This discussion assumes that the SM has transmitted a request SMP to a device's SMA and it is now being received by a CA or router port. When a CA or a router port's Link Layer receives an inbound request SMP from the SM, it is processed as follows:
The SMP packet is received into the port's VL15 receive buffer. It should be noted that if the buffer is currently full—the minimum required buffer depth is one SMP packet—then the inbound SMP is discarded.
The SMP's DLID address may be either one of the receiving port's assigned LID addresses or may be the PLID address. In either case, the packet is passed to the port's SMI RQ Logic for processing. This example ...