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Network Working Group                                    F. Templin, Ed.
Internet-Draft                              Boeing Research & Technology
Intended status: Informational                         December 18, 2018
Expires: June 21, 2019


           IPv6 Prefix Delegation and Multi-Addressing Models
                   draft-templin-v6ops-pdhost-23.txt

Abstract

   Requesting nodes typically acquire IPv6 prefixes from a prefix
   delegation service for the network.  The requesting node can
   provision the prefix according to whether it acts as a router on
   behalf of any downstream networks and/or as a host on behalf of its
   local applications.  In the latter case, the requesting node can use
   portions of the delegated prefix for its own multi-addressing
   purposes.  This document therefore considers prefix delegation models
   for both the classic routing and various multi-addressing use cases.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on June 21, 2019.

Copyright Notice

   Copyright (c) 2018 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
   (https://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



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   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 . . . . . . . . . . . . . . . . . . . . . . . . .   6
   3.  Multi-Addressing Considerations . . . . . . . . . . . . . . .   6
   4.  Multi-Addressing Alternatives for Delegated Prefixes  . . . .   7
   5.  Address Autoconfiguration Considerations  . . . . . . . . . .   8
   6.  MLD/DAD Implications  . . . . . . . . . . . . . . . . . . . .   8
   7.  Dynamic Routing Protocol Implications . . . . . . . . . . . .   9
   8.  IPv6 Neighbor Discovery Implications  . . . . . . . . . . . .   9
   9.  Prefix Delegation Services  . . . . . . . . . . . . . . . . .   9
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  10
   11. Security Considerations . . . . . . . . . . . . . . . . . . .  10
   12. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  10
   13. References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     13.1.  Normative References . . . . . . . . . . . . . . . . . .  11
     13.2.  Informative References . . . . . . . . . . . . . . . . .  12
   Appendix A.  Change Log . . . . . . . . . . . . . . . . . . . . .  13
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  14

1.  Introduction

   IPv6 Neighbor Discovery (ND) is the process by which nodes on the
   link discover each other's presence as well as advertise and receive
   configuration information.  IPv6 Prefix Delegation (PD) entails 1)
   the communication of a prefix from a delegation service to a
   requesting node, 2) a representation of the prefix in the network's
   Routing Information Base (RIB) and the first-hop router's Forwarding
   Information Base (FIB), and 3) a control messaging service to
   maintain prefix lifetimes.  Following delegation, the prefix is
   available for the requesting node's exclusive use and is not shared
   with any other nodes.  This document considers prefix delegation
   models and multiaddressing considerations for requesting nodes that
   act as a router on behalf of any downstream networks and/or as a host
   on behalf of their local applications.

   For nodes that connect downstream-attached networks (e.g., a
   cellphone that connects a "tethered" Internet of Things (IoT), a
   laptop computer with a complex internal network of virtual machines,
   etc.), the classic routing model applies as shown in Figure 1:







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                               .---------.
                            ,-(           )-.
                          (   +----------+   )
                         (    |Server 'S'|    )
                          (   +----------+   )
                           (   Network 'N'  )
                            `-(__________)-'
                                   |
                        +----------+----------+
                        | first-hop router 'F'|
                        +----------+----------+
                                   |
                     upstream link |
                                   |
                        +----------+----------+
                        |  upstream interface |
                        +---------------------+
                        |                     |
                        | requesting node 'R' |
                        |    (Prefix 'P')     |
                        |                     |
                        +--+-+--+-+--+-----+--+
                        |A1| |A2| |A3| ... |Aj|
                        +--+-+--+-+--+-----+--+
                        |downstream interfaces|
                        +----------+----------+
                                   |
          internal and/or external |
              downstream links     |
       X----+-------------+--------+----+---------------+---X
            |             |             |               |
       +---++-+--+   +---++-+--+   +---++-+--+     +---++-+--+
       |   |Ak|  |   |   |Al|  |   |   |Am|  |     |   |A*|  |
       |   +--+  |   |   +--+  |   |   +--+  |     |   +--+  |
       | host H1 |   | host H2 |   | host H3 | ... | host Hn |
       +---------+   +---------+   +---------+     +---------+

          <-------------- Downstream Network ------------->

                      Figure 1: Classic Routing Model

   In the classic routing model, requesting node 'R' has one or more
   upstream interfaces and connects zero or more internal and/or
   external downstream networks.  When 'R' requests a prefix delegation,
   the following sequence of events transpires:

   o  Server 'S' located in network 'N' delegates prefix 'P' to
      requesting node 'R'.



