NCP-AIN NVIDIA-Certified Professional AI Networking Free Practice Exam Questions (2026 Updated)

The "What Just Happened" (WJH) service on Cumulus switches provides real-time visibility into network problems by monitoring various layers and components, including layer 1, layer 2, layer 3, tunnel, buffer, and Access Control List (ACL) related issues. WJH streams detailed and contextual telemetry data, enabling administrators to diagnose and troubleshoot network problems effectively.​

Reference Extracts from NVIDIA Documentation:

"WJH can monitor layer 1, layer 2, layer 3, tunnel, buffer and ACL related issues."​

"The WJH service enables you to diagnose network problems by looking at dropped packets."​

The tool specifically designed for testing InfiniBand connectivity is **ibping**. It functions similarly to the traditional ping utility but is optimized for InfiniBand fabrics .

From the NVIDIA InfiniBand Diagnostic Utilities Documentation :

"ibping tests the connectivity of InfiniBand nodes by sending management datagrams (MADs) and verifying the response from the destination LID or GUID."

Tests basic node-to-node reachability

Supports testing via LID, GUID , or port number

Helps verify subnet manager routing and fabric health

Incorrect Options:

ping and traceroute are IP-based, not fabric-aware.

ibnetdiscover maps topology but doesn't test live connectivity.

Direct Memory Access (DMA) in InfiniBand networks allows data to be transferred directly between the memory of two devices without involving the CPU. This capability significantly reduces CPU overhead, lowers latency, and increases throughput, making it ideal for AI workloads that demand efficient data transfers.

Modern AI training (especially with LLMs) requires extremely high-speed, parallel access to large datasets. A dedicated storage fabric separates data I/O traffic from the training compute path and avoids contention.

From NVIDIA DGX Infrastructure Reference Architectures :

"Dedicated storage networks eliminate I/O bottlenecks by providing low-latency, high-bandwidth access to distributed storage for large-scale training jobs."

"Parallel access to datasets is key for performance, especially in multi-node, multi-GPU AI clusters."

Security (B) is important, but not the core reason for a storage fabric.

Cost (D) is typically increased , not reduced, with dedicated fabrics.

MLNX-OS, the operating system for NVIDIA's networking devices, defines two primary user account types: admin and monitor . The admin account has full administrative privileges, allowing for complete configuration and management of the system. The monitor account, on the other hand, is designed for users who need to view system configurations and statuses without making any changes. This separation ensures a clear distinction between users who manage the system and those who monitor its operations.​

Reference Extracts from NVIDIA Documentation:

"There are two user roles or account types: admin and monitor. As 'admin', the user is privileged to run all the available commands. As 'monitor', the user can run commands that show system configuration and status, or set terminal settings."​

MLNX-OS is the network operating system used on NVIDIA’s Mellanox Ethernet switches, including the Spectrum family (e.g., Spectrum-4 switches in the Spectrum-X platform), designed for high-performance Ethernet networking in AI and HPC data centers. MLNX-OS provides a command-line interface (CLI) for configuring and managing switch operations, with user accounts controlling access to various commands and functions. The question asks for the two general user account types in MLNX-OS, which define the primary privilege levels for user access.

According to NVIDIA’s official MLNX-OS documentation, the two general user account types in MLNX-OS are:

monitor : This account type has read-only access, allowing users to view configurations, status, and logs but not modify settings. It is used for monitoring and troubleshooting without risking unintended changes.

admin : This account type has full read-write access, enabling users to view and modify all configurations, execute commands, and manage the switch’s operations. It is intended for administrators with complete control over the system.

These two account types represent the primary privilege levels in MLNX-OS, providing a clear distinction between read-only monitoring and full administrative access.

Exact Extract from NVIDIA Documentation:

“MLNX-OS supports two primary user account types for managing switch operations:

monitor : Users with monitor privileges have read-only access to the system. They can view configuration details, system status, and logs but cannot make changes to the configuration.

admin : Users with admin privileges have full read-write access, allowing them to configure, manage, and troubleshoot all aspects of the switch, including executing privileged commands. These account types ensure secure and controlled access to the switch’s management functions.” — NVIDIA MLNX-OS User Manual

This extract confirms that options B (monitor) and C (admin) are the correct answers. These account types are the standard privilege levels in MLNX-OS, used to manage access for monitoring and administrative tasks on Spectrum switches, including those in Spectrum-X deployments.

