the problem is: Customer did some fail over tests in his core network. 

If they put one link to down then one ping lost. He set created 100ms BFD on the interfaces in question, 

but still lost 1 ping. After the link is recovered 2 ping lost, that means around 1-3 seconds outage. 

He want ho help him to reduce the time outage. 

the solution is :Generally, if short switching time is not required, you are advised to use default values of min-rx-interval, min-tx-interval, and detect-multiplier. 

If short switching time is required, you are advised to set min-rx-interval to 50, min-tx-interval to 50, and detect-multiplier to 3.