Internet DRAFT - draft-winters-v6ops-cpe-lan-pd
draft-winters-v6ops-cpe-lan-pd
Internet Engineering Task Force T. Winters
Internet-Draft QA Cafe
Updates: 7084 (if approved) 13 March 2023
Intended status: Informational
Expires: 14 September 2023
IPv6 CE Routers LAN Prefix Delegation
draft-winters-v6ops-cpe-lan-pd-02
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.
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This Internet-Draft will expire on 14 September 2023.
Copyright Notice
Copyright (c) 2023 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
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Please review these documents carefully, as they describe your rights
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provided without warranty as described in the Revised BSD License.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 2
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Architecture . . . . . . . . . . . . . . . . . . . . . . . . 3
5. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . 5
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
9.1. Normative References . . . . . . . . . . . . . . . . . . 5
9.2. Informative References . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6
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 an 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 than /64. Supporting IA_PD on the LAN interfaces will allow
for those unused prefixes to be distributed into a network. This
document does not cover dealing with multi-provisioned networks with
more than one provider.
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.
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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 not explicitly addressed to itself as
defined in [RFC7084].
* 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 |
| | | |
+--------+ +------------+
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5. Requirements
The IPv6 CE Router distributes configuration information obtained
during WAN interface provisioning to IPv6 hosts and routers.
Previously, a router based on [RFC7084] would only provide IPv6 hosts
with individual addresses; this update allows for addressing and
routing of IPv6 prefixes to both hosts and routers.
LAN Prefix Delegation (PD) Requirements
LPD-1: The IPv6 CE Router MUST support a DHCPv6 server capable of
IPv6 prefix assignment according to [RFC8415] (Identity Association
for Prefix Delegation (IA_PD) option).
LPD-2: The IPv6 CE Router MUST assign a prefix from the delegated
prefix to each of its LAN links. If not enough addresses are
available the IPv6 CE Router SHOULD log a system management error.
LPD-3: The prefix assigned to a link MUST NOT change in the absence
of topology or configuration changes.
LPD-4: After LAN link prefix assignment the IPv6 CE Router MUST make
the remaining IPv6 prefixes available to other routers via Prefix
Delegation
LPD-5: Available prefixes must be provisioned IA_PD IA prefixes MUST
have a prefix-length of 64.
LPD-6: The IPv6 CE Router MUST install a route to the assigned IA_PD
with a next-hop of the IPv6 node that was assigned the prefix. The
IPv6 CE Router MUST remove the route when IA_PD lease expires.
LPD-7: By default, the IPv6 CE Router firewall MUST allow forwarding
of packets with an outer IPv6 header containing a source address
belonging to Delegated Prefixes, along with reciprocal packets from
the same flow, following the recommendations of [RFC6092]
LPD-8: If an IPv6 CE Router receives a single IA_PD IA Prefix with a
prefix-length of 64. IPv6 prefixes of size 64 it MUST act as
delegating relay according to [RFC8987] specifically requirements G-2
to G-7, G-9, and S-2. DHCPv6 messages without IA-PD option MUST NOT
be relayed.
LPD-9: A CE Router MUST only be a delegating relay with DHCPv6
messages with IA_PD options present.
LPD-10: A CE Router assigning prefixes MUST NOT assign IA_NA in the
same DHCPv6 exchange.
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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. Acknowledgements
Thanks to the following people for their guidance and feedback:
Marion Dillon, Erik Auerswald, Esko Dijk, Tim Carlin, Richard
Patterson, Ted Lemon, Michael Richardson, Martin Hunek.
9. References
9.1. 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>.
[RFC6092] Woodyatt, J., Ed., "Recommended Simple Security
Capabilities in Customer Premises Equipment (CPE) for
Providing Residential IPv6 Internet Service", RFC 6092,
DOI 10.17487/RFC6092, January 2011,
<https://www.rfc-editor.org/info/rfc6092>.
[RFC6177] Narten, T., Huston, G., and L. Roberts, "IPv6 Address
Assignment to End Sites", BCP 157, RFC 6177,
DOI 10.17487/RFC6177, March 2011,
<https://www.rfc-editor.org/info/rfc6177>.
[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>.
[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>.
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[RFC8213] Volz, B. and Y. Pal, "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., 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>.
[RFC8987] Farrer, I., Kottapalli, N., Hunek, M., and R. Patterson,
"DHCPv6 Prefix Delegating Relay Requirements", RFC 8987,
DOI 10.17487/RFC8987, February 2021,
<https://www.rfc-editor.org/info/rfc8987>.
9.2. Informative References
[RFC7695] Pfister, P., Paterson, B., and J. Arkko, "Distributed
Prefix Assignment Algorithm", RFC 7695,
DOI 10.17487/RFC7695, November 2015,
<https://www.rfc-editor.org/info/rfc7695>.
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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