

   Global IPv6 connectivity still has issues; for example, ISPs in the
   Pacific region may have to obtain IPv6 transit via the USA (a
   situation faced by IPv4 operators in Europe about twenty years ago).
   Also, there are persistent Path MTU Discovery (PMTUD) issues in
   various places on the net, and a lack of multicast peering.

   Finally, there was a comment that real deployment case studies must
   be shown to operators along with multihoming and traffic engineering
   best practices.

5.  Security Considerations

   As a report on a survey, this document creates no security issues in
   itself.  ISPs did not register any general concerns about IPv6
   security.  However, we note that about half of all firewall and
   intrusion detection products are still reported not to support IPv6.
   Some ISPs expressed concern about firewall performance and about the
   need for separate firewall configurations for IPv4 and IPv6.

6.  Acknowledgements

   We are grateful to all those who answered the questionnaire: Stewart
   Bamford, Pete Barnwell, Cameron Byrne, Gareth Campling, Kevin
   Epperson, David Freedman, Wesley George, Steinar Haug, Paul
   Hoogsteder, Mario Iseli, Christian Jacquenet, Kurt Jaeger, Seiichi
   Kawamura, Adrian Kennard, Simon Leinen, Riccardo Loselli, Janos
   Mohacsi, Jon Morby, Michael Newbery, Barry O'Donovan, Al Pooley,
   Antonio Querubin, Anthony Ryan, Marc Schaeffer, Valeriu Vraciu, Bill
   Walker, and those who preferred to remain anonymous.

   The ISPs willing to be named were: AISP, Alphanet, Breedband Delft,
   Claranet, E4A, Fidonet, Finecom, France Telecom, Hungarnet, Imagine,
   LavaNet, Level 3 Communications LLC, NEC BIGLOBE, Nepustilnet, Net
   North West, RoEduNet, SWITCH, Snap, Sprint, Star Technology, T-Mobile
   USA, Ventelo, and Whole Ltd.

   Useful comments and contributions were also made by Shane Amante,
   Mohamed Boucadair, Mark Smith, and others.

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







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7.  Informative References

   [APLUSP]   Bush, R., "The A+P Approach to the IPv4 Address Shortage",
              Work in Progress, October 2009.

   [CGN]      Yamagata, I., Miyakawa, S., Nakagawa, A., and H. Ashida,
              "Common requirements for IP address sharing schemes", Work
              in Progress, July 2010.

   [DSLITE]   Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual-
              Stack Lite Broadband Deployments Following IPv4
              Exhaustion", Work in Progress, August 2010.

   [NODEREQ]  Jankiewicz, E., Loughney, J., and T. Narten, "IPv6 Node
              Requirements RFC 4294-bis", Work in Progress, July 2010.

   [PRANGE]   Boucadair, M., Levis, P., Bajko, G., and T. Savolainen,
              "IPv4 Connectivity Access in the Context of IPv4 Address
              Exhaustion: Port Range based IP Architecture", Work
              in Progress, July 2009.

   [RFC2629]  Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
              June 1999.

   [RFC4029]  Lind, M., Ksinant, V., Park, S., Baudot, A., and P.
              Savola, "Scenarios and Analysis for Introducing IPv6 into
              ISP Networks", RFC 4029, March 2005.

   [RFC4294]  Loughney, J., "IPv6 Node Requirements", RFC 4294,
              April 2006.

   [RFC4659]  De Clercq, J., Ooms, D., Carugi, M., and F. Le Faucheur,
              "BGP-MPLS IP Virtual Private Network (VPN) Extension for
              IPv6 VPN", RFC 4659, September 2006.

   [RFC4779]  Asadullah, S., Ahmed, A., Popoviciu, C., Savola, P., and
              J. Palet, "ISP IPv6 Deployment Scenarios in Broadband
              Access Networks", RFC 4779, January 2007.

   [RFC4798]  De Clercq, J., Ooms, D., Prevost, S., and F. Le Faucheur,
              "Connecting IPv6 Islands over IPv4 MPLS Using IPv6
              Provider Edge Routers (6PE)", RFC 4798, February 2007.

   [RFC4864]  Van de Velde, G., Hain, T., Droms, R., Carpenter, B., and
              E. Klein, "Local Network Protection for IPv6", RFC 4864,
              May 2007.





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   [RFC4942]  Davies, E., Krishnan, S., and P. Savola, "IPv6 Transition/
              Co-existence Security Considerations", RFC 4942,
              September 2007.

   [RFC5006]  Jeong, J., Park, S., Beloeil, L., and S. Madanapalli,
              "IPv6 Router Advertisement Option for DNS Configuration",
              RFC 5006, September 2007.

