PCIefabric

PCIefabric is a term used to describe a scalable, component-based approach to extending PCIe connectivity beyond a single host into a fabric that can interconnect multiple hosts, switches, and devices across a data center. It envisions a shared pool of PCIe resources that can be accessed by compute nodes and storage devices through a network of PCIe-aware switches and routers.

Core elements include PCIe endpoints, PCIe switches, fabric controllers or routers, and a fabric manager software that handles topology discovery, address space allocation, device enumeration, and I/O routing. The fabric typically uses a hierarchical or mesh topology with PCIe-aware components that forward transactions between endpoints and hosts. High-speed interconnects and lane widths may be adapted to maintain PCIe protocol integrity across longer distances and through multiple interconnects.

Management software provides topology discovery, dynamic reconfiguration, hot-plug support, and security policies; it may annotate devices with fabric-local addresses and perform PCIe hot-plug and I/O virtualization. The software stack is responsible for maintaining correct transaction routing, isolation between tenants, and consistent device addressing as devices are added, removed, or moved within the fabric.

Use cases include scalable storage (for example, NVMe devices across multiple servers via NVMe over Fabrics), GPU or accelerator sharing, remote I/O access, and high-performance computing clusters requiring large numbers of PCIe devices. PCIefabric concepts aim to increase resource utilization and flexibility in data centers, while introducing complexity in management, latency considerations, and cost.

Standards: PCI-SIG defines PCIe as a protocol; there is not a universal, single PCIefabric standard, and implementations vary. NVMe over Fabrics is often used alongside PCIe fabrics to enable remote access to storage and devices. Vendors may provide fabric controllers, switches, and software suites tailored to their architectures.