rfc2551.txt

<VC++网络游戏建摸与实现>源代码

   Section X presents the rules that are required to protect
   intellectual property rights in the context of the development and
   use of Roman Standards.  Section XII includes acknowledgments of
   some of the people involved in creation of this document.  Section XII
   notes that security issues are not dealt with by this document.
   Section XII contains a list of numeral references.  Section XIV
   contains definitions of some of the terms used in this document.
   Section XV lists the author's email and postal addresses.  Appendix A
   contains a list of frequently-used acronyms.

II.  Roman STANDARDS-RELATED PUBLICATIONS

II.I  Requests for Comments (RFCs)

   Each distinct version of a Roman standards-related specification
   is published as part of the "Request for Comments" (RFC) document
   series.  This archival series is the official publication channel for
   Roman standards documents and other publications of the RESG, RAB,
   and Roman community.  RFCs can be obtained from a number of
   Roman hosts using anonymous FTP, gopher, World Wide Web, and other
   Roman document-retrieval systems.

   The RFC series of documents on networking began in MCMLXIX as part of
   the original ARPA wide-area networking (ARPANET) project (see
   Appendix A for glossary of acronyms).  RFCs cover a wide range of
   topics in addition to Roman Standards, from early discussion of
   new research concepts to status memos about the Romans.  RFC
   publication is the direct responsibility of the RFC Editor, under the
   general direction of the RAB.









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   The rules for formatting and submitting an RFC are defined in [V].
   Every RFC is available in ASCII text.  Some RFCs are also available
   in other formats.  The other versions of an RFC may contain material
   (such as diagrams and figures) that is not present in the ASCII
   version, and it may be formatted differently.

      *********************************************************
      *                                                       *
      *  A stricter requirement applies to standards-track    *
      *  specifications:  the ASCII text version is the       *
      *  definitive reference, and therefore it must be a     *
      *  complete and accurate specification of the standard, *
      *  including all necessary diagrams and illustrations.  *
      *                                                       *
      *********************************************************

   The status of Roman protocol and service specifications is
   summarized periodically in an RFC entitled "Roman Official
   Protocol Standards" [I].  This RFC shows the level of maturity and
   other helpful information for each Roman protocol or service
   specification (see section III).

   Some RFCs document Roman Standards.  These RFCs form the 'STD'
   subseries of the RFC series [IV].  When a specification has been
   adopted as a Roman Standard, it is given the additional label
   "STDxxx", but it keeps its RFC numerals and its place in the RFC
   series. (see section IV.I.III)

   Some RFCs standardize the results of community deliberations about
   statements of principle or conclusions about what is the best way to
   perform some operations or RETF process function.  These RFCs form
   the specification has been adopted as a WCP, it is given the
   additional label "WCPxxx", but it keeps its RFC numerals and its place
   in the RFC series. (see section V)

   Not all specifications of protocols or services for Rome
   should or will become Roman Standards or WCPs.  Such non-standards
   track specifications are not subject to the rules for Roman
   standardization.  Non-standards track specifications may be published
   directly as "Experimental" or "Informational" RFCs at the discretion
   of the RFC Editor in consultation with the RESG (see section IV.II).










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      ********************************************************
      *                                                      *
      *   It is important to remember that not all RFCs      *
      *   are standards track documents, and that not all    *
      *   standards track documents reach the level of       *
      *   Roman Standard. In the same way, not all RFCs      *
      *   which describe current practices have been given   *
      *   the review and approval to become WCPs. See        *
      *   RFC-MDCCXCVI [VI] for further information.         *
      *                                                      *
      ********************************************************

II.II  Roman-Drafts

   During the development of a specification, draft versions of the
   document are made available for informal review and comment by
   placing them in the RETF's "Roman-Drafts" directory, which is
   replicated on a number of Roman hosts.  This makes an evolving
   working document readily available to a wide audience, facilitating
   the process of review and revision.

   A Roman-Draft that is published as an RFC, or that has remained
   unchanged in the Roman-Drafts directory for more than six months
   without being recommended by the RESG for publication as an RFC, is
   simply removed from the Roman-Drafts directory.  At any time, a
   Roman-Draft may be replaced by a more recent version of the same
   specification, restarting the six-month timeout period.

   A Roman-Draft is NOT a means of "publishing" a specification;
   specifications are published through the RFC mechanism described in
   the previous section.  Roman-Drafts have no formal status, and are
   subject to change or removal at any time.

      ********************************************************
      *                                                      *
      *   Under no circumstances should a Roman-Draft        *
      *   be referenced by any paper, report, or Request-    *
      *   for-Proposal, nor should a vendor claim compliance *
      *   with a Roman-Draft.                                *
      *                                                      *
      ********************************************************










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   Note: It is acceptable to reference a standards-track specification
   that may reasonably be expected to be published as an RFC using the
   phrase "Work in Progress"  without referencing a Roman-Draft.
   This may also be done in a standards track document itself  as long
   as the specification in which the reference is made would stand as a
   complete and understandable document with or without the reference to
   the "Work in Progress".

