rfc1031.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

Networking Working Group                                       W. Lazear
Request for Comments: 1031                                         MITRE
                                                           November 1987


                     MILNET NAME DOMAIN TRANSITION


STATUS OF THIS MEMO

   This RFC consolidates information necessary for the implementation of
   domain style names throughout the DDN/MILNET Internet community.
   Although no official policy has been published, the introduction of
   domain style names will impact all hosts in the DDN/MILNET Internet.
   The RFC is designed as an aid to implementors and administrators by
   providing 1) an overview of the transition process from host tables
   to domains, 2) a potential timetable for the transition, and 3)
   references to documentation and software relating to the DDN/ARPANET
   domain system.  Distribution of this RFC is unlimited.

BACKGROUND

   All MILNET hosts are expected to have a way of translating the name
   of any other host into its Internet address.  Although the current
   method of name resolution is to look up the information in a table of
   all hosts, this method of operation is cumbersome and relies on a
   central point of information.  The Network Information Center (NIC)
   maintains a table of hosts registered in the MILNET Internet and
   their addresses.  The size of this table and the frequency of updates
   has reached the limits of manageability.  The central host table is
   FTP'd by a host on a timely basis from the NIC, processed locally (to
   pare or reformat the table), and used in name resolution.

   The domain system uses a distributed database and software to perform
   the same functions as the host table.  In this system, host resolvers
   query domain servers for name resolution.  They may cache answers for
   performance improvement.  The domain servers each maintain a portion
   of the hierarchical database under separate administrative authority
   and control.  Redundancy is obtained by transferring data between
   cooperating servers.

   The domain system has been operating successfully on the ARPANET for
   over a year.  One indication of success is that the NIC's central
   host table is no longer a complete list (i.e., ARPANET does not
   depend primarily on the host table).  The domain system is being
   implemented on the MILNET with DoD military standard protocols.  The
   first step in changing to the domain system has been taken, as
   required by DDN Management Bulletin #32 (22 Jan 1987).  All host



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RFC 1031                MILNET DOMAIN TRANSITION           November 1987


   names were converted from a simple, flat namespace to a structured
   name consistent with domains.  In the second step, servers acting as
   the root of the database hierarchy were put in place.  In the next
   step, hosts are moving away from host table usage.

MIGRATION PATH

   All hosts will not change from host table to domain server usage at
   one time.  Accordingly, three stages of conversion to the domain
   system are envisaged.  These stages roughly correspond to 1)
   continuing to use the host table for all applications, 2) using the
   domain system for only some applications, and 3) using the domain
   system for all applications.  These stages will exist simultaneously
   as various hosts convert their application software according to
   available resources.  The following paragraphs discuss these stages
   in more detail.

   Host Table Only

      In the first stage, a host depends entirely on the host table for
      name resolution.  The table is obtained from the NIC's central
      copy and the resolution is done by local table scanning.  Most
      hosts are in this stage.

      Certain hosts may find it infeasible ever to convert to the domain
      system, owing to older architectures, unchangeable software, or
      other considerations.  At the end of the conversion period, the
      NIC will stop maintaining an internet host table.  To continue
      operations, hosts that do not convert will need to obtain an
      equivalent of the host table from some source.  This source may be
      another host with which a bilateral agreement has been negotiated
      offline, a community-of-interest host acting as central repository
      for that community, or a locally-maintained table of host names
      and addresses.  Transfer of the table from the source is a matter
      of local implementation and bilateral agreements.

   Domain System and Host Table

      In the second stage, a host will use both the host table and the
      domain system.  A likely scenario is that applications like TELNET
      and FTP will use the domain system and that MAIL will continue to
      use the host table for name resolution.  An alternate scenario is
      that batchstyle applications like MAIL would use the domain system
      and that the interactive applications would convert later.

      This stage is viewed as transitory, as hosts convert over to use
      the domain system exclusively.  It is highlighted as a separate
      stage to emphasize the need during transition for both the host



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RFC 1031                MILNET DOMAIN TRANSITION           November 1987


      table and the domain system.

