FCAL Address Selection

When a loop initialize, or when a node powers up or when a node joins the loop, it sends a loop initialization primitive (LIP) frame. This causes every other node in the loop to send a LIP frame. The loop becomes unusable.

Each node then continues to transmit the loop initialization select master (LISM) frame to select a master. If the loop is also connected to a fabric (via FL port), the fabric port becomes the loop master. If not, the port with the lowest port name is chosen as loop master.

The next step is every node must select an AL_PA. The loop master sends a loop initialization select AL_PA (LISA) frame around the loop. Each L port on the loop selects a free AL_PA in the frame and marks that AL_PA used. It then forwards the frame to the next L port in the loop. In case of reinitialization, the node will attempt to select the previous AL_PA whenever possible.

Once the LISA returns to the master, it sends the CLS (close) grame to notify all nodes that the initialization process has completed.