Network Working Group                                             B. Liu
Internet Draft                                                  S. Jiang
Intended status: Informational                       Huawei Technologies
Expires: April 24, August 18, 2014                               February 14, 2014                                       C. Byrne
                                                          T-Mobile USA
                                                      October 21, 2013

              Recommendations of Using Unique Local Addresses
             draft-ietf-v6ops-ula-usage-recommendations-01.txt
             draft-ietf-v6ops-ula-usage-recommendations-02.txt

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Abstract

   This document provides guidance of how to use ULA. ULAs. It analyzes ULA
   usage scenarios and recommends use cases where ULA address addresses might be
   beneficially used.

Table of Contents

   1. Introduction ................................................. 3
   2. The analysis of ULA features ................................. 3
      2.1. Automatically Generated ................................. 3
      2.2. Globally unique.......................................... 3
      2.3. Independent address space ............................... 4
      2.4. Well known prefix ....................................... 4
      2.5. Stable or Temporary Prefix .............................. 4
   3. Enumeration of Scenarios Using ULAs .......................... 4
      3.1. Isolated network ........................................ 4
      3.2. Connected network ....................................... 6 5
         3.2.1. ULA-only Deployment ................................ 6 5
         3.2.2. ULA along with GUA ................................. 7
      3.3. IPv4 Co-existence consideration ......................... 9
   4. General Guidelines of using ULA .............................. 9
      4.1. Do not treat ULA equal to RFC1918 ....................... 9
      4.2. Using ULAs in a limited scope .......................... 10
   5. ULA usage recommendations ................................... 10
      5.1. Used in Isolated Networks .............................. 10
      5.2. ULA along with GUA ..................................... 10
      5.3. Recommended Specific Use Cases ......................... 10
         5.3.1. Special routing ................................... 10 11
         5.3.2. Used as NAT64 prefix .............................. 11
         5.3.3. Used as identifier ................................ 11 12
   6. Security Considerations ..................................... 12
   7. IANA Considerations ......................................... 12 13
   8. Conclusions ................................................. 12 13
   9. References .................................................. 13
      9.1. Normative References ................................... 13
      9.2. Informative References ................................. 13
   10. Acknowledgments ............................................ 14

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1. Introduction

   Unique Local Addresses (ULAs) are defined in [RFC4193] as provider-
   independent prefixes that can be used on isolated networks, internal
   networks, and VPNs. Although ULAs may be treated like global scope by
   applications, normally they should not be used on the publicly
   routable internet.

    However, the ULAs haven't been widely used since IPv6 hasn't been
   widely deployed yet. The use of ULA addresses in various types of
   networks has been confusing to network operators. Some network operators believe ULAs
   are not useful at all while other network operators have run ULAs
   beneficially in their networks. This document attempts aims
   to clarify the advantages and disadvantages of ULAs and how they can
   be most appropriately used.

2. The analysis of ULA features

2.1. Automatically Generated

   ULA prefixes could be automatically generated according to the
   algorithms described in [RFC4193]. This feature allows automatic
   address allocation, which is beneficial for some lightweight systems
   and can leverage minimal human management.

2.2. Globally unique

   ULA is intended to have an extremely low probability of collision.
   Since the hosts assigned with ULA may occasionally be merged into one
   network, this uniqueness is necessary. The prefix uniqueness is based
   on randomization of 40 bits and is considered random enough to ensure
   a high degree of uniqueness (refer to [RFC4193] section 3.2.3 for
   details)and make merging of networks simple and without the need to
   renumbering overlapping IP address space. Overlapping is cited as a
   deficiency with how [RFC1918] addresses were deployed, and ULA was
   designed to overcome this deficiency.

   Notice that, as described in [RFC4864], in practice, applications may
   treat ULAs like global-scope addresses, but address selection
   algorithms may need to distinguish between ULAs and ordinary GUA
   (Global-scope Unicast Address) to ensure bidirectional communications.

