Cisco Nexus switches are generally categorized into two distinct architectural tiers, often described as "modular" vs. "fixed" or "spine" vs. "leaf."

The Spine-Leaf Architecture: This is the standard for modern data centers.

Unlike traditional monolithic operating systems, NX-OS employs a pre-emptive, message-passing microkernel architecture.

Consider a research lab building a GPU cluster for LLM training. They chose the Nexus 93180YC-FX leaf and Nexus 9232E spine running NX-OS 10.2(1):