Summary: This Cisco PDF overview (from an industry event) explains how modern AI training and inference workloads generate massive east–west traffic and demand lossless, highly-predictable Ethernet-based fabrics. It walks through fabric design principles (Clos/leaf-spine), congestion management, observability, and the vendor’s latest networking innovations (switching silicon, optics, and unified operations) aimed at scaling data center networks to meet AI-era requirements. 
Source: https://www.cisco.com/c/dam/en_us/training-events/events/cisco-connect-us/data-center-networking-for-the-ai-era.pdf