PeSIT PI code descriptions

This topic provides a description for each of the PeSIT parameter identifiers, PI, codes used with Transfer CFT.

About PeSIT PI codes

During the file transfer phase, as seen in How PeSIT works, messages called FPDU (File transfer Protocol Data Units) are exchanged between partners. Each FPDU comprises a header (six bytes) that specifies the type of data transferred. The body of the FPDUs comprises a series of parameter identifiers (PI) used to specify and negotiate all the transfer elements.

Each parameter PI has an assigned a number and value per the PeSIT protocol specifications. These PI codes are used for the session negotiation between partners.

Furthermore, each parameter group unit is identified by a numeric code named PGI (Parameters Group Identifier).

Parameter identifiers (PI) in the message body negotiate the session

For more information on the PeSIT protocol, refer to documentation published by the GSIT (Groupement pour un Système Interbancaire de Télécompensation).

Descriptions

PI 01 Use of a CRC (deprecated)

This field indicates the implementation of transmission error detection.

PI 02 PeSIT diagnostic code

Refer to Protocol diagnostic codes.

PI 03 Requester identification 

This field specifies the name of the Partner requesting the connection:

  • Establishing the protocol connection (FPDU CONNECT)

Format: 24 characters.

In requester mode, this field is defined using the local partner (NSPART) parameter of the partner object (CFTPART). It identifies the network name by which the Transfer CFT identifies itself to its partner.

In server mode, this field identifies the network name of the remote partner. It provides the local Transfer CFT with a search criterion for the remote user definition in the PARTNERS file, the equivalent to the remote partner (NRPART) parameter of the partner object (CFTPART).

  • Creating a file (FPDU CREATE)

Format: 24 characters

  • bytes 1 to 8: sending the application name
  • bytes 9 to 16: sending the user name
  • bytes 17 to 24: free field

In requester mode, the first two fields are respectively defined using the SAPPL and SUSER parameters of the SEND command. If the transfer command does not specify these parameters, the PI 3 code is not sent. The last free field is never defined by Transfer CFT.

In server mode, Transfer CFT recovers the PI 3 code in order to be able to define the &SAPPL and &SUSER symbolic variables. The free field is not used by Transfer CFT.

  • Selecting a file (FPDU SELECT)

As the PeSIT protocol imposes no constraints as to the contents of this PI code, Transfer CFT does not define or use it.

  • Sending a message (SEND TYPE = MESSAGE, ...)

The PI 3 code contains the same value as the one conveyed by the protocol connection request (FPDU CONNECT) previously required to send this message.

  • Sending an acknowledgement (SEND TYPE = REPLY, ...)

The PI 3 code contains the value of the PI 4 code conveyed by the file creation request (FPDU CREATE) whose receipt is acknowledged.

PI 03 Requester identification 

Format: 16 characters

This field specifies the connection requester Partner's name.

  • In requester mode, this field is defined using the local partner (NSPART) parameter of the partner object (CFTPART). It identifies the network name by which the requester Transfer CFT identifies itself to its partner.
  • In server mode, this field identifies the network name of the remote partner. It provides Transfer CFT with a criterion for searching for the remote user definition in the partner object (equivalent to the remote partner (NRPART) parameter of a partner object (CFTPART)).

PI 04 Server identification 

This field specifies the name of the connection server partner. It takes various formats depending on the PeSIT service used.

  • Establishing the protocol connection (FPDU CONNECT)

Format: 24 characters

In requester mode, this field is defined using the remote partner (NRPART) parameter of the partner object (CFTPART). It identifies the Partner's network name.

In server mode, Transfer CFT does not process this field. Logically, it is defined by the specific network identification of the local site relative to the requester Partner (the local partner (NSPART) parameter of the partner object (CFTPART)).

Creating a file (FPDU CREATE)

Format: 24 characters

  • bytes 1 to 8: receiver application name
  • bytes 9 to 16: receiver user name
  • bytes 17 to 24: free field

In requester mode, the first two fields are respectively defined using the RAPPL and RUSER parameters of the CFTSEND or SEND command. If the transfer command does not specify these parameters, the PI 3 code is not sent. The last free field is never defined by Transfer CFT.

