Introduction to the PCIe interconnect
The Peripheral Component Interface Express (PCIe) is a high-speed, multi-layer, and serial interconnect protocol. Its predecessor, the Peripheral Component Interface eXtended (PCI-X), was a parallel interface, but most of its base architectural properties are included in PCIe. The PCIe protocol defines three protocol layers: the transaction layer, the data link layer, and the physical layer. The physical layer uses multi-gigabit transceivers and can communicate at tens of gigabits per second. The physical layer topology is formed of multiple parallel transceivers known as lanes to transport data at a high bandwidth to match the application data transfer rates requirement. There are now many generations of PCIe protocol and all are backward compatible, from generation 1 (Gen1) to generation 6 (Gen6).
Historical overview of the PCIe interconnect
The first PCIe generation, Gen1, was introduced in 2003 as a replacement for the PCI-X parallel...