Error Detection

Cyclic Redundancy Check (CRC) and checksum methods are used for error detection.
SDLC/HDLC supports 16 bit CRC error detection. CRC can detect all the single errors,double errors and burst errors up to 16 bits in length and can detect 95 to 99 % of burst errors of >16 bits.

For example,you can treat the binary data as message polynomial of certain degree as G(X) .A generator polynomial is a type of code used in CRC-12,CRC-16 and CRC-CCITT - P(X).
n= total no. of bits in the message,k=no. of data bits.n-k = BCC= no. of bits in the BCC.

G(X) * X ^ n-k / P(X).
The ramainder is sent along with the data as CRC.
The data sent = (G(X) * X ^n-k) + C(X).

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