📄 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
---------------------->
Robert Informational [Page 8]
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Robert Informational [Page 9]
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) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Robert Informational [Page 10]
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 |
+--------------------------+
Robert Informational [Page 11]
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:
Robert Informational [Page 12]
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.
Robert Informational [Page 13]
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.
Robert Informational [Page 14]
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.
Robert Informational [Page 15]
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
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