56 IBM BladeCenter PS703 and PS704 Technical Overview and IntroductionFigure 2-13 PS704 I/O Hub subsystem architecture2.7.1 PCI Express busPCIe uses a serial interface and allows for point-to-point interconnections between devicesusing a directly wired interface between these connection points. A single PCIe serial link is adual-simplex connection using two pairs of wires, one pair for transmit and one pair forreceive, and can only transmit one bit per cycle. It can transmit at the extremely high speed of5 Gbps. These two pairs of wires is called a lane. A PCIe link might be comprised of multiplelanes. In such configurations, the connection is labeled as x1, x2, x8, x12, x16, or x32, wherethe number is the number of lanes.The PCIe expansion card options for the PS700, PS701, PS702, PS703, and PS704 bladessupport Extended Error Handling (EEH). The card ports are routed through the BladeCentermid-plane to predetermined I/O switch bays. The switches installed in these switch bays mustmatch the type of expansion card installed, Ethernet, Fibre Channel, and so forth.2.7.2 PCIe slotsThe two PCIe slots are connected to the three x8 Gen2 PCIe links on the GX++multifunctional host bridge chip. One of the x8 links supports the CIOv connector and theother two links support the CFFh connector on the blade. All PCIe slots are Enhanced ErrorHandling (EEH). PCI EEH-enabled adapters respond to a special data packet generated fromthe affected PCIe slot hardware by calling system firmware, which examines the affected bus,allows the device driver to reset it, and continues without a system reboot. For Linux, EEHTwo x8 Gen2x8 Gen1HDD/SSD connectorTo chassisI/O bays1 & 2x4 Gen1 x8 Gen2 CIOv I/O connectorGX++ busCFFh I/O connectorP7IOCI/O hubTo processor 0SAS pass-throughTwo x8 Gen2To chassisI/O bays1 & 2Tomediatrayx1 Gen1x4 Gen1USBcontrollerx8 Gen2GX++ busCFFh I/O connectorPCIe toPCIP7IOCI/O hubTo processor 0BCM5387EthernetswitchBCM5709GigabitEthernetSAS pass-through3GbSASHDD/SSD connectorCIOv I/O connectorPS704baseplanarPS704SMPplanarBCM5709GigabitEthernet
