Internet-Draft IPv6 CE Routers LAN Prefix Delegation November 2022
Winters Expires 21 May 2023 [Page]
Workgroup:
Internet Engineering Task Force
Internet-Draft:
draft-winters-v6ops-cpe-lan-pd-00
Updates:
7084 (if approved)
Published:
Intended Status:
Informational
Expires:
Author:
T. Winters
QA Cafe

IPv6 CE Routers LAN Prefix Delegation

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

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

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."

This Internet-Draft will expire on 21 May 2023.

Table of Contents

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.

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).

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, , <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, , <https://www.rfc-editor.org/info/rfc6177>.
[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, , <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, , <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, , <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, , <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, , <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