Fully Reliable Service

The File Transfer control implements a Fully Reliable service for multicasting, ensuring that each packet sent is received, undamaged and intact. If the receiver determines that packets are missing or damaged, it can send a negative acknowledgment (NAK) to the sender requesting that the packets be resent.

In the Fully Reliable service mode, the File Transfer service performs flow control; this is in addition to the rate control performed by the sender. If the sender is transmitting packets too fast, the receiver sends a throttle NAK indicating that the transfer must slow down. The receiver also sends an idle NAK when it is busy and cannot accept any more packets, or has not received any packets from the sender for a while.

The File Transfer control uses the Fully Reliable service mode as the default. If the sender does not use the Fully Reliable mode, however, the control can still receive transfers, but cannot request the retransmission of any missing packets. The Fully Reliable service mode can be turned off by using the FullyReliableService property.

A two-way (bidirectional) network is required for the Fully Reliable service.

The Fully Reliable service mode requires that forward error-correction (FEC) be used.