   [RFC5121]  Patil, B., Xia, F., Sarikaya, B., Choi, JH., and S.
              Madanapalli, "Transmission of IPv6 via the IPv6
              Convergence Sublayer over IEEE 802.16 Networks", RFC 5121,
              February 2008.

   [RFC5181]  Shin, M-K., Han, Y-H., Kim, S-E., and D. Premec, "IPv6
              Deployment Scenarios in 802.16 Networks", RFC 5181,
              May 2008.

   [RFC5211]  Curran, J., "An Internet Transition Plan", RFC 5211,
              July 2008.

   [RFC5692]  Jeon, H., Jeong, S., and M. Riegel, "Transmission of IP
              over Ethernet over IEEE 802.16 Networks", RFC 5692,
              October 2009.




























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Appendix A.  Summary of Replies

   This summarizes the 31 replies received by April 14, 2010.  Note that
   the answers to some questions do not total to 31, due to missing
   answers or to multiple choices in some cases.  The ISPs are
   distributed as follows:

      Europe: 20

      North America: 7

      Asia/Pacific: 4

   They can additionally be classified as:

      Commercial: 26

      Academic/research: 4

      Operating internationally: 6

      Operating nationally: 25

   Basic data about IP service offerings:

   o  Offering both origin-only and transit service: 25

   o  Offering no transit: 6

   o  Number of private/small office customers (one IPv4 address): a few
      with zero, then from 30 units up to 40 million

   o  Number of corporate customers (block of IPv4 addresses): a few
      with zero, then from 40 units up to 40000

   o  IP multicast service? 9 yes, 22 no

   o  Do any customers require multihoming to multiple ISPs? 25 yes, 6
      no

   o  Access technologies used: xDSL, DOCSIS, leased line (X.25, TDM/
      PDH, SDH), ATM, frame relay, dialup, microwave, FTTP, CDMA, UMTS,
      LTE, WiMAX, BWA, WiFi, Ethernet (100M-10G), Ether/SONET, Ether/
      MPLS, IPv6-in-IPv4 tunnels.







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   Customer Premises Equipment:

   o  Do customers use CPE that ISP supplies? 27 yes (10% to 100% of
      customers), 4 no

   o  Does the CPE provided support native IPv6? 17 yes (some), 10 no

   o  (Note that these numbers include answers that apply to tens of
      millions of mobile handsets.)

   IPv4 Address Space:

   o  When do you expect to run out of public IPv4 address space inside
      your own network?  Estimates run from "now" to 2020, but 5 ISPs
      say "never" or "unforeseeable".

   o  Do you run RFC1918 addresses and NAT within your network? 9 yes;
      18 no; 3 others say yes, but only for equipment management or
      L3VPN.

   o  What % of IPv4 space is needed for ISP use (not for customers)? 1%
      to 30% (and 100% for NRENs with PI customers).

   o  When do you expect to run out of public IPv4 address space for
      customers?  Answers range from 2010 to 2015; 4 ISPs say it depends
      on their registry. 4 or 5 give answers suggesting it will never
      happen.

   o  Do you offer RFC1918 addresses to customers? 6 yes, 24 no

   IPv6 Requirements:

   o  Are some big customers requesting IPv6? 19 yes, 12 no

   o  When do you predict 10% and 50% of customers to require IPv6
      service?  Ignoring unclear answers, answers for 10% range from
      2010 to 2017, and for 50% from 2011 to 2020.

   o  When do you require IPv6 to be a standard service available to all
      customers?  Answers range from 2010 to 2015; the most common
      answer is 2011.

   o  When do you predict IPv6 traffic to reach 50% of total traffic?
      Answers range from 2011 to 2020; the most common answer is 2015.







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   IPv6 Status and Plans:

   o  Do you currently offer IPv6 as a regular service? 13 yes, 5
      partial, 12 no

   o  What % of customers currently use IPv6? <1% to 30%; mostly 0 or
      <1%

   o  When do you plan to start IPv6 deployment? 12 complete, 12 in
      progress, 3 in plan, 4 have no plan

   o  When do you plan to offer IPv6 as a special or beta-test service?
      For all those in progress or with a plan, the answer was either
      "now" or during 2010.

   o  When do you plan to offer IPv6 as a regular service to all
      customers?  For all those in progress or with a plan, the answer
      was between "now" and 2013 (except for one ISP who replied that it
      depends on the marketing department).

   IPv6 Technologies.  Note the answers refer to actual deployment or to
   plans, as the case may be:

   o  Which basic IPv6 access method(s) apply?

