NCP-AIN Questions and Answers

The ibstat command is utilized to display the operational status of InfiniBand Host Channel Adapters (HCAs). It provides detailed information, including the state (e.g., Active, Down), physical state (e.g., LinkUp, Polling), and link layer (e.g., InfiniBand, Ethernet) of each port on the HCA. This information is crucial for diagnosing connectivity issues and ensuring that the InfiniBand interfaces are functioning correctly.​

Reference Extracts from NVIDIA Documentation:

"The ibstat command displays the status of the host channel adapters (HCAs) in your InfiniBand fabric. The status includes the HCAs' state, physical state, and link layer."​

"For proper operation, you are looking for ‘State: Active‘ and ‘Physical State: LinkUp’."​

Before upgrading Cumulus Linux, it's essential to back up configuration files to a different server. The /etc directory is the primary location for all configuration data in Cumulus Linux. Specifically, the following files and directories should be backed up:​

/etc/frr/ - Routing application (responsible for BGP and OSPF)

/etc/hostname - Configuration file for the hostname of the switch

/etc/network/ - Network configuration files, most notably /etc/network/interfaces and /etc/network/interfaces.d/

/etc/cumulus/acl - Access control list configurations​

Cumulus Linux is a network operating system used on NVIDIA Spectrum switches, including those in the Spectrum-X platform, to provide a Linux-based environment forEthernet networking in AI and HPC data centers. When upgrading Cumulus Linux to a new version, it’s critical to migrate specific configuration files to preserve network settings and ensure continuity. The question asks for the two configuration file locations that should be migrated from the old installation during an upgrade.

According to NVIDIA’s official Cumulus Linux documentation, the key directories containing configuration files that should be migrated during an upgrade are /etc/cumulus/acl (for access control list configurations) and /etc/network (for network interface configurations). These directories store critical network settings that define the switch’s behavior, such as ACL rules and interface settings, which must be preserved to maintain network functionality after the upgrade.

Exact Extract from NVIDIA Documentation:

“When upgrading Cumulus Linux, you must back up and migrate specific configuration files to ensure continuity of network settings. The following directories should be included in the backup:

/etc/cumulus/acl: Contains access control list (ACL) configuration files that define packet filtering and security policies.

/etc/network: Contains network interface configuration files, such as interfaces and ifupdown2 settings, which define the network interfaces and their properties.Back up these directories before upgrading and restore them after the new version is installed to maintain consistent network behavior.”—NVIDIA Cumulus Linux Upgrade Guide

This extract confirms that options A and B are the correct answers, as /etc/cumulus/acl and /etc/network contain essential configuration files that must be migrated during a Cumulus Linux upgrade. These files ensure that ACL policies and network interface settings are preserved, which are critical for Spectrum-X configurations in AI networking environments.

The NVIDIA NVUE Collection for Ansible includes pre-built roles designed to streamline automation tasks across various switch models and configurations. These roles encapsulate common network configurations, allowing for efficient and consistent deployment.​

By utilizing these roles, network administrators can:​

Apply standardized configurations across different devices.​

Reduce the complexity of playbooks by reusing modular components.​

Ensure consistency and compliance with organizational policies.​

This approach aligns with Ansible best practices, promoting maintainability and scalability in network automation.​

FromNVIDIA Performance Tuning Guide (ib_write_bw Tool Usage):

"-S <SL>: Specifies the Service Level (SL) to use for the InfiniBand traffic. SL is used for setting priority and mapping to virtual lanes (VLs) on the IB fabric."

This flag is useful when testing QoS-aware setups or validating SL/VL mappings.

Incorrect Options:

A– No such flag for burst size.

B– -q defines number of QPs.

C– --rate or -R is used for rate-limiting.

TheNVIDIA Network Operatoris designed to simplify and automate the deployment and management of networking components in Kubernetes clusters, particularly those utilizing NVIDIA Spectrum-X switches. It manages the installation and configuration of necessary drivers, plugins, and other networking resources to enable features like RDMA and GPUDirect RDMA, which are essential for high-performance AI workloads.​

By leveraging Kubernetes Custom Resource Definitions (CRDs) and the Operator Framework, the Network Operator ensures that networking components are consistently and correctly configured across the cluster, reducing manual intervention and potential configuration errors.​

NVIDIA NetQ is a comprehensive network operations tool designed to provide real-time visibility into the health and performance of NVIDIA networking environments, including Spectrum-X. It offers detailed telemetry and analytics, allowing administrators to monitor adaptive routing behaviors, detect congestion, and analyze traffic patterns. By leveraging NetQ, you can ensure that adaptive routing is functioning as intended and that the network is optimized for AI workloads.​

Reference Extracts from NVIDIA Documentation:

"The NVIDIA NetQ network validation and ASIC monitoring tool set provide visibility into the network health and behavior. The NetQ flow telemetry analysis shows the paths that data flows take as they traverse the network, providing network latency and performance insights."​

"By leveraging telemetry from Spectrum Ethernet switches and BlueField-3 SuperNICs, NVIDIA NetQ can detect network issues proactively and troubleshoot network issues faster for optimal use of network capacity."​

UFM Telemetry: Provides real-time monitoring and analysis of network performance, collecting data such as port counters and cable information to assess the health and efficiency of the network.

