When a packet is sent from the origin to the destination, the packet must be checked at the destination to see if it has arrived correctly. Origin and destination They use the CRC formula to find out if a packet sent over the network has reached its destination safely. It is a formula that all network devices know.
CRC stands for Cyclic Redundancy Check, simply put, an error detection code used to send and receive data correctly. In this method, a code is added at the end of the data strings. In this way, it finds the changes that have occurred during the transfer in their content. This code is added to the end of the packets by the sender and the recipient checks them to make sure the packets are safe. The CRC code works in the data link layer, and if used correctly, it has a 99% chance of being correctly detected.
In general, a CRC is a type of hash function used to generate a checksum. Hash Function is a method of generating rotating data (usually a message or a file) to an appropriate number controlled by a computer.
When a packet is ready to be sent, the sender must generate an error detection code. To generate the CRC code, the sender needs a key that has already been agreed with the receiver on the value of this key. After agreeing on the value of the key, the sender first adds some zeros to the original data and then divides it by the key. It then attaches the result to the end of the data and sends the packet. When the receiver receives the package, it crosses the data and the CRC code. If the result is zero, it means that no error occurred in the closed content.