DIP OF IT COMPUTER NETWORKS.pdf

B6. BCS THE CH
a) The following character encoding is used in a data link protocol:
BCS HIGHER
A: 01000111 BCS
B: 11100011
FLAG: 01111110
ESC: 11100000
Wednesda

When using the following four-character frame: COM

A B ESC FLAG.
Answer any FOUR questio
Show the bit sequence transmitted (in binary) for the four-character frame for each
of these framing methods;

i) Byte count Answer any Section A
ii) Flag bytes with byte stuffing.
(8 marks) Answer any Section B

b) For this data link protocol, what is the maximum overhead in a byte-stuffing The marks given in brackets are ind
algorithm?
(3 marks) Only non-programmabl

c) Sixteen-bit messages are transmitted using a Hamming code.

i) How many check bits are needed to ensure that the receiver can detect and
correct single-bit errors?
(2 marks)

ii) Show the bit pattern transmitted for the message 1101 0011 0011 0101.
Assume that even parity is used in the Hamming code.
(8 marks)

d) What are the TWO main causes of error for digital transmission systems?
Illustrate your answer.

(4 marks)