Message switching in APPC conversations

With the system service DFSAPPC, you can transfer messages between separate LU 6.2 devices and between an LU 6.2 device and another terminal supported by IMS TM. Message delivery with DFSAPPC is asynchronous, so messages are held on the IMS TM message queue until they can be delivered.

To send a message with DFSAPPC, specify the logical terminal name of an IMS TM terminal or the Transaction Program (TP) name of an LU 6.2 device.

DFSAPPC format

The message format for DFSAPPC is as follows:

DFSAPPC (options)user_data

DFSAPPC can be coded as follows:

A blank (b) is required between DFSAPPC and the specified options.

Blanks are valid within the specified options except within keywords or values. Either commas or blanks can be used as delimiters between options, but because the use of commas is valid, the TP name must be followed by at least one blank.

If an LU 6.2 conversation has not been established from other sources (for example, during a CPI-C driven application program), DFSAPPC is used to establish the conversation with a partner LU 6.2 device. If no options are specified with DFSAPPC, IMS TM default options are used.

Option keywords

LTERM=: Specifies the LTERM name of an IMS TM logical terminal. An LTERM name can contain up to eight alphanumeric or national (@, $, #) characters. If you specify LTERM, you cannot specify the other option keywords.
LU=: Specifies the LU name of the partner in an LU 6.2 conversation. The LU name can contain up to eight alphanumeric or national characters, but the first character must be a letter or a national character. If both LU and SIDE options are specified, LU overrides the LU name contained in the side information entry but does not change that LU name.
If the LU name is a network-qualified name, it can be up to 17 characters long and consist of the network ID of the originating system, followed by a '.', and the LU name (for example, netwrkid.luname). The LU name and the network ID can be up to eight characters long.
MODE=: Specifies the MODE name of the partner in an LU 6.2 conversation. The MODE name can contain up to eight alphanumeric or national characters, but the first character must be a letter or a national character. If both MODE and SIDE option keywords are specified, MODE overrides the MODE name contained in the side information entry but does not change that MODE name.
TPN=: Specifies the transaction program (TP) name of the partner in an LU 6.2 conversation. The TP name can contain up to 64 characters from the 00640 character set. Because the character set allows commas, at least one blank must follow the TP name. If both TPN and SIDE option keywords are specified, TPN overrides the TP name contained in the side information entry but does not change that name.
Related Reading: The CPI Communications Specification describes the 00640 character set, which contains all alphanumeric and national characters and 20 special characters.
SIDE=: Specifies the name of the side information entry for the partner in an LU 6.2 conversation. The side information entry name can contain up to eight characters from the 01134 character set. If the SIDE option keyword is specified, it can be overridden with LU, MODE, and TPN option keywords.
Related Reading: The CPI Communications Specification describes the 01134 character set, which contains the uppercase alphabet and the digits, 0-9.
SYNC=N|C: Specifies the synchronization level of the LU 6.2 conversation. N selects none as the synchronization level, and C selects confirm as the synchronization level.
TYPE=B|M: Specifies the conversation type for the LU 6.2 conversation. B selects a basic conversation type, and M selects a mapped conversation type.