padding bit (PAD)

Padding bits (PAD) are used when data frames do not correspond to the required packet length.

The inserted padding bits do not contain any information, they only have the task of extending frames that do not correspond to the required frame length to the specified number of bits, thus ensuring functional operation. The insertion of bits is called bit stuffing. A special form of bit stuffing is bit padding.

Bit padding is used, among other things, in the CSMA/ CD method or in the IP header, where a special padding field is available for padding. Padding is also used in encryption when plaintext must be padded to a certain block length, for example in the Data Encryption Standard( DES) when the plaintext block is less than 64 bits.