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.