NVIDIA NetQ is a network operations tool that provides real-time visibility and automated validation of the network fabric. It helps in identifying misconfigurations, monitoring network health, and ensuring that the fabric meets the required specifications for AI workloads.​

For optimal performance in multi-node, multi-GPU AI workloads:

NVLink provides high-speed, low-latency communication between GPUs within the same node.

InfiniBand offers efficient, scalable communication between nodes in a data center. Combining these technologies ensures both intra-node and inter-node communication needs are effectively met.​

Adaptive Routing in InfiniBand networks dynamically selects the optimal path for data packets based on current network conditions, such as congestion levels and link utilization. This approach ensures that traffic is evenly distributed across the network, preventing bottlenecks and maximizing overall throughput.​

By continuously monitoring the network and adjusting routes in real-time, Adaptive Routing enhances performance and reliability, making it the preferred choice for high-performance computing environments where consistent low latency and high bandwidth are critical.​

To enable SHARP (Scalable Hierarchical Aggregation and Reduction Protocol) aggregation using the NCCL-SHARP plugin , the following two environment variables are required:

NCCL_COLLNET_ENABLE=1

Enables NCCL’s support for CollNet (Collective Network) operations, including SHARP.

NCCL_SHARP_AUTOINIT=1

Automatically initializes the SHARP plugin when available, activating SHARP-based collectives.

From the NVIDIA NCCL User Guide – SHARP Plugin Section :

"NCCL_COLLNET_ENABLE must be set to enable collective network acceleration features."

"NCCL_SHARP_AUTOINIT enables automatic SHARP plugin integration at NCCL runtime."

Incorrect Options:

B. NCCL_ALGO=CollNet – This variable controls the algorithm used for collectives but does not enable SHARP.

C. NCCLSPECTRUM_ENABLE – This is not a documented NCCL variable.

NetQ integrates multiple telemetry sources, including WJH , DOCA , and notably, Behavioral Telemetry .

From the NetQ Documentation – Behavioral Telemetry Section :

"Behavioral telemetry in NetQ correlates server and application behavior with network events, offering insights into root cause analysis by detecting anomalies in protocol, path, or performance behavior."

This helps identify patterns like:

Misbehaving applications causing retransmits.

Sudden changes in traffic flows.

Latency spikes correlated with app-level issues.

It complements device-level telemetry by introducing intent-based anomaly detection , crucial for proactive operations.

Incorrect Options:

Flow telemetry and packet capture offer raw data but not behavioral insights.

Application telemetry is too vague and is not the term NetQ uses for this feature.

Configuring NVUE to ignore certain underlying Linux files allows administrators to manage specific settings manually or through automation tools like Ansible without NVUE overwriting these configurations. This approach enables the persistent manipulation of settings using both NVUE and flat-file methods, providing flexibility in network management.

RoCE Adaptive Routing is a key feature of NVIDIA Spectrum-X that ensures high performance and resiliency in the network, even in the event of a link failure. This technology dynamically reroutes traffic to the least congested and operational paths, effectively mitigating the impact of link failures. By continuously evaluating the network's egress queue loads and receiving status notifications from neighboring switches, Spectrum-X can adaptively select optimal paths for data transmission. This ensures that the network maintains high throughput and low latency, crucial for AI workloads, even when certain links are down.​

Reference Extracts from NVIDIA Documentation:

"Spectrum-X employs global adaptive routing to quickly reroute traffic during link failures, minimizing disruptions and preserving optimal storage fabric utilization."​

"RoCE Adaptive Routing avoids congestion by dynamically routing large AI flows away from congestion points. This approach improves network resource utilization, leaf/spine efficiency, and performance."​

Virtual Routing and Forwarding (VRF) is the most effective method to achieve network segmentation and isolation in a multi-tenant environment.

From the NVIDIA Cumulus Linux Documentation – VRF Section :

"VRF allows multiple instances of routing tables to coexist within the same switch, effectively isolating traffic between tenants or departments."

Each department can:

Operate in its own VRF domain

Have independent routing tables

Maintain strict separation of Layer 3 paths

Incorrect Options:

A (Port Mirroring) – Used for traffic monitoring, not isolation.

