we have modes of CAR in Cisco routers , normal burst and extended burst
and i need to know which mode should be used in the exam if the task didn't guide me to spesific one ?
each has different formula to calculate CAR paramaters
If the task wasn't specific, then it really doesn't matter - just make something up. I saw somewhere that a good formula is Bc = 1/8 of CIR. And often Be is configured the same as Bc.
So let's say you rate limit to 64K, then your Bc and Be will be 8K.
this is normal burst formula BC=BE and BC=CIR/8
but extended burst formula is
BC = 1.5 X (CIR/8)
BE= 2 X BC
so when each should be used ?
Normal burst formula is most common. I would use it.