--- 1/draft-ietf-6man-addr-select-opt-02.txt 2012-02-21 12:14:02.511006528 +0100 +++ 2/draft-ietf-6man-addr-select-opt-03.txt 2012-02-21 12:14:02.527004255 +0100 @@ -1,21 +1,21 @@ 6man Working Group A. Matsumoto Internet-Draft T. Fujisaki Intended status: Standards Track J. Kato -Expires: August 18, 2012 NTT +Expires: August 24, 2012 NTT T. Chown University of Southampton - February 15, 2012 + February 21, 2012 Distributing Address Selection Policy using DHCPv6 - draft-ietf-6man-addr-select-opt-02.txt + draft-ietf-6man-addr-select-opt-03.txt Abstract RFC 3484 defines default address selection mechanisms for IPv6 that allow nodes to select appropriate address when faced with multiple source and/or destination addresses to choose between. The RFC 3484 allowed 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 @@ -30,21 +30,21 @@ 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 http://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 August 18, 2012. + This Internet-Draft will expire on August 24, 2012. Copyright Notice Copyright (c) 2012 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 Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -91,105 +91,114 @@ The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 1.2. Terminology This document uses the terminology defined in [RFC2460] and the DHCPv6 specification defined in [RFC3315] -2. Address Selection Policy Option +2. Address Selection Policy option - The Address Selection Policy Option provides the policy table for + The Address Selection Policy option provides the policy table for address selection rules as described in RFC 3484 and in [I-D.ietf-6man-rfc3484-revise]. Each end node is expected to configure its policy table, as described - in RFC 3484, using the Address Selection Policy option information as - described in the section below on processing the option. + in RFC 3484, using the Address Selection Policy option as described + in the section below on processing the option. - The format of the Address Selection Policy option is given below: + Multiple Address Selection Policy options MAY appear in a DHCPv6 + message. They constitute a single policy table. - 0 1 2 3 + The format of the Address Selection Policy option is given below. + 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OPTION_DASP | option-len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | label | precedence |z| reserved | prefix-len | - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | label | precedence | prefix-len | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | + | | + | prefix (variable length) | | | - | Prefix (Variable Length) +-+-+-+-+-+-+-+-+ - | | suboption-len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | suboption-zone-index (if present (z = 1)) | + | | + . DASP options . + . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - [Fig. 1] + Figure 1: Address Selection Policy option format - Fields: + option-code: OPTION_DASP (TBD). - option-code: OPTION_DASP (TBD) - option-len: The total length of the label fields, precedence fields, - zone-index fields, prefix-len fields, and prefix fields in + option-len: The total length of the label field, precedence field, + prefix-len field, prefix field, and DASP options field in octets. label: An 8-bit unsigned integer; this value is used to make a combination of source address prefixes and destination address prefixes. precedence: An 8-bit unsigned integer; this value is used for sorting destination addresses. - z bit: 'zone-index' bit. If z bit is set to 1, 32 bit zone-index - value is included right after the "prefix-len" field, and - "Prefix" value continues after the "zone-index" field. If z bit - is 0, "Prefix" value continues right after the "prefix-len" - value. - - reserved: 6-bit reserved field. Initialized to zero by sender, and - ignored by receiver. - - suboption-len: 'suboption-len' specifies the length of the suboption - fields in bytes. Currently, the only defined suboption is zone- - index, described as 'suboption-zone-index'. - - suboption-zone-index: If the z-bit is set to 1, this field is - inserted between "prefix-len" field and "Prefix" field. The - zone-index field is an 32-bit unsigned integer and used to - specify zones for scoped addresses. The zone-index is defined - in RFC 3493 [RFC3493] as 'scope ID'. - 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. - 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 be used to represent an IPv4 address as a prefix value. The Prefix should be truncated on the byte boundary. So the length of this field should be between 0 and 16 bytes. - Multiple Address Selection Policy options MAY appear in a DHCPv6 - message. They MUST be treated in the way that they constitute a - single policy table. + DASP options: Options specific to this particular Address Selection + Policy option. This includes, but not limited to, zero or one + PREFIX_ZONE option that specify the zone index of the prefix in + this option. -3. Appearance of the Address Selection Policy Option + The format of the Zone Index option is given below. + + 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 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | OPTION_ZONE_INDEX | option-len | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | zone-index | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Figure 2: Zone Index option format + + option-code: OPTION_ZONE_INDEX (TBD). + + option-len: 4. + + zone-index: The zone-index field is an 32-bit unsigned integer, and + used to specify the zone for scoped addresses. The zone-index + is defined in RFC 3493 [RFC3493] as 'scope ID'. + +3. Appearance of the Address Selection Policy option The Address Selection Policy option MUST NOT appear in any messages other than the following ones: Solicit, Advertise, Request, Renew, Rebind, Reconfigure, Information-Request, and Reply. -4. Processing the Address Selection Policy Option +4. Processing the Address Selection Policy option This section describes how to process received Address Selection - Policy Options at the DHCPv6 client. + Policy options at the DHCPv6 client. + + When a host receives a DHCPv6 message that includes multiple Address + Selection Policy options, they MUST be treated as a single policy + table. This option's concept is to serve as a hint for a node about how to behave in the network. So, basically, it should be up to the node's administrator how to make use of or even ignore the received policy information. 4.1. Handling of the local policy table RFC 3484 defines the default policy table. Also, a user is usually able to configure the policy table to satisfy his requirement.