RTU 2016 Question Paper Semester VIII Electronics and Communication Engineering Computer Networks

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v B.Tech. Vm Semester(Old/Back) Examination ApriUMay - 2016
\f, Electronics & Comm. Engg.
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€ SEC1 (O) Computer Networks

Time : 3 Hours Maximum Manks : 80
Min. Passing Marks : 24

Instructions to Candiclates;
Attempt any tive questions, selecting one qercstionfror* efrch unit. All questions
carry equal marks. (Schematic diagrams must be shown wherever necessary.
Any data you fee! missing suitably be assumed and stated clearly. Units of
quantities used/cqlculated rnust be stated clearly.)

Unit - I
1. a) Assuming that customers arrive in a Poisson fashion to the counter of
supermarket at an average rate of l5 per hour and the service by the clerk has
an exponential distrib ution.
Determine at what average rate must a clerk work in order ensure a probability
of 0.90 that the customer will not wait longer than 12 minutes. (8)
b) Explainmathematicalmodel forM/Nf/m/m queues. (8)
OR
t. a) The capacity of communication line is 2000 bit/second. This line is used to
transmit eight bit characters, so the rnaxirnum rate is 250 characters/second.
The application calls for traffic ftom many devices to be sent on the line with
a total volume of 12,000 characters/minute.

Determine
t) The lineutilization (3)
ii) The average number of characters waiting to be transmitted. (3)
iii) The average fransmission time (including queuing delay) per character.(2)
b) Consider the M/NI/I/K queuing system show that
Lo= L-(1-Pr)

w'=L 1
p

8E4088/zorc (1) [Contd....

yy =Lg+g
lt
Where
queue
L": Average number of customers.m
in system
L": Average number of customers in the queue'
a customer spends waiting
wa: Average amount of time that
W:Amountoftimethatacustomerspendsinsystem.(2+3+3)
Unit - il

2. a) AmessageisbrokenupintothrTpieces.Discussthetransmissionofthe
p"t" switching (6)
packet using,h" ;;;;il upp*t't'I"
b) AthreestageswitchingstructurerstoaccomodatedN=128inputand128 of
For 16 first stage u,a ro ru.t stage determine the number
outputterminals. (6)
croru points for non blocking' t_-^-t_r^,,a,rerirrr layer
network layer delivery and transport (4)
c) What is the difference between
delivery.
OR
2. a) Achannelhasabitrateof4kbpsandpropogationdelayof20msec.For
gives an efficiency of at least
stop and wait
50
what range of frame size does (8)
percent. (8)
b) Describe the Go Back N Protocol'
Unit - III
3. a) ShowthatslottedAloHAhasamaximumthroughputoft'wicethemaximum
(8)
b) Briefly describe various CSMA
protocols'
OR
3. a) InapureALOHAsystemthera3|ltarrivaltimefromapoissondistribution
iii rate is 10 mbps and there are 10'000
having arateof 103 packets/se.. fftfr.
bits/Packet, find
D Normalizedthroughputofthesystem (4+4)
that will maximize the throughput'
ii) Number of bits per packet
scheme' Explain briefly
---'e L priority
b) Draw the diagram for IEEEJ eva'J
802'5 token ring (8)
the steps for working'
Unit - IV
to route the packet
distance vector routing is used
4. a) Explain with example how
pioblem arises and how does to
get solved' (10)
and why count to infinity
needs six
u ,i," address 20|.70.64.0. The company
b) A company is granted (6)
subnets' Design the subnets'
/r\

OR
(5)
4. a) Compare IPV. and IPV6. ^ i will
mask of 255'255'240'0'what
b) A class B network on internet has a subnet
(5)
be the maximum number of hosts per subnet'
(6)
c) Write short note on network layer design issues'
Unit - V
a) List the merits and demerits of frame relay with respect to X' 25"
(6)
5.
b) with a suitable sketch explainATM cell format for user network interfuce'(4)
(6)
c) Compare the three B - ISDN access methods'
OR
(8)
5. a) ExplainAlM adaptionlayerin detail'
b) Write short notes on
D DTE - DCE interface (4+4',)
ii) B-ISDNserv-ices'

RIl,408* (3)