NIELIT 2017 OCT Scientific Assistant A (IT) - Section C: 4

Question

Bit stuffing refers to

• A. Inserting a $’0’$ in user data stream to differentiate it with a flag
• B. Inserting a $’0’$ in flag stream to avoid ambiguity
• C. Appending a nibble to the flag sequence
• D. Appending a nibble to the user data stream

Comments

https://gateoverflow.in/336896/Nielit-2017-oct-scientific-assistant-a-cs-section-b-24

Answer 1

Purpose of Bit Stuffing

In Data Link layer, the stream of bits from the physical layer is divided into data frames. The data frames can be of fixed length or variable length. In variable - length framing, the size of each frame to be transmitted may be different. So, a pattern of bits is used as a delimiter to mark the end of one frame and the beginning of the next frame. However, if the pattern occurs in the message, then mechanisms needs to be incorporated so that this situation is avoided.

So A is correct.

Ref: https://www.tutorialspoint.com/what-is-bit-stuffing-in-computer-networks

 

Answer 2

1)The term "bit stuffing" broadly refers to a technique whereby extra bits are added to a data stream, which do not themselves carry any information, but either assist in management of the communications or deal with other issues.
2)The receiver knows how to detect and remove or disregard the stuffed bits