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   o  'P' is injected into the RIB for 'N', and first hop router 'F'
      configures a FIB entry with 'R' as the next hop.

   o  R' receives 'P' and assigns zero or more addresses 'A(*)' taken
      from 'P' to its downstream interfaces

   o  'R' advertises zero or more sub-prefixes taken from 'P' to hosts
      'H(i)' on downstream networks.

   o  'R' delegates zero or more sub-prefixes taken from 'P' to
      requesting nodes in downstream networks.

   o  'R' acts as a router for hosts 'H(i)' on downstream networks and
      as a host on behalf of its local applications.

   This document also considers the case when 'R' uses portions of 'P'
   for its own internal multi-addressing purposes.  [RFC7934] provides
   Best Current Practice (BCP) motivations for the benefits of multi-
   addressing, while an operational means for providing nodes with
   multiple addresses is given in [RFC8273].  The following multi-
   addressing alternatives for delegated prefixes compliment this
   framework.

   In a first alternative, when requesting node 'R' receives prefix 'P',
   it can assign addresses taken from 'P' to downstream virtual
   interfaces (e.g., a loopback) as shown in Figure 2:

                                   x
                                   |
                     upstream link |
                                   |
                        +----------+----------+
                        |  upstream interface |
                        +---------------------+
                        |                     |
                        | requesting node 'R' |
                        |                     |
                        +--+-+--+-+--+-----+--+
                        |A1| |A2| |A3| ... |An|
                        +--+-+--+-+--+-----+--+
                        |  virtual interfaces |
                        +---------------------+

       Figure 2: Address Assignment to Downstream Virtual Interfaces

   In a second alternative, 'R' could assign IPv6 addresses taken from
   'P' to the upstream interface over which the prefix was received as
   shown in Figure 3:



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                                   x
                                   |
                     upstream link |
                                   |
                        +----------+----------+
                        |  upstream interface |
                        +--+-+--+-+--+-----+--+
                        |A1| |A2| |A3| ... |An|
                        +--+-+--+-+--+-----+--+
                        |                     |
                        | requesting node 'R' |
                        |                     |
                        +---------------------+

              Figure 3: Upstream Interface Address Assignment

   In a third alternative, 'R' could assign IPv6 addresses taken from
   'P' to its local applications which appear as "psuedo" virtual
   interfaces as shown in Figure 4:

                                   x
                                   |
                     upstream link |
                                   |
                        +----------+----------+
                        |  upstream interface |
                        +---------------------+
                        |                     |
                        | requesting node 'R' |
                        |                     |
                        +--+-+--+-+--+-----+--+
                        |A1| |A2| |A3| ... |An|
                        +--+-+--+-+--+-----+--+
                        |     Applications    |
                        +---------------------+

                  Figure 4: Application Addresssing Model

   With these IPv6 PD-based multi-addressing considerations, the node
   can configure an unlimited supply of addresses to make them available
   for local applications without requiring coordination with other
   nodes on upstream interfaces.  The following sections present
   considerations for nodes that employ IPv6 PD mechanisms.








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2.  Terminology

   The terms "node", "host" and "router" are the same as defined in
   [RFC8200].  The terms Router Solicitation (RS), Router Advertisement
   (RA), Neighbor Solicitation (NS), Neighbor Advertisment (NA),
   Redirect and Prefix Information Option (PIO) are the same as defined
   in [RFC4861].  All other terminology in the normative references
   applies, while the following terms are defined within the context of
   this document:

   shared prefix
      an IPv6 prefix that may be advertised to more than one node on the
      link.  The router that advertises the prefix must consider the
      prefix as on-link so that the IPv6 ND address resolution function
      will identify the correct neighbor for each packet.

