NCP-AIN Exam Dumps - NVIDIA-Certified Professional AI Networking

In InfiniBand networks, P_Keys (Partition Keys) control communication boundaries. Each port can belong to one or more partitions with either full or limited membership.

From NVIDIA InfiniBand Documentation (Partitioning and P_Keys):

"A limited (or partial) membership permits a port to communicate only with other ports in the same partition that have full membership. It cannot communicate with other limited members, even if they are in the same P_Key partition."

This makes limited/partial membership ideal for multi-tenant security , where tenant ports can reach infrastructure ports (full members) but not other tenant ports (limited members).

Incorrect Options:

A & B are not valid InfiniBand P_Key types.

C (Full membership) allows unrestricted communication within the same partition.

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.​

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 for Ethernet 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 DGX SuperPOD is a turnkey AI supercomputing infrastructure designed for large-scale deep learning and high-performance computing workloads. It integrates multiple DGX systems with high-speed networking and storage solutions, providing a scalable and efficient platform for AI research institutions. The architecture supports rapid deployment and is optimized for training complex models, making it the ideal choice for environments demanding top-tier AI performance.​

The correct utility is ibnetdiscover .

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.

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."​

An InfiniBand (IB) Router connects two or more InfiniBand subnets , making it possible for nodes in different subnets to communicate through route-managed communication .

From the official NVIDIA 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:

A and B are incorrect: InfiniBand does not connect directly to Ethernet or SANs without a gateway.

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

The correct answer is PXN (Peer eXchange Network) .

From the NVIDIA NCCL Documentation :

"PXN enables communication between GPUs connected via NVLink and NICs by treating the GPUs as a distributed switch. This architecture improves bandwidth utilization by enabling any GPU to communicate with the NIC via the shortest path available, even if it's not directly connected to the NIC."

This enhances GPU-to-NIC and NIC-to-GPU transfers, leveraging the NVLink topology. It significantly boosts performance in multi-GPU setups where not every GPU is directly connected to the NIC.

Other options:

Adaptive Routing is a fabric-level feature for dynamic path rerouting.

Graph Search Optimization is used internally for topology modeling in NCCL.

SHARP v2 is a switch-based collective acceleration method, unrelated to PXN.