IPv6 CE Routers LAN Prefix Delegation
draft-winters-v6ops-cpe-lan-pd-00

Internet Engineering Task Force                               T. Winters
Internet-Draft                                                   QA Cafe
Updates: 7084 (if approved)                             17 November 2022
Intended status: Informational                                          
Expires: 21 May 2023

                 IPv6 CE Routers LAN Prefix Delegation
                   draft-winters-v6ops-cpe-lan-pd-00

Abstract

   This document defines requirements for IPv6 CE Routers to support
   DHCPv6 Prefix Delegation for redistributing any unused prefix(es)
   that were delegated to the IPv6 CE Router.  This document updates RFC
   7084.

Status of This Memo

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   This Internet-Draft will expire on 21 May 2023.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   2
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   4.  Architecture  . . . . . . . . . . . . . . . . . . . . . . . .   3
   5.  Requirements  . . . . . . . . . . . . . . . . . . . . . . . .   3
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   8.  Acknowledements . . . . . . . . . . . . . . . . . . . . . . .   4
   9.  Normative References  . . . . . . . . . . . . . . . . . . . .   4
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   This document defines DHCPv6 Prefix Delegation in IPv6 CE Routers
   ([RFC7084]) in order to properly utilize the IPv6 prefixes assigned
   by service providers.  Many ISP will assign a prefix larger then /64
   to the CE Router as recommended in [RFC6177].  If a IPv6 CE Router
   doesn't support IA_PD on the LAN it will not be able to assign any
   prefixes beyond itself limiting the usefulness of assigning prefixes
   larger then /64.  Supporting IA_PD on the LAN interfaces will allow
   for those prefixes to be distributed into a network to be useable.

2.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   This document also makes use of internal conceptual variables to
   describe protocol behavior and external variables that an
   implementation must allow system administrators to change.  The
   specific variable names, how their values change, and how their
   settings influence protocol behavior are provided to demonstrate
   protocol behavior.  An implementation is not required to have them in
   the exact form described here, as long as its external behavior is
   consistent with that described in this document.

3.  Terminology

   The following terminology is defined for this document.

   *  IPv6 CE Router: A router intended for home or small-office use
      that forwards packets explicitly addressed to itself as defined in
      [RFC7084].

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   *  Internet Service Provider (ISP): An entity that provides access to
      the Internet.  In this document, a service provider specifically
      offers Internet access using IPv6, and may also offer IPv4
      Internet access.  The service provider can provide such access
      over a variety of different transport methods such as DSL, cable,
      wireless, and others.

4.  Architecture

                        +-----------+
                        |  Service  |
                        |  Provider |
                        |   Router  |
                        +-----+-----+
                              |
                              |
                              |  Customer
                              |  Internet Connection
                              |
                        +-----v-----+
                        |   IPv6    |
                        |    CE     |
                        |  Router   |
                        +-----+-----+
                              |
                       +----+-+-------+
                       |              |
                       |              |
                   +---+----+   +-----+------+
                   |  IPv6  |   |            |
                   |  Host  |   |  Router    |
                   |        |   |            |
                   +--------+   +------------+

5.  Requirements

   The IPv6 CE Router distributes configuration information obtained
   during WAN interface provisioning to IPv6 hosts and routers.  A
   router based on [RFC7084] previously would only address IPv6 hosts,
   this update to allow for addressing and routing of routers.

   LAN Prefix Delegation (PD) Requirements

   LPD-1: The IPv6 CE Router MUST support DHCPv6 server capable of IPv6
   prefix assignment according to [RFC8415] (Idenity Association for
   Prefix Delegation (IA_PD) option).

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   LPD-2: The IPv6 CE Router MUST assign addresses from the delegated
   prefix to the number of interfaces.  If not enough addresses are
   available the IPv6 CE Router SHOULD log a system management error.

   LPD-3: After interface address assignment the IPv6 CE Router MUST
   make the remaining IPv6 prefixes available to other Routers via
   Prefix Delegation

   LPD-4: The IPv6 CE Router MUST give out a IA_PD of the remaining
   prefixes with a IA_PD size of 64.

   LPD-5: The IPv6 CE Router MUST install a route to the IA_PD assigned
   with a next-hop of the IPv6 node assigned the address.

   LPD-6: If a IPv6 CE Router recieves IPv6 prefixes of size 64 it MUST
   enable delegating relay according to [RFC8987].  The MUST forward all
   the DHCPv6 Relay messages to the All_DHCP_Relay_Agents_and_Servers
   multicast address.

6.  Security Considerations

   This document does not add any new security considerations beyond
   those mentioned in Section 4 of [RFC8213] and Section 22 of
   [RFC8415].

7.  IANA Considerations

   This document makes no request of IANA.

8.  Acknowledements

   Thanks to the following people (in alphabetical order) for their
   guidance and feedback: Marion Dillon, Esko Dijk, Ted Lemon, Michael
   Richardson.

9.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC6177]  Narten, T., Huston, G., Roberts, L., and RFC Publisher,
              "IPv6 Address Assignment to End Sites", BCP 157, RFC 6177,
              DOI 10.17487/RFC6177, March 2011,
              <https://www.rfc-editor.org/info/rfc6177>.

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

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8213]  Volz, B., Pal, Y., and RFC Publisher, "Security of
              Messages Exchanged between Servers and Relay Agents",
              RFC 8213, DOI 10.17487/RFC8213, August 2017,
              <https://www.rfc-editor.org/info/rfc8213>.

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

   [RFC8987]  Farrer, I., Kottapalli, N., Hunek, M., Patterson, R., and
              RFC Publisher, "DHCPv6 Prefix Delegating Relay
              Requirements", RFC 8987, DOI 10.17487/RFC8987, February
              2021, <https://www.rfc-editor.org/info/rfc8987>.

Author's Address

   Timothy Winters
   QA Cafe
   100 Main Street, Suite #212
   Dover, NH 03820
   United States of America
   Email: tim@qacafe.com

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