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   (Note: the new address selection standard has supported this in the
   default policy table. [RFC6724])

2.3. Independent address space

   ULA provides an internal address independence capability in IPv6ULA
   can be used for internal communications without having any permanent
   or only intermittent Internet connectivity. And it needs no
   registration so that it can support on-demand usage and does not
   carry any RIR documentation burden or disclosures.

2.4. Well known prefix

   The prefixes of ULAs are well known and they are easy to be
   identified and easy to be filtered.

   This feature may be convenient to management of security policies and
   troubleshooting. For example, the administrators can decide what
   parameters have to be assembled or transmitted globally, by a
   separate function, through an appropriate gateway/firewall, to the
   Internet or to the telecom network.

2.5. Stable or Temporary Prefix

   A ULA prefix can be generated once, at installation time or "factory
   reset", and then never change unless the network manager wants to
   change. Alternatively, it could be regenerated regularly, if desired
   for some reason.

3. Enumeration of Scenarios Using ULAs

   In this section, we cover possible ULA use cases. Some of them might
   have been discussed in other documents and are briefly reviewed in
   this document as well as other potential valid usage is discussed.

3.1. Isolated network

   IP is used ubiquitously. Some networks like industrial control bus
   (e.g. [RS-485], [SCADA], or even non-networked digital interface like
   [MIL-STD-1397] began to use IP protocol. In such kind of networks,
   the system might lack the ability/requirement of connecting to the
   Internet. or explicitly designed not to connect.

   Besides, there might be some networks which could connect to the
   Internet, but prohibited by administration or just temporally not
   connected. These networks may include machine-to-machine (e.g.

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   vehichle networks), sensor networks, or even normal LANs, which may
   include very large numbers of addresses.

   Since the serious disadvantages and impact on applications by
   ambiguous address space have been well documented in [RFC1918], ULA
   is a straightforward way to assign the IP addresses in these kinds of
   networks with minimal administrative cost or burden. And since ULA
   support Also, ULAs fit
   in multiple subnets, it is scalable. subnet scenarios, in which each subnet has its own ULA
   prefix. For example, when we assign vehicles with ULA addresses, it
   is then possible to separate in-
   vehicle in-vehicle embedded networks into
   different subnets depending on real-
   time real-time requirements, devices types,
   services and more.

   o  Pros  Benefits of Using ULAs in Isolated Networks:
      - No cost of RIR/LIR fees or operational burden
      - Support Could be used instantly on-demand
      - Scalable to support multiple subnets comparing to link-local addresses
      - Support isolated networks merge without renumbering, because of
      its extremely Extremely low probability of collision when isolated networks
      merge

   o  Cons:  Drawbacks:
      - The global uniqueness of prefixes the global ULA prefix is not guaranteed,
      however, the probability of collision is extremely low

   o  Operational considerations
      - Prefix generation: Randomly generated according to the
      algorithms defined in [RFC4193] or literally assigned by human.
      Normally, it is recommended to following the standard way to
      automatically generate the prefixes; if there are some specific
      reasons that need to be assigned by human, the administrators must
      carefully plan the prefixes to avoid collision.

      - Prefix announcement: In some cases, the networks might need to
      announce prefixes to each other, for example in vehicle networks
      with infrastructure-less settings such as Vehicle-to-Vehicle (V2V)
      settings, prior knowledge of respective prefixes is unlikely.
      Hence, a prefix announcement mechanism is needed to enable inter-
      vehicles communications based on IP. For instance, such
      announcement could rely on an extension of the Router
      Advertisement message of Neighbor Discovery Protocol (e.g.
      [I-D.petrescu-autoconf-ra-based-routing] and
      [I-D.jhlee-mext-mnpp]).

