Procedures and IANA Guidelines for Definition of New DHCP Options and Message Types
RFC 2939
| Document | Type |
RFC - Best Current Practice
(September 2000; Errata)
Obsoletes RFC 2489
Also known as BCP 43
|
|
|---|---|---|---|
| Last updated | 2013-03-02 | ||
| Stream | IETF | ||
| Formats | plain text pdf html bibtex | ||
| Stream | WG state | (None) | |
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 2939 (Best Current Practice) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | (None) | ||
| Send notices to | (None) | ||
Network Working Group R. Droms
Request for Comments: 2939 Bucknell University
BCP: 43 September 2000
Obsoletes: 2489
Category: Best Current Practice
Procedures and IANA Guidelines for Definition of
New DHCP Options and Message Types
Status of this Memo
This document specifies an Internet Best Current Practices for the
Internet Community, and requests discussion and suggestions for
improvements. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2000). All Rights Reserved.
Abstract
The Dynamic Host Configuration Protocol (DHCP) provides a framework
for passing configuration information to hosts on a Transmission
Control Protocol/Internet Protocol (TCP/IP) network. Configuration
parameters and other control information are carried in tagged data
items that are stored in the 'options' field of the DHCP message.
The data items themselves are also called "options".
DHCP protocol messages are identified by the 'DHCP Message Type'
option (option code 51). Each message type is defined by the data
value carried in the 'DHCP Message Type' option.
New DHCP options and message types may be defined after the
publication of the DHCP specification to accommodate requirements for
conveyance of new configuration parameters or to accommodate new
protocol semantics. This document describes the procedure for
defining new DHCP options and message types.
1. Introduction
The Dynamic Host Configuration Protocol (DHCP) [1] provides a
framework for passing configuration information to hosts on a TCP/IP
network. Configuration parameters and other control information are
carried in tagged data items that are stored in the 'options' field
of the DHCP message. The data items themselves are also called
"options" [2].
Droms Best Current Practice [Page 1]
RFC 2939 Procedures for New DHCP Options September 2000
DHCP protocol messages are identified by the 'DHCP Message Type'
option (option code 51). Each message type is defined by the data
value carried in the 'DHCP Message Type' option.
This document describes the procedure for defining new DHCP options
and message types. The procedure will guarantee that:
* allocation of new option numbers and message type numbers is
coordinated from a single authority,
* new options and message types are reviewed for technical
correctness and appropriateness, and
* documentation for new options and message types is complete and
published.
As indicated in, "Guidelines for Writing an IANA Considerations
Section in RFCs", (see references), IANA acts as a central authority
for assignment of numbers such as DHCP option and message type codes.
The new procedure outlined in this document will provide guidance to
IANA in the assignment of new option and message type codes.
This document updates and replaces RFC 2489.
2. Overview and background
This document specifies procedures for defining new option codes and
message types.
2.1 New DHCP option codes
The procedure described in this document modifies and clarifies the
procedure for defining new options in RFC 2131 [2]. The primary
modification is to the time at which a new DHCP option is assigned an
option number. In the procedure described in this document, the
option number is not assigned until specification for the option is
about to be published as an RFC.
Since the publication of RFC 2132, the option number space for
publicly defined DHCP options (1-127) has almost been exhausted.
Many of the defined option numbers have not been followed up with
Internet Drafts submitted to the DHC WG. There has been a lack of
specific guidance to IANA from the DHC WG as to the assignment of
DHCP option numbers.
The procedure as specified in RFC 2132 does not clearly state that
new options are to be reviewed individually for technical
correctness, appropriateness and complete documentation. RFC 2132
also does not require that new options are to be submitted to the
IESG for review, and that the author of the option specification is
Droms Best Current Practice [Page 2]
RFC 2939 Procedures for New DHCP Options September 2000
responsible for bringing new options to the attention of the IESG.
Finally, RFC 2132 does not make clear that newly defined options are
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