NVIDIA NCP-AII Practice Test Questions Answers

In NVIDIA Base Command Manager (BCM), the management and storage traffic often requires redundancy via NIC bonding (Link Aggregation). The cmsh utility uses a hierarchical command structure to modify node configurations. To create a bond, the administrator must first navigate to the specific node ' s interface configuration (device use < node > ). The correct sequence involves adding a new interface of type " bond " (interfaces add bond bond0). After the bond object is created, the physical slave interfaces must be associated with it using the append interfaces command. Finally, the bonding mode (e.g., Mode 1 for Active-Backup or Mode 4 for LACP) and the logical network assignment must be defined. Option B correctly follows this logic. Assigning networks directly to physical ports (Option C) would prevent the use of a unified bond IP, and Option A incorrectly attempts to add a VLAN before the underlying bond is established. This configuration is essential for ensuring the control plane remains reachable even if a single management cable or switch port fails.

The first hardware check should be cable compatibility and connector inspection. A “No Signal” result from the Cable Validation Tool indicates that the physical layer is not establishing a usable signal, even though the cable appears to be inserted. In DGX H100 and NVIDIA high-speed networking environments, DAC cables must be validated for the correct speed, adapter generation, switch platform, firmware compatibility, and physical form factor. A damaged connector, unsupported cable, poorly seated latch, excessive bend radius, or wrong cable type can cause intermittent “Link Down” events. Replacing an optical transceiver is not appropriate because the issue is on a DAC connection, not an optical link. Reconfiguring the port to 100G may mask the failure but does not validate the required 200G operation. Upgrading all switches for RS-FEC is too broad and does not address a local “No Signal” condition. Proper physical-layer bring-up requires confirming the cable is supported, visually inspecting both ends, reseating it, and checking whether the link comes up cleanly before moving to firmware or switch-level troubleshooting.

NVIDIA ' s Cable Validation Tool (CVT) and the Unified Fabric Manager (UFM) use strict Bit Error Rate (BER) thresholds to ensure the stability of NDR (400G) and HDR (200G) InfiniBand fabrics. Because modern high-speed links rely on Forward Error Correction (FEC) to fix minor bit flips, a " Raw BER " (errors before FEC) is expected, but must remain within a specific envelope—typically better than $10^{-12}$. However, the " Effective BER " (errors after FEC) should ideally be zero or incredibly low (less than $1.5 \times 10^{-254}$) over a long observation window. If these thresholds are exceeded within a standard 6-hour monitoring period, it indicates that the signal-to-noise ratio is too low for the FEC to maintain a reliable stream. This leads to packet drops and " Symbol Errors " that trigger InfiniBand " Retransmissions, " which are catastrophic for the performance of AI collectives like all_reduce. While Rx power variance (Option A) and temperature (Option D) are health indicators, they are causes of poor BER, not the BER threshold itself.

The correct best practice is to install only the GPU and DOCA driver versions that are validated for the current operating system, kernel, hardware platform, and NVIDIA software release. In NVIDIA AI infrastructure, driver compatibility is critical because GPU drivers, CUDA libraries, DCGM, Fabric Manager, DOCA-OFED, network adapters, DPUs, and kernel modules must align. Installing the newest driver without checking compatibility can cause driver/library mismatches, failed nvidia-smi, broken RDMA, or unsupported DOCA behavior. NVIDIA DGX documentation notes that DGX OS updates include coordinated OS, kernel, GPU driver, CUDA toolkit, and DCGM updates, and NVIDIA AI Enterprise provides support matrices to confirm supported platform combinations. DOCA-OFED is also tied to the operating system and kernel environment, so version selection must be deliberate. Legacy drivers may lack required fixes or hardware support, and default distribution drivers are usually not sufficient for validated DGX or AI Enterprise deployments. After installation, administrators should reboot if required, validate GPU visibility, confirm networking driver status, and run health checks before returning the node to production.

The correct command is sudo nvsm stress-test --force. NVIDIA recommends using NVSM for the DGX pre-flight stress test before putting a DGX H100 system into production or after servicing. The documented NVSM stress test can run checks across supported components, including GPUs, CPU, memory, and storage, and the recommended command for all supported components is sudo nvsm stress-test --force. nvidia-smi -q provides detailed GPU information, but it does not execute a full platform stress test. The Linux stress command can load CPU and I/O subsystems, but it is generic and does not validate the DGX platform using NVIDIA’s health model. gpu_burn may stress GPUs, but it does not cover CPU, system memory, storage, and DGX-specific platform checks in the recommended way. During server bring-up, NVSM is preferred because it understands DGX hardware components and can identify platform health issues before the node is released to production workloads.