NVIDIA NCP-AIN NVIDIA-Certified Professional AI Networking Exam Practice Test

The Network Traffic Map in NVIDIA's Unified Fabric Manager (UFM) provides a visual representation of the network topology and traffic flows, which is particularly useful for identifying congestion points, verifying network configurations, and optimizing workload distribution.

However, when troubleshooting a single node's hardware failure, the Network Traffic Map is less effective, as it focuses on network-level issues rather than individual hardware components.​

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 /

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.

To check the status and link layer of InfiniBand interfaces, the ibstat command is used. For example:​

ibstat -d mlx5_0

This command provides detailed information about the InfiniBand device, including its state (e.g., Active), physical state (e.g., LinkUp), and link layer (e.g., InfiniBand).​

TheNVIDIA UFM Cyber-AI Platformis specifically designed to enhance security and operational efficiency in InfiniBand data centers. It leverages AI-powered analytics to detect security threats, operational anomalies, and predict potential network failures. By analyzing real-time telemetry data, it identifies abnormal behaviors and performance degradation, enabling proactive maintenance and threat mitigation.​

This platform integrates with existing UFM Enterprise and Telemetry services to provide a comprehensive view of the network's health and security posture. It utilizes machine learning algorithms to establish baselines for normal operations and detect deviations that may indicate security breaches or hardware issues.​

Inmulti-subnet InfiniBand environments, AI training clusters are segmented across network zones (or subnets). Direct GPU-to-GPU communication (especially for collective ops like AllReduce, Broadcast, etc.) requires inter-subnet reachability. NCCL supports this via theInfiniBand Router (IB Router)feature.

From theNCCL User Guide – Environment Variables Section:

"NCCL_IB_USE_IB_ROUTER: Enables NCCL support for IB routers which are used in multi-subnet InfiniBand fabrics. When enabled, NCCL can traverse IB subnets using a properly configured IB router."

This is critical because without IB Router support:

NCCL would be restricted to intra-subnet GPU collectives.

Multi-node training across subnets would fail or fall back to slower TCP fallback mechanisms.

Technical Explanation:

IB Routers usesubnet managers(like OpenSM with routing tables) to bridge communication across different InfiniBand partitions.

NCCL queries the subnet topology, discovers routing paths, and usesRDMA CM(Connection Manager) to establish GPU transport over routers.

This capability is especially important in data center-scale AI clusters spanning multiple racks or zones, connected viaIB routers like Mellanox SB7800 or QM8700 series.

When NCCL_IB_USE_IB_ROUTER=1 is set:

NCCL includes router-aware route resolution in its path selection logic.

Enables efficientzero-copy communicationacross GPUs in different IB domains, maintaining low latency.

Other Options Explained:

A. Lazy connection establishment– controls when peer connections are made but does not enable cross-subnet reach.

B. GPU Direct RDMA– enables intra-node direct memory access, not applicable for routing across subnets.

C. Static plugin linking– affects how NCCL links plugins, not related to IB topology.

Exact Extract Reference:

Source: NVIDIA NCCL User Guide – Environment Variables Section

Extract: "NCCL_IB_USE_IB_ROUTER: Enables NCCL support for IB routers, required for multi-subnet InfiniBand configurations. Ensures proper routing of collectives over fabric-wide topologies."

NVIDIA AIR (AI-Ready Infrastructure) is a cloud-based simulation platform designed to model and validate data center network deployments, including Spectrum-X Ethernet networks, using realistic topologies and configurations. When creating a custom topology in NVIDIA AIR, users can define network links between devices (e.g., spine and leaf switches) using a DOT file format, which is based on the Graphviz graph visualization software. The question asks for the correct syntax to define a link between port 1 on a spine switch (spine-01) and port 41 on a leaf switch (gpu-leaf-01) in a NVIDIA AIR simulation.

According to NVIDIA’s official NVIDIA AIR documentation, the DOT file format is used to specify network topologies, including nodes (devices) and links (connections between ports). The syntax for defining a link in a DOT file uses a double dash (--) to indicate a connection between two ports, with each port specified in the format "":"". For Spectrum-X networks, which typically use Cumulus Linux or SONiC on NVIDIA Spectrum switches, ports are commonly labeled as swpX (switch port X) rather than ethX (Ethernet interface), especially for switch-to-switch connections in a leaf-spine topology. The correct syntax for the link between port 1 on spine-01 and port 41 on gpu-leaf-01 is:

"spine-01":"swp01" -- "gpu-leaf-01":"swp41"

This syntax uses swp01 and swp41 to denote switch ports, consistent with Cumulus Linux conventions, and the double dash (--) to indicate the link, as required by the DOT file format.

Exact Extract from NVIDIA Documentation:

“You can create custom topologies in Air using a DOT file, which is the file type used with the open-source graph visualization software, Graphviz. DOT files define nodes, attributes, and connections for generating a topology for a network. The following is an example of a link definition in a DOT file:

"leaf01":"swp31" -- "spine01":"swp1"

This specifies a connection between port swp31 on leaf01 and port swp1 on spine01. Port names typically follow the switch port naming convention (e.g., swpX) for Cumulus Linux-based switches.”

