rfc924.txt

RFC 相关的技术文档

      DEPENDENCIES: Internet Protocol

      CONTACT: [e-mail]









Reynolds & Postel                                               [Page 9]



Official ARPA-Internet Protocols                                 RFC 924


   Multiplexing Protocol  ---------------------------------------- (MUX)

      STATUS:  Experimental

      SPECIFICATION:  IEN 90

      COMMENTS:

         Defines a capability to combine several segments from different
         higher level protocols in one IP datagram.

         No current experiment in progress.  There is some question as
         to the extent to which the sharing this protocol envisions can
         actually take place.  Also, there are some issues about the
         information captured in the multiplexing header being (a)
         insufficient, or (b) over specific.

         Please discuss any plans for implementation or use of this
         protocol with the contact.

      OTHER REFERENCES:

      DEPENDENCIES: Internet Protocol

      CONTACT: [e-mail]

   Stream Protocol  ----------------------------------------------- (ST)

      STATUS:  Experimental

      SPECIFICATION:  IEN 119

      COMMENTS:

         A gateway resource allocation protocol designed for use in
         multihost real time applications.

         The implementation of this protocol has evolved and may no
         longer be consistent with this specification.  The document
         should be updated and issued as an RFC.

         Please discuss any plans for implementation or use of this
         protocol with the contact.

      OTHER REFERENCES:

      DEPENDENCIES: Internet Protocol

      CONTACT: [e-mail]


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Official ARPA-Internet Protocols                                 RFC 924


   Network Voice Protocol  ------------------------------------ (NVP-II)

      STATUS:  Experimental

      SPECIFICATION:  ISI Internal Memo

      COMMENTS:

         Defines the procedures for real time voice conferencing.

         The specification is an ISI Internal Memo which should be
         updated and issued as an RFC.

         Please discuss any plans for implementation or use of this
         protocol with the contact.

      OTHER REFERENCES:  RFC 741

      DEPENDENCIES:  Internet Protocol, Stream Protocol

      CONTACT:  [e-mail]

   Reliable Data Protocol  --------------------------------------- (RDP)

      STATUS:  Experimental

      SPECIFICATION:  RFC 908

      COMMENTS:

         This protocol is designed to efficiently support the bulk
         transfer of data for such host monitoring and control
         applications as loading/dumping and remote debugging.  The
         protocol is intended to be simple to implement but still be
         efficient in environments where there may be long transmission
         delays and loss or non-sequential delivery of message segments.

      OTHER REFERENCES:

      DEPENDENCIES:  Internet Protocol

      CONTACT:  [e-mail]









Reynolds & Postel                                              [Page 11]



Official ARPA-Internet Protocols                                 RFC 924


APPLICATION LEVEL

   Telnet Protocol  ------------------------------------------- (TELNET)

      STATUS:  Recommended

      SPECIFICATION:  RFC 854 (in "Internet Telnet Protocol and
      Options")

      COMMENTS:

         The protocol for remote terminal access.

         This has been revised since the IPTW.  RFC 764 in IPTW is now
         obsolete.

      OTHER REFERENCES:

         MIL-STD-1782 - Telnet Protocol and Options (TELNET)

      DEPENDENCIES:  Transmission Control Protocol

      CONTACT:  [e-mail]




























Reynolds & Postel                                              [Page 12]



Official ARPA-Internet Protocols                                 RFC 924


   Telnet Options  ------------------------------------ (TELNET-OPTIONS)

      STATUS:  Elective

      SPECIFICATION:  General description of options:  RFC 855
      (in "Internet Telnet Protocol and Options")

