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Encoding Long Options in the Dynamic Host Configuration Protocol (DHCPv4) (RFC3396)

IP.com Disclosure Number: IPCOM000010234D
Original Publication Date: 2002-Nov-01
Included in the Prior Art Database: 2002-Nov-08
Document File: 10 page(s) / 19K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

T. Lemon: AUTHOR [+2]

Abstract

This document specifies the processing rules for Dynamic Host Configuration Protocol (DHCPv4) options that appear multiple times in the same message. Multiple instances of the same option are generated when an option exceeds 255 octets in size (the maximum size of a single option) or when an option needs to be split apart in order to take advantage of DHCP option overloading. When multiple instances of the same option appear in the options, file and/or sname fields in a DHCP packet, the contents of these options are concatenated together to form a single option prior to processing.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 15% of the total text.

Network Working Group                                           T. Lemon

Request for Comments: 3396                                 Nominum, Inc.

Updates: 2131                                                S. Cheshire

Category: Standards Track                           Apple Computer, Inc.

                                                           November 2002

                         Encoding Long Options

          in the Dynamic Host Configuration Protocol (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 (2002).  All Rights Reserved.

Abstract

   This document specifies the processing rules for Dynamic Host

   Configuration Protocol (DHCPv4) options that appear multiple times in

   the same message.  Multiple instances of the same option are

   generated when an option exceeds 255 octets in size (the maximum size

   of a single option) or when an option needs to be split apart in

   order to take advantage of DHCP option overloading.  When multiple

   instances of the same option appear in the options, file and/or sname

   fields in a DHCP packet, the contents of these options are

   concatenated together to form a single option prior to processing.

1. Introduction

   This document updates RFC 2131 [3] by clarifying the rules for option

   concatenation specified in section 4.1.  It is expected that the

   reader will be familiar with this portion of RFC 2131.  The text in

   section 4.1 that reads "Options may appear only once, unless

   otherwise specified in the options document."  should be considered

   as deleted.

   The DHCP protocol [3] specifies objects called "options" that are

   encoded in the DHCPv4 packet to pass information between DHCP

   protocol agents.  These options are encoded as a one-byte type code,

   a one-byte length, and a buffer consisting of the number of bytes

   specified in the length, from zero to 255.

Lemon & Cheshire            Standards Track                     [Page 1]

RFC 3396            Encoding Long Options in DHCPv4        November 2002

   However, in some cases it may be useful to send options that are

   longer than 255 bytes.  RFC 2131 [3] specifies that when more than

   one option with a given type code appears in the DHCP packet, all

   such options should be concatenated together.  It does not, however,

   spe...