data link layer , PCIe PHY-MAC interface protocols, Physical Layer, flow control, CDC synchronizers, SerDes PHY, async FIFO, integrating PCIe hard IP controller, PnR constraints, CXL 1.1 2.0 or 3.0 protocol knowledge, reset sequencing, Transaction Layer, multi-clock-domain design, wrapper RTL, error handling, SystemVerilog RTL, clock crossing, PCIe power management, PCI-SIG certification process, PCIe architecture, Virtual Channels, PCIe compliance testing, TLP structure