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3.2. Connected network

3.2.1. ULA-only Deployment

   In some situations, hosts/interfaces are assigned with ULA-only, but
   the networks need to communicate with the outside. It mainly includes
   the following two models.

   o  Using Network Prefix Translation

   Network Prefix Translation (NPTv6) [RFC6296] is an experimental
   specification that provides a stateless one to one mapping between
   internal addresses and external addresses.

   In some very constrained situations(for example, in the sensors), the
   network needs ULA as the on-demand and stable addressing which
   doesn't need much code to support address assignment mechanisms like
   DHCP or full ND (Note: surely it needs SLAAC). If the network also
   needs to connect to the outside, then there can be an NPTv6 gateway
   which is not subject to extreme resource constraints. Especially when
   a lightweight isolated network needs to add Internet connectivity,
   this is quite a straightforward and efficient way.

   This document does not intend to encourage the ULA binding with NPTv6
   model, since in [RFC5902] the IAB had already gave opinions on IPv6
   NAT; but this document considers it as a valid use case an effective approach in some
   specific situations as described above.

   o  Using application-layer proxies

   The proxies terminate the network-layer connectivity of the hosts and
   delegate the outgoing/incoming connections.

   In some environments (e.g. information security sensitive enterprise
   or government), the endpoints are default disconnected to the
   Internet, and need the proxies to connect for central control. In
   IPv4, using private address space with proxies is an effective and
   common practice for this purpose, and it is natural to pick ULA in
   IPv6.

   o  Pros  Benefits of Using ULAs in This Scenario:
      - Allowing minimal management burden on address assignment for
      some specific environments.

   o  Cons:  Drawbacks:
      - The serious disadvantages and impact on applications by NAT have

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      been well documented in [RFC2993] and [RFC3027]. However, it
      should be noted that, For NPTv6, as described in [RFC6296], it is
      "a mechanism that has fewer architectural problems than merely
      implementing a traditional stateful Network Address Translator in
      an IPv6 environment."

   o  Operational considerations
      - Firewall Issue: When use NPTv6, Deployment: As described in [RFC6296], firewall is
      recommended to be implemented with NPTv6 translator. Then the
      administrators need to care know about where the firewall need to be, because NPTv6 is stateless
      and makes located.
      If the ULAs wide open to firewall is located outside the Internet. And NPTv6 translator, then the
      filtering is based on the translated GUA prefixes, and when renumber, the firewall(s) needs
      internal ULA prefixes are renumbered, the filtering rules don't
      need to be reconfigured changed (however, when it is located
      outside GUA prefixes of the NPTv6 translator. are
      renumbered, the filtering rules need to be updated accordingly.).
      If the firewall(s) firewall is located inside the NPTv6 translator, the administrators
      filtering is then based on the ULA prefixes, and the rules need to use the ULAs for filtering
      instead of
      be updated according to the global ones. ULA prefixes renumbering (but don't
      need to update when NPTv6 GUA prefixes are renumbered.).

3.2.2. ULA along with GUA

   There are two classes of network probably to use ULA with GUA
   addresses:

      - Home network. Home networks are normally assigned with one or
      more globally routed PA prefixes to connect to the uplink of some
      an ISP. And besides, they may need internal routed networking even
      when the ISP link is down. Then ULA is a proper tool to fit the
      requirement. And in [RFC6204], it requires the CPE to support ULA.
      Note, ULAs provide more benefit for multiple-segment home networks;
      for home networks only containing one segment, link-local
      addresses are better alternative.

      - Enterprise network. An enterprise network is usually a managed
      network with one or more PA prefixes or with a PI prefix, all of
      which are globally routed. The ULA could be used for internal
      connectivity redundancy and better internal connectivity or
      isolation of certain functions like OAM of servers.

   o  Pros  Benefits of Using ULAs in This Scenario:
      - Separated Local Communication Plane: For either home networks or
      enterprise networks, the main purpose of using ULA along with GUA
      is to provide a logically local routing plane separated from the
      globally routing plane. The benefit is to ensure stable and
      specific local communication regardless of the ISP uplink failure.
      This benefit is especially meaningful for the home network or
      private OAM function in an enterprise.

