draft-ietf-6man-addr-select-opt-11.txt   draft-ietf-6man-addr-select-opt-12.txt 
6man Working Group A. Matsumoto 6man Working Group A. Matsumoto
Internet-Draft T. Fujisaki Internet-Draft T. Fujisaki
Intended status: Standards Track NTT Intended status: Standards Track NTT
Expires: February 08, 2014 T. Chown Expires: March 25, 2014 T. Chown
University of Southampton University of Southampton
August 07, 2013 September 21, 2013
Distributing Address Selection Policy using DHCPv6 Distributing Address Selection Policy using DHCPv6
draft-ietf-6man-addr-select-opt-11.txt draft-ietf-6man-addr-select-opt-12.txt
Abstract Abstract
RFC 6724 defines default address selection mechanisms for IPv6 that RFC 6724 defines default address selection mechanisms for IPv6 that
allow nodes to select an appropriate address when faced with multiple allow nodes to select an appropriate address when faced with multiple
source and/or destination addresses to choose between. RFC 6724 source and/or destination addresses to choose between. RFC 6724
allows for the future definition of methods to administratively allows for the future definition of methods to administratively
configure the address selection policy information. This document configure the address selection policy information. This document
defines a new DHCPv6 option for such configuration, allowing a site defines a new DHCPv6 option for such configuration, allowing a site
administrator to distribute address selection policy overriding the administrator to distribute address selection policy overriding the
skipping to change at page 1, line 40 skipping to change at page 1, line 40
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on February 08, 2014. This Internet-Draft will expire on March 25, 2014.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 27 skipping to change at page 2, line 27
the copyright in such materials, this document may not be modified the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other it for publication as an RFC or to translate it into languages other
than English. than English.
1. Introduction 1. Introduction
[RFC6724] describes default algorithms for selecting an address when [RFC6724] describes default algorithms for selecting an address when
a node has multiple destination and/or source addresses to choose a node has multiple destination and/or source addresses to choose
from by using an address selection policy. In Section 2 of RFC 6724, from by using an address selection policy. This specification
it is suggested that the default policy table may be administratively defines a new DHCPv6 option for configuring the default policy table.
configured to suit the specific needs of a site. This specification
defines a new DHCPv6 option for such configuration.
Some problems were identified with the default address selection Some problems were identified with the default address selection
policy as originally defined in [RFC3484]. As a result, RFC 3484 was policy as originally defined in [RFC3484]. As a result, RFC 3484 was
updated and obsoleted by [RFC6724]. While this update corrected a updated and obsoleted by [RFC6724]. While this update corrected a
number of issues identifed from operational experience, it is number of issues identifed from operational experience, it is
unlikely that any default policy will suit all scenarios, and thus unlikely that any default policy will suit all scenarios, and thus
mechanisms to control the source address selection policy will be mechanisms to control the source address selection policy will be
necessary. Requirements for those mechanisms are described in necessary. Requirements for those mechanisms are described in
[RFC5221], while solutions are discussed in [RFC5221], while solutions are discussed in
[I-D.ietf-6man-addr-select-considerations]. Those documents have [I-D.ietf-6man-addr-select-considerations]. Those documents have
helped shape the improvements in the default address selection helped shape the improvements in the default address selection
algorithm in [RFC6724] as well as the requirements for the DHCPv6 algorithm in [RFC6724] as well as the requirements for the DHCPv6
option defined in this specification. option defined in this specification.
1.1. Conventions Used in This Document 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", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
1.2. Terminology 1.2. Terminology
This document uses the terminology defined in [RFC2460] and the This document uses the terminology defined in [RFC2460] and the
DHCPv6 specification defined in [RFC3315] DHCPv6 specification defined in [RFC3315]
2. Address Selection options 2. Address Selection options
skipping to change at page 4, line 9 skipping to change at page 4, line 14
A: Automatic Row Addition flag. This flag toggles the Automatic A: Automatic Row Addition flag. This flag toggles the Automatic
Row Addition flag at client hosts, which is described in section Row Addition flag at client hosts, which is described in section
2.1 of [RFC6724]. If this flag is set to 1, it does not change 2.1 of [RFC6724]. If this flag is set to 1, it does not change
client host behavior, that is, a client MAY automatically add client host behavior, that is, a client MAY automatically add
additional site-specific rows to the policy table. If set to 0, additional site-specific rows to the policy table. If set to 0,
the Automatic Row Addition flag is disabled, and a client SHOULD the Automatic Row Addition flag is disabled, and a client SHOULD
NOT automatically add rows to the policy table. If the option NOT automatically add rows to the policy table. If the option
contains a POLICY TABLE option, this flag is meaningless, and contains a POLICY TABLE option, this flag is meaningless, and
automatic row addition SHOULD NOT be performed against the automatic row addition SHOULD NOT be performed against the
distributed policy table. distributed policy table. This flag SHOULD be set to 0 only
when the Automatic Row Addition at client hosts is harmful for
site-specific reasons.
