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US206

Two Hours



UNIVERSITY OF MANCHESTER

INSTITUTE OF SCIENCE AND TECHNOLOGY




CT211 Networking and Open Systems




For candidates taking:


BSc IN COMPUTATION

SECOND YEAR SESSIONAL


BSc IN COMPUTING SCIENCE

SECOND YEAR SESSIONAL


BSc IN INFORMATION SYSTEMS ENGINEERING

SECOND YEAR SESSIONAL


BSc IN PURE MATHEMATICS AND COMPUTATION

FINAL EXAMINATION


MEng, BEng IN SOFTWARE ENGINEERING

SECOND YEAR SESSIONAL



Thursday 3 June 1999









9.30
-
11.30



Answer

three

questions


The use of electronic calculators is NOT permitted








Note: Do not answer more than the required number of questions. Clearly

cross out anything you do not wish to be marked

PTO



(2)



1)

Answer
all

parts



Explain what is meant by an
open

system, and why such a system usually has a
layered

architecture.










(4 marks)



Describe, in general terms, the functions of each layer in a simple 3
-
layer model of a
computer communications architecture.










(6

marks)



Explain why the reference models used in practice have more than 3
-
layers, and describe the
functions of each layer in
one

reference model.










(10 marks)










2)

Answer
all

parts



Briefly compare and contrast each of the following communication technologies:



(a)

analogue

and
digital

data transmission




(5 marks)



(b)

guided

and
unguided

transmission media




(5 marks)



(c)

synchronous

and
asysnchronous

transmission modes


(5

marks)



(d)

circuit

and
packet

switching






(5 marks)



US206

(3)



3)

Answer
all

parts


Explain, giving examples, the difference between
point
-
to
-
point

and
broadcast
(multi
-
access)

channels.










(6 marks)


Describe the following access control techniques for multi
-
access channels such as in
LANs:



(a)

CSMA/CD








(7 marks)



(b)

Token ring







(7 marks)










4)

Answer
all

parts



Explain the main features of both a
connection
-
orientated

and a
connectionless

service.


(8 marks)



The service provided by the Network and Transport layers in the OSI Reference Model may
be either connection
-
orientated or connectionless. Describe the factors that affect the choice
of service in these layers in a part
icular networking application.










(8 marks)



What choices of service have been made in the TCP/IP protocol suite?










(4 marks)










PTO

(4)



5)

Answer
all

parts



Describe the networking aspects of
two

of the following:



(a)

The telelphone system







(10 marks)



(b)

The World
-
Wide
-
Web







(10 marks)



(c)

Cable Television







(10 marks)






END OF PAPER