      - Renumbering: In some special cases such as renumbering,
      enterprise administrators may want to avoid the need to renumber
      their internal-only, private nodes when they have to renumber the
      PA addresses of the whole network because of changing ISPs, ISPs
      restructure their address allocations, or whatever reasons. In

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      these situations, ULA is an effective tool for the internal-only
      nodes.
      Besides the internal-only nodes, the public nodes can also benefit
      from ULA for renumbering. When renumbering, as RFC4192 suggested,
      it has a period to keep using the old prefix(es) before the new
      prefix(es) is(are) stable. In the process of adding new prefix(es)
      and deprecating old prefix(es), it is not easy to keep the local
      communication immune of global routing plane change. If we use ULA
      for the local communication, the separated local routing plane can
      isolate the affecting by global routing change.

   o  Cons:  Drawbacks:
      - Operational Complexity: There are some arguments that in
      practice the ULA+PA makes additional operational complexity. It is
      not a ULA-specific problem; the multiple-addresses-per-interface
      is an important feature of IPv6 protocol. Never the less, running
      multiple prefixes needs more operational considerations than
      running a single one.

   o  Operational considerations
      - Default Routing: connectivity might be broken if ULAs are used
      as default route.

      - SLAAC/DHCPv6 co-existing: Since SLAAC and DHCPv6 might be
      enabled in one network simultaneously; the administrators need to
      carefully plan how to assign ULA and GUA prefixes in accordance
      with the two mechanisms. The administrators need to know the
      current issue of the SLAAC/DHCPv6 interaction (please refer to
      [I-D.liu-bonica-dhcpv6-slaac-problems] for details).

      - Address Selection: As mentioned in [RFC5220], there is a
      possibility that the longest matching rule will not be able to
      choose the correct address between ULAs and global unicast
      addresses for correct intra-site and extra-site communication. In
      [RFC6724], it claimed that a site-specific policy entry can be
      used to cause ULAs within a site to be preferred over global
      addresses.

      - DNS Relevant: if administrators chose not to do reverse DNS
      delegation inside of their local control of ULA prefixes, a
      significant amount of information about the ULA population will might
      leak to the outside world. Because reverse queries will be made
      and naturally routed to the global reverse tree, so people will be
      exposed to the existence of population the ULA uses, not in
      traffic terms, but in knowledge terms. [ULA-IN-WILD] provides more
      detailed situations on this issue.

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3.3. IPv4 Co-existence consideration

      Administrators may need a split DNS to separate the queries from
      internal and external for ULA entries and GUA entries.

3.3. IPv4 Co-existence consideration

   Generally, this document only concerns IPv6-only scenarios. But one
   specific does not consider IPv4 co-existence problem need relevant as in the
   scope But regarding ULA, there is a special case needs to be noted.

   As noticed,
   which is described in section 2.2.2 of [RFC5220], when [RFC5220]. When an enterprise
   has IPv4 Internet connectivity but does not yet have IPv6 Internet
   connectivity, then and the enterprise chose wants to provide site-local IPv6
   connectivity, a ULA is the best choice for site-local IPv6
   connectivity. Each employee host will have both an IPv4 global or
   private address and a ULA. Here, when this host tries to connect to
   an outside node that has registered both A and AAAA records in the
   DNS, the host will choose AAAA as the destination address and the ULA
   for the source address according to the IPv6 preference of the
   default address selection policy [RFC3484]. policy. This will clearly result in a
   connection failure. (The new address selection standard [RFC6724]
   has added ULA specific rules to prefer IPv4 over ULA, but the
   majority of current existing hosts might still under the old [RFC3484]
   specification.)

