rfc1155.txt

开发snmp的开发包有两个开放的SNMP开发库

                      atNetAddress
                          NetworkAddress
                  }

   The first five definitions describe object types, relating, for
   example, the OBJECT DESCRIPTOR atIndex to the OBJECT IDENTIFIER {
   atEntry 1 }.  In addition, the syntax of this object is defined
   (INTEGER) along with the access permitted (read-write) and status
   (mandatory).  The sixth definition describes an ASN.1 type called
   AtEntry.







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5.  Extensions to the MIB

   Every Internet-standard MIB document obsoletes all previous such
   documents.  The portion of a name, termed the tail, following the
   OBJECT IDENTIFIER

      { mgmt version-number }

   used to name objects shall remain unchanged between versions.  New
   versions may:

      (1) declare old object types obsolete (if necessary), but not
      delete their names;

      (2) augment the definition of an object type corresponding to a
      list by appending non-aggregate object types to the object types
      in the list; or,

      (3) define entirely new object types.

   New versions may not:

      (1) change the semantics of any previously defined object without
      changing the name of that object.

   These rules are important because they admit easier support for
   multiple versions of the Internet-standard MIB.  In particular, the
   semantics associated with the tail of a name remain constant
   throughout different versions of the MIB.  Because multiple versions
   of the MIB may thus coincide in "tail-space," implementations
   supporting multiple versions of the MIB can be vastly simplified.

   However, as a consequence, a management agent might return an
   instance corresponding to a superset of the expected object type.
   Following the principle of robustness, in this exceptional case, a
   manager should ignore any additional information beyond the
   definition of the expected object type.  However, the robustness
   principle requires that one exercise care with respect to control
   actions:  if an instance does not have the same syntax as its
   expected object type, then those control actions must fail.  In both
   the monitoring and control cases, the name of an object returned by
   an operation must be identical to the name requested by an operation.









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6.  Definitions

           RFC1155-SMI DEFINITIONS ::= BEGIN

           EXPORTS -- EVERYTHING
                   internet, directory, mgmt,
                   experimental, private, enterprises,
                   OBJECT-TYPE, ObjectName, ObjectSyntax, SimpleSyntax,
                   ApplicationSyntax, NetworkAddress, IpAddress,
                   Counter, Gauge, TimeTicks, Opaque;

            -- the path to the root

            internet      OBJECT IDENTIFIER ::= { iso org(3) dod(6) 1 }

            directory     OBJECT IDENTIFIER ::= { internet 1 }

            mgmt          OBJECT IDENTIFIER ::= { internet 2 }

            experimental  OBJECT IDENTIFIER ::= { internet 3 }

            private       OBJECT IDENTIFIER ::= { internet 4 }
            enterprises   OBJECT IDENTIFIER ::= { private 1 }


            -- definition of object types

            OBJECT-TYPE MACRO ::=
            BEGIN
                TYPE NOTATION ::= "SYNTAX" type (TYPE ObjectSyntax)
                                  "ACCESS" Access
                                  "STATUS" Status
                VALUE NOTATION ::= value (VALUE ObjectName)

                Access ::= "read-only"
                                | "read-write"
                                | "write-only"
                                | "not-accessible"
                Status ::= "mandatory"
                                | "optional"
                                | "obsolete"
            END

               -- names of objects in the MIB

               ObjectName ::=
                   OBJECT IDENTIFIER




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               -- syntax of objects in the MIB

               ObjectSyntax ::=
                   CHOICE {
                       simple
                           SimpleSyntax,

               -- note that simple SEQUENCEs are not directly
               -- mentioned here to keep things simple (i.e.,
               -- prevent mis-use).  However, application-wide
               -- types which are IMPLICITly encoded simple
               -- SEQUENCEs may appear in the following CHOICE

                       application-wide
                           ApplicationSyntax
                   }

                  SimpleSyntax ::=
                      CHOICE {
                          number
                              INTEGER,

                          string
                              OCTET STRING,

                          object
                              OBJECT IDENTIFIER,

                          empty
                              NULL
                      }

                  ApplicationSyntax ::=
                      CHOICE {
                          address
                              NetworkAddress,

                          counter
                              Counter,

                          gauge
                              Gauge,

                          ticks
                              TimeTicks,

                          arbitrary
                              Opaque



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                  -- other application-wide types, as they are
                  -- defined, will be added here
                      }


