4-1 B.Tech ECE CN Important Questions - nri.edu.in

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Oct 30, 2013 (3 years and 11 months ago)

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COMPUTER NETWORKS

QUESTION BANK





Unit
-
1

Theoretical Questions


1. (a) Give a detailed description of the Novell Netware IPX packet?


(b) Compare connection less and connection orien
ted services with su
itable exam
ples?
[8+8]

(
Feb
-
2008
)(
Set
-
1
)

2
. (a) Discuss the basic functions performed by different layers of ISO
-
OSI reference
model.

(b) List two advantages and two disadvantages of having international standards

for
network protocols. [10+6]

(
Set
-
1
)
(Nov
-
2009)

3. (a) How does Internet differs from WAN?

(b) Give an example where we require

i. Simplex communication

ii. Half duplex communication

iii. Full duplex communication.

(c) What are the two reasons
for using layered
protocols?

[6+6+4]

(
Set
-
1)
(
Nov
-
2009
)

4
. (a) What are the various applications of computer networks?

(b) What are the advantages of multipoint connection over a point
-
to
-
point connection?
What are some of the factors that determine whethe
r a communication system is a LAN,
MAN or WAN? [8+8]

(
Set
-
3
)
(Nov
-
2009)

5. (a) What are the advantages of having layered architecture? Mention the layers

of ISO
-
OSI reference model?

(b) What is Internet? Mention some of the applications of Internet?(
Set
-
3)(Feb

2008)

6
. (a) How would you utilize an existing telephone network for Computer
-
to
-
Computer

data communications?

(b) “Bad Timing” is also a problem for OSI

reference model. Discuss. [
(
Set

4
)(Feb

2008)

7
. (a) List two advantages and two disadvantages o
f having international standards

for
network, Protocols?

(b) Write short notes on interfaces an
d services of ISO layers. [8+8]
(Set
-
1)(Aug

-
2008
)

8
. (a) Explain in detail ISO
-
OSI reference model.

(b) Write short notes on interface, service and protocol. [8+
8]


(
Set
-
2)(Aug
-
2008
)
(
Set

4
)(Aug

2008)

9
. (a) Write any four reasons for using layered protocols.

(b) Compare and contrast OSI and TCP/IP models. [8+8] ](
Set
-
3)(Aug
-
2008
)

10.

(a) What are the header _elds in
TCP segment header that are required for ow

control & congestion control? Explain how these _elds are used for ow control

and congestion control?

(b) What are the header _elds in TCP segment header that are required for error

control? What are the limitati
ons of it?

(Dec
-
2011, set
-
2)

11.
a) Explain about TCP/IP reference model.


b) Explain interface, service and protocol.

(Nov
-
2010, set
-
1)




Unit
-
2


Theoretical Questions


1
. (a) What are the reasons for choosing cell switching in ATM?

(b) Discus
s about the ISDN architecture in detail? [6+10]
(
Feb
-
2008
)(
Set
-
1
)

2
. (a) Explain about ISDN architecture?


(b) Differentiate between optical fiber and coax? [10+6]
(
Set
-
2
)
(Nov
-
2009)

3)

Which switching method allows real
-
time data transfer? Mention the adv
an
-

tages of packet switching? (set
-
3
)(F
eb
-
2008)


4)
How does a virtual circuit differ from a physical circuit? What advantages

would a virtual circuit provide? [8+8](
Set
-
3)(Nov 2010
)

5
)

a)
Write about guided transmission media?

b)
Write about unguided tra
nsmission media?

(Dec
-
2011, set
-
2)


Unit
-
3

Theoretical Questions


1.

(a) Discuss the basic functions of data link layer in brief?

(b) What is pipelining? Discuss the two approaches of dealing with errors in the

presences of pipelining? [8+8]


(
Set
-
1
)(
Feb
-
2008
)

2
. (a) Discuss the error control technique which is commonly used in data
network. What

value of N is used in go
-
back
-
N ARQ technique used in ARPANET and

why?

(b) Imagine that you are writing the data link software for a line us
ed to send

Data

to you, but not from you. The other end uses HDLC, with a 3
-
bit

sequence number and a window size of seven frames. You would like to bu_er

as many out of sequence frames as possible to enhance e_ciency, but you are

not allowed to modify the

software on the sending side. Is it possible to have

a receiver window greater than one, and still guarantee that the protocol will

never fail? If so, what is the largest window that can be safely used? [8+8]



(Set
-
2 Nov
2009)
(
Set
-
2 Feb

2008)

3. (a) How POP works? What are the advantages of IMAP over POP?

(b) What is the role played by message transfer agent? Explain.

)(set
-
2 feb 2008)


(b) Give the detailed description of HDLC frame format? [8+8
]? (Set
-
3

Feb

2008)

4
. (a) Explain about the various services that the data link layer

offers to the upper
layers?

(b) Compute the fraction of the bandwidth that is wasted on overhead (headers

and retransmissions) for sliding window protocol using selectiv
e repeat on a

heavily loaded 50
-
kbps satellite channel with data frames consisting of 40

headre and 3960 data bits. ACK frames never occur. NAK frames are 40 bits.

The error rate for data frames is 1 percent, and the error rate for NAK frames

is negligible
. The sequence numbers are 8 bits.(set 4 feb 2008)


(c) Explain any one C
ollision free protocol. [4+6+6](
Set
-
4

Aug

2008)

5
. (a) Explain one
-
bit sliding window protocol. Give the advantages and
disadvantages

of one
-
bit sliding window protocol?

(b) Discuss
the services provided by the data link layer to the network layer?

[8+8](
Set
-
1

nov 2008
)

6
. When bit stuffing is used, is it possible for the loss, insertion, or modification

of a single bit to cause an error not detected by the checksum? If not, why

not?
If so, how? Does the checksum length play a role here?

(c) Data link protocols almost always put the CRC in a trailer, rather than in a

header. Why? [6+6+4(set
-
1)( aug 2008)(