   individual prefix
      an IPv6 prefix that is advertised to exactly one node on the link,
      where the node may be unaware that the prefix is individual and
      may not participate in prefix maintenance procedures.  The router
      that advertises the prefix can consider the prefix as on-link or
      not on-link.  In the former case, the router performs address
      resolution and only forwards those packets that match one of the
      node's configured addresses so that the node will not receive
      unwanted packets.  In the latter case, the router can simply
      forward all packets matching the prefix to the node which must
      then drop any packets that do not match one of its configured
      addresses.  An example individual prefix service is documented in
      [RFC8273].

   delegated prefix
      an IPv6 prefix that is explicitly conveyed to a node for its own
      exclusive use, where the node is an active participant in prefix
      delegation and maintenance procedures.  The first-hop router
      simply forwards all packets matching the prefix to the requesting
      node.  The requesting node associates the prefix with downstream
      and/or internal virtual interfaces (i.e., and not the upstream
      interface).

3.  Multi-Addressing Considerations

   IPv6 allows nodes to assign multiple addresses to a single interface.
   [RFC7934] discusses options for multi-addressing as well as use cases
   where multi-addressing may be desirable.  Address configuration
   options for multi-addressing include StateLess Address
   AutoConfiguration (SLAAC) [RFC4862], Dynamic Host Configuration
   Protocol for IPv6 (DHCPv6) address configuration [RFC8415], manual
   configuration, etc.



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   Nodes configure addresses from a shared or individual prefix and
   assign them to the upstream interface over which the prefix was
   received.  When the node assigns the addresses, it is required to use
   Multicast Listener Discovery (MLD) [RFC3810] to join the appropriate
   solicited-node multicast group(s) and to use the Duplicate Address
   Detection (DAD) algorithm [RFC4862] to ensure that no other node
   configures a duplicate address.

   In contrast, a node that configures addresses from a delegated prefix
   can assign them without invoking MLD/DAD on an upstream interface,
   since the prefix has been delegated to the node for its own exclusive
   use and is not shared with any other nodes.

4.  Multi-Addressing Alternatives for Delegated Prefixes

   When a node receives a delegated prefix, it has many alternatives for
   provisioning the prefix to its local interfaces and/or downstream
   networks.  [RFC7278] discusses alternatives for provisioning a prefix
   obtained by a User Equipment (UE) device under the 3rd Generation
   Partnership Program (3GPP) service model.  This document considers
   the more general case when the node receives a delegated prefix
   explicitly provided for its own exclusive use.

   When the node receives the prefix, it can distribute the prefix to
   internal (virtual) or external (physical) downstream networks and
   optionally configure addresses for itself on downstream interfaces.
   The node then acts as a router on behalf of its downstream networks.

   The node could instead (or in addition) use portions of the delegated
   prefix for its own multi-addressing purposes.  In a first
   alternative, the node can assign as many addresses as it wants from
   the prefix to downstream virtual interfaces.

   In a second alternative, the node can assign as many addresses as it
   wants from the prefix to the upstream interface over which the prefix
   was received, but in normal practice does not assign the prefix
   itself (or subnets from the prefix) to the upstream interface.  If
   the node assigned the prefix to the upstream interface, any neighbors
   on the upstream link receiving an RA could configure addresses from
   the prefix and a default route with the node as the next hop.  This
   could create a loop where upstream link neighbors send packets to the
   node which in turn forwards them to another upstream link neighbor.
   Still, there may be cases where the node provides services for
   dependent neighbors on the upstream link that have no other means of
   connecting to the network.  ([RFC8415] chose to remain silent on this
   subject since it is operational rather than functional in nature.)





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   In a third alternative, the node can assign addresses taken from the
   delegated prefix to its local applications.  The applications
   themselves then serve as virtual interfaces.  (Note that, in the
   future, the practice of assigning unique non-link-local IPv6
   addresses to applications could obviate the need for transport
   protocol port numbers.)

   In these multi-addressing cases, the node normally assigns the prefix
   itself to a virtual interface such as a loopback so that unused
   portions of the prefix are correctly identified as unreachable.  The
   node then acts as a host on behalf of its local applications even
   though neighbors on the upstream link consider it as a router.

5.  Address Autoconfiguration Considerations

   Nodes autoconfigure addresses according to Section 6 of IPv6 Node
   Requirements [I-D.ietf-6man-rfc6434-bis].

