CYCLIC REDUNDANCY CHECK (CRC)

To activate a network system to check move error without increasing the amount of information in every packet another most successful method is made which is named CRC.

To understand the functions of CRC consider data in a packet as co-efficient of a polynomial. Their co-efficient set is divided by a given polynomial. The remainder of this division is then transferred as checked and CRC at the receiver to check errors. CRC has good error detection properties. It is easy to understand in hardware.

HARDWARE COMPONENTS USED IN CRC:

CRC needs just two hardware elements:

• Shift register
• Exclusive OR ( XOR unit )

The XOR unit is given in the figure below.

Shift register is also given in figure. It operates two operations.

• Initialize: puts all bits to zero
• Shift: replaced all bits to the left position.