      Number   Name                                RFC  NIC  ITP APH USE
      ------   ---------------------------------   --- ----- --- --- ---
         0     Binary Transmission                 856 ----- yes obs yes
         1     Echo                                857 ----- yes obs yes
         2     Reconnection                        ... 15391  no yes  no
         3     Suppress Go Ahead                   858 ----- yes obs yes
         4     Approx Message Size Negotiation     ... 15393  no yes  no
         5     Status                              859 ----- yes obs yes
         6     Timing Mark                         860 ----- yes obs yes
         7     Remote Controlled Trans and Echo    726 39237  no yes  no
         8     Output Line Width                   ... 20196  no yes  no
         9     Output Page Size                    ... 20197  no yes  no
        10     Output Carriage-Return Disposition  652 31155  no yes  no
        11     Output Horizontal Tabstops          653 31156  no yes  no
        12     Output Horizontal Tab Disposition   654 31157  no yes  no
        13     Output Formfeed Disposition         655 31158  no yes  no
        14     Output Vertical Tabstops            656 31159  no yes  no
        15     Output Vertical Tab Disposition     657 31160  no yes  no
        16     Output Linefeed Disposition         658 31161  no yes  no
        17     Extended ASCII                      698 32964  no yes  no
        18     Logout                              727 40025  no yes  no
        19     Byte Macro                          735 42083  no yes  no
        20     Data Entry Terminal                 732 41762  no yes  no
        21     SUPDUP                          734 736 42213  no yes  no
        22     SUPDUP Output                       749 45449  no  no  no
        23     Send Location                       779 -----  no  no  no
        24     Terminal Type                       884 -----  no  no yes
        25     End of Record                       885 -----  no  no yes
       255     Extended-Options-List               861 ----- yes obs yes

                                                        (obs = obsolete)

      The ITP column indicates if the specification is included in the
      Internet Telnet Protocol and Options.  The APH column indicates if
      the specification is included in the ARPANET Protocol Handbook.
      The USE column of the table above indicates which options are in
      general use.

      COMMENTS:

         The Binary Transmission, Echo, Suppress Go Ahead, Status,
         Timing Mark, and Extended Options List options have been


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Official ARPA-Internet Protocols                                 RFC 924


         recently updated and reissued.  These are the most frequently
         implemented options.

         The remaining options should be reviewed and the useful ones
         should be revised and reissued.  The others should be
         eliminated.

         The following are recommended:  Binary Transmission, Echo,
         Suppress Go Ahead, Status, Timing Mark, and Extended Options
         List.

      OTHER REFERENCES:

      DEPENDENCIES: Telnet

      CONTACT: [e-mail]

   File Transfer Protocol  --------------------------------------- (FTP)

      STATUS:  Recommended

      SPECIFICATION:  RFC 765 (in IPTW)

      COMMENTS:

         The protocol for moving files between Internet hosts.  Provides
         for access control and negotiation of file parameters.

         There are a number of minor corrections to be made.  A major
         change is the deletion of the mail commands, and a major
         clarification is needed in the discussion of the management of
         the data connection.  Also, a suggestion has been made to
         include some directory manipulation commands (RFC 775).

         Even though the MAIL features are defined in this document,
         they are not to be used.  The SMTP protocol is to be used for
         all mail service in the Internet.

         Data Connection Management:

            a.  Default Data Connection Ports:  All FTP implementations
            must support use of the default data connection ports, and
            only the User-PI may initiate the use of non-default ports.

            b.  Negotiating Non-Default Data Ports:   The User-PI may
            specify a non-default user side data port with the PORT
            command.  The User-PI may request the server side to
            identify a non-default server side data port with the PASV
            command.  Since a connection is defined by the pair of


Reynolds & Postel                                              [Page 14]



Official ARPA-Internet Protocols                                 RFC 924


            addresses, either of these actions is enough to get a
            different data connection, still it is permitted to do both
            commands to use new ports on both ends of the data
            connection.

            c.  Reuse of the Data Connection:  When using the stream
            mode of data transfer the end of the file must be indicated
            by closing the connection.  This causes a problem if
            multiple files are to be transfered in the session, due to
            need for TCP to hold the connection record for a time out
            period to guarantee the reliable communication.  Thus the
            connection can not be reopened at once.

               There are two solutions to this problem.  The first is to
               negotiate a non-default port (as in (b) above).  The
               second is to use another transfer mode.

               A comment on transfer modes.  The stream transfer mode is
               inherently unreliable, since one can not determine if the
               connection closed prematurely or not.  The other transfer
               modes (Block, Compressed) do not close the connection to
               indicate the end of file.  They have enough FTP encoding
               that the data connection can be parsed to determine the
               end of the file.  Thus using these modes one can leave
               the data connection open for multiple file transfers.