In server mode, Transfer CFT recovers the PI 3 code in order to be able to define the &RAPPL and &RUSER symbolic variables. The free field is not used by Transfer CFT.

Selecting a file (FPDU SELECT)

As the PeSIT protocol imposes no constraints as to the contents of this PI code, Transfer CFT does not define or use it.

Sending a message (SEND TYPE = MESSAGE, ...)

The PI 4 code contains the same value as the one conveyed by the protocol connection request (FPDU CONNECT) previously required to send this message.

Sending an acknowledgement (SEND TYPE = REPLY, ...)

The PI 4 code contains the value of the PI 3 code conveyed by the file creation request (FPDU CREATE) whose receipt is acknowledged.

PI 04 Server identification

Format: 16 characters

This field specifies the connection server partner's name.

In requester mode, this field is defined using the NRPART parameter of the CFTPART command. It identifies the Partner's network name.

In server mode, Transfer CFT does not process this field. Logically, it is defined by the specific network identification of the local site relative to the requester Partner (NSPART parameter of the CFTPART command).

PI 05 Access control

  • Format: 16 characters
  • Bytes 1 to 8: partner password
  • Bytes 9 to 16: the partner's new password

This parameter is exchanged at the time the protocol connection is established. The Transfer CFT using the F.CONNECT service (request or response) defines the first field using the local partner password (NSPASSW) parameter of the CFTPART command. It identifies its own password as regards the transfer partner. On receipt of an incoming connection (F.CONNECT indication), Transfer CFT checks the equivalence between this password and the value of the NRPASSW parameter of the CFTPART command associated with the partner.

The second field is used to dynamically modify the password. As Transfer CFT does not support this facility, the area associated with the new password is not defined and not used.

PI 06 Version number

This field indicates the version number of the PeSIT protocol.

PI 07 Synchronization points option

This field indicates the interval between synchronization points and the acknowledgement window. The values negotiated by Transfer CFT depend on the type of access to the protocol connection (see PI22).

If a connection is required with a mixed type of access, Transfer CFT negotiates the smallest value of the Data transferred between sync points(S/RPACING) parameters of the of the protocol object (CFTPROT).

In server mode, Transfer CFT cannot increase the value proposed by the requester partner. The Acknowledgement window size parameters negotiate in the same way as the synchronization interval (S/RCHKW of the protocol object (CFTPROT)).

PI 11 File type 

This field conveys the class the file belongs to and contributes to identifying the file, particularly for resuming transfers.

When a file creation/selection FPDU is sent, Transfer CFT sets this PI code to zero. On receiving such FPDUs, its value is entered in the catalog request associated with the transfer. This value cannot be 0xFFFF, 0xFFFE or 0xFFFD or the transfer is refused.

For message transfers (FPDU.MSG), this field characterizes the message type. Transfer CFT processes this field in accordance with the specifications of the PeSIT protocol and defines it using the TYPE parameter of the transfer command:

TYPE parameter Description

SEND TYPE = MESSAGE,...

Outgoing message

SEND TYPE = REPLY,...

 PI 11 of the file for which the message conveys the acknowledgement

 Transfer CFT reserves the 0xFFFD value for subsequent use.

PI 11 File type 

Transfer CFT sends and expects to receive the value 0.

PI 12 File name

Format: 76 characters

When sending a file, Transfer CFT defines this field using the file network identifier, the NIDF parameter of the transfer command. When receiving a file, Transfer CFT uses the file network identifier to generate a local file identifier (IDF). Transfer CFT recovers the PI 12 to set the value of the &NIDF symbolic variable.

When sending a file, Transfer CFT defines this field using the message identifier, the IDM parameter of the transfer command. When receiving a message, Transfer CFT recovers the PI 12 to set the value of the &IDM symbolic variable.

When an acknowledgement is sent (SEND TYPE = REPLY, ...), this field contains the PI 12 of the file whose reception is acknowledged.

PI 13 Transfer identifier

This parameter is used to identify a transfer through a numerical value. Transfer CFT manages this field internally and sets its value in accordance with the specifications of the PeSIT protocol. In the case of a retry, in particular, it must be the same as the one used during the initial transfer.

