Tele-Communication (Telecom) Terms Glossary and Dictionary
Bit Stuffing refers to the the practice of inserting non-information of bits to a stream of data. Bit stuffing is required by many network and communications protocols for the following reasons:
1. To prevent data being interpreted as control information. For instance, many frame-based protocols, such as X.25, signal the beginning and end of a frame with six consecutive 1 bits. Therefore, if the actual data being transmitted has six 1-bits in a row, a zero is inserted after the first 5 so that the dat is not interpreted as a frame delimiter. Of course, on the receiving end, the stuffed bits must be discarded.
2. For protocols that require a fixed-size frame, bits are sometimes inserted to make the frame size equal to this set size.
3. For protocols that required a continuous stream of data, zero bits are sometimes inserted to ensure that the stream is not broken.