credit method
The credit procedure is a procedure for flow control in Fibre Channel and StarFabric. Fibre Channel distinguishes between buffer-to-buffer credit( BBC) for link flow control and end-to-end credit for flow control between two end devices.
In this isametric method, credits are assigned for the entire network. If a credit is available, a sender can place a message on the network. When the message arrives at the receiver, new credits are issued.
The number of credits a receiver awards is equal to the number of data packets the sender is allowed to transmit to the receiver. For example, if the receiver has granted the sender a credit of 6, then the sender can transmit six data packets to the receiver without a buffer overflow occurring. After that, he must abort the transmission and wait for the new credits.