Serial Storage Architecture. An architecture defining a serial physical interface and supporting protocol developed by IBM and now supported by the ANSI X3T10.1 committee. SSA supports point-to-point, loop, and multiple-ring topologies. Each node of an SSA topology can support up to 2 full duplex ports operating at 20 MBytes/sec per port. SCSI commands, data transfers, and responses are transported across an SSA topology.