You are looking at a Fibre Channel trace log and you notice that the class 2 communication session between one initiator and target continually stops and then restarts. You suspect that there is a flo

The port login (PLOGI) is a fundamental Fibre Channel login process where an N_Port establishes a session with another N_Port or an F_Port to exchange operational parameters, including buffer-to-buffer credits (BB_credits) which are crucial for flow control. Analyzing the PLOGI parameters reveals the number of allocated credits, directly impacting flow control.

Loop login (RLOGI or FLOGI followed by PLOGI on an arbitrated loop) is for devices on a Fibre Channel arbitrated loop, but the primary exchange of flow control credits between two N_Ports occurs during PLOGI.

Fabric login (FLOGI) is performed by an N_Port to log into the Fibre Channel fabric (F_Port) and acquire an N_Port ID, but it does not directly exchange buffer-to-buffer flow control credits between two end-node ports.

Process login (PRLI) is used to establish communication between two Fibre Channel application processes (e.g., SCSI initiators and targets), but it occurs after the port login and does not dictate the buffer-to-buffer flow control credits.