rfc2351.txt

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   - Open Confirm (OC) to confirm the SO command.
   - Session close (SC) to close the current session.

   A MATIP session can be up only if the associated TCP connection is
   up.  However it is not mandatory to close the TCP connection when
   closing the associated MATIP session.

   Typical exchange is:

                      TCP session establishment

             Session Open --------->
                            <-----------   Open confirm
                          data exchange
             ---------------------->



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RFC 2351                         MATIP                          May 1998


                             <-------------------------
                             .
                             .
                             .
    Session Close ----------------->
                             .
                             .
                             .
                              <-------------------------   Session Open
   Open confirm ------------------->
                        data exchange
                               <-------------------------
             ---------------------->

   The Session Open command may contain configuration elements. An
   Session Open command received on a session already opened (i.e., same
   IP address and port number) will automatically clear the associated
   configuration and a new configuration will be set up according to the
   information contained in the new open session command.

   As illustrated above, the open and close commands are symmetrical.

   For type A conversational traffic, the SO and OC commands contain
   information for the identification of the ASCUs and the session.
   ASCUs are identified within a session by two or 4 bytes. A flag is
   set to indicate if the ASCU is identified by 4 bytes (H1H2A1A2) or by
   2 bytes (A1A2). In the latter case, H1H2 is reserved for session
   identification.

   The SO command is sent to open the MATIP session. In Type A
   conversational it may contains the list of ASCUs configured in this
   session.

   The OC command confirms the SO command. It can refuse or accept it,
   totally or conditionally. In Type A, it contains the list of the
   ASCUs either rejected or configured in the session.

7. OVERALL PACKET FORMAT FOR TYPE A & TYPE B

   The first 4 bytes of the MATIP header follow the following rules.

     0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0|0|0|0|0| Ver |C|     Cmd     |            length             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+





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RFC 2351                         MATIP                          May 1998


   Ver
   The `Ver' (Version) field represents the version of the MATIP. It
   must contain the value 001 otherwise the packet is considered as
   invalid.

   C
   Identifies a CONTROL packet.
     When set to 1, the packet is a Control packet
     When set to 0, the packet is a Data packet

   Cmd
   This field identifies the control command if the flag C is set to 1.

   Length
   This field indicates the number of bytes of the whole packet, header
   included.

   Notes : Fields identified as optional (Opt) are not transmitted if
   not used.

8. MATIP FORMAT FOR TYPE A CONVERSATIONAL TRAFFIC

8. 1 Control Packet Format

   There are 3 control packets to open or close the session at the MATIP
   level.

8.1.1 Session Open format (SO)

   To be able to identify the session and before sending any data
   packets, a Session Open command is sent. It can be initiated by
   either side. In case of collision, the open session from the side
   having the lower IP address is ignored.

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |0|0|0|0|0| Ver |1|1 1 1 1 1 1 0|           length              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |0 0|0 1|0| CD  | STYP  |0 0 0 0|       RFU     |MPX|HDR| PRES. |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |      H1       |      H2       |           RFU                 |
      |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   Reserved    |              RFU              | Nbr of ASCUs  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Nbr of ASCUs |        ASCU list (opt)                        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+




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RFC 2351                         MATIP                          May 1998


   RFU
   Reserved for future use. Must be set to zero.

   CD
   This field specifies the Coding
      000 : 5 bits (padded baudot)
      010 : 6 bits (IPARS)
      100 : 7 bits (ASCII)
      110 : 8 bits (EBCDIC)
      xx1 : R.F.U

   STYP
   This is the traffic subtype (type being TYPE A).
      0001 : TYPE A Conversational

   MPX
   This flag specifies the multiplexing used within the TCP session.
   Possible values are:
      00 : Group of ASCU with 4 bytes identification per ASCU (H1H2A1A2)
      01 : Group of ASCUs with 2 bytes identification per ASCU (A1A2)
      10 : single ASCU inside the TCP session.


   HDR
   This field specifies which part of the airline's specific address is
   placed ahead of the message texts transmitted over the session.
   Possible values are:
      00 : ASCU header = H1+H2+A1+A2
      01 : ASCU Header = A1+A2
      10 : No Header
      11 : Not used

   The MPX and HDR must be coherent. When ASCUs are multiplexed, the data
   must contain the ASCU identification. The table below summarizes the
   allowed combinations:

       +--------------------------+
       |       MPX | 00 | 01 | 10 |
       +--------------------------+
       | HDR       |              |
       | 00        | Y  | Y  | Y  |
       | 01        | N  | Y  | Y  |
       | 10        | N  | N  | Y  |
       +--------------------------+







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RFC 2351                         MATIP                          May 1998


   PRES
   This field indicates the presentation format
      0001 : P1024B presentation
      0010 : P1024C presentation
      0011 : 3270 presentation


   H1 H2
   These fields can logically identify the session if MPX is not equal to
   00. When this field is not used, it must be set to 0. If used in
   session (MPX <> 0) with HDR=00, H1H2 in data packet must have the same
   value as set in SO command.

   Nbr of ASCUs
   Nbr_of_ASCUs field is mandatory and gives the number of ASCUs per
   session. A 0 (zero) value means unknown. In this case the ASCU list is
   not present in the `Open Session' command and must be sent by the
   other end in the `Open Confirm' command.

   ASCU LIST
   Contains the list of identifier for each ASCU. If MPX=00 it has a
   length of four bytes (H1H2A1A2) for each ASCU, otherwise it is two
   bytes (A1A2).

