NCS 1004 has a front to back airflow scheme. The air inlet is at the front side of the chassis and the exhaust is on the rear side. This ensures that the airflow is not obstructed or impeded by any object as it may lead to reduced airflow in the system, causing components to operate at a higher temperature. The controller is on the front side and the PSUs and the fan units are on the rear side of the chassis. NCS1004 can host upto 4x single slot NCS1004 line cards, but has been designed also to accommodate 2x double-high line cards.