Vendor-Identifying Vendor Options for Dynamic Host Configuration Protocol version 4 (DHCPv4)
RFC 3925

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• 03

Network Working Group                                     J. Littlefield
Request for Comments: 3925                           Cisco Systems, Inc.
Category: Standards Track                                   October 2004

                 Vendor-Identifying Vendor Options for
         Dynamic Host Configuration Protocol version 4 (DHCPv4)

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2004).

Abstract

   The Dynamic Host Configuration Protocol (DHCP) options for Vendor
   Class and Vendor-Specific Information can be limiting or ambiguous
   when a DHCP client represents multiple vendors.  This document
   defines two new options, modeled on the IPv6 options for vendor class
   and vendor-specific information, that contain Enterprise Numbers to
   remove ambiguity.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  2
       1.1.  Conventions Used in This Document. . . . . . . . . . . .  2
   2.  Supporting Multiple Vendor Instances . . . . . . . . . . . . .  3
   3.  Vendor-Identifying Vendor Class Option . . . . . . . . . . . .  3
   4.  Vendor-Identifying Vendor-Specific Information Option  . . . .  5
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  7
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . .  7
   7.  References . . . . . . . . . . . . . . . . . . . . . . . . . .  8
       7.1.  Normative References . . . . . . . . . . . . . . . . . .  8
       7.2.  Informative References . . . . . . . . . . . . . . . . .  8
   8.  Author's Address . . . . . . . . . . . . . . . . . . . . . . .  8
   9.  Full Copyright Statement . . . . . . . . . . . . . . . . . . .  9

Littlefield                 Standards Track                     [Page 1]
RFC 3925           Vendor-Identifying Vendor Options        October 2004

1.  Introduction

   The DHCP protocol for IPv4, RFC 2131 [2], defines options that allow
   a client to indicate its vendor type (option 60), and the DHCP client
   and server to exchange vendor-specific information (option 43) [5].
   Although there is no prohibition against passing multiple copies of
   these options in a single packet, doing so would introduce ambiguity
   of interpretation, particularly if conveying vendor-specific
   information for multiple vendors.  The vendor identified by option 60
   defines the interpretation of option 43, which itself carries no
   vendor identifier.  Furthermore, the concatenation of multiple
   instances of the same option, required by RFC 2131 and specified by
   RFC 3396 [4], means that multiple copies of options 60 or 43 would
   not remain independent.

   In some circumstances, an implementation may need to support
   multiple, independently defined forms of vendor-specific information.
   For example, implementations that must conform to an industry-
   standard use of DHCPv4, to allow interoperability in a particular
   technology space, may be required to support the vendor-specific
   options of that industry group.  But the same implementation may also
   require support for vendor-specific options defined by the
   manufacturer.  In particular, this is an issue for vendors of devices
   supporting CableLabs [9] standards, such as DOCSIS, CableHome, and
   PacketCable, as those standards define an industry-specific use for
   options 60 and 43.

   This document defines two new options, modeled on the IPv6 options
   for vendor class and vendor-specific information defined in RFC 3315
   [6], that contain IANA-assigned Enterprise Numbers [3] to remove
   ambiguity about the interpretation of their contents.  If desired,
   these new options can be used in addition to the current vendor class
   and vendor information options, whose definition is unaffected by
   this document.

1.1.  Conventions Used in This Document

   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 BCP 14, RFC 2119 [1].

Littlefield                 Standards Track                     [Page 2]
RFC 3925           Vendor-Identifying Vendor Options        October 2004

2.  Supporting Multiple Vendor Instances

   The options defined in this document may each contain data
   corresponding to more than one vendor.  The data portion of each
   option defined here contains an enterprise number (assigned by IANA
   [3]), followed by an internal data length, followed by vendor-
   specific data.  This sequence may be repeated multiple times within
   each option.  Because the aggregate of the vendor-specific data for