rfc1441.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

          Network Working Group                                  J. Case
          Request for Comments: 1441                 SNMP Research, Inc.
                                                           K. McCloghrie
                                                      Hughes LAN Systems
                                                                 M. Rose
                                            Dover Beach Consulting, Inc.
                                                           S. Waldbusser
                                              Carnegie Mellon University
                                                              April 1993


                         Introduction to version 2 of the
                  Internet-standard Network Management Framework


          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
          2 Components of the SNMPv2 Framework ....................    3
          2.1 Structure of Management Information .................    3
          2.2 Textual Conventions .................................    4
          2.3 Protocol Operations .................................    4
          2.4 Transport Mappings ..................................    4
          2.5 Protocol Instrumentation ............................    5
          2.6 Administrative Framework ............................    5
          2.7 Conformance Statements ..............................    5
          3 Acknowledgements ......................................    7
          4 References ............................................   11
          5 Security Considerations ...............................   13
          6 Authors' Addresses ....................................   13













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          1.  Introduction

          The purpose of this document is to provide an overview of
          version 2 of the Internet-standard Network Management
          Framework, termed the SNMP version 2 framework (SNMPv2).  This
          framework is derived from the original Internet-standard
          Network Management Framework (SNMPv1), which consists of these
          three documents:

               RFC 1155 [1] which defines the Structure of Management
               Information (SMI), the mechanisms used for describing and
               naming objects for the purpose of management.

               RFC 1212 [2] which defines a more concise description
               mechanism, which is wholly consistent with the SMI.

               RFC 1157 [3] which defines the Simple Network Management
               Protocol (SNMP), the protocol used for network access to
               managed objects.

          For information on coexistence between SNMPv1 and SNMPv2,
          consult [4].




























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          2.  Components of the SNMPv2 Framework

          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.


          2.1.  Structure of 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)
          [5].  It is the purpose of the Structure of Management
          Information for SNMPv2 document [6] to define that subset.

          The SMI is divided into three parts: module definitions,
          object definitions, and, trap definitions.

          (1)  Module definitions are used when describing information
               modules.  An ASN.1 macro, MODULE-IDENTITY, is used to
               concisely convey the semantics of an information module.

          (2)  Object definitions are used when describing managed
               objects.  An ASN.1 macro, OBJECT-TYPE, is used to
               concisely convey the syntax and semantics of a managed
               object.

          (3)  Notification definitions are used when describing
               unsolicited transmissions of management information.  An
               ASN.1 macro, NOTIFICATION-TYPE, is used to concisely
               convey the syntax and semantics of a notification.






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          2.2.  Textual Conventions

          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 the Textual
          Conventions for SNMPv2 document [7] 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.


          2.3.  Protocol Operations

          The management protocol provides for the exchange of messages
          which convey management information between the agents and the
          management stations.  The form of these messages is a message
          "wrapper" which encapsulates a Protocol Data Unit (PDU).  The
          form and meaning of the "wrapper" is determined by an
          administrative framework which defines both authentication and
          authorization policies.

          It is the purpose of the Protocol Operations for SNMPv2
          document [8] to define the operations of the protocol with
          respect to the sending and receiving of the PDUs.


          2.4.  Transport Mappings

          The management protocol, version 2 of the Simple Network
          Management Protocol, may be used over a variety of protocol
          suites.  It is the purpose of the Transport Mappings for
          SNMPv2 document [9] to define how the SNMPv2 maps onto an
          initial set of transport domains.  Other mappings may be
          defined in the future.







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          Although several mappings are defined, the mapping onto UDP is
          the preferred mapping.  As such, to provide for the greatest
          level of interoperability, systems which choose to deploy
          other mappings should also provide for proxy service to the
          UDP mapping.


          2.5.  Protocol Instrumentation

          It is the purpose of the Management Information Base for
          SNMPv2 document [10] to define managed objects which describe
          the behavior of a SNMPv2 entity.  The Manager-to-Manager MIB
          document [11] defines an initial set of managed objects which
          describe the behavior of a SNMPv2 entity which acts in a
          manager role.  It is expected that extensions to this MIB will
          be defined in the future.


          2.6.  Administrative Framework

          It is the purpose of the Administrative Model for SNMPv2
          document [12] to define the behavior of a SNMPv2 party - a
          conceptual, virtual execution context whose operation is
          restricted (for security or other purposes) to an
          administratively defined subset of all possible operations of
          a particular SNMPv2 entity.

          Associated with each SNMPv2 party is a single authentication
          protocol and a single privacy protocol.  It is the purpose of
          the Security Protocols for SNMPv2 document [13] to define
          those protocols.

          The Party MIB for SNMPv2 document [14] defines managed objects
          which correspond to the properties associated with a SNMPv2
          party.


          2.7.  Conformance Statements

          It may be useful to define the acceptable lower-bounds of
          implementation, along with the actual level of implementation
          achieved.  It is the purpose of the Conformance Statements for
          SNMPv2 document [15] to define the notation used for these
          purposes.  There are two kinds of notations:






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          (1)  Compliance statements are used when describing
               requirements for agents with respect to object
               definitions.  An ASN.1 macro, MODULE-COMPLIANCE, is used
               to concisely convey such requirements.

          (2)  Capability statements are used when describing
               capabilities of agents with respect to object
               definitions.  An ASN.1 macro, AGENT-CAPABILITIES, is used
               to concisely convey such capabilities.

          Finally, collections of related objects are grouped together
          to form a unit of conformance.  An ASN.1 macro, OBJECT-GROUP,
          is used to concisely convey the syntax and semantics of a
          group.




































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          3.  Acknowledgements

          The SNMPv2 framework is based on the outstanding technical
          direction pioneered by the original authors of the SGMP: James
          R. (Chuck) Davin, of the MIT Laboratory for Computer Science,
          Mark S. Fedor, of Performance Systems International, Inc.,
          Martin L. Schoffstall, also of PSI, and Jeffrey D. Case.

          Since the invention of the SGMP in 1987, many individuals have
          devoted much energy toward creating the unprecedented success
          of the Internet-standard Network Management Framework.  As
          such, the list of people worthy of acknowledgement is too
          great to enumerate here.

          However, in retrospect, it seems clear that the concepts in
          the original architecture, as envisioned by Chuck Davin, have
          provided the basis for the success of the current framework.
          We hope that the SNMPv2 framework will be able to successfully
          build on this work.

          Finally, the comments of the SNMP version 2 working group are
          gratefully acknowledged:

               Beth Adams, Network Management Forum