A frame that enters a switch fails the Frame Check Sequence. Which two interface counters are incremented? (Choose two.) (Select two.)
input errors
frame
giants
CRC
runts
collisions
Explanations
Answer A (Correct): Input errors are incremented for various reasons, including CRC errors, frames that are too short or too long, and others. A Frame Check Sequence error will therefore cause this counter to increase.
Answer D (Correct): CRC (Cyclic Redundancy Check) is the method used for FCS verification. If a frame fails this check, the CRC counter is incremented.
When a frame enters a switch, it is checked to ensure that it has not been altered during transmission. This check is called Frame Check Sequence (FCS). If this check fails, it usually means that there has been an error in the transmission of this frame. Cisco switches keep a record of these errors by incrementing certain interface counters.
Answer B (Incorrect): “frame” is not a counter in itself. This is a general term for a data unit.
Answer C (Incorrect): “giants” refer to frames that exceed the maximum size allowed for a frame on a given network. If a frame fails the FCS check, this does not necessarily mean that it is too large.
Answer E (Incorrect): “runts” refer to frames that are smaller than the minimum size allowed. Once again, if a frame fails the FCS check, this does not mean that it is too small.
Answer F (Incorrect): “collisions” refers to situations where two devices attempt to transmit data simultaneously on the same channel. This has nothing to do with an FCS verification error.