8.1.2 Open Confirm format (OC)

   The OC (Open Confirm) command is a response to an SO (Session Open)
   command and is used to either refuse the session or accept it
   conditionally upon checking hte configuration of each ASCU.

   In case of acceptance, the OC indicates the number and the address of
   the rejected ASCUs, if any. Alternatively, it indicates the list of
   ASCUs configured for that MATIP session if the list provided by the
   SO command was correct or the number of ASCUs configured in the
   session was unknown (n. of ASCU equals 0).

8.1.2.1 Refuse the connection

     0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0|0|0|0|0| Ver |1|1 1 1 1 1 0 1|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     cause     |
     +-+-+-+-+-+-+-+-+

   Cause
   This field indicates the reason for the MATIP session refusal:



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RFC 2351                         MATIP                          May 1998


       0 0 0 0 0 0 0 1 : No Traffic Type matching between Sender &
           Recipient
       0 0 0 0 0 0 1 0 : Information in SO header incoherent

       1 0 0 0 0 1 0 0
           up to       : Application dependent
       1 1 1 1 1 1 1 1

       Other values reserved.

8.1.2.2 Accept the connection

     0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0|0|0|0|0| Ver |1|1 1 1 1 1 0 1|            length             |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0 0 R 0 0 0 0 0| Nbr of ASCUs  |Nbr of ASCU(opt|  ASCU LIST    |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   R
   Flag indicating an error in the ASCU configuration provided in the SO
   command.

   NBR of ASCUs
   If the MPX value is equal to 00 in the SO command, this field is two
   bytes long. Otherwise, it is one byte.
   If the R flag is set, the Nbr_of_ASCUs field represents the number of
   ASCUs in error. Otherwise, it indicates the number of ASCUs configured
   for that MATIP session.

   Notes: The length of this field is either one or two bytes. In the SO
   command, the length is always two bytes. This discrepancy comes from
   backward compatibility with AX25 (see chapter 4). In the SO command,
   it is possible to use a free byte defined in the AX25 call user data.
   Unfortunately, there is no such free byte in the AX25 clear user
   data.

   ASCU LIST
   Depending on the R flag, this field indicates the list of ASCUs  (A1A2
   or H1H2A1A2) either in error or within the session.






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RFC 2351                         MATIP                          May 1998


8.1.3 Session Close (SC)

   The SC (Session Close) command is used to close an existing MATIP
   session.

     0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0|0|0|0|0| Ver |1|1 1 1 1 1 0 0|0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Close  Cause  |
     +-+-+-+-+-+-+-+-+

   Close Cause
   Indicates the reason for the session closure:

       0 0 0 0 0 0 0 0 : Normal Close

       1 0 0 0 0 1 0 0
            up to      : Application dependent
       1 1 1 1 1 1 1 1

       Other values reserved.

8.2 Data Packet Format


     0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0|0|0|0|0| Ver |0|0 0 0 0 0 0 0|          length               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                         ID (optional)                         |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     |                         Payload                               |
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   ID
   This field is optional and has a different length and format
   according to the value of HDR, PRES indicated during the session
   establishment.








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RFC 2351                         MATIP                          May 1998


     +------------------------------+-------------------------------+
     |HDR |  PRES = P1024B and 3270 |     PRES = P1024C             |
     +------------------------------+-------------------------------+
     |00  |ID = 4 bytes H1-H2-A1-A2 | ID = 5 bytes H1-H2-A1-0x01-A2 |
     +------------------------------+-------------------------------+
     |01  |ID = 2 bytes A1-A2       | ID = 3 bytes A1-0x01-A2       |
     +------------------------------+-------------------------------+
     |10  |ID = 0 bytes             | ID = 0 bytes                  |
     +------------------------------+-------------------------------+

   H1, H2 value must match the value given in the SO command if MPX is
   different from 0.

   Payload
   payload begins with the terminal identification:
      - One byte Terminal identifier (TA) in P1024B
      - Two bytes SID/DID Terminal identifier in P1024C.

9. MATIP FORMAT FOR TYPE A HOST-TO-HOST TRAFFIC

9. 1 Control Packet Format

   There are 3 control packets to open or close the session at the MATIP
   level.

9.1.1 Session Open format (SO)

   To be able to identify the session and before sending any data
   packet, a Session Open command is sent. It can be initiated by either
   side. In case of collision, the open session from the side having the
   lower IP address is ignored.

      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0|0|0|0|0| Ver |1|1 1 1 1 1 1 0|     length                    |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |0 0|0 1|0| CD  | STYP  |0 0 0 0|       RFU     |MPX|HDR|0 0 0 0|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |      H1       |      H2       |           RFU                 |
     |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |   Flow ID(opt)|
     +-+-+-+-+-+-+-+-+

   RFU
   Reserved for future use. Must be set to zero.





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RFC 2351                         MATIP                          May 1998


   CD
   This field specifies the Coding, as defined in section 8.1.1.1.

   STYP
   This is the traffic subtype (type being Type A).
   0010 : TYPE A IATA Host to Host
   1000 : SITA Host to Host

   MPX
   This flag specifies the multiplexing used within the MATIP session in
   TYPE A SITA host to host. Possible values are:

   00 : irrelevant
   01 : multiple flow inside the TCP connection
   10 : single flow inside the TCP connection