Virtual Subnet Selection Options for DHCPv4 and DHCPv6
RFC 6607

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Internet Engineering Task Force (IETF)                        K. Kinnear
Request for Comments: 6607                                    R. Johnson
Updates: 3046                                                   M. Stapp
Category: Standards Track                                  Cisco Systems
ISSN: 2070-1721                                               April 2012

         Virtual Subnet Selection Options for DHCPv4 and DHCPv6

Abstract

   This memo defines a DHCPv4 Virtual Subnet Selection (VSS) option, a
   DHCPv6 VSS option, and the DHCPv4 VSS and VSS-Control sub-options
   carried in the DHCPv4 Relay Agent Information option.  These are
   intended for use by DHCP clients, relay agents, and proxy clients in
   situations where VSS information needs to be passed to the DHCP
   server for proper address or prefix allocation to take place.

   For the DHCPv4 option and Relay Agent Information sub-options, this
   memo documents and extends existing usage as per RFC 3942.  This memo
   updates RFC 3046 regarding details relating to the copying of sub-
   options (see Section 8).

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (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.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6607.

Kinnear, et al.              Standards Track                    [Page 1]
RFC 6607            Virtual Subnet Selection Options          April 2012

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   document authors.  All rights reserved.

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   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.

Kinnear, et al.              Standards Track                    [Page 2]
RFC 6607            Virtual Subnet Selection Options          April 2012

Table of Contents

   1. Introduction ....................................................3
   2. Terminology .....................................................4
   3. Virtual Subnet Selection Options and Sub-Options: Definitions ...6
      3.1. DHCPv4 Virtual Subnet Selection Option .....................6
      3.2. DHCPv4 Virtual Subnet Selection Sub-Option .................6
      3.3. DHCPv4 Virtual Subnet Selection Control Sub-Option .........7
      3.4. DHCPv6 Virtual Subnet Selection Option .....................7
      3.5. Virtual Subnet Selection Type and Information ..............8
   4. Overview of Virtual Subnet Selection Usage ......................8
      4.1. VPN Assignment by the DHCP Relay Agent .....................9
      4.2. VPN Assignment by the DHCP Server .........................12
      4.3. Required Support ..........................................14
      4.4. Alternative VPN Assignment Approaches .....................14
   5. Relay Agent Behavior ...........................................15
      5.1. VPN Assignment by the DHCP Server .........................16
      5.2. DHCP Leasequery ...........................................17
   6. Client Behavior ................................................17
   7. Server Behavior ................................................19
      7.1. Returning the DHCPv4 or DHCPv6 Option .....................20
      7.2. Returning the DHCPv4 Sub-Option ...........................20
      7.3. Making Sense of Conflicting VSS Information ...............21
   8. Update to RFC 3046 .............................................22