      *  Dual-stack routing backbone: 29 yes, 1 maybe

      *  Separate IPv4 and IPv6 backbones: 2 yes, 1 maybe

      *  6to4 relay: 12 yes

      *  Teredo server: 5 yes

      *  Tunnel broker: Unfortunately this question was unclear and
         obviously misunderstood by most respondents.  Several
         respondents mentioned that they are getting their own transit
         connectivity via static tunnels.

      *  Something else: Answers were 6VPE + NAT64/DNS64; PNAT;
         "considering 6RD"

   o  Please briefly explain the main reasons/issues behind your choice:
      The best summary of the answers is "dual stack is simplest, why do
      anything else?".

   o  Which types of equipment in your network are unable to support
      IPv6?  The most common answer was CPE (9 mentions).  Also
      mentioned: handsets; DSLAMs; routers (including several specific



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      models); traffic management boxes; load balancers; VPN boxes; some
      SIP platforms; management interfaces & systems; firewalls; billing
      systems.

   o  Can they be field-upgraded? 5 yes, 4 partially, 10 no and numerous
      "don't know" or "hopefully"

   o  Is any equipment 100% dedicated to IPv6? 7 yes, 24 no

   o  Is IPv6 an opportunity to restructure your whole topology? 2 yes,
      5 partial, 23 no

   o  Do you include support for DNS AAAA queries over IPv6? 21 yes, 5
      plan, 4 no

   o  Do you include support for reverse DNS for IPv6 addresses? 22 yes,
      3 plan, 5 no

   o  What length(s) of IPv6 prefix do you have or need from the
      registry? 1 /19, 1 /21 (plus several /32s), 1 /22 1 /30, 3
      multiple /32s, 21 /32, 3 /48

   o  What length(s) of IPv6 prefix are offered to customers? 15 ISPs
      offer more than one of /48, /52, /56, /60 or /64. 2 offer /56
      only, 8 offer /48 only.  Two wired operators offer /64 only.
      Mobile operators offer /64 in accordance with 3GPP, but at least
      one would like to be allowed to offer /128 or /126.

   o  Do any customers share their IPv6 prefix among multiple hosts?
      Unfortunately this question was unclear and obviously
      misunderstood by most respondents.

   o  Do any of your customers prefer to use PI IPv6 prefixes? 10 yes,
      17 no

   o  How are IPv6 prefixes delegated to CPEs? 16 manual, 10
      DHCPv6[-PD], 8 SLAAC, 8 RADIUS, 2 PPPoE.  (Note: RADIUS and PPP
      cannot in fact delegate prefixes.)

   o  Are your SMTP, POP3 and IMAP services dual stack? 10 yes, 6 plan,
      13 no

   o  Are your HTTP services, including caching and webmail, dual-stack?
      9 yes, 1 partial, 4 plan, 15 no

   o  Are any other services dual stack? 11 yes, 2 plan, 11 no





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   o  Is each of the following dual stack?

      *  Firewalls: 12 yes, 3 partial, 3 plan, 9 no

      *  Intrusion detection: 10 yes, 2 plan, 13 no

      *  Address management software: 15 yes, 1 plan, 13 no

      *  Accounting software: 7 yes, 21 no

      *  Monitoring software: 16 yes, 2 partial, 2 plan, 11 no

      *  Network management tools: 13 yes, 4 partial, 1 plan, 11 no

   o  Do you or will you have IPv6-only customers? 13 yes (or maybe), 18
      no (or not likely)

   o  Do you have customers who have explicitly refused to consider
      IPv6? 5 yes, 23 no

   o  Interworking issues:

      *  How many years do you expect customers to run any IPv4-only
         applications?  Answers range from 2 years to infinity, most
         frequent answer is >10 years.

      *  Is IPv6-IPv4 interworking at the IP layer needed? 16 yes, 9
         uncertain, 3 no

      *  Do you include a NAT-PT IPv6/IPv4 translator? 2 yes, 1 plan, 26
         no

      *  If yes, does that include DNS translation? 1 plan, 2 no

      *  If not, do you plan to operate an IPv6/IPv4 translator? 10 plan
         (NAT64), 8 no, others uncertain

      *  If not, how do you plan to connect IPv6-only customers to IPv4-
         only services? 7 rely on dual stack; 4 have no plan (one said
         "their problem")

      *  If you offer IP multicast, will that need to be translated too?
         2 yes, 2 uncertain, 5 no

   o  Any plans for Mobile IPv6 (or Nemo mobile networks)? 6 yes, 2
      uncertain, 22 no





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Appendix B.  Questionnaire

   This appendix reproduces the technical body of the questionnaire that
   was made available for ISPs to express their requirements, plans, and
   experience.

