Internet Engineering Task Force (IETF) A. Matsumoto
Request for Comments: 7078 T. Fujisaki
Category: Standards Track NTT
ISSN: 2070-1721 T. Chown
University of Southampton
Distributing Address Selection Policy Using DHCPv6
RFC 6724 defines default address selection mechanisms for IPv6 that
allow nodes to select an appropriate address when faced with multiple
source and/or destination addresses to choose between. RFC 6724
allows for the future definition of methods to administratively
configure the address selection policy information. This document
defines a new DHCPv6 option for such configuration, allowing a site
administrator to distribute address selection policy overriding the
default address selection parameters and policy table, and thus
allowing the administrator to control the address selection behavior
of nodes in their site.
Status of This Memo
This is an Internet Standards Track document.
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(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
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Matsumoto, et al. Standards Track [Page 1]RFC 7078 DHCPv6 Address Selection Policy Opt January 2014
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[RFC6724] describes default algorithms for selecting an address when
a node has multiple destination and/or source addresses to choose
from by using an address selection policy. This specification
defines a new DHCPv6 option for configuring the default policy table.
Some problems were identified with the default address selection
policy as originally defined in [RFC3484]. As a result, RFC 3484 was
updated and obsoleted by [RFC6724]. While this update corrected a
number of issues identified from operational experience, it is
unlikely that any default policy will suit all scenarios, and thus
mechanisms to control the source address selection policy will be
necessary. Requirements for those mechanisms are described in
[RFC5221], while solutions are discussed in [ADDR-SEL]. Those
documents have helped shape the improvements in the default address
selection algorithm in [RFC6724] as well as the requirements for the
DHCPv6 option defined in this specification.
This option's concept is to serve as a hint for a node about how to
behave in the network. Ultimately, while the node's administrator
can control how to deal with the received policy information, the
implementation SHOULD follow the method described below uniformly to
ease troubleshooting and to reduce operational costs.
1.1. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",