Network Working Group                                           R. Droms
INTERNET DRAFT                                       Bucknell University
Obsoletes: draft-ietf-dhc-options-opt127-00.txt            February 1996
                                                     Expires August 1996

                 An Extension to the DHCP Option Codes
                 <draft-ietf-dhc-options-opt127-00.txt>
                 <draft-ietf-dhc-options-opt127-01.txt>

Status of this memo

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Abstract

   The Dynamic Host Configuration Protocol (DHCP) provides a framework
   for passing configuration information to hosts on a TCP/IP network.
   This document defines a new option to extend the available option
   codes.

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."

   Each option is assigned a one-octet option code.  Options 128-254 are
   reserved for local use and at this time over half of the available
   options in the range 0-127 and option 255 have been assigned.  This
   document defines a new option to extend the available option codes.

DRAFT            An extension to the DHCP Option Codes     February 1996

Definition of option 127

   Option code 127 indicates that the DHCP option has a two-octet
   extended option code.  The format of these options is:

                Extended
    Code   Len  option code   Data...
   +-----+-----+-----+-----+-----+----
   +-----+-----+-----+-----+-----+-----+----
   | 127 | XXX |  n  oh |  ol |  d1 |  d2 | ...
   +-----+-----+-----+-----+-----+----
   +-----+-----+-----+-----+-----+-----+----

   Other than the two-octet extended option code, these options are
   encoded and carried in DHCP messages identically to the options
   defined in RFC 1533 [2].  The high-order and low-order octets of the
   extended option code are stored in 'oh' and 'ol', respectively.  The
   number of octets given in the 'len' field includes the two-octet
   extended option code.

   The two-octet extended option codes will be assigned through the
   mechanisms defined for the assignment of new options [3] after the
   current one-octet option codes have been exhausted.

References

   [1] Droms, R., "Dynamic Host Configuration Protocol", RFC 1531,
       Bucknell University, October 1993.

   [2] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
       Extensions", RFC 1533, Lachman Associates, October 1993.

   [3] Droms, R., "Procedure for Defining New DHCP Options", Work in
       progress, February, 1996.

Security Considerations

   Security issues are not discussed in this document.

Author's Address

   Ralph Droms
   Computer Science Department
   323 Dana Engineering
   Bucknell University
   Lewisburg, PA 17837

   Phone: (717) 524-1145
   EMail: droms@bucknell.edu