rfc1443.txt

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          Network Working Group                                  J. Case
          Request for Comments: 1443                 SNMP Research, Inc.
                                                           K. McCloghrie
                                                      Hughes LAN Systems
                                                                 M. Rose
                                            Dover Beach Consulting, Inc.
                                                           S. Waldbusser
                                              Carnegie Mellon University
                                                              April 1993


                               Textual Conventions
                               for version 2 of the
                   Simple Network Management Protocol (SNMPv2)


          Status of this Memo

          This RFC specifes an IAB standards track protocol for the
          Internet community, and requests discussion and suggestions
          for improvements.  Please refer to the current edition of the
          "IAB Official Protocol Standards" for the standardization
          state and status of this protocol.  Distribution of this memo
          is unlimited.


          Table of Contents


          1 Introduction ..........................................    2
          1.1 A Note on Terminology ...............................    3
          2 Definitions ...........................................    4
          3 Mapping of the TEXTUAL-CONVENTION macro ...............   22
          3.1 Mapping of the DISPLAY-HINT clause ..................   22
          3.2 Mapping of the STATUS clause ........................   24
          3.3 Mapping of the DESCRIPTION clause ...................   24
          3.4 Mapping of the REFERENCE clause .....................   24
          3.5 Mapping of the SYNTAX clause ........................   24
          4 Acknowledgements ......................................   26
          5 References ............................................   30
          6 Security Considerations ...............................   31
          7 Authors' Addresses ....................................   31












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          1.  Introduction

          A network management system contains: several (potentially
          many) nodes, each with a processing entity, termed an agent,
          which has access to management instrumentation; at least one
          management station; and, a management protocol, used to convey
          management information between the agents and management
          stations.  Operations of the protocol are carried out under an
          administrative framework which defines both authentication and
          authorization policies.

          Network management stations execute management applications
          which monitor and control network elements.  Network elements
          are devices such as hosts, routers, terminal servers, etc.,
          which are monitored and controlled through access to their
          management information.

          Management information is viewed as a collection of managed
          objects, residing in a virtual information store, termed the
          Management Information Base (MIB).  Collections of related
          objects are defined in MIB modules.  These modules are written
          using a subset of OSI's Abstract Syntax Notation One (ASN.1)
          [1], termed the Structure of Management Information (SMI) [2].

          When designing a MIB module, it is often useful to new define
          types similar to those defined in the SMI.  In comparison to a
          type defined in the SMI, each of these new types has a
          different name, a similar syntax, but a more precise
          semantics.  These newly defined types are termed textual
          conventions, and are used for the convenience of humans
          reading the MIB module.  It is the purpose of this document to
          define the initial set of textual conventions available to all
          MIB modules.

          Objects defined using a textual convention are always encoded
          by means of the rules that define their primitive type.
          However, textual conventions often have special semantics
          associated with them.  As such, an ASN.1 macro, TEXTUAL-
          CONVENTION, is used to concisely convey the syntax and
          semantics of a textual convention.

          For all textual conventions defined in an information module,
          the name shall be unique and mnemonic, and shall not exceed 64
          characters in length.  All names used for the textual
          conventions defined in all "standard" information modules





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          RFC 1443        Textual Conventions for SNMPv2      April 1993


          shall be unique.


          1.1.  A Note on Terminology

          For the purpose of exposition, the original Internet-standard
          Network Management Framework, as described in RFCs 1155, 1157,
          and 1212, is termed the SNMP version 1 framework (SNMPv1).
          The current framework is termed the SNMP version 2 framework
          (SNMPv2).








































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          RFC 1443        Textual Conventions for SNMPv2      April 1993


          2.  Definitions

          SNMPv2-TC DEFINITIONS ::= BEGIN

          IMPORTS
              ObjectSyntax, Integer32, TimeTicks
                  FROM SNMPv2-SMI;


          -- definition of textual conventions

          TEXTUAL-CONVENTION MACRO ::=
          BEGIN
              TYPE NOTATION ::=
                            DisplayPart
                            "STATUS" Status
                            "DESCRIPTION" Text
                            ReferPart
                            "SYNTAX" type(Syntax)

              VALUE NOTATION ::=
                            value(VALUE Syntax)

              DisplayPart ::=
                            "DISPLAY-HINT" Text
                          | empty

              Status ::=
                            "current"
                          | "deprecated"
                          | "obsolete"

              ReferPart ::=
                            "REFERENCE" Text
                          | empty

              -- uses the NVT ASCII character set
              Text ::= """" string """"
          END











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          RFC 1443        Textual Conventions for SNMPv2      April 1993


          DisplayString ::= TEXTUAL-CONVENTION
              DISPLAY-HINT "255a"
              STATUS       current
              DESCRIPTION
                      "Represents textual information taken from the NVT
                      ASCII character set, as defined in pages 4, 10-11
                      of RFC 854.  Any object defined using this syntax
                      may not exceed 255 characters in length."
              SYNTAX       OCTET STRING (SIZE (0..255))


          PhysAddress ::= TEXTUAL-CONVENTION
              DISPLAY-HINT "1x:"
              STATUS       current
              DESCRIPTION
                      "Represents media- or physical-level addresses."
              SYNTAX       OCTET STRING


          MacAddress ::= TEXTUAL-CONVENTION
              DISPLAY-HINT "1x:"
              STATUS       current
              DESCRIPTION
                      "Represents an 802 MAC address represented in the
                      'canonical' order defined by IEEE 802.1a, i.e., as
                      if it were transmitted least significant bit
                      first, even though 802.5 (in contrast to other
                      802.x protocols) requires MAC addresses to be
                      transmitted most significant bit first."
              SYNTAX       OCTET STRING (SIZE (6))


          TruthValue ::= TEXTUAL-CONVENTION
              STATUS       current
              DESCRIPTION
                      "Represents a boolean value."
              SYNTAX       INTEGER { true(1), false(2) }













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          TestAndIncr ::= TEXTUAL-CONVENTION
              STATUS       current
              DESCRIPTION
                      "Represents integer-valued information used for
                      atomic operations.  When the management protocol
                      is used to specify that an object instance having
                      this syntax is to be modified, the new value
                      supplied via the management protocol must
                      precisely match the value presently held by the
                      instance.  If not, the management protocol set
                      operation fails with an error of
                      'inconsistentValue'.  Otherwise, if the current
                      value is the maximum value of 2^31-1 (2147483647
                      decimal), then the value held by the instance is
                      wrapped to zero; otherwise, the value held by the
                      instance is incremented by one.  (Note that
                      regardless of whether the management protocol set
                      operation succeeds, the variable-binding in the
                      request and response PDUs are identical.)

                      The value of the ACCESS clause for objects having
                      this syntax is either 'read-write' or 'read-
                      create'.  When an instance of a columnar object
                      having this syntax is created, any value may be
                      supplied via the management protocol."
              SYNTAX       INTEGER (0..2147483647)
























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          RFC 1443        Textual Conventions for SNMPv2      April 1993


          AutonomousType ::= TEXTUAL-CONVENTION
              STATUS       current
              DESCRIPTION
                      "Represents an independently extensible type
                      identification value.  It may, for example,