P: Privacy Preference flag. This flag toggles the Privacy P: Privacy Preference flag. This flag toggles the Privacy
Preference flag on client hosts, which is described in section 5 Preference flag on client hosts, which is described in section 5
of [RFC6724]. If this flag is set to 1, it does not change of [RFC6724]. If this flag is set to 1, it does not change
client host behavior, that is, a client will prefer temporary client host behavior, that is, a client will prefer temporary
addresses [RFC4941]. If set to 0, the Privacy Preference flag addresses [RFC4941]. If set to 0, the Privacy Preference flag
is disabled, and a client will prefer public addresses. is disabled, and a client will prefer public addresses. This
flag SHOULD be set to 0 only when the temporary addresses should
not be preferred for site-specific reasons.
POLICY TABLE OPTIONS: Zero or more Address Selection Policy Table POLICY TABLE OPTIONS: Zero or more Address Selection Policy Table
options, as described below. This option corresponds to a row options, as described below. This option corresponds to a row
in the policy table defined in section 2.1 of [RFC6724]. in the policy table defined in section 2.1 of [RFC6724].
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_ADDRSEL_TABLE | option-len | | OPTION_ADDRSEL_TABLE | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 5, line 10 skipping to change at page 5, line 18
label: An 8-bit unsigned integer; this value is for correlation of label: An 8-bit unsigned integer; this value is for correlation of
source address prefixes and destination address prefixes. This source address prefixes and destination address prefixes. This
field is used to deliver a label value in the [RFC6724] policy field is used to deliver a label value in the [RFC6724] policy
table. table.
precedence: An 8-bit unsigned integer; this value is used for precedence: An 8-bit unsigned integer; this value is used for
sorting destination addresses. This field is used to to deliver sorting destination addresses. This field is used to to deliver
a precedence value in [RFC6724] policy table. a precedence value in [RFC6724] policy table.
prefix-len: An 8-bit unsigned integer; the number of leading bits in prefix-len: An 8-bit unsigned integer; the number of leading bits in
the prefix that are valid. The value ranges from 0 to 128. the prefix that are valid. The value ranges from 0 to 128. If
an option with a prefix length greater than 128 is included, the
whole Address Selection option MUST be ignored.
prefix: A variable-length field containing an IP address or the prefix: A variable-length field containing an IP address or the
prefix of an IP address. An IPv4-mapped address [RFC4291] must prefix of an IP address. An IPv4-mapped address [RFC4291] must
be used to represent an IPv4 address as a prefix value. This be used to represent an IPv4 address as a prefix value. This
field is padded with zeros up to the nearest octet boundary when field is padded with zeros up to the nearest octet boundary when
prefix-len is not divisible by 8. This can be expressed using prefix-len is not divisible by 8. This can be expressed using
the following equation: (prefix-len + 7)/8 So the length of this the following equation: (prefix-len + 7)/8 So the length of this
field should be between 0 and 16 bytes. For example, the prefix field should be between 0 and 16 bytes. For example, the prefix
2001:db8::/60 would be encoded with an prefix-len of 60, the 2001:db8::/60 would be encoded with an prefix-len of 60, the
prefix would be 8 octets and would contains octets 20 01 0d b8 prefix would be 8 octets and would contains octets 20 01 0d b8
skipping to change at page 6, line 8 skipping to change at page 6, line 21
(a) replace the existing flags and active policy table with the (a) replace the existing flags and active policy table with the
DHCPv6 distributed flags and policy table. DHCPv6 distributed flags and policy table.
(b) preserve the existing flags and active policy table, whether (b) preserve the existing flags and active policy table, whether
this be the default policy table, or user configured policy. this be the default policy table, or user configured policy.
Choice (a) SHOULD be the default, i.e. that the policy table is not Choice (a) SHOULD be the default, i.e. that the policy table is not
explictly configured by the user. explictly configured by the user.
3.2. Handling stale policy tables 3.2. Handling stale distributed flags and policy table
When the information from the DHCP server goes stale, the policy When the information from the DHCP server goes stale, the flags and
received from the DHCP server SHOULD be deprecated. the policy table received from the DHCP server SHOULD be deprecated.
The received information can be considered stale in several cases, The received information can be considered stale in several cases,
e.g., when the interface goes down, the DHCP server does not respond e.g., when the interface goes down, the DHCP server does not respond
for a certain amount of time, and the Information Refresh Time is for a certain amount of time, and the Information Refresh Time is
expired. expired.
3.3. Handling multiple interfaces 3.3. Handling multiple interfaces
The policy table, and other parameters specified in this document, The policy table, and other parameters specified in this document,
are node-global information by their nature. One reason being that are node-global information by their nature. One reason being that
 End of changes. 12 change blocks. 
15 lines changed or deleted 24 lines changed or added

This html diff was produced by rfcdiff 1.41. The latest version is available from http://tools.ietf.org/tools/rfcdiff/