A bit string, 0111101111101111110, needs to be transmitted

Q: A bit string, 0111101111101111110, needs to be transmitted at the data link layer.

What is the string actually transmitted after bit stuffing?

 

Solution:

 

 The output is 011110111110011111010.

The following data fragment occurs in the middle of a data

Q: The following data fragment occurs in the middle of a data stream for which the byte-stuffing algorithm described in the text is used: A B ESC C ESC FLAG FLAG D.

What is the output after stuffing?

 

Solution:

 

 After stuffing we get: A B ESC ESC C ESC ESC ESC FLAG ESC FLAG D.

The following character encoding is used in a data link protocol

Q: The following character encoding is used in a data link protocol:

A:01000111; B:11100011; FLAG:01111110; ESC: 11100000

Show the bit sequence transmitted (in binary) for the four-character frame: A B ESC

FLAG when each of the following framing methods are used:

(a) Character count.

(b) Flag bytes with byte stuffing.

(c) Starting and ending flag bytes, with bit stuffing.

 

Solution:

 

a. 00000100 0100011111100011 11100000 01111110

b. 01111110 0100011111100011 11100000 11100000 11100000 01111110

01111110

c. 01111110 01000111110100011 111000000 011111010 01111110