   I.  General questions about IP service

   1.  Do you offer origin-only (stub, end-user) IP service, transit IP
       service, or both?

   2.  Approximate number of private/small office customers (one IPv4
       address)

   3.  Approximate number of corporate customers (block of IPv4
       addresses, not included in Q2)

   4.  Do you offer IP multicast service?

   5.  Do any of your customers require multihoming to multiple ISPs?

   6.  Access technologies used (ADSL,etc.)

   7.  Do your customers use CPE that you supply?

       7.1.  What % of customers?

       7.2.  Does the CPE that you provide support native IPv6?

   8.  When do you expect to run out of public IPv4 address space inside
       your own network?

       8.1.  Do you run private (RFC1918) addresses and NAT within your
          network (i.e., a second layer of NAT in the case of customers
          with their own NAT)?

       8.2.  What % of your IPv4 space is needed for your own use (not
          for customers)?

   9.  When do you expect to run out of public IPv4 address space for
       customers?

       9.1.  Do you offer private (RFC1918) addresses to your customers?








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   II.  Questions about requirements for IPv6 service

   10.  Are some big customers requesting IPv6?

   11.  When do you predict 10% and 50% of your customers to require
        IPv6 service?

   12.  When do you require IPv6 to be a standard service available to
        all customers?

   13.  When do you predict IPv6 traffic to reach 50% of total traffic?

   III.  Questions about status and plans for IPv6 service

   14.  Do you currently offer IPv6 as a regular service?

        14.1.  What % of your customers currently use IPv6?

        14.2.  When do you plan to start IPv6 deployment?

        14.3.  When do you plan to offer IPv6 as a special or beta-test
           service to customers?

   15.  When do you plan to offer IPv6 as a regular service to all
        customers?

   IV.  Questions about IPv6 technologies

   16.  Which basic IPv6 access method(s) apply:

        16.1.  dual stack routing backbone?

        16.2.  separate IPv4 and IPv6 backbones?

        16.3.  6to4 relay?

        16.4.  Teredo server?

        16.5.  tunnel broker?  If so, which one?

        16.6.  Something else?  Please briefly describe your method:

        16.7.  If possible, please briefly explain the main reasons/
           issues behind your choice.

   17.  Which types of equipment in your network are unable to support
        IPv6?




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        17.1.  Can they be field-upgraded to support IPv6?

        17.2.  Is any equipment 100% dedicated to IPv6?

   18.  Is IPv6 an opportunity to restructure your whole topology?

   19.  Do you include support for DNS AAAA queries over IPv6?

   20.  Do you include support for reverse DNS for IPv6 addresses?

   21.  What length(s) of IPv6 prefix do you have or need from the
        registry?

   22.  What length(s) of IPv6 prefix are offered to customers?

        22.1.  Do any customers share their IPv6 prefix among multiple
           hosts?

   23.  Do any of your customers prefer to use PI IPv6 prefixes instead
        of a prefix from you?

   24.  How are IPv6 prefixes delegated to CPEs?  (Manual, PPPoE,
        RADIUS, DHCPv6, stateless autoconfiguration/RA, etc...)

   25.  Are your SMTP, POP3 and IMAP services dual-stack?

   26.  Are your HTTP services, including caching and webmail, dual-
        stack?

   27.  Are any other services dual-stack?

   28.  Is each of the following dual-stack?

        28.1.  Firewalls

        28.2.  Intrusion detection

        28.3.  Address management software

        28.4.  Accounting software

        28.5.  Monitoring software

        28.6.  Network management tools







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   29.  Do you or will you have IPv6-only customers?

   30.  Do you have customers who have explicitly refused to consider
        IPv6?

   31.  How many years do you expect customers to run any IPv4-only
        applications?

   32.  Is IPv6-IPv4 interworking at the IP layer needed?

   33.  Do you include a NAT-PT IPv6/IPv4 translator?

        33.1.  If yes, does that include DNS translation?

        33.2.  If not, do you plan to operate an IPv6/IPv4 translator?

        33.3.  If not, how do you plan to connect IPv6-only customers to
           IPv4-only services?

        33.4.  If you offer IP multicast, will that need to be
           translated too?

   34.  Any plans for Mobile IPv6 (or Nemo mobile networks)?

   35.  What features and tools are missing today for IPv6 deployment
        and operations?

   36.  Any other comments about your IPv6 experience or plans?  What
        went well, what was difficult, etc.






















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Authors' Addresses

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

   EMail: brian.e.carpenter@gmail.com


   Sheng Jiang
   Huawei Technologies Co., Ltd
   KuiKe Building, No.9 Xinxi Rd.,
   Shang-Di Information Industry Base, Hai-Dian District, Beijing
   P.R. China

   EMail: shengjiang@huawei.com
































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