               Why this was not a problem with the old NCP FTP:

                  The NCP was designed with only the ARPANET in mind.
                  The ARPANET provides very reliable service, and the
                  NCP counted on it.  If any packet of data from an NCP
                  connection were lost or damaged by the network the NCP
                  could not recover.  It is a tribute to the ARPANET
                  designers that the NCP FTP worked so well.

                  The TCP is designed to provide reliable connections
                  over many different types of networks and
                  interconnections of networks.  TCP must cope with a
                  set of networks that can not promise to work as well
                  as the ARPANET.  TCP must make its own provisions for
                  end-to-end recovery from lost or damaged packets.
                  This leads to the need for the connection phase-down
                  time-out.  The NCP never had to deal with
                  acknowledgements or retransmissions or many other
                  things the TCP must do to make connection reliable in
                  a more complex world.





Reynolds & Postel                                              [Page 15]



Official ARPA-Internet Protocols                                 RFC 924


         LIST and NLST:

            There is some confusion about the LIST an NLST commands, and
            what is appropriate to return.  Some clarification and
            motivation for these commands should be added to the
            specification.

      OTHER REFERENCES:

         RFC 678 - Document File Format Standards

         MIL-STD-1780 - File Transfer Protocol (FTP)

      DEPENDENCIES: Transmission Control Protocol

      CONTACT: [e-mail]

   Trivial File Transfer Protocol  ------------------------------ (TFTP)

      STATUS:  Elective

      SPECIFICATION:  RFC 783 (in IPTW)

      COMMENTS:

         A very simple file moving protocol, no access control is
         provided.

         This is in use in several local networks.

         Ambiguities in the interpretation of several of the transfer
         modes should be  clarified, and additional transfer modes could
         be defined.  Additional error codes could be defined to more
         clearly identify problems.

      OTHER REFERENCES:

      DEPENDENCIES: User Datagram Protocol

      CONTACT: [e-mail]











Reynolds & Postel                                              [Page 16]



Official ARPA-Internet Protocols                                 RFC 924


   Simple File Transfer Protocol  ------------------------------- (SFTP)

      STATUS:  Experimental

      SPECIFICATION:  RFC 913

      COMMENTS:

         SFTP is a simple file transfer protocol.  It fills the need of
         people wanting a protocol that is more useful than TFTP but
         easier to implement (and less powerful) than FTP.  SFTP
         supports user access control, file transfers, directory
         listing, directory changing, file renaming and deleting.

         SFTP can be implemented with any reliable 8-bit byte stream
         oriented protocol, this document describes its TCP
         specification.  SFTP uses only one TCP connection; whereas TFTP
         implements a connection over UDP, and FTP uses two TCP
         connections (one using the TELNET protocol).

         Please discuss any plans for implementation or use of this
         protocol with the contact.

      OTHER REFERENCES:

      DEPENDENCIES: Transmission Control Protocol

      CONTACT: [e-mail]

   Simple Mail Transfer Protocol  ------------------------------- (SMTP)

      STATUS:  Recommended

      SPECIFICATION:  RFC 821 (in "Internet Mail Protocols")

      COMMENTS:

         The procedure for transmitting computer mail between hosts.

         This has been revised since the IPTW, it is in the "Internet
         Mail Protocols" volume of November 1982.  RFC 788 (in IPTW) is
         obsolete.

         There have been many misunderstandings and errors in the early
         implementations.  Some documentation of these problems can be
         found in the file [ISIF]<SMTP>MAIL.ERRORS.

         Some minor differences between RFC 821 and RFC 822 should be
         resolved.


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Official ARPA-Internet Protocols                                 RFC 924


      OTHER REFERENCES:

         RFC 822 - Mail Header Format Standards

            This has been revised since the IPTW, it is in the "Internet
            Mail Protocols" volume of November 1982.  RFC 733 (in IPTW)
            is obsolete.  Further revision of RFC 822 is needed to
            correct some minor errors in the details of the
            specification.

         MIL-STD-1781 - Simple Mail Transfer Protocol (SMTP)

      DEPENDENCIES: Transmission Control Protocol

      CONTACT: [e-mail]

   Resource Location Protocol  ----------------------------------- (RLP)

      STATUS:   Elective

      SPECIFICATION:   RFC 887

      COMMENTS:

         A resource location protocol for use in the ARPA-Internet.