rfc1646.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

                               R = 0XD9
                               S1 = Status/Sense Byte 0
                               S2 = Status/Sense Byte 1
                               IAC = Telnet IAC Character
                               EOR = Telnet EOR Character

5.1   Status/Sense Byte description

5.1.1.  S/S Byte 0:

        High Order                                          Low Order


        _____________________________________________________________
        |                                                           |
        |   0      1      2      3      4      5      6      7      |
        |___________________________________________________________|


          Bit Number:       Bit Definition:

                0           Always Zero

                1           Always Zero



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                2           Always Zero

                3           Always Zero

                4           Always Zero

                5           Unit Specify - is set due to an error
                            condition.  The reason for the error
                            condition will be indicated in S/S Byte 1.
                            See Note 1*.

                6           Device End - when this bit sent in response
                            to a data message it indicates the client
                            has successfully processed the data message
                            from the server and notifies the server to
                            send a new data message to the client when
                            available.   See Note 2*.

                7           Always Zero


   Note 1*:   A negative response to the Server's data message would be
   S/S Byte 0 Bit 5 "Unit Specify condition".  The possible Unit Specify
   conditions are listed below.  (See Section 3.2 for bit settings for
   the Unit Specify conditions listed below.)

                Unit Specify Condition:    SNA Sense Code sent to host:

                Command Rejected                     0X10030000
                Intervention Required                0X08020000
                Data Check                           0X10010000
                Operation Check                      0X10050000
                Component Disconnected (LU)          0X08020000

   Note 2*:   Device End -  A positive response to the Server's data
   message would be the "Device End" bit (S/S Byte 0 Bit 6) to indicate
   a ready to receive data from the host condition.  This will also be
   sent after clearing a previous Unit Specify condition of
   "Intervention Required".












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5.1.2.  S/S Byte 1:

         High Order                                           Low Order

       ______________________________________________________________
       |                                                            |
       |    0      1      2      3      4      5      6      7      |
       |____________________________________________________________|


          Bit Number:       Bit Definition:


               0            Always Zero

               1            Always Zero

               2            Command Rejected (CR) -- This bit
                            indicates an invalid 3270 command
                            generated.

               3            Intervention Required - Printer Not Ready.
                            See Note 3*.

               4            Component Disconnected - Printer is powered
                            off or printer cable not connected.  See
                            Note 4*.

               5            Data Check - Invalid print data

               6            Always Zero

               7            Operation Check - An illegal buffer address
                            or incomplete order sequence

   Note 3*:  The Intervention Required is cleared by sending an S/S
   message with the "Device End" bit (Bit 6 of S/S byte  0).  The LUSTAT
   sent to the host is 0X00010000.  The IBM host interprets this as a
   "printer now ready" condition.

   Note 4*:  The Component disconnected is cleared by sending an S/S
   message with the "Device End" bit  (Bit 6 of S/S byte 0).  The LUSTAT
   sent to the host is 0X082B0000.  The IBM host interprets this as a
   "printer now ready -- presentation space integrity may be lost"
   condition.






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6.  The following is an example of the Client-Server negotiation
    process.

      Server:   IAC DO TERMINAL-TYPE
      Client:        IAC WILL TERMINAL-TYPE
      Server:   IAC SB TERMINAL-TYPE SEND IAC SE
      Client:        IAC SB TERMINAL-TYPE IS IBM-3287-1 IAC SE

      Note: To request a specific LU the TERMINAL-TYPE string would be:
      IAC SB TERMINAL-TYPE IS IBM-3287-1 @ LUNAME IAC SE
      (The client has specified its terminal type is an IBM-3287-1)


      Server:   IAC DO END-OF-RECORD
      Client:        IAC WILL END-OF-RECORD
      Server:   IAC WILL END-OF-RECORD
      Client:        IAC DO END-OF-RECORD

      (The Server and Client have both agreed to transmit End-Of-Record
      (EOR)).


      Server:   IAC DO TRANSMIT-BINARY
      Client:        IAC WILL TRANSMIT-BINARY
      Server:   IAC WILL TRANSMIT-BINARY
      Client:        IAC DO TRANSMIT-BINARY
      (The Server and Client have both agreed to use binary
      transmission)


      Server:   0x00 (3270 PRINT DATA)
      Client:        (S/S with DEV END) IAC EOR
      Server:   0x00 (3270 PRINT DATA) IAC EOR

      NOTE:  LU 1 type data is prefaced with a 0x00 character. LU 3
      type data is not prefaced with a special character.  This
      character will precede print data in each chain, and should be
      discarded before the print data is processed.   An <IAC EOR> must
      be received before changing to LU 1 or LU 3 type data.