   Nodes that connect to a network that spans more than just a single
   LAN configure at least one non-link-local adddress, i.e., for network
   management and error reporting purposes.

   Nodes recognize the Subnet Router Anycast address [RFC4291] for each
   delegated prefix.  Therefore, the node's use of the Subnet Router
   Anycast address must be indistinguishable from the behavior of an
   ordinary router when viewed from the outside world.

6.  MLD/DAD Implications

   When a node configures addresses for itself from a shared or
   individual prefix (and when the interface variable
   'DupAddrDetectTransmits' is non-zero [RFC4862]), the node performs
   MLD/DAD by sending multicast messages over the upstream interface to
   test whether there is another node on the link that configures a
   duplicate address.  When there are many such addresses and/or many
   such nodes, this could result in substantial multicast traffic that
   affects all nodes on the link.

   When a node configures addresses for itself from a delegated prefix
   and assigns them on downstream interfaces, it can configure as many
   addresses as it wants without performing MLD/DAD for any of the
   addresses over the upstream interface.

   When a node configures addresses for itself from a delegated prefix
   and assigns them on the upstream interface over which the prefix was
   received, the node honors MLD/DAD procedures according the the
   interface's 'DupAddrDetectTransmits' variable.




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7.  Dynamic Routing Protocol Implications

   Nodes that receive delegated prefixes can be configured to either
   participate or not participate in a dynamic routing protocol over the
   upstream interface.  When there are many nodes on the upstream link,
   dynamic routing protocol participation might be impractical due to
   scaling limitations, and may also be exacerbated by factors such as
   node mobility.

   Unless it participates in a dynamic routing protocol, the node
   initially has only a default route pointing to a neighbor via an
   upstream interface.  This means that packets sent by the node over an
   upstream interface will initially go through a default router even if
   there is a better first-hop node on the link.  The node may
   subsequently receive Redirect messages from the default router that
   identify a better first-hop.

8.  IPv6 Neighbor Discovery Implications

   According to [RFC4861], when a node receives a shared or individual
   prefix with "L=1" and has a packet to send to an IPv6 destination
   within the prefix, it is required to use the IPv6 ND address
   resolution function to resolve the link-layer address of a neighbor
   on the link that configures the address.

   Also according to [RFC4861], when a node receives a shared or
   individual prefix with "L=0" and has a packet to send to an IPv6
   destination within the prefix, it sends the packet to a default
   router since "L=0" makes no statement about on-link or off-link
   properties of the prefix.

   When a node requires a delegated prefix, it acts as a simple host by
   sending RS messages over the upstream interface in the manner
   described in Section 4.2 of [RFC7084] and invokes prefix delegation
   services as discussed in Section 9.  The node considers the upstream
   interface as a non-advertising interface [RFC4861], i.e., it does not
   send RA messages over the upstream interface.  The node further does
   not perform the IPv6 ND address resolution function over the upstream
   interface, since the delegated prefix is by definition not associated
   with the upstream interface.

9.  Prefix Delegation Services

   Selection of prefix delegation services must be considered according
   to specific use cases.  An example service is that offered by
   standard DHCPv6 Prefix Delegation [RFC8415].  Alternative services
   based on IPv6 ND messaging have also been proposed
   [I-D.templin-6man-dhcpv6-ndopt][I-D.naveen-slaac-prefix-management].



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   Other, non-router, mechanisms may exist, such as proprietary IPAMs,
   [I-D.ietf-anima-prefix-management] and
   [I-D.li-opsawg-address-pool-management-arch].  Requirements for
   extending an IPv6 /64 Prefix from a Third Generation Partnership
   Project (3GPP) Mobile Interface to a LAN Link are discussed in
   [RFC7278].

10.  IANA Considerations

   This document introduces no IANA considerations.

11.  Security Considerations

   Security considerations for IPv6 Neighbor Discovery [RFC4861] and any
   applicable PD mechanisms apply to this document.  Nodes that manage
   their delegated prefixes such that MLD/DAD procedures are not needed
   on the upstream interface can avoid introducing multicast messaging
   congestion on the upstream link.  Also, routers that delegate
   prefixes keep only a single neighbor cache entry for each prefix
   delegation recipient, meaning that the router's neighbor cache cannot
   be subject to address resolution-based resource exhaustion attacks.

