The Cisco Nexus 5548 switches uses a front-end power supply. The chassis has slots for two power supplies. Two power supplies can be used for redundancy, but the Cisco Nexus 5548 switch is fully functional with one power supply. Note that the Cisco Nexus 5548P switch supports only front-to-back (port-side exhaust) airflow and the Cisco Nexus 5548UP switch supports either front-to-back (port-side exhaust) or back-to-front (port-side intake) airflows.