UFM Enterprise: Focuses on comprehensive network management and optimization, enabling administrators to monitor, operate, and optimize InfiniBand scale-out computing environments effectively.

UFM Cyber AI: Detects and mitigates network security threats by analyzing telemetry data to identify anomalies and potential security issues within the network infrastructure.​

Reference Extracts from NVIDIA Documentation:

"UFM Telemetry provides real-time monitoring and analysis of network performance."​

"UFM Enterprise is a powerful platform for managing InfiniBand scale-out computing environments."​

"UFM Cyber-AI enhances the benefits of UFM Telemetry and UFM Enterprise services by detecting and mitigating network security threats."​

The NVIDIA Spectrum-X Reference Architecture (RA) 1.0.1 is designed for Ethernet AI cloud deployments and includes the SN5600 Spectrum-4 switches and BlueField-3 SuperNICs. This architecture supports adaptive routing and DOCA programmable congestion control (PCC) for lossless RoCE traffic, optimizing performance for AI workloads.

The SN5600 switch offers 64 ports of 800GbE in a dense 2U form factor, providing high throughput and low latency essential for AI applications.

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'."

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.

The ibnetdiscover utility is used to perform InfiniBand subnet discovery and outputs a human-readable topology file. GUIDs, node types, and port numbers are displayed, as well as port LIDs and node descriptions. All nodes and links are displayed, providing a full topology. This utility can also be used to list the current connected nodes. The output is printed to the standard output unless a topology file is specified.​

InfiniBand is a high-performance, low-latency interconnect technology used in AI and HPC data centers, particularly for east-west traffic between compute nodes in large-scale fabrics. Ensuring seamless data flow requires tools to troubleshoot and monitor the network, including the ability to trace and discover network paths between nodes. The question asks for the specific tool used to trace and discover paths in an InfiniBand fabric, which is a key task in InfiniBand troubleshooting.

According to NVIDIA’s official InfiniBand documentation, the ibnetdiscover tool is designed to discover and map the topology of an InfiniBand fabric, including the paths between nodes. It scans the fabric, queries the subnet manager, and generates a topology map that details the connections between switches, Host Channel Adapters (HCAs), and other devices. This tool is essential for verifying connectivity, identifying routing paths, and troubleshooting issues like misconfigured routes or link failures in large-scale InfiniBand fabrics.

Exact Extract from NVIDIA Documentation:

“The ibnetdiscover tool is used to discover the InfiniBand fabric topology and generate a map of the network. It queries the subnet manager to retrieve information about all nodes, switches, and links in the fabric, providing a detailed view of the paths between nodes. This tool is critical for troubleshooting connectivity issues and ensuring proper routing in InfiniBand networks.”

—NVIDIA InfiniBand Networking Guide

This extract confirms that ibnetdiscover is the correct tool for discovering network paths in an InfiniBand east-west fabric. It provides a comprehensive view of the fabric’s topology, enabling administrators to trace paths between compute nodes and ensure seamless data flow.

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 NVIDIA Spectrum-X networking platform is an Ethernet-based solution optimized for AI workloads, combining Spectrum-4 switches, BlueField-3 SuperNICs, and advanced software to deliver high performance and low latency. Gathering telemetry data is critical for optimizing Spectrum-X networks, as it provides visibility into network performance, congestion, and potential issues. The question asks for the tool used to collect telemetry data in a Spectrum-X network.

According to NVIDIA’s official documentation, NVIDIA NetQ is the primary tool for gathering telemetry data in Ethernet-based networks, including those running on Spectrum-X platforms with Cumulus Linux or SONiC. NetQ is a network operations toolset that provides real-time monitoring, telemetry collection, and analytics for network health, enabling administrators to optimize performance, troubleshoot issues, and validate configurations. It collects detailed telemetry data such as link status, packet drops, latency, and congestion metrics, which are essential for Spectrum-X optimization.

Exact Extract from NVIDIA Documentation:

“NVIDIA NetQ is a highly scalable network operations tool that provides telemetry-based monitoring and analytics for Ethernet networks, including NVIDIA Spectrum-X platforms. NetQ collects real-time telemetry data from switches and hosts, offering insights into network performance, congestion, and connectivity. It supports Cumulus Linux and SONiC environments, making it ideal for optimizing Spectrum-X networks by providing visibility into key metrics like latency, throughput, and packet loss.”

—NVIDIA NetQ User Guide

This extract confirms that option C, NetQ, is the correct tool for gathering telemetry data in a Spectrum-X network. NetQ’s integration with Spectrum-X switches and its ability to collect and analyze telemetry data make it the go-to solution for network optimization tasks.

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. ​

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).​

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.​