      Client:        (S/S with IR) IAC EOR (This indicates a paper jam
                    at printer.)
      Client:        (S/S with DE) IAC EOR (This indicates the clearing
                    of above condition.)
      Server:  0x00 (3270 PRINT DATA) (This indicates start of LU 1
               data)

      Server:   (3270 PRINT DATA)



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      Server:   (3270 PRINT DATA)
      Server:   (3270 PRINT DATA) IAC EOR
      Client:        (S/S with DE) IAC EOR
      Server:   0x00 (LAST 3270 PRINT DATA) IAC EOR


      Client:        (S/S with DE) IAC EOR
      Server:   IAC AO
      (The Abort Output <AO> signifies the end-of-bracket -- end of
      print job)

7.  SECURITY CONSIDERATIONS

   This document does not specify a security methodology to insure that
   the client requesting a printer LU name is authorized to access that
   LU.  Currently, this is left up to individual server implementations.
   The design of the protocols described in this document allow for the
   future incorporation of the RFCs regarding encryptions and
   authentication protocols and services.  However, before this may
   occur, certain extensions may be required to the protocols defined in
   this document or to the encryptions and authentication services and
   protocols.

8. ERROR CONDITIONS

   After a client and server have successfully completed negotiation, a
   number of potential error conditions may be detected by the server
   which require notifying the client and aborting the connection.

   When an error condition is detected by the server, the client must be
   negotiated back into NVT mode by the server sending a "WONT/DONT
   BINARY" TELNET sequence and the client responding with the
   appropriate "DONT/WONT BINARY" TELNET sequence.

   The server should immediately send the appropriate error message to
   the client as an ASCII string and then close the connection. The
   error message should be prefixed by a numeric identifier to precisely
   notify the client of the specific error condition. The error message
   sent to the client should be routed to the proper console or log for
   corrective action.

   Below is a list of error conditions identified by numeric value,
   error text, meaning of the error and recovery procedure.

      Message: "01 No LU's of the type configured"

         Meaning: The configuration definition on the server
                  does not include the LU type requested.



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         Recovery: Notify your Systems Administrator as this
                   is a permanent error condition.

      Message: "02 Requested LU unavailable"

         Meaning: The requested LU is not available at
                  this time.

         Recovery: This may be a temporary error and may
                   be retried periodically.  If the condition
                   persists contact your Systems Administrator.

      Message: "03 Requested LU type is inconsistent with configuration"

         Meaning: The LU requested does not match the terminal
                  type in the server configuration.

         Recovery: Notify your Systems Administrator as this
                   is a permanent error condition.

      Message: "04 Requested LU is not configured"

         Meaning: The LU is not defined in server configuration.

         Recovery: Notify your Systems Administrator as this
                   is a permanent error condition.

   When a client receives a message not defined in the above list, the
   message should be displayed to a console or log and the connection to
   the server should be closed.  No other recovery should be attempted
   as this is most likely a fatal error condition.  (Notify your Systems
   Administrator.)

9. REFERENCES

   [1] Postel, J., and J. Reynolds, "TELNET Protocol Specification", STD
       8, RFC 854, USC/Information Services Institute, May 1983.

   [2] VanBokkeln, J., "TELNET Terminal-Type Option" RFC 1091, FTP
       Software Inc., February 1989.

   [3] Postel, J., and J. Reynolds, "TELNET Binary Transmission", STD
       27, RFC 856, USC/Information Services Institute, May 1983.








Graves, Butts & Angel                                          [Page 12]

RFC 1646                   TN3270 Extensions                   July 1994


Authors' Addresses

       Cleve Graves
       2711 LBJ Freeway
       Dallas, Texas  75234

       Phone: [phone]
       EMail: [e-mail]


       Thomas Butts
       2711 LBJ Freeway
       Dallas, Texas  75234

       Phone: [phone]
       EMail: [e-mail]


       Michelle Angel
       2711 LBJ Freeway
       Dallas, Texas  75234

       Phone: [phone]
       EMail: [e-mail]



























Graves, Butts & Angel                                          [Page 13]