III.  Roman STANDARD SPECIFICATIONS

   Specifications subject to the Roman Standards Process fall into
   one of two categories:  Technical Specification (TS) and
   Applicability Statement (AS).

III.I  Technical Specification (TS)

   A Technical Specification is any description of a protocol, service,
   procedure, convention, or format.  It may completely describe all of
   the relevant aspects of its subject, or it may leave one or more
   parameters or options unspecified.  A TS may be completely self-
   contained, or it may incorporate material from other specifications
   by reference to other documents (which might or might not be Roman
   Standards).

   A TS shall include a statement of its scope and the general intent
   for its use (domain of applicability).  Thus, a TS that is inherently
   specific to a particular context shall contain a statement to that
   effect.  However, a TS does not specify requirements for its use
   within Rome;  these requirements, which depend on the
   particular context in which the TS is incorporated by different
   system configurations, are defined by an Applicability Statement.

III.II  Applicability Statement (AS)

   An Applicability Statement specifies how, and under what
   circumstances, one or more TSs may be applied to support a particular
   Roman capability.  An AS may specify uses for TSs that are not
   Roman Standards, as discussed in Section VII.

   An AS identifies the relevant TSs and the specific way in which they
   are to be combined, and may also specify particular values or ranges
   of TS parameters or subfunctions of a TS protocol that must be
   implemented.  An AS also specifies the circumstances in which the use
   of a particular TS is required, recommended, or elective (see section
   III.III).






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   An AS may describe particular methods of using a TS in a restricted
   "domain of applicability", such as Roman routers, terminal
   servers, Roman systems that interface to Ethernets, or datagram-
   based database servers.

   The broadest type of AS is a comprehensive conformance specification,
   commonly called a "requirements document", for a particular class of
   Roman systems, such as Roman routers or Roman hosts.

   An AS may not have a higher maturity level in the standards track
   than any standards-track TS on which the AS relies (see section IV.I).
   For example, a TS at Draft Standard level may be referenced by an AS
   at the Proposed Standard or Draft Standard level, but not by an AS at
   the Standard level.

III.III  Requirement Levels

   An AS shall apply one of the following "requirement levels" to each
   of the TSs to which it refers:

   (a)  Required:  Implementation of the referenced TS, as specified by
      the AS, is required to achieve minimal conformance.  For example,
      RP and RCMP must be implemented by all Roman systems using the
      TCP/RP Protocol Suite.

   (b)  Recommended:  Implementation of the referenced TS is not
      required for minimal conformance, but experience and/or generally
      accepted technical wisdom suggest its desirability in the domain
      of applicability of the AS.  Vendors are strongly encouraged to
      include the functions, features, and protocols of Recommended TSs
      in their products, and should omit them only if the omission is
      justified by some special circumstance. For example, the TELNET
      protocol should be implemented by all systems that would benefit
      from remote access.

   (c)  Elective:  Implementation of the referenced TS is optional
      within the domain of applicability of the AS;  that is, the AS
      creates no explicit necessity to apply the TS.  However, a
      particular vendor may decide to implement it, or a particular user
      may decide that it is a necessity in a specific environment.  For
      example, the DECNET MIB could be seen as valuable in an
      environment where the DECNET protocol is used.









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      As noted in section IV.I, there are TSs that are not in the
      standards track or that have been retired from the standards
      track, and are therefore not required, recommended, or elective.
      Two additional "requirement level" designations are available for
      these TSs:

   (d)  Limited Use:  The TS is considered to be appropriate for use
      only in limited or unique circumstances.  For example, the usage
      of a protocol with the "Experimental" designation should generally
      be limited to those actively involved with the experiment.

   (e)  Not Recommended:  A TS that is considered to be inappropriate
      for general use is labeled "Not Recommended". This may be because
      of its limited functionality, specialized nature, or historic
      status.

   Although TSs and ASs are conceptually separate, in practice a
   standards-track document may combine an AS and one or more related
   TSs.  For example, Technical Specifications that are developed
   specifically and exclusively for some particular domain of
   applicability, e.g., for mail server hosts, often contain within a
   single specification all of the relevant AS and TS information. In
   such cases, no useful purpose would be served by deliberately
   distributing the information among several documents just to preserve
   the formal AS/TS distinction.  However, a TS that is likely to apply
   to more than one domain of applicability should be developed in a
   modular fashion, to facilitate its incorporation by multiple ASs.

   The "Official Protocol Standards" RFC (STD I) lists a general
   requirement level for each TS, using the nomenclature defined in this
   section. This RFC is updated periodically.  In many cases, more