Describe CRC technique for error detection.

Cyclic Redundancy Check (CRC): CRC is a different approach to detect if the received frame contains valid data. This technique involves binary division of the data bits being sent. The divisor is generated using polynomials. The sender performs a division operation on the bits being sent and calculates the remainder. Before sending the actual bits, the sender adds the remainder at the end of the actual bits. Actual data bit plus the remainder is called a codeword. 

The sender transmits data bits as codeword.

At the other end, the receiver performs division operation on codeword using the same CRC divisor. If the remainder contains all zeros the data bits are accepted, otherwise it is considered as there some data corruption occurred in transit.