All of our 10G switches have an “R” model which means it has reverse airflow.
When installed in a rack in a data center, switches are normally placed in the rear. This is because most network cables are in the rear of the servers.
Normal airflow is from front to back of the switch. This is not so good when the switch is installed in the rear of a rack in a data center that has alternating hot and cold aisles – it results in the switch drawing in hot air to try to cool itself. So the reverse airflow model draws air in from the rear of the switch, thus giving a better chance of pulling in cooler air for better thermal control.
There is no other difference between the two models.