rfc1442.txt

<VC++网络游戏建摸与实现>源代码

          descriptor.

          Finally, by convention, if the descriptor refers to an object
          with a SYNTAX clause value of either Counter32 or Counter64,
          then the descriptor used for the object should denote
          plurality.


          3.1.1.  Textual Clauses

          Some clauses in a macro invocation may take a textual value
          (e.g., the DESCRIPTION clause).  Note that, in order to
          conform to the ASN.1 syntax, the entire value of these clauses
          must be enclosed in double quotation marks, and therefore
          cannot itself contain double quotation marks, although the
          value may be multi-line.


          3.2.  IMPORTing Symbols

          To reference an external object, the IMPORTS statement must be
          used to identify both the descriptor and the module defining
          the descriptor.

          Note that when symbols from "enterprise-specific" information
          modules are referenced  (e.g., a descriptor), there is the
          possibility of collision.  As such, if different objects with
          the same descriptor are IMPORTed, then this ambiguity is





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          resolved by prefixing the descriptor with the name of the
          information module and a dot ("."), i.e.,

               "module.descriptor"

          (All descriptors must be unique within any information
          module.)

          Of course, this notation can be used even when there is no
          collision when IMPORTing symbols.

          Finally, the IMPORTS statement may not be used to import an
          ASN.1 named type which corresponds to either the SEQUENCE or
          SEQUENCE OF type.




































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          4.  Naming Hierarchy

          The root of the subtree administered by the Internet Assigned
          Numbers Authority (IANA) for the Internet is:

               internet       OBJECT IDENTIFIER ::= { iso 3 6 1 }

          That is, the Internet subtree of OBJECT IDENTIFIERs starts
          with the prefix:

               1.3.6.1.

          Several branches underneath this subtree are used for network
          management:

               mgmt           OBJECT IDENTIFIER ::= { internet 2 }
               experimental   OBJECT IDENTIFIER ::= { internet 3 }
               private        OBJECT IDENTIFIER ::= { internet 4 }
               enterprises    OBJECT IDENTIFIER ::= { private 1 }

          However, the SMI does not prohibit the definition of objects
          in other portions of the object tree.

          The mgmt(2) subtree is used to identify "standard" objects.

          The experimental(3) subtree is used to identify objects being
          designed by working groups of the IETF.  If an information
          module produced by a working group becomes a "standard"
          information module, then at the very beginning of its entry
          onto the Internet standards track, the objects are moved under
          the mgmt(2) subtree.

          The private(4) subtree is used to identify objects defined
          unilaterally.  The enterprises(1) subtree beneath private is
          used, among other things, to permit providers of networking
          subsystems to register models of their products.














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          5.  Mapping of the MODULE-IDENTITY macro

          The MODULE-IDENTITY macro is used to provide contact and
          revision history for each information module.  It must appear
          exactly once in every information module.  It should be noted
          that the expansion of the MODULE-IDENTITY macro is something
          which conceptually happens during implementation and not
          during run-time.


          5.1.  Mapping of the LAST-UPDATED clause

          The LAST-UPDATED clause, which must be present, contains the
          date and time that this information module was last edited.


          5.2.  Mapping of the ORGANIZATION clause

          The ORGANIZATION clause, which must be present, contains a
          textual description of the organization under whose auspices
          this information module was developed.


          5.3.  Mapping of the CONTACT-INFO clause

          The CONTACT-INFO clause, which must be present, contains the
          name, postal address, telephone number, and electronic mail
          address of the person to whom technical queries concerning
          this information module should be sent.


          5.4.  Mapping of the DESCRIPTION clause

          The DESCRIPTION clause, which must be present, contains a
          high-level textual description of the contents of this
          information module.


          5.5.  Mapping of the REVISION clause

          The REVISION clause, which need not be present, is repeatedly
          used to describe the revisions made to this information
          module, in reverse chronological order.  Each instance of this
          clause contains the date and time of the revision.






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          5.6.  Mapping of the DESCRIPTION clause

          The DESCRIPTION clause, which must be present for each
          REVISION clause, contains a high-level textual description of
          the revision identified in that REVISION clause.


          5.7.  Mapping of the MODULE-IDENTITY value

          The value of an invocation of the MODULE-IDENTITY macro is an
          OBJECT IDENTIFIER.  As such, this value may be authoritatively
          used when referring to the information module containing the
          invocation.





































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          5.8.  Usage Example

          Consider how a skeletal MIB module might be constructed: e.g.,

          FIZBIN-MIB DEFINITIONS ::= BEGIN

          IMPORTS
              MODULE-IDENTITY, OBJECT-TYPE, experimental
                  FROM SNMPv2-SMI;


          fizbin MODULE-IDENTITY
              LAST-UPDATED "9210070433Z"
              ORGANIZATION "IETF SNMPv2 Working Group"
              CONTACT-INFO
                      "        Marshall T. Rose

                       Postal: Dover Beach Consulting, Inc.
                               420 Whisman Court
                               Mountain View, CA  94043-2186
                               US

                          Tel: [phone]
                          Fax: [phone]

                       E-mail: [e-mail]"
              DESCRIPTION
                      "The MIB module for entities implementing the xxxx
                      protocol."
              REVISION      "9210070433Z"
              DESCRIPTION
                      "Initial version of this MIB module."
          -- contact IANA for actual number
              ::= { experimental xx }


          END













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          6.  Mapping of the OBJECT-IDENTITY macro

          The OBJECT-IDENTITY macro is used to define information about
          an OBJECT IDENTIFIER assignment.  It should be noted that the
          expansion of the OBJECT-IDENTITY macro is something which
          conceptually happens during implementation and not during
          run-time.


          6.1.  Mapping of the STATUS clause

          The STATUS clause, which must be present, indicates whether
          this definition is current or historic.

          The values "current", and "obsolete" are self-explanatory.


          6.2.  Mapping of the DESCRIPTION clause

          The DESCRIPTION clause, which must be present, contains a
          textual description of the object assignment.


          6.3.  Mapping of the REFERENCE clause

          The REFERENCE clause, which need not be present, contains a
          textual cross-reference to an object assignment defined in
          some other information module.


          6.4.  Mapping of the OBJECT-IDENTITY value

          The value of an invocation of the OBJECT-IDENTITY macro is an
          OBJECT IDENTIFIER.
















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          6.5.  Usage Example

          Consider how an OBJECT IDENTIFIER assignment might be made:
          e.g.,

          fizbin69 OBJECT-IDENTITY
              STATUS  current
              DESCRIPTION
                      "The authoritative identity of the Fizbin 69
                      chipset."
              ::= { fizbinChipSets 1 }







































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