The Route Switch Feature Card (RSFC) provides multiprotocol routing for Catalyst LAN switches. The RSFC is a fully functional Cisco IOS router feature card available on the Catalyst 5000 series Supervisor Engine II G (WS-X5540) and Supervisor Engine III G (WS-X5550). The RSFC contains no physical interfaces. InterVLAN routing is accomplished using virtual interfaces that correspond one-to-one with the VLANs configured on the switch.