Hello @UncleJP ,
in modern platforms all features require CEF enabled.
In the case of BFD CEF is needed to be able to offload to linecards the BFD messages handling.
The idea behind BFD is to have a lightweight simple protocol that can be managed in hardware without involving the main CPU.
The old approach was to use short timers in routing protocols but this didn't scale well as these messages have to be processed by the main CPU.
Enabling CEF is required also on low end platforms that can have a software based low level forwarding engine.
Hope to help
Giuseppe
