HP Cluster Platform Interconnects v2010 Quadrics QsNetII Interconnect - Page 21

A federated network, (greater than 128 nodes) can support a theoretical maximum topology of 4096 nodes, although the actual maximum is constrained by the limits of physical connection, such as cabling constraints. For 256 nodes or greater, interconnects are connected in four stages; for larger networks, the interconnects are connected in five stages. Note HP Cluster Platform supports only the number of nodes specified for any given release. The maximum number of nodes is further constrained by the operating environment. 2.2.1 64-Port Network A fully populated interconnect fitted with the QM540 midplane can connect up to 64 nodes, each fitted with a QM500 network adapter. The interconnect houses up to 4 QM501 16-port switch cards and 4 QM502 switch cards. The QM501 switch card comprises 8 Elite switches connected in a 2-stage fat tree topology with 16 link ports. The QM502 switch card forms the third stage of the network. It contains 4 Elite switches. Each Elite switch has four downlinks that are connected to uplinks from interconnects in the second stage of a QM501 switch card. Each Elite switch has 4 uplinks that remain unused in this configuration, as shown in Figure 2-2. Figure 2-2: 64 Node, 3 Stage Network 2.2.2 128-Port Network QM511L A fully populated interconnect fitted with the QM542 midplane can connect up to 128 nodes, each fitted with a QM500 network adapter. Up to 8 QM511C modules can be fitted into any of the four front and four rear slots. Each QM511C Switch Module provides 16 link ports. Slots not occupied by QM511C modules must be filled with QM511L top-level modules. These have no link ports, but are necessary to complete the top stage of the fat tree. Quadrics Interconnect Overview 2-3