The WS-F6700-CFC is a daughtercard that provides centralized forwarding for the 67xx linecards. The CFC is the base requirement for 67xx linecard operation and is a zero cost option. The daughtercard houses two ASICs that function only as a bus interface. That is, these ASICs form truncated or compact headers, which are sent to the central PFC3* for forwarding decisions.
As the name implies, the CFC is only used for centralized forwarding. The centralized forwarding rate for the Catalyst 6500 is 30 Mpps, maximun. The CFC does not provide any local forwarding capabilities. This is different from any other type of module on the Catalyst 6500; typically, the centralized forward capability is inherent to the baseboard, and any daughtercards provide additional (non-standard) functionality.
When a DFC3** is added to a 67xx linecard, the CFC needs to be removed. The DFC3 daughtercard provides distributed forwarding (dCEF). The CFC and DFC3 each use the same linecard connector, so they are mutually exclusive on a particular module.
* PFC3 can be PFC3A, PFC3B, or PFC3BXL.
** DFC3 daughtercard options are WS-F6700-DFC3A, WS-F6700-DFC3B, WS-F6700-DFC3BXL, WS-F6700-DFC3C, or WS-F6700-DFC3CXL.