   For shared and individual prefixes, if the advertising router
   considers the prefix as on-link the IPv6 ND address resolution
   function will prevent unwanted IPv6 packets from reaching the node.
   For delegated prefixes and individual prefixes that are not
   considered on-link, the router delivers all packets that match the
   prefix to the node.  In that case, the node may receive unwanted IPv6
   packets via an upstream interface for which it has no matching
   configured address.  The node then drops the packets and observes the
   ICMPv6 "Destination Unreachable - Address/Port unreachable"
   procedures discussed in [RFC4443].

   The node may also receive IPv6 packets via an upstream interface that
   do not match any of the node's delegated prefixes.  In that case, the
   node drops the packets and observes the ICMPv6 "Destination
   Unreachable - No route to destination" procedures discussed in
   [RFC4443].  Dropping the packets is necessary to avoid a reflection
   attack that would cause the node to forward packets received from an
   upstream interface via the same or a different upstream interface.

12.  Acknowledgements

   This work was motivated by discussions on the v6ops list.  Mark
   Smith, Ricardo Pelaez-Negro, Edwin Cordeiro, Fred Baker, Ron Bonica,
   Naveen Lakshman, Ole Troan, Bob Hinden, Brian Carpenter, Joel
   Halpern, Albert Manfredi, Dusan Mudric, Paul Marks, Joe Touch, Alex




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   Petrescu, Lorenzo Colitti, Tatuya Jinmei and Naveen Kottapalli
   provided useful comments that have greatly improved the document.

   This work is aligned with the NASA Safe Autonomous Systems Operation
   (SASO) program under NASA contract number NNA16BD84C.

   This work is aligned with the FAA as per the SE2025 contract number
   DTFAWA-15-D-00030.

   This work is aligned with the Boeing Information Technology (BIT)
   MobileNet program and the Boeing Research & Technology (BR&T)
   enterprise autonomy program.

13.  References

13.1.  Normative References

   [RFC3810]  Vida, R., Ed. and L. Costa, Ed., "Multicast Listener
              Discovery Version 2 (MLDv2) for IPv6", RFC 3810,
              DOI 10.17487/RFC3810, June 2004,
              <https://www.rfc-editor.org/info/rfc3810>.

   [RFC4443]  Conta, A., Deering, S., and M. Gupta, Ed., "Internet
              Control Message Protocol (ICMPv6) for the Internet
              Protocol Version 6 (IPv6) Specification", STD 89,
              RFC 4443, DOI 10.17487/RFC4443, March 2006,
              <https://www.rfc-editor.org/info/rfc4443>.

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
              DOI 10.17487/RFC4861, September 2007,
              <https://www.rfc-editor.org/info/rfc4861>.

   [RFC4862]  Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
              Address Autoconfiguration", RFC 4862,
              DOI 10.17487/RFC4862, September 2007,
              <https://www.rfc-editor.org/info/rfc4862>.

   [RFC8200]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", STD 86, RFC 8200,
              DOI 10.17487/RFC8200, July 2017,
              <https://www.rfc-editor.org/info/rfc8200>.

   [RFC8415]  Mrugalski, T., Siodelski, M., Volz, B., Yourtchenko, A.,
              Richardson, M., Jiang, S., Lemon, T., and T. Winters,
              "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)",
              RFC 8415, DOI 10.17487/RFC8415, November 2018,
              <https://www.rfc-editor.org/info/rfc8415>.



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13.2.  Informative References

   [I-D.ietf-6man-rfc6434-bis]
              Chown, T., Loughney, J., and T. Winters, "IPv6 Node
              Requirements", draft-ietf-6man-rfc6434-bis-09 (work in
              progress), July 2018.

   [I-D.ietf-anima-prefix-management]
              Jiang, S., Du, Z., Carpenter, B., and Q. Sun, "Autonomic
              IPv6 Edge Prefix Management in Large-scale Networks",
              draft-ietf-anima-prefix-management-07 (work in progress),
              December 2017.