—NVIDIA Air Custom Topology Guide

This extract confirms that option A is the correct answer, as it uses the proper DOT file syntax with swp01 and swp41 for port names and the double dash (--) for the link, aligning with NVIDIA AIR’s topology definition process for Spectrum-X simulations.

Analysis of Other Options:

B. "spine-01":"swp1" to "gpu-leaf-01":"swp41": This option uses the correct port naming convention (swp1 and swp41) but incorrectly uses the word to as the connector instead of the double dash (--). The DOT file format requires -- to define links, making this syntax invalid for NVIDIA AIR.

C. "spine-01":"eth1" to "gpu-leaf-01":"eth41": This option uses ethX port names, which are typically used for host interfaces (e.g., servers) rather than switch ports in Cumulus Linux or SONiC environments. Switch ports in Spectrum-X topologies are labeled swpX. Additionally, the use of to instead of -- is incorrect for DOT file syntax, making this option invalid.

D. "spine-01":"eth1" - "gpu-leaf-01":"eth41": This option uses a single dash (-) instead of the required double dash (--) and incorrectly uses ethX port names instead of swpX. The ethX naming is not standard for switch ports in Spectrum-X, and the single dash is not valid DOT file syntax, making this option incorrect.

Why "spine-01":"swp01" -- "gpu-leaf-01":"swp41" is the Correct Answer:

Option A correctly adheres to the DOT file syntax used in NVIDIA AIR for defining network links:

Node and Port Naming: The nodes spine-01 and gpu-leaf-01 are specified with their respective ports swp01 and swp41, following the swpX convention for switch ports in Cumulus Linux-based Spectrum-X switches.

Link Syntax: The double dash (--) is the standard connector in DOT files to indicate a link between two ports, as required by Graphviz and NVIDIA AIR.

Spectrum-X Context: In a Spectrum-X leaf-spine topology, connections between spine and leaf switches (e.g., Spectrum-4 switches) use switch ports labeled swpX, making swp01 and swp41 appropriate for this simulation.

This syntax ensures that the NVIDIA AIR simulation accurately models the physical connection between spine-01 port 1 and gpu-leaf-01 port 41, enabling validation of the Spectrum-X network topology. The DOT file can be uploaded to NVIDIA AIR to generate the topology, as described in the documentation.

TheCloudAI Benchmarkis designed to evaluate and establish performance baselines in AI-optimized networking environments like NVIDIA Spectrum-X. It assesses various performance metrics, including throughput and latency, ensuring that the network meets the demands of AI workloads. This benchmarking is essential for validating the benefits of Spectrum-X and for ongoing performance monitoring.​

To identify the activeSubnet Manager (SM)node in an InfiniBand fabric, the correct command sequence is:

sminfo

Displays general information about the active SM in the fabric, including itsLID.

smpquery ND <LID>

Resolves theNode Description (ND)at the given LID, revealing the exact hostname or label of the SM server.

From the InfiniBand Tools Guide:

"The sminfo utility provides the LID of the master SM. Use smpquery ND <LID> to resolve the node name hosting the SM."

This two-step approach is standard for locating and validating the SM identity in fabric diagnostics.

Incorrect Options:

B (Nl)is an invalid query type.

CandDdo not identify SMs.

NVIDIA NetQ is a highly scalable network operations toolset that provides visibility, troubleshooting, and validation of networks in real-time. It delivers actionable insights and operational intelligence about the health of data center networks—from the container or host all the way to the switch and port—enabling a NetDevOps approach.

NetQ can be used as the functional test platform for the network CI/CD in conjunction with NVIDIA Air. Customers benefit from testing the new configuration with NetQ in the NVIDIA Air environment (“digital twin”) and fix errors before deploying to their production. ​

In the Spectrum-X architecture,BlueField-3 SuperNICsare 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.​

MLNX_OFED (Mellanox OpenFabrics Enterprise Distribution) is an NVIDIA-tested and packaged version of the OpenFabrics Enterprise Distribution (OFED) for Linux. It provides the necessary drivers and tools to support InfiniBand and Ethernet interconnects using the same RDMA (Remote Direct Memory Access) and kernel bypass APIs. MLNX_OFED enables high-performance networking capabilities essential for AI clusters, including support for up to 400Gb/s InfiniBand and RoCE (RDMA over Converged Ethernet).​

Reference Extracts from NVIDIA Documentation:

"MLNX_OFED is an NVIDIA tested and packaged version of OFED that supports two interconnect types using the same RDMA (remote DMA) and kernel bypass APIs called OFED verbs – InfiniBand and Ethernet."​

"Up to 400Gb/s InfiniBand and RoCE (based on the RDMA over Converged Ethernet standard) over 10/25/40/50/100/200/400GbE are supported."​

The correct utility isibnetdiscover.

