The ibnetdiscover utility is the standard tool used to scan an InfiniBand fabric and discover its complete topology. It traverses the network starting from a local port and reports all Host Channel Adapters (HCAs) and switches it finds, along with the links connecting them. This provides a comprehensive map of the fabric, which is the foundational step for understanding and tracing all potential data paths between nodes. It is the most appropriate tool for the broad task of discovering the network layout in a large-scale InfiniBand fabric.

A. NetQ is an NVIDIA telemetry and validation tool primarily designed for modern data centers running Ethernet fabrics with network operating systems like Cumulus Linux or SONiC, not for native InfiniBand path discovery.

B. ibpathverify is used to verify the connectivity and path records between two specific endpoints. It does not discover the overall fabric topology but rather validates pre-existing paths calculated by the Subnet Manager.

D. tracert (or traceroute) is a diagnostic utility for IP-based networks. It operates at Layer 3 to trace the hop-by-hop route of packets and is not applicable to the InfiniBand fabric layer.

1. NVIDIA Mellanox OFED User Manual (v5.8-LTS):

Section 6.1.1, "ibnetdiscover": Describes the tool's function: "ibnetdiscover is a standard InfiniBand diagnostic tool that discovers the InfiniBand topology using directed route packets... It can be used to discover the fabric topology and to make sure that all the fabric links are up." This directly supports its use for discovering network paths.

Section 6.1.5, "ibpathverify": States, "ibpathverify is a standard InfiniBand diagnostic tool that verifies the paths between two nodes." This confirms its role is verification, not discovery.

2. NVIDIA Networking Documentation, NetQ:

NVIDIA NetQ 4.4 User Guide, "What is NVIDIA NetQ?": The documentation consistently describes NetQ in the context of Ethernet fabrics, stating, "NVIDIA NetQ is a highly-scalable, modern network operations tool that provides real-time visibility of your overlay and underlay networks." The focus is on Ethernet/IP constructs.

3. Stanford University, CS 144: Introduction to Computer Networking:

Course materials on "Routing and the Network Layer": Courseware from institutions like Stanford explains that tools like traceroute (tracert on Windows) are fundamental to IP networking for tracing packet routes across routers, which is a different networking paradigm from an InfiniBand fabric.