HTTP/1.1 200 OK Date: Tue, 09 Apr 2002 01:50:49 GMT Server: Apache/1.3.20 (Unix) Last-Modified: Tue, 04 Jun 1996 16:45:44 GMT ETag: "323946-1387-31b46838" Accept-Ranges: bytes Content-Length: 4999 Connection: close Content-Type: text/plain Network Working Group R. Droms INTERNET DRAFT Bucknell University Obsoletes: draft-ietf-dhc-options-opt127-01.txt April 1996 Expires October 1996 An Extension to the DHCP Option Codes Status of this memo This document is an Internet-Draft. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as ``work in progress.'' To learn the current status of any Internet-Draft, please check the ``1id-abstracts.txt'' listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe), munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or ftp.isi.edu (US West Coast). 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 and new option to request the parameters represented by those new Droms [Page 1] DRAFT An extension to the DHCP Option Codes April 1996 option codes. 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 | 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. Definition of option 126 This option is used by a DHCP client to request values for specified configuration paramaters that are identified by extended option codes as defined above. The list of n requested parameters is specified as 2n octets, where each pair of octets is a valid extended option code. The client MAY list the options in order of preference. The DHCP server is not required to return the options in the requested order, but MUST try to insert the requested options in the order requested by the client. The code for this option is 126. Its minimum length is 2. Extended Code Len option codes +-----+-----+-----+-----+-----+-----+---- | 126 | XXX | c1h | c1l | c2h | c2l | ... +-----+-----+-----+-----+-----+-----+---- Droms [Page 2] DRAFT An extension to the DHCP Option Codes April 1996 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 Droms [Page 3]