   Domain System Only

      In the third and final stage, a host will have completed
      conversion and will be using the domain system exclusively.  This
      includes correct processing of the mailbox and mail exchanger
      resource records.

MIGRATION TIMETABLE

   Table 1 shows the events and dates involved in the MILNET transition
   from host table to domain system.  The operational testing of the
   root server software has been completed.  Voluntary conversion can
   begin immediately, with mandatory conversion required by October
   1989.  After this date, hosts not converted need to obtain the host
   table equivalent by private arrangement (see "Migration Path" above).

                                                      Start     End
        Milestone                                      Date     Date
        ===========================================   ======   ======
        Root server operational testing               Dec 86   Jul 87
        Policy announced in DDN Management Bulletin   Oct 87
        Host conversion                               Oct 87   Oct 89
        Host table discontinued                       Oct 89

                       MILNET Name Domain Timetable

                                  Table 1

DOCUMENTATION

   The Name Domain system is described in several documents that are
   maintained and available from the NIC in both online and in hardcopy
   form.  The documents are in "Request For Comments" format (RFC)
   commonly used in the Internet to document and discuss various
   networking issues.  The documents noted in Table 2 fully describe the
   concepts, conventions, enhancements, requirements, and operation of
   the Name Domain system.  The following paragraphs give a brief
   synopsis of each document.











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RFC 1031                MILNET DOMAIN TRANSITION           November 1987


     RFC    PH   DOCUMENT TITLE
     ===    ==   =======================================================

      799   *    Internet Name Domains
      819        Domain Naming Convention for Internet User Applications
      920        Domain Requirements
      921        Domain Name System Implementation Schedule - Revised
      952   *    Internet Host Table Specification
      953   *    Hostnames Server
      974        Mail Routing and the Domain System
     1032        Domain Administrators Guide
     1033        Domain Administration Operations Guide
     1034        Domain Names - Concepts and Facilities
     1035        Domain Names - Implementation Specification

   *  Included in the DDN Protocol Handbook

                           Name Domain Documents

                                  Table 2

   RFC-799

      This RFC is an early description of the concepts of a name domain
      system. It is exploratory in nature and offers scenarios for name
      resolution and mail forwarding.

   RFC-819

      This RFC is a think peice about hierarchical naming conventions
      for internetworking applications.  The conventions proposed are
      aligned along administrative rather than topological boundaries
      and is designed for interoperation among heterogeneous naming
      environments.  Further topics of discussion include mail relaying,
      name service approaches, and naming authorities.

   RFC-920

      This RFC contains a policy statement on the requirements of
      establishing a new domain in the ARPA Internet and introduces the
      limited set of top level domains.

   RFC-921

      This RFC contains a policy statement on the implementation
      schedule of the ARPA Internet domain system (as of October 1984).
      The discussion describes schedule and future operational
      scenarios, as well as the transition between the two.



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   RFC-952

      This RFC specifies the format of the host/address table maintained
      by the NIC.

   RFC-953

      This RFC contains the official specification of the Hostname
      Server Protocol.  This TCP-based protocol accesses machine-
      readable name/address information in the format described by RFC-
      952 and is used by hosts to obtain all or a portion of the
      centralized host table.

   RFC-974

      This RFC presents a description of how mail systems are expected
      to route messages based on domain system information.  In
      particular, it discusses how mailers should interpret mail
      exchanger resource records for message routing to both host and
      domain names.

   RFC-1032

      This RFC describes the guidelines for a domain administrator to
      follow to establish a new domain.

   RFC-1033

      This RFC provides procedures for domain administrators in
      operating a domain server and maintaining their portion of the
      hierarchical database.

   RFC-1034

      This RFC introduces domain style names, their use for ARPA
      Internet mail and host address support, and the protocols and
      servers used to implement domains.  The concepts and facilities of
      the domain system are described.  The RFC also discusses the
      hierarchical database model, resource record usage, query
      formation, query resolution, and domain control.

   RFC-1035

      This RFC specifies the format of domain system transactions,
      discusses the implementation of domain servers, and explores the
      use of domain names in the context of mail and other network
      software.




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RFC 1031                MILNET DOMAIN TRANSITION           November 1987