Designs reference architectures for AI data center networks, including L2/L3 fabrics, BGP, EVPN/VXLAN, RoCEv2, and QoS. Builds and operates labs to qualify switches, NICs, and network operating systems; performs interoperability and performance testing; reproduces complex customer issues; and troubleshoots congestion, packet loss, MTU, latency, PFC, and ECN behavior. Documents best practices, develops automation, collaborates with vendors and internal teams, and provides feedback to product R&D.