Many Arista switches support reversible air flow. When the fans installed on such a switch have red handles, which of the following statements would…

Arista uses color-coding on its fan and power supply modules to indicate the direction of airflow, but this coding has not been consistent across all hardware platforms. On several switch series, such as the 7150S and 7280R3, red handles or markings signify a forward airflow pattern. This is also known as front-to-rear or port-side intake airflow. In this configuration, the switch draws cool air in from the port side (front) and exhausts the heated air out through the fan side (rear). Therefore, with red-handled fans on these specific platforms, hot air is ejected from the fan side of the switch.

A. This describes the intake side of a forward airflow pattern. While technically correct, option D more directly describes the action performed by the fan module itself, which is to exhaust the air.

B. "Starboard" is not a standard term for switch airflow direction. Furthermore, cooling systems are designed to pull in cool air, not warm air.

C. Fans are designed to pull in cool ambient air to cool the internal components. Pulling in hot air would defeat the purpose of the cooling system.

1. Arista Networks, "7150S Series Quick Start Guide," Document Number: QSG-00041-08, Page 5, "Fan Modules."

The guide states: "Fan modules are color-coded to indicate airflow direction. Modules with red latches indicate front-to-back airflow. Modules with blue latches indicate back-to-front airflow." (Front-to-back airflow ejects hot air from the fan side).

2. Arista Networks, "7280R3 Series Quick Start Guide," Document Number: QSG-00113-04, Page 6, "Fan Modules."

This document specifies: "Fan modules are color-coded to indicate airflow direction. Modules with red markings indicate port-to-power airflow." (Port-to-power airflow is another term for front-to-rear, where hot air is exhausted from the power/fan side).

3. Arista Networks, "Data Center Design with Arista 7050X3 Series," November 2018, Page 10, Section 2.2.2 "Cooling."

This document illustrates the alternate color-coding on newer platforms for context: "The fan and power supply modules are color coded to indicate the direction of airflow. Blue indicates front-to-rear airflow and Red indicates rear-to-front airflow." This highlights the platform-dependent nature of the color-coding.