C (ACLs) – Useful for fine-grained filtering, but not scalable tenant isolation.

D (LLDP) – Used for neighbor discovery, not security or isolation.

To enforce strict multi-tenancy , where:

Tenant A’s GPU cannot talk to Tenant B’s GPU

But both can access shared storage

The correct solution is:

Storage system → Full PKey membership

Each tenant’s GPU → Limited PKey membership

From the NVIDIA InfiniBand P_Key Partitioning Guide :

"A port with limited membership can only communicate with full members of the same PKey. It cannot communicate with other limited members, even within the same partition."

This isolates tenants from each other , while allowing shared access to storage .

Incorrect Options:

A permits tenant-to-tenant communication.

B isolates everything, including access to storage.

C prevents GPU access to storage.

In SONiC, to assign a static IP address to the management interface, the correct command is:

sudo config interface ip add eth0 20.11.12.13/24 20.11.12.254

This command sets the IP address and the default gateway for the management interface.​

SONiC (Software for Open Networking in the Cloud) is an open-source network operating system used on NVIDIA Spectrum-X platforms, including Spectrum-4 switches, to provide a flexible and scalable networking solution for AI and HPC data centers. Configuring the management interface in SONiC is a critical task for enabling remote access and network management. The question asks for the correct command to assign the IP address 20.11.12.13 to the management interface, typically identified as eth0 in SONiC, as it is the default management interface for out-of-band management.

Based on NVIDIA’s official SONiC documentation, the correct command to assign an IP address to the management interface involves using the config command-line utility, which is part of SONiC’s configuration framework. The command sudo config interface ip add eth0 20.11.12.13/24 20.11.12.254 is the standard method to configure the IP address and gateway for the eth0 management interface. This command specifies the interface (eth0), the IP address with its subnet mask (20.11.12.13/24), and the default gateway (20.11.12.254), ensuring proper network connectivity.

Exact Extract from NVIDIA Documentation:

“To configure the management interface in SONiC, use the config interface ip add command. For example, to assign an IP address to the eth0 management interface, run:

sudo config interface ip add eth0 < IP_ADDRESS > / < PREFIX_LENGTH > < GATEWAY >

Example:

sudo config interface ip add eth0 20.11.12.13/24 20.11.12.254

This command adds the specified IP address and gateway to the management interface, enabling network access.”

— NVIDIA SONiC Configuration Guide

This extract confirms that option C is the correct command for assigning the IP address to the management interface in SONiC. The use of sudo ensures the command is executed with the necessary administrative privileges, and the syntax aligns with SONiC’s configuration model, which persists the changes in the configuration database.

In the Spectrum-X architecture, BlueField-3 SuperNICs are responsible for executing the congestion control algorithm. They handle millions of congestion control events per second with microsecond reaction latency, applying fine-grained rate decisions to manage data flow effectively. This ensures optimal network performance by preventing congestion and packet loss.​

The RDMA Shared Device Plugin is a critical component in the NicClusterPolicy custom resource for enabling Remote Direct Memory Access (RDMA) capabilities in Kubernetes clusters. RDMA allows for high-throughput, low-latency networking, which is essential for efficient GPU-to-GPU communication across nodes in AI workloads. By deploying the RDMA Shared Device Plugin, the cluster can leverage RDMA-enabled network interfaces, facilitating direct memory access between GPUs without involving the CPU, thus optimizing performance.​

Reference Extracts from NVIDIA Documentation:

"RDMA Shared Device Plugin: Deploy RDMA Shared device plugin. This plugin enables RDMA capabilities in the Kubernetes cluster, allowing high-speed GPU-to-GPU communication across nodes."​

"The RDMA Shared Device Plugin is responsible for advertising RDMA-capable network interfaces to Kubernetes, enabling pods to utilize RDMA for high-performance networking."​

The ib_write_bw tool is part of the Perftest package and is specifically designed to measure the bandwidth of RDMA write operations between two InfiniBand endpoints. It provides accurate assessments of RDMA throughput, which is crucial for verifying the performance of InfiniBand networks in high-performance computing and AI training environments.​

The SN5600 smart-leaf/spine/super-spine switch offers 64 ports of 800GbE in a dense 2U form factor. The SN5600 offers diverse connectivity in combinations of 1 to 800GbE and boasts an industry-leading total throughput of 51.2Tb/s.​