upper layers can support and ask about what theirs support.
N
N
O D E
Port F Port
PRLI
Switch F Port F Port
N Port
NODE
F Port N Port
PRLI
N
O D E
Now that the N_Port knows about each of the other ports and the driver has stored their details in a parameter block, the driver in this Node can open a channel with each of the other drivers associated with each Node.
When a channel has been successfully opened, like in the case of a SCSI Initiator opening a channel with a SCSI Target, an Image Pair is established and communication can take place while the channel is open.
If an Image Pair is closed by the driver when it logs out (PRLO), the image pair must be established again before further communication can take place.