IPv6 CE Routers LAN Prefix DelegationQA Cafe100 Main Street, Suite #212DoverNH03820United States of Americatim@qacafe.com
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Internet Engineering Task ForceIPv6Internet Protocol Version 6DHCPv6This 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.This document defines DHCPv6 Prefix Delegation in IPv6 CE Routers ()
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 . 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.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
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.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 .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.
+-----------+
| Service |
| Provider |
| Router |
+-----+-----+
|
|
| Customer
| Internet Connection
|
+-----v-----+
| IPv6 |
| CE |
| Router |
+-----+-----+
|
+----+-+-------+
| |
| |
+---+----+ +-----+------+
| IPv6 | | |
| Host | | Router |
| | | |
+--------+ +------------+
The IPv6 CE Router distributes configuration information obtained during WAN interface
provisioning to IPv6 hosts and routers. A router based on previously
would only address IPv6 hosts, this update to allow for addressing and routing of routers.LAN Prefix Delegation (PD) RequirementsLPD-1: The IPv6 CE Router MUST support DHCPv6 server capable of IPv6 prefix assignment
according to (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 DelegationLPD-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 . The MUST forward all the DHCPv6 Relay messages to the
All_DHCP_Relay_Agents_and_Servers multicast address.This document does not add any new security considerations beyond those mentioned in
Section 4 of and Section 22 of . This document makes no request of IANA. Thanks to the following people (in alphabetical order) for their guidance and feedback:
Marion Dillon, Esko Dijk, Ted Lemon, Michael Richardson.