   Although with Happy Eyeballs [RFC6555] this connection failure
   problem could be solved, but unwanted timeouts would obviously lower
   the user experience. One possible approach of eliminating the
   timeouts is deprecating IPv6 default route and simply configuring a
   scoped route on hosts (in the context of this document, only
   configure the ULA prefix routes).

   Another alternative is configuring IPv4 preference on the hosts, and
   not including DNS A records but only AAAA records for the internal
   nodes in the internal DNS server, then outside nodes have both A and
   AAAA records could be connected through IPv4 as default and internal
   nodes could be always connected through IPv6. But since IPv6
   preference is default, changing the default in all nodes is not easy.
   suitable at scale.

4. General Guidelines of using ULA

4.1. Do not treat ULA equal to RFC1918

   ULA and [RFC1918] are similar in some aspects. The most obvious one
   is as described in section 2.1.3 that ULA provides an internal
   address independence capability in IPv6 that is similar to how
   [RFC1918] is commonly used. ULA allows administrators to configure
   the internal network of each platform the same way it is configured
   in IPv4. On the other hand, many Many organizations have security policies and architectures
   based around the local-only routing of [RFC1918] addresses and those
   policies may directly map to ULA [RFC4864].

   But it doesn't mean ULA is equal to an IPv6 version of [RFC1918]
   deployment. [RFC1918] usually combines with NAT/NAPT for global
   connectivity. But it is not necessarily to combine ULAs with any kind
   of NAT. People could use ULA for local communications along with

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   global addresses for global communications (see section 5.2). This is
   a big advantage brought by default support of multiple-addresses-per-
   interface feature in IPv6. (People might still have requirement of
   ULA with NAT, this is discussed in section 3.2.1. But people also
   should keep in mind that ULA is not intentionally designed for this
   kind of use case.)

   Another important difference is the ability to merge two ULA networks
   without renumbering (because of the uniqueness), which is a big
   advantage over [RFC1918].

4.2. Using ULAs in a limited scope

   A ULA is by definition a prefix that is never advertised outside a
   given domain, and is used within that domain by agreement of those
   networked by the domain.

   So when using ULAs in a network, the administrators should clearly
   set the scope of the ULAs and configure ACLs on relevant border
   routers to block them out of the scope. And if internal DNS are
   enabled, the administrators might also need to use internal-only DNS
   names for ULAs. ULAs and should split the DNS so that the internal DNS
   server includes records that are not presented in the external DNS
   server.

5. ULA usage recommendations

5.1. Used in Isolated Networks

   As analyzed in section 3.1, ULA is very suitable for isolated
   networks. Especially when you have subnets in the isolated networks,
   ULA is the best choice.

5.2. ULA along with GUA

   As the benefits described in Section 3.2.2, using ULA along with GUA
   to provide a logically separated local plane could benefit to OAM
   functions and renumbering.

5.3. Recommended Specific Use Cases

   Along with the general scenarios, this section provide provides some specific
   use cases that could benefit from using ULA.

5.3.1. Special routing

   For various reasons the administrators might want to have private
   routing be controlled and separated from other routing. For example,

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   in the b2b case described in
   [I-D.baker-v6ops-b2b-private-routing], two companies might want to
   use direct connectivity that only connects stated machines, such as a
   silicon foundry with client engineers that use it. A ULA provides a
   simple way to assign such prefixes that would be used in accordance
   with an agreement between the parties.

5.3.2. Used as NAT64 prefix

   Since the NAT64 pref64 is just a group of local fake addresses for
   the DNS64 to point traffic to a NAT64, When using a ULA prefix as the
   pref64, it could easily ensures that only local systems can use the
   translation resources of the NAT64 system since the ULA is not
   intended to be globally routable and helps clearly identify traffic
   that is locally contained and destine to a NAT64. Using ULA for
   Pref64 is deployed and it is an operational model.