When sending an acknowledgement (SEND TYPE = REPLY, ...), this field contains the PI 13 of the file transfer acknowledged.

PI 14 Requested attributes

This parameter indicates the file attributes whose values have to be communicated in response to a file selection request. This involves a combination of the logical, physical and log attributes. In requester/receiver mode, Transfer CFT systematically requests all the attributes. In server/sender mode, Transfer CFT adapts itself to the request made by the requester partner.

When transferring a message or acknowledgement, Transfer CFT does not define or use this field.

PI 15 Restarted transfer

This parameter indicates that a transfer is a new occurrence of a transfer which has already been attempted.

  • In requester mode, Transfer CFT manages this field internally, according to the transfer characteristic (new or restarted).
  • In server mode, if the remote Partner indicates a restart, the search criteria for a catalog entry relative to the network values received are as follows:
  • File type (PI 11)
  • File identifier (PI 12)
  • Transfer identifier (PI 13)
  • Connect Partner (PI 3 of FPDU CONNECT)
  • Initial sender name (PI 61)
  • Final receiver name (PI 62)

If no catalog entry corresponds to the restart request, Transfer CFT rejects the transfer request.

PI 16 Data code

This parameter indicates the type of coding (ASCII, EBCDIC or BINARY) used to send the file data or the message.

In sending mode, this field is defined using the NCODE parameter of the SEND transfer command.

In receiving mode, this field supplies the network code of the data so that they can be used by the local Transfer CFT.

PI 17 Transfer priority

This parameter provides the relative priority assigned by the requester of a transfer.

In requester mode, this field is defined using the PRI parameter of the RECV and CFTRECV commands (for a read transfer) or of the SEND and CFTSEND commands (for a write transfer). In Central Governance, use the Transfer priority parameter.
As PeSIT only recognizes three priority levels, the following conversions are performed:

  • PRI > 128     PI 17 = 0 (high)
  • PRI = 128     PI 17 = 1 (medium)
  • PRI < 128     PI 17 = 2 (low)

In server mode, the PI 17 value is entered for information in the Transfer CFT catalog and under no circumstances affects the transfers in process. The PI 17 network values 0, 1 and 2 provide a priority of 255, 128 and 0 respectively in the Transfer CFT catalog.

PI 18 Restart point

This is the synchronization point number used to locate the position in the file from which the transmission is to be resumed. Transfer CFT manages this field internally and sets its value in accordance with the specifications of the PeSIT protocol.

PI 19 End of transfer code

This code specifies the type of end-of-transfer in the event of a voluntary interruption (F.CANCEL primitive). Transfer CFT manages this field internally and sets its value in accordance with the specifications of the PeSIT protocol.

A HALT command causes an end-of-transfer type of 4.

PI 20 Synchronization point number

This numerical value expresses the synchronization point number. Transfer CFT manages this field internally and sets its value in accordance with the specifications of the PeSIT protocol.

PI 21 Compression

This field is used to negotiate the use of compression during the transmission of the file data.

PI 22 Access type 

This field indicates the type of transfers authorized for the required connection: write, read or mixed.

PI 23 Resynchronization

This parameter indicates the use of the resynchronization functional unit as required.

PI 25 Maximum size of a data entity

This parameter corresponds to the maximum number of bytes which can be sent in a data entity of the network service (NSDU).

PI 27 Number of data bytes

This field indicates the number of file data bytes which have been transferred. If compression is used, this value includes the size of the headers of compression strings. Transfer CFT manages this field internally and sets its value in accordance with the specifications of the PeSIT protocol.

PI 28 Number of articles

This field indicates the number of file records which have been transferred. Transfer CFT manages this field internally and sets its value in accordance with the specifications of the PeSIT protocol.

PI 31 Article format

This parameter specifies the file article format. It is defined using the NRECFM parameter of the SEND command, or specify the Record format in the send template (CFTSEND).
The following conversions are performed:

  • NRECFM = F     PI 31 = 0x00 (fixed)
  • NRECFM = V     PI 31 = 0x80 (variable)
  • NRECFM = U     PI 31 = 0x80 (variable)

PI 32 Article length

This parameter specifies the length in bytes of a file record. It is defined using the NLRECL parameter of the SEND command, or the Max record length of the send template (CFTSEND).

