• How data interchange is controlled • Real time feedback:
– buffer-to-buffer (Port to Port ) – end-to-end (Source to Destination )
• High performance with heavy traffic • Prevents loss of frames through buffer overrun
Flow control is a mechanism for ensuring that traffic (frames) only move when there is somewhere for them to go: • Using flow control, the receiving port indicates to the transmitting port that it can accept the next frame. The transmitting port will not transmit the next frame until it knows that the receiving port has a buffer available to accept the frame. The receiving port is always in control.
• Just as traffic lights are used to control the flow of traffic in city centres so Flow Control manages the data flow in a Fibre Channel fabric. The transmitting port must wait for the ‘green light’ before it can send any more traffic (frames) through the network.