PCI Express (PCIe) offers the benefits of reduced power consumption, scalability of bandwidth, increased data throughput and improved signal integrity. Now PCIe has replaced legacy bus-based PCI and PCI-X, and become the de facto standard for on-board chip-to-chip connectivity. The old system topologies of PCIe-based systems have been characterized by single root systems. With the move to bladed, multicard, chassis-based systems, designers and architects are seeking to leverage the high bandwidth, scalability, low power and system costs of PCIe interconnects to provide the primary system interconnect for multiroot and multiprocessor systems.

This white paper outlines key multiroot computing, storage and communications usage models with details on how PCIe can be employed as the primary system interconnect. Additionally, the redundancy for coherency and failover common to many multiroot applications is also covered.