Exp	A 6500 comprises a chassis, power supplies, one or two supervisors, line cards and service modules. A chassis can have 3, 4, 6, 9 or 13 slots each (Catalyst model 6503, 6504, 6506, 6509, or 6513, respectively) with the option of one or two modular power supplies. The supervisor engine provides centralized forwarding information and processing; up to two of these cards can be installed in a chassis to provide active/standby failover. The line cards provide port connectivity and service modules to allow for devices such as firewalls to be integrated within the switch.