Bit Stuffing

Question

In a data link protocol, the following character encoding is used:
A → 01000111 B → 11100011 FLAG → 01111110 ESC → 11100000
Assuming that byte stuffing is employed for the four character frame A B ESC FLAG, transmitter sends it as:

A. 01111110 01000111 11100011 11100000 11100000 01111110

B. 01111110 01000111 11100011 11100000 11100000 01111110 01111110

C. 01111110 01000111 11100011 11100000 11100000 11100000 01111110 01111110

D. None of these

Comments

Byte stuffing

FLAG | A B ESC FLAG | FLAG  =>  FLAG | A B ESC(byte stuffed) ESC ESC(byte stuffed) FLAG | FLAG 

Answer 1

Answer would be C.

First octet represents Start and Last Octet represent Stop.

And both ESC and FLAG will follow a Escape character so as to not get misinterpreted during communication.

01111110[START] 01000111[A] 11100011[B] 11100000[ESC] 11100000[ESC] 11100000[ESC] 01111110[FLAG] 01111110[STOP]

Comments

https://cs.stackexchange.com/questions/33684/why-escape-and-escape-in-byte-stuffing