The ibstat command is the standard utility used to query the status of local InfiniBand Host Channel Adapters (HCAs). When executed, it provides a detailed summary for each port on the specified device. This summary explicitly includes the State (e.g., Active), Physical state (e.g., LinkUp), and Link layer (e.g., InfiniBand), which directly addresses the requirements of the troubleshooting scenario. The command is typically invoked as ibstat , such as ibstat mlx50.

A. ibvdevices lists InfiniBand devices available to user-space applications but lacks the detailed port state, physical state, and link layer information.

B. cat /proc/net/ib/device reads raw kernel data. It is not the standard, user-friendly tool for displaying formatted interface status.

C. ibnodes is used to display the topology of the entire InfiniBand fabric, showing discovered nodes, not the specific status of a local HCA port.

1. NVIDIA Mellanox OFED for Linux User Manual (Doc-Rev 23.10-1.1.9.0): In Section 5.1.1, "Basic InfiniBand Utilities," the ibstat command is described as the tool to "Query the basic status of an InfiniBand HCA." The sample output clearly shows fields for "State," "Physical state," and "Link layer."

2. Linux Man Pages - ibstat(8): The official man page for ibstat states its purpose is to "query the status of an InfiniBand HCA." The description of the output confirms it displays the port state, physical state, and other low-level details.

3. Ohio Supercomputer Center (OSC) Documentation, "InfiniBand (IB) Network": University HPC documentation frequently provides practical examples. The OSC guide shows sample ibstat output, which includes the required fields: State: Active, Physical state: LinkUp, and Link layer: InfiniBand. This confirms its use in academic and research environments for this exact purpose.