Abstract: Methods and structure for reduced layout congestion in a switching device integrated circuit. A switching device such as a Serial Attached SCSI (SAS) expander comprises a switching circuit to couple any of a plurality (“N”) of physical links of the switching device with any other physical link of the switching device. The switching circuit comprises a first stage circuit adapted to couple any of the N physical links with a selected one of N/2 communication paths of the switching circuit and comprises a second stage circuit adapted to couple any of the N/2 communication paths with any of the N physical links. Since only N/2 communication paths may be active at any time in such a switching device, a control unit of the switching device tracks which of the N/2 communication paths are presently in use or unused so that an unused path may be selected for a new connection.

Abstract: Methods and structure for reduced layout congestion in a switching device integrated circuit. A switching device such as a Serial Attached SCSI (SAS) expander comprises a switching circuit to couple any of a plurality (“N”) of physical links of the switching device with any other physical link of the switching device. The switching circuit comprises a first stage circuit adapted to couple any of the N physical links with a selected one of N/2 communication paths of the switching circuit and comprises a second stage circuit adapted to couple any of the N/2 communication paths with any of the N physical links. Since only N/2 communication paths may be active at any time in such a switching device, a control unit of the switching device tracks which of the N/2 communication paths are presently in use or unused so that an unused path may be selected for a new connection.