300-640 DCAI case studies
300-640 DCAI · Put your knowledge to work in context.
The Designing Cisco Data Center AI Infrastructure (300-640 DCAI) exam is a Cisco specialist-level certification exam focused on planning and designing data center infrastructure for AI and machine learning workloads. It targets data center architects, pre-sales and design engineers, and senior network or compute engineers who translate AI workload requirements into validated data center designs. The 300-640 DCAI case studies are 5 cases and about 4,051 words.
1Sizing a 1,024-GPU Training Hall Against a 1.2 MW Power Ceiling
A colocation provider has allocated a 900 m2 hall with 1.2 MW of usable critical power and 1.1 MW of cooling for a new AI training cluster. The data science team wants 1,024 NVIDIA H100 GPUs in 128 eight-GPU nodes, a 20 PB parallel file system, and 12 management servers.
834 words, about 4 min2PCIe Affinity and GPU Direct RDMA on a Mixed-Generation Fine-Tuning Cluster
A research lab runs parameter-efficient fine-tuning on 32 GPU servers, each with four A100 80 GB PCIe GPUs and one 200G RoCE NIC. Half are older PCIe Gen3 servers and half are Gen4.
841 words, about 4 min3Checkpoint Storm: Diagnosing a Storage Fabric That Collapses Every 15 Minutes
A 64-node training cluster writes a 1.2 TB checkpoint every 15 minutes. Each node has eight H100 GPUs and two 100G storage NICs; the parallel file system presents two 100G uplinks.
797 words, about 4 min4PFC Storms and ECN Policy in a 400G Two-Tier RoCE Fabric
A two-tier 400G RoCEv2 fabric carries distributed training between 64 leaf switches and 32 spines. PFC is enabled on priority 3 and ECN is configured, but after a new all-to-all workload is introduced, PFC pause frames propagate across the fabric and PFC watchdog shuts several leaf ports.
788 words, about 4 min5From Spreadsheet to GitOps: Onboarding 40 AI Tenants Across Three Data Centers
An enterprise has 96 Nexus switches across three data centers, 40 internal AI tenants, and a six-week lead time for new tenant capacity. Today engineers configure VLANs, VRF leaking, QoS, and ACLs by CLI from a spreadsheet; a recent audit found 17% drift between intended and running configuration, including a tenant ACL that exposed a storage subnet.
791 words, about 4 min