Network Working Group R. Presuhn Internet-Draft None Intended status: Standards Track December 6, 2010 Expires: June 9, 2011 Textual Conventions for the Representation of Floating-Point Numbers draft-presuhn-floats-02.txt Abstract This memo defines a Management Information Base (MIB) module containing textual conventions (TCs) to represent floating-point numbers. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on June 9, 2011. Copyright Notice Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Presuhn Expires June 9, 2011 [Page 1]
Internet-Draft Floating-Point Textual Conventions December 2010 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. The Internet-Standard Management Framework . . . . . . . . . . 3 3. Structure of the MIB Module . . . . . . . . . . . . . . . . . . 4 3.1. MIB modules required for IMPORTS . . . . . . . . . . . . . 4 3.2. Documents required for REFERENCE clauses . . . . . . . . . 4 4. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 6 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 8.1. Normative References . . . . . . . . . . . . . . . . . . . 6 8.2. Informative References . . . . . . . . . . . . . . . . . . 7 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 7 Presuhn Expires June 9, 2011 [Page 2]
Internet-Draft Floating-Point Textual Conventions December 2010 1. Introduction This memo defines textual conventions for the representation of floating-point numbers. All of these definitions are in terms of the IEEE Standard for Floating-Point Arithmetic, IEEE 754-2008 [IEEE.754.2008]. The IEEE Standard for Floating-Point Arithmetic, IEEE 754-2008 [IEEE.754.2008], provides for a variety of interchange formats for floating point numbers. The need for three of these, namely o 32-bit, o 64-bit, o 128-bit, has been recognized in network management. For example, Section 4.2.3 of the SMIng Objectives [RFC3216] elaborates the need for these three floating-point data types in network management protocols. The selection of a floating-point format involves many considerations and trade-offs, and an exhaustive discussion of these is beyond the scope of this menu. However, one consideration peculiar to the SNMP environment bears mentioning here: the SNMP "lexicographical" ordering for INDEX objects using these textual conventions will simply be that of the octet strings corresponding to the floating point representations, which will not in general reflect the numerical ordering of the corresponding floating point values. 2. The Internet-Standard Management Framework For a detailed overview of the documents that describe the current Internet-Standard Management Framework, please refer to section 7 of RFC 3410 [RFC3410]. Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. MIB objects are generally accessed through the Simple Network Management Protocol (SNMP). Objects in the MIB are defined using the mechanisms defined in the Structure of Management Information (SMI). This memo specifies a MIB module that is compliant to the SMIv2, which is described in STD 58, RFC 2578 [RFC2578], STD 58, RFC 2579 [RFC2579] and STD 58, RFC 2580 [RFC2580]. Presuhn Expires June 9, 2011 [Page 3]
Internet-Draft Floating-Point Textual Conventions December 2010 3. Structure of the MIB Module This MIB module defines three textual conventions. It defines no MIB objects. 3.1. MIB modules required for IMPORTS This MIB module employs definitions from [RFC2578] and [RFC2579]. 3.2. Documents required for REFERENCE clauses This MIB module contains REFERENCE clauses making reference to IEEE 754-2008 [IEEE.754.2008]. 4. Definitions FLOAT-TC-MIB DEFINITIONS ::= BEGIN IMPORTS MODULE-IDENTITY, mib-2 FROM SNMPv2-SMI TEXTUAL-CONVENTION FROM SNMPv2-TC; floatTcMIB MODULE-IDENTITY LAST-UPDATED "201012050000Z" -- 05 December, 2010 ORGANIZATION "None" CONTACT-INFO "Randy Presuhn Email: randy_presuhn@mindspring.com" DESCRIPTION "Textual conventions for the representation of floating-point numbers. Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Simplified BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info). This version of this MIB module is part of RFC XXXX; Presuhn Expires June 9, 2011 [Page 4]
Internet-Draft Floating-Point Textual Conventions December 2010 see the RFC itself for full legal notices." REVISION "201012050000Z" DESCRIPTION "Initial version, published as RFC XXXX." ::= { mib-2 XXX } -- RFC Ed.: replace XXX with IANA-assigned number & remove this note -- RFC Ed.: replace XXXX with the RFC number & remove this note Float32TC ::= TEXTUAL-CONVENTION STATUS current DESCRIPTION "This type represents a 32-bit (4-octet) IEEE floating-point number in binary interchange format." REFERENCE "IEEE Standard for Binary Floating-Point Arithmetic, Standard 754-2008" SYNTAX OCTET STRING (SIZE(4)) Float64TC ::= TEXTUAL-CONVENTION STATUS current DESCRIPTION "This type represents a 64-bit (8-octet) IEEE floating-point number in binary interchange format." REFERENCE "IEEE Standard for Binary Floating-Point Arithmetic, Standard 754-2008" SYNTAX OCTET STRING (SIZE(8)) Float128TC ::= TEXTUAL-CONVENTION STATUS current DESCRIPTION "This type represents a 128-bit (16-octet) IEEE floating-point number in binary interchange format." REFERENCE "IEEE Standard for Binary Floating-Point Arithmetic, Standard 754-2008" SYNTAX OCTET STRING (SIZE(16)) END 5. Security Considerations This module does not define any management objects. Instead, it defines a set of textual conventions that may be used by other MIB modules to define management objects. Presuhn Expires June 9, 2011 [Page 5]
Internet-Draft Floating-Point Textual Conventions December 2010 Meaningful security considerations can only be written in the MIB modules that define management objects. Therefore, this memo has no impact on the security of the Internet. 6. IANA Considerations The MIB module in this document uses the following IANA-assigned OBJECT IDENTIFIER value recorded in the SMI Numbers registry: Descriptor OBJECT IDENTIFIER value ---------- ----------------------- floatTcMIB { mib-2 XXX } Editor's Note (to be removed prior to publication): the IANA is requested to assign a value for "XXX" under the 'mib-2' subtree and to record the assignment in the SMI Numbers registry. When the assignment has been made, the RFC Editor is asked to replace "XXX" (here and in the MIB module) with the assigned value and to remove this note. 7. Contributors The following people provided helpful comments during the development of this document: o Juergen Quittek o Juergen Schoenwaeder o Robert Story 8. References 8.1. Normative References [IEEE.754.2008] Institute of Electrical and Electronics Engineers, "Standard for Binary Floating-Point Arithmetic", IEEE Standard 754, August 2008. [RFC2578] McCloghrie, K., Ed., Perkins, D., Ed., and J. Schoenwaelder, Ed., "Structure of Management Information Presuhn Expires June 9, 2011 [Page 6]
Internet-Draft Floating-Point Textual Conventions December 2010 Version 2 (SMIv2)", STD 58, RFC 2578, April 1999. [RFC2579] McCloghrie, K., Ed., Perkins, D., Ed., and J. Schoenwaelder, Ed., "Textual Conventions for SMIv2", STD 58, RFC 2579, April 1999. [RFC2580] McCloghrie, K., Perkins, D., and J. Schoenwaelder, "Conformance Statements for SMIv2", STD 58, RFC 2580, April 1999. 8.2. Informative References [RFC3216] Elliott, C., Harrington, D., Jason, J., Schoenwaelder, J., Strauss, F., and W. Weiss, "SMIng Objectives", RFC 3216, December 2001. [RFC3410] Case, J., Mundy, R., Partain, D., and B. Stewart, "Introduction and Applicability Statements for Internet- Standard Management Framework", RFC 3410, December 2002. Author's Address Randy Presuhn None San Jose, CA 95120 USA Email: randy_presuhn@mindspring.com Presuhn Expires June 9, 2011 [Page 7]