   But there's an issue should be noticed. The NAT64 standard [RFC6146)
   mentioned the pref64 should align with [RFC6052], in which the IPv4-
   Embedded IPv6 Address format was specified. If we pick a /48 for
   NAT64, it happened to be a standard 48/ part of ULA (7bit ULA famous
   prefix+ 1 "L" bit + 40bit Global ID). Then the 40bit of ULA is not
   violated to be filled with part of the 32bit IPv4 address. This is
   important, because the 40bit assures the uniqueness of ULA, if the
   prefix is shorter than /48, the 40bit would be violated, and this may
   cause conformance issue. But it is considered that the most common
   use case will be a /96 PREF64, or even /64 will be used. So it seems
   this issue is not common in current practice.

   It is most common that ULA Pref64 will be deployed on a single
   internal network, where the clients and the NAT64 share a common
   internal network. ULA will not be effective as Pref64 when the access
   network must use an Internet transit to receive the translation
   service of a NAT64 since the ULA will not route across the internet.

   According to the default address selection table specified in
   [RFC6724], the host would always prefer IPv4 over ULA. This could be
   a problem in NAT64-CGN scenario as analyzed in Section 8 of
   [I-D.ietf-v6ops-nat64-experience]. So administrators need to add
   additional site-specific address selection
   policy rules to the default table would be needed.
   to steer traffic flows going through NAT64-CGN. However, it updating the
   default policy tables in all hosts involves significant costs
   to change terminal's behavior. management
   cost. This may be possible in an enterprise (using a group policy
   object, or other configuration mechanisms), but it is not suitable at
   scale for home networks.

5.3.3. Used as identifier

   Since ULA

   ULAs could be self-generated and easily grabbed from the standard
   IPv6 stack, it is stack. And ULAs don't need to be changed as the GUA prefixes do.
   So they are very suitable to be used as identifiers by

Internet-Draft  draft-ietf-v6ops-ula-usage-recommendations-01   October
2013 the up layer
   applications. And since ULA is not intended to be globally routed, it
   is not harmful to the routing system.

   Such kind of benefit has been utilized in real implementations. For
   example, in [RFC6281], the protocol BTMM (Back To My Mac) needs to
   assign a topology-independent identifier to each client host
   according to the following considerations:

   o  TCP connections between two end hosts wish to survive in network
      changes.

   o  Sometimes one needs a constant identifier to be associated with a
      key so that the Security Association can survive the location
      changes.

   It should be noticed again that in theory ULA has the possibility of
   collision. However, the probability is desirable small enough and
   could be ignored by most of the cases when used as identifiers.

6. Security Considerations

   Security considerations regarding ULAs, in general, please refer to
   the ULA specification [RFC4193].

   Also refer to [RFC4864], which shows how ULAs help with local network
   protection.

   As mentioned in Section 3.2.1, when use NPTv6, the administrators
   need to know about where the firewall is located to set proper
   filtering rules.

   As mentioned in Section 3.2.2, if administrators chose not to do
   reverse DNS delegation inside their local control of ULA prefixes, a
   significant amount of information about the ULA population might leak
   to the outside world.

7. IANA Considerations

   IANA considerations should be updated to point to RFC4193 in a
   similar manner to section 4.

8. Conclusions

   ULA is a useful tool, tool; it could be successfully deployed in a diverse
   set of circumstances including large private machine-to-machine type
   networks, enterprise networks with private systems, and within
   service providers to limit Internet communication with non-public
   services such as caching DNS servers and NAT64 translation resources.
   Some of the deployment is already in real production networks.

   We should eliminate the misunderstanding that ULA is just an IPv6
   version of [RFC1918]. The features of ULA could be beneficial for
   various use cases.

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9. References

9.1. Normative References

   [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", RFC 2119, BCP14, March 1997.

   [RFC4193] Hinden, R., B. Haberman, "Unique Local IPv6 Unicast
             Addresses", RFC 4193, October 2005.

9.2. Informative References

   [RFC1918] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and
             E. Lear, "Address Allocation for Private Internets",BCP 5,
             RFC 1918, February 1996.

