Port Side Intake vs Port Side Exhaust: What's the Difference?

In modern network data transmission, switches play a crucial role. With the development of network scale and the increase in data volume, we have higher requirements for the stability and reliability of switches. The heat dissipation of switches ensures effective temperature reduction during prolonged operation, maintaining a stable working state. When it comes to the cooling function of a switch, two key factors that determine the heat dissipation cannot be ignored, which are cooling fans and switch airflow.

Introduction to Cooling Fans and Switch Airflow

A switch fan promotes heat dissipation by drawing in cold air and expelling hot air. The types of cooling fans can be divided into built-in fans and hot-swappable fans. Built-in fans are installed internally in the switch and cannot be easily replaced. For example, the S3900-48T4S switch is equipped with built-in fans, and the direction of the switch airflow is left-to-right.

Hot-swappable fans, on the other hand, are designed to be removable, allowing for easy replacement and maintenance. Hot-swappable fans are hot-insertable and hot-removable field-replaceable units, and you can remove and replace the fan without interrupting normal switch operation. Switches equipped with hot-swappable fans typically have an airflow direction of front-to-back or back-to-front, which is a common configuration. For example, the S5860-20SQ switch is equipped with hot-swappable fans, and the switch airflow is front-to-back. The following will focus on the two typical switch airflow (front-to-back and back-to-front), also known as port side intake and port side exhaust, and explain the differences between them.

Port Side Intake vs Port Side Exhaust

Port side intake and port side exhaust refer to the intake and exhaust directions of switch airflow. These two switch airflow configurations differ in terms of heat dissipation methods and application scenarios.

Heat Dissipation Method

Port side intake refers to the configuration where cool air enters the switch from the front, and hot air is expelled from the rear air vent of the switch. In this setup, the cooling fans are located at the rear of the switch, and air enters the switch through the port side (the side with Ethernet or fiber ports) and exits through the power side. This means that the cold aisle (the side with cooler ambient air) should align with the port side.

Port side exhaust, on the other hand, refers to the configuration where cool air enters the switch from the back, and hot air is expelled from the front air vent of the switch. In this setup, the switch fans are located at the front of the switch, and air enters the switch through the power side and exits through the port side. Therefore, the cold aisle should align with the power side.

Application Scenarios

Installation Location

• Port side intake is suitable for mounting switches on a rack. In a rack setup, multiple switches can be installed consecutively, and hot air can be expelled through the rear air vent, maximizing the rack's cooling capacity.

• Port side exhaust is suitable for mounting switches on a wall. Wall installation typically restricts airflow at the back of the switch, and port side exhaust allows cool air to enter from the back of the switch, pass through the internal components, and quickly expel hot air.

Installation Environment

Port side intake is more suitable for installation environments with higher temperatures or poor air circulation. Because the heat dissipation method can leverage the cooling capacity of external devices like racks or equipment shelves, offering better cooling performance.

Cabling Requirements

• Port side exhaust is suitable for cabling scenarios that require access to the rear of the switch. Which ensures that the rear is not obstructed by a large number of cables or other obstacles. Hot air is expelled from the front air vent of the switch, allowing easier access to the ports and other connections at the rear.

• Port side exhaust is also suitable for scenarios with high-density cabling requirements. In this case, the rear of the switch may be restricted, preventing sufficient space for heat dissipation. Port side exhaust can directly expel hot air outside the cabinet, reducing the space occupied within the cabinet and improving overall heat dissipation efficiency.

Related Switch Products

The following table summarizes the enterprise network switches available on FS.com that differ only in the direction of the switch airflow. You can choose the most suitable product based on your requirements.

Conclusion

The heat dissipation function of a switch is a critical factor in ensuring its normal operation and stability. Depending on the installation method, installation environment, and specific cabling requirements, choosing a suitable switch with either port side intake or port side exhaust can maximize the heat dissipation efficiency and help the switch perform at its best in various application scenarios, providing stable and reliable data transmission services for the network. If you would like to learn about other types of switch airflow, you can visit the following resource for more information.

Related resource: Airflow (Left-Right) and Fanless Enterprise Switches