PCIe/CXL Deep Dive · All levels

PCIe/CXL Glossary

Shared vocabulary across PCIe/CXL protocol layers, enumeration, LTSSM, and RAS.

Terms to use precisely

  • TLP: transaction layer packet carrying memory, config, or IO requests across the fabric.

  • LTSSM: link training state machine governing Detect through L0 and Recovery.

  • Credit flow control: receiver buffer pools advertised via UpdateFC DLLPs.

  • AER: Advanced Error Reporting for correctable and uncorrectable PCIe errors.

  • Equalization: Gen3+ PHY tuning phases for transmitter presets and receiver CTLE/DFE.

  • HDM: Host-managed device memory decode for CXL.mem expansion regions.