PI 33 File organization

This parameter describes the organization of the data within the file and, consequently, the type of access to its data for the transfer: sequential, relative or indexed.

It is defined using the NORG parameter of the SEND command.

PI 37 File label

Format: 80 characters (maximum length supported by Transfer CFT: 512 characters).

This field can be used to associate a symbolic name to a transferred file.

In sending mode, Transfer CFT defines this field using the File name sent parameter of the of the send template (CFTSEND), or the (NFNAME) of the SEND command, to designate the name of the file on the receiver site.

In reception mode, Transfer CFT recovers the PI 37 in order to be able to define the symbolic variable &NFNAME. Otherwise, this field is only used if the transfers with the partner can be performed in open mode. In other words, if the local Transfer CFT authorizes the sending partner to set the physical name of the receiver file (CFTRECV/RECV FNAME = &NFNAME, ... ).

PI 38 Key length 

Where the organization of the announced file is indexed (see PI 33), this parameter contains the length in bytes of the file access key.

It is defined using the NKEYLEN parameter of the SEND command.

In reception mode, Transfer CFT recovers the PI 38 in order to be able to define the symbolic variable &FKEYLEN as required.

PI 39 Key offset 

Where the organization of the announced file is indexed (see PI 33), this parameter contains the offset of the file access key in bytes relative to the start of the article.

It is defined using the NKEYPOS parameter of the SEND commands.

In reception mode, Transfer CFT recovers the PI 39 in order to be able to define the symbolic variable &FKEYPOS as required.

PI 41 Space reservation unit

This field defines the unit used to express the space reservation value. The possible units are kilo-bytes or articles.

In sending mode, Transfer CFT always expresses the space reservation unit in kilo-bytes.

In reception mode, Transfer CFT supports both types of possible units.
The reservation unit can only be the article when the file format is fixed (see PI 31).

PI 42 Space reservation maximum value

This field defines the size that the file cannot exceed. It is defined using the NSPACE parameter of the SEND command and is always expressed in kilo-bytes.

PI 51 Creation data and time

This field indicates the file creation date and time.

In sending mode, it is defined using the FDATE and FTIME parameters of the SEND commands. If these parameters are not expressed at the time the transfer command is sent, Transfer CFT assigns them with the date and time the catalog takes them into account.

In reception mode, Transfer CFT recovers the PI 51 in order to be able to define the &FDATE and &FTIME symbolic variables.

When an acknowledgement is sent (SEND TYPE = REPLY, ...), this field contains the PI 51 of the file whose reception is acknowledged.

PI 52 Last extraction date and time

This field indicates the date and time the last transfer was normally terminated or interrupted.

In file sending mode, Transfer CFT sets this field to the PI 51 value. In reception mode, Transfer CFT does not use this field.

PI 61 Initial sender name 

Format: 24 characters

This field contains the identifier of the initial sender of the transfer.

In store and forward mode, it can be distinguished from the requester identifier (PI 3), thereby allowing relay Transfer CFTs, if any, to route the transfer to the next computer. For write transfers, this field corresponds to the local partner (NSPART) parameter of the partner the transfer was originally sent from.

PI 62 Final receiver name 

Format: 24 characters.

This field contains the identifier of the final recipient of the transfer.

In store and forward mode, it can be distinguished from the server identifier (PI 4), thereby allowing relay Transfer CFTs, if any, to route the transfer to the next computer. For write transfers, this field corresponds to the remote partner (NRPART) parameter of the final partner the transfer is intended for.

PI 91 Message 

Format: 4096 characters

This field allows a message to be conveyed from one user to another by means of the message transfer service.

It is defined using the MSG parameter of the SEND TYPE = MESSAGE command or SEND TYPE = REPLY command.

In message reception mode, Transfer CFT recovers the PI 91 in order to define the &MSG symbolic variable.

PI 99 Free message

Format: 254 characters

This parameter allows a message to be conveyed from one user to another in the free field of the PeSIT service primitives. No control concerning the coding, structure or semantics of its contents is imposed by the protocol.

During file sending, PI 99 contains the value in the PARM field of the SEND command. Character type coding with a maximum length of 80 bytes is permitted.

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