From the official NVIDIA InfiniBand Utilities Guide:

"ibnetdiscover scans the fabric and returns a topology of all switches and end nodes, including their GUIDs, LIDs, port numbers, and link speeds."

It generates a fabric map with node-to-port relationships and shows:

GUIDs

LIDs (Local IDs)

Link speeds and widths

Switch-to-host connections

This is essential for network topology validation and mapping physical port additions.

Incorrect Options:

ib_check_routes– for routing table diagnostics.

ibhosts– shows host information but not switch-level port mapping.

ibswitches– shows switch info, but lacks port-level LID/link speed mapping.

The ibdiagnet utility is a fundamental tool for InfiniBand fabric discovery, error detection, and diagnostics. It provides comprehensive reports on the fabric's health, including error reporting, switch and Host Channel Adapter (HCA) configuration dumps, various counters reported by the switches and HCAs, and parameters of devices such as switch fans, power supply units, cables, and PCI lanes. Additionally, ibdiagnet performs validation for Unicast Routing, Adaptive Routing, and Multicast Routing to ensure correctness and a credit-loop-free routing environment.​

Reference Extracts from NVIDIA Documentation:

"The ibdiagnet utility is one of the basic tools for InfiniBand fabric discovery, error detection and diagnostic. The output files of the ibdiagnet include error reporting, switch and HCA configuration dumps, various counters reported by the switches and the HCAs."​

"ibdiagnet also performs Unicast Routing, Adaptive Routing and Multicast Routing validation for correctness and credit-loop free routing."​

To upgrade the MLNX-OS on InfiniBand switches, the recommended procedure is as follows:​

Connect to the switch via SSH: Establish a secure shell connection to the switch using its management IP address.​

Fetch the MLNX-OS software image: Obtain the appropriate MLNX-OS software image from the official source or repository.​

Use the 'install' command to perform the upgrade: Execute the 'install' command on the switch to initiate the upgrade process with the fetched software image.​

This method ensures a smooth and efficient upgrade without the need for physical intervention or service disruption.​

Reference Extracts from NVIDIA Documentation:

"Click on Systems → MLNX-OS Upgrade. Select the desired upgrade method (e.g. 'Install from local file'). Select your image and click 'Install Image'."

AnInfiniBand (IB) Routerconnects two or moreInfiniBand subnets, making it possible for nodes in different subnets to communicate throughroute-managed communication.

From the officialNVIDIA InfiniBand Routers Documentation:

"An InfiniBand router provides connectivity between two or more InfiniBand subnets, enabling communication between hosts that are not on the same subnet while preserving isolation and scalability."

Ensures fabric scalability by allowing subnet segmentation.

Uses LID routing across subnet managers (SMs).

Essential in large clusters with thousands of nodes.

Incorrect Options:

AandBare incorrect: InfiniBand does not connect directly to Ethernet or SANs without a gateway.

Cis unrelated: NVLink is a GPU interconnect, not tied to InfiniBand routers.

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.​

NVIDIA Air is a cloud-based network simulation tool designed to create digital twins of data center infrastructure, including Spectrum-X networks. It allows users to model switches, SuperNICs, and storage components, enabling the simulation, validation, and automation of network configurations before physical deployment. This facilitates Day 0, 1, and 2 operations, ensuring that network designs are tested and optimized for AI workloads.​

Reference Extracts from NVIDIA Documentation:

"NVIDIA Air enables cloud-scale efficiency by creating identical replicas of real-world data center infrastructure deployments."​

"NVIDIA Air allows users to model data center deployments with full software functionality, creating a digital twin. Transform and accelerate time to AI by simulating, validating, and automating changes and updates."​

"NVIDIA Air supports simulation of NVIDIA Spectrum Ethernet (Cumulus Linux and SONiC) switches and NVIDIA BlueField DPUs and SuperNICs as well as the NetQ network operations toolset."​

NVIDIA's What Just Happened (WJH) is a feature that provides real-time visibility into network problems by analyzing all packets passing through the switch and alerting on performance issues caused by packet drops, congestion, high latency, or misconfigurations.

WJH retains the last packets that were dropped from the switch with complete packet headers and the actual drop reason. This enhances the ability to debug network problems, identify affected flows, and decrease time-to-repair.

In InfiniBand networks,Partitioning using Partition Keys (PKeys)is the standard method for implementing multi-tenancy and traffic isolation. PKeys allow administrators to define logical partitions within the fabric, ensuring that traffic is confined to designated groups of nodes. This mechanism is essential for creating secure and isolated environments in multi-tenant architectures.​

The Unified Fabric Manager (UFM) leverages PKeys to manage these partitions effectively, enabling administrators to assign and control access rights across different tenants. This approach ensures that each tenant's traffic remains isolated, maintaining both security and performance integrity within the shared fabric.​

NetQintegrates multiple telemetry sources, includingWJH,DOCA, and notably,Behavioral Telemetry.

From theNetQ 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 introducingintent-based anomaly detection, crucial for proactive operations.

Incorrect Options:

Flow telemetryandpacket captureoffer raw data but not behavioral insights.

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

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.