Errors in information transmission are called transmission errors in order to improve the accuracy of data transmission and reduce the channel bandwidth occupied by erroneous data transmission in the channel. There are many reasons for data errors. For the data link layer, it may be frame duplication, frame disorder and frame loss.
Deviation of signal from original signal or standard during transmission. In an ideal amplifier, except for amplification, the output waveform should be exactly the same as the input waveform.