                  -- application-wide types

                  NetworkAddress ::=
                      CHOICE {
                          internet
                              IpAddress
                      }

                  IpAddress ::=
                      [APPLICATION 0]          -- in network-byte order
                          IMPLICIT OCTET STRING (SIZE (4))

                  Counter ::=
                      [APPLICATION 1]
                          IMPLICIT INTEGER (0..4294967295)

                  Gauge ::=
                      [APPLICATION 2]
                          IMPLICIT INTEGER (0..4294967295)

                  TimeTicks ::=
                      [APPLICATION 3]
                          IMPLICIT INTEGER (0..4294967295)

                  Opaque ::=
                      [APPLICATION 4]          -- arbitrary ASN.1 value,
                          IMPLICIT OCTET STRING   --   "double-wrapped"

                  END

















Rose & McCloghrie                                              [Page 19]

RFC 1155                          SMI                           May 1990


7.  Acknowledgements

   This memo was influenced by three sets of contributors to earlier
   drafts:

   First, Lee Labarre of the MITRE Corporation, who as author of the
   NETMAN SMI [4], presented the basic roadmap for the SMI.

   Second, several individuals who provided valuable comments on this
   memo prior to its initial distribution:

         James R. Davin, Proteon
         Mark S. Fedor, NYSERNet
         Craig Partridge, BBN Laboratories
         Martin Lee Schoffstall, Rensselaer Polytechnic Institute
         Wengyik Yeong, NYSERNet


   Third, the IETF MIB working group:

         Karl Auerbach, Epilogue Technology
         K. Ramesh Babu, Excelan
         Lawrence Besaw, Hewlett-Packard
         Jeffrey D. Case, University of Tennessee at Knoxville
         James R. Davin, Proteon
         Mark S. Fedor, NYSERNet
         Robb Foster, BBN
         Phill Gross, The MITRE Corporation
         Bent Torp Jensen, Convergent Technology
         Lee Labarre, The MITRE Corporation
         Dan Lynch, Advanced Computing Environments
         Keith McCloghrie, The Wollongong Group
         Dave Mackie, 3Com/Bridge
         Craig Partridge, BBN (chair)
         Jim Robertson, 3Com/Bridge
         Marshall T. Rose, The Wollongong Group
         Greg Satz, cisco
         Martin Lee Schoffstall, Rensselaer Polytechnic Institute
         Lou Steinberg, IBM
         Dean Throop, Data General
         Unni Warrier, Unisys










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RFC 1155                          SMI                           May 1990


8.  References

   [1] Information processing systems - Open Systems Interconnection,
       "Specification of Abstract Syntax Notation One (ASN.1)",
       International Organization for Standardization, International
       Standard 8824, December 1987.

   [2] McCloghrie K., and M. Rose, "Management Information Base for
       Network Management of TCP/IP-based Internets", RFC 1156,
       Performance Systems International and Hughes LAN Systems, May
       1990.

   [3] Case, J., M. Fedor, M. Schoffstall, and J. Davin, The Simple
       Network Management Protocol", RFC 1157, University of Tennessee
       at Knoxville, Performance Systems International, Performance
       Systems International, and the MIT Laboratory for Computer
       Science, May 1990.

   [4] LaBarre, L., "Structure and Identification of Management
       Information for the Internet", Internet Engineering Task Force
       working note, Network Information Center, SRI International,
       Menlo Park, California, April 1988.

   [5] Cerf, V., "IAB Recommendations for the Development of Internet
       Network Management Standards", RFC 1052, IAB, April 1988.

   [6] Cerf, V., "Report of the Second Ad Hoc Network Management Review
       Group", RFC 1109, IAB, August 1989.

   [7] Information processing systems - Open Systems Interconnection,
       "Specification of Basic Encoding Rules for Abstract Notation One
       (ASN.1)", International Organization for Standardization,
       International Standard 8825, December 1987.

Security Considerations

   Security issues are not discussed in this memo.














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Authors' Addresses

   Marshall T. Rose
   PSI, Inc.
   PSI California Office
   P.O. Box 391776
   Mountain View, CA 94039

   Phone: [phone]

   EMail: [e-mail]


   Keith McCloghrie
   The Wollongong Group
   1129 San Antonio Road
   Palo Alto, CA 04303

   Phone: [phone]

   EMail: sytek![e-mail]






























Rose & McCloghrie                                              [Page 22]