Dual peer pci bus?

The Octane's system-board is designated as IP30. The system is based on SGI's Xtalk architecture. This means it does not use a system bus; instead it has a router (Xbow) that connects any two of its ports. One of the ports is used for the processor and memory subsystem, one is available for PCI (actually PCI-64) expansion and four are XIO slots (packet-based high-bandwidth bus, somewhat similar to HyperTransport). This makes it very similar to a single node of the SGI Origin 200 system.