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

   [RFC5220] Matsumoto, A., Fujisaki, T., Hiromi, R., and K. Kanayama,
             "Problem Statement for Default Address Selection in Multi-
             Prefix Environments: Operational Issues of RFC 3484 Default
             Rules", RFC 5220, July 2008.

   [RFC6281] Cheshire, S., Zhu, Z., Wakikawa, R., and L. Zhang,
             "Understanding Apple's Back to My Mac (BTMM) Service", RFC
             6281, June 2011.

   [RFC6296] Wasserman, M., and F. Baker, "IPv6-to-IPv6 Network Prefix
             Translation", RFC 6296, June 2011.

   [RFC6555] Wing, D. and A. Yourtchenko, "Happy Eyeballs: Success with
             Dual-Stack Hosts", RFC 6555, April 2012.

   [RFC6724] Thaler, D., Ed., Draves, R., Matsumoto, A., and T. Chown,
             "Default Address Selection for Internet Protocol Version 6
             (IPv6)", RFC 6724,

   [I-D.ietf-v6ops-nat64-experience]
             Chen G., Cao Z., Xie C., and D. Binet, "NAT64 Operational
             Experiences", Working in Progress, October, 2013

   [I-D.baker-v6ops-b2b-private-routing]
             F. Baker, "Business to Business Private Routing", Expired

Internet-Draft  draft-ietf-v6ops-ula-usage-recommendations-01   October
2013

   [I-D.petrescu-autoconf-ra-based-routing]
             Petrescu, A., Janneteau, C., Demailly, N. and S. Imadali,
             "Router Advertisements for Routing between Moving Networks",
             Working in Progress, October, 2013

   [I-D.jhlee-mext-mnpp]
             Lee, J.-H., and T. Ernst, "Mobile Network Prefix
             Provisioning", Expired

   [RS-485]  http://en.wikipedia.org/wiki/RS-485

   [MIL-STD-1397]
             http://en.wikipedia.org/wiki/MIL-STD-1397

   [SCADA]   http://en.wikipedia.org/wiki/SCADA

   [ULA-IN-WILD]
             G. Michaelson, "www.ietf.org/proceedings/87/slides/slides-
             87-v6ops-0.pdf"

10. Acknowledgments

   Many valuable comments were received in the IETF v6ops WG mail list,
   especially from Fred Baker, Brian Carpenter, Lee Howard, Victor
   Kuarsingh, Alexandru Petrescu, Mikael Abrahamsson, Jong-Hyouk Lee,
   Doug Barton, Owen Delong, Anders Brandt Brandt, Tim Chown, Jen Linkova,
   Christopher Palmer and Wesley George.

   Some contribution regarding vehicle networks is from Sofiane Imadali. test of using ULA in the lab was done by our research partner
   BNRC-BUPT (Broad Network Research Centre in Beijing University of
   Posts and Telecommunications). Thanks for the work of Prof. Xiangyang
   Gong and student Dengjia Xu.

   This document was prepared using 2-Word-v2.0.template.dot.

Internet-Draft  draft-ietf-v6ops-ula-usage-recommendations-01   October
2013

   Authors' Addresses

   Bing Liu
   Huawei Technologies Co., Ltd
   Huawei Q14 Building, No.156 Beiqing Rd.,
   Zhong-Guan-Cun Environmental Protection Park, Beijing
   P.R. China

   EMail: leo.liubing@huawei.com

   Sheng Jiang
   Huawei Technologies Co., Ltd
   Huawei Q14 Building, No.156 Beiqing Rd.,
   Zhong-Guan-Cun Environmental Protection Park, Beijing
   P.R. China

   EMail: jiangsheng@huawei.com

   Cameron Byrne
   T-Mobile USA
   Bellevue, Washington  98006
   USA

   Email: cameron.byrne@t-mobile.com