   [I-D.li-opsawg-address-pool-management-arch]
              Li, C., Xie, C., Kumar, R., Fioccola, G., Xu, W., LIU, W.,
              Ma, D., and J. Bi, "Coordinated Address Space Management
              architecture", draft-li-opsawg-address-pool-management-
              arch-01 (work in progress), July 2018.

   [I-D.naveen-slaac-prefix-management]
              Kottapalli, N., "IPv6 Stateless Prefix Management", draft-
              naveen-slaac-prefix-management-00 (work in progress),
              November 2018.

   [I-D.templin-6man-dhcpv6-ndopt]
              Templin, F., "A Unified Stateful/Stateless Configuration
              Service for IPv6", draft-templin-6man-dhcpv6-ndopt-07
              (work in progress), December 2018.

   [I-D.templin-6man-rio-redirect]
              Templin, F. and j. woodyatt, "Route Information Options in
              IPv6 Neighbor Discovery", draft-templin-6man-rio-
              redirect-07 (work in progress), December 2018.

   [RFC4291]  Hinden, R. and S. Deering, "IP Version 6 Addressing
              Architecture", RFC 4291, DOI 10.17487/RFC4291, February
              2006, <https://www.rfc-editor.org/info/rfc4291>.

   [RFC7084]  Singh, H., Beebee, W., Donley, C., and B. Stark, "Basic
              Requirements for IPv6 Customer Edge Routers", RFC 7084,
              DOI 10.17487/RFC7084, November 2013,
              <https://www.rfc-editor.org/info/rfc7084>.

   [RFC7278]  Byrne, C., Drown, D., and A. Vizdal, "Extending an IPv6
              /64 Prefix from a Third Generation Partnership Project
              (3GPP) Mobile Interface to a LAN Link", RFC 7278,
              DOI 10.17487/RFC7278, June 2014,
              <https://www.rfc-editor.org/info/rfc7278>.



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   [RFC7934]  Colitti, L., Cerf, V., Cheshire, S., and D. Schinazi,
              "Host Address Availability Recommendations", BCP 204,
              RFC 7934, DOI 10.17487/RFC7934, July 2016,
              <https://www.rfc-editor.org/info/rfc7934>.

   [RFC8273]  Brzozowski, J. and G. Van de Velde, "Unique IPv6 Prefix
              per Host", RFC 8273, DOI 10.17487/RFC8273, December 2017,
              <https://www.rfc-editor.org/info/rfc8273>.

Appendix A.  Change Log

   << RFC Editor - remove prior to publication >>

   Changes from -22 to -23:

   o  Changed DHCPv6 references to RFC8415.  Deprecate RFC3315 and
      RFC3633.

   o  New text on assignment of addresses and prefixes on the upstream
      interface.

   Changes from -21 to -22:

   o  Changes to address list comments contributed by Lorenzo Colitti,
      Tatuya Jinmei, Brian Carpenter and Fred Baker.

   o  Deleted section on ICMPv6 - now defer to normative reference
      [RFC4443].

   o  Discuss 'DupAddrDetectTransmits' variable implications under MLD/
      DAD considerations.

   Changes from -20 to -21:

   o  Re-worked classic routing model section

   o  Included multi-addressing case where addresses may be assigned to
      applications

   o  Removed strong/weak end system discussions

   Changes from -19 to -20:

   o  figure 1 updates to show Server as being somewhere in the network

   o  Introductory material to show relation to other RFCs on multi-
      addressing




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Internet-DraftIPv6 Prefix Delegation and Multi-Addressing MDecember 2018


   Changes from -18 to -19:

   o  added new section on Prefix Delegation Services

   Changes from -17 to -18:

   o  re-worked discussion on the prefix delegation service in Section 1

   o  updated figures in Section 1

   Changes from -16 to -17:

   o  added supporting text in the introduction to discuss the
      Delegating Router's relationship with the Requesting Router and
      with supporting intrastructure in the operator's network

   o  updated figures in introduction to include representation of
      operator's network

   o  added new section on Address Autoconfiguration Considerations

Author's Address

   Fred L. Templin (editor)
   Boeing Research & Technology
   P.O. Box 3707
   Seattle, WA  98124
   USA

   Email: fltemplin@acm.org





















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