Restarting a transfer :
This function allows the caller to restart a prematurely interrupted transfer. Restarting is possible whether the transfer is performing a read or a write, but it is always decided by the caller. Which checkpoint is used for restarting the transfer is decided by the party receiving the file.

Resynch during transfer :
This function allows a user to request the remote party to restart the transfer from an earlier checkpoint if a fault occurred during the data transfer. Unlike restarting - which occurs after interruption of the transfer (accompanied by closing and deactivation of the file) - resynch takes place during the transfer and the file remains open and active.

Suspended transfer :
This function allows a user to interrupt a transfer (that is, close and deselect the file in question) in order to use the current connection for running a higher-priority transfer. The suspended transfer will afterwards be processed under the restart procedure.

Transfer protection :
This function allows PESIT users to implement mechanisms offering various functions such as :

• reverse authentication of parties,

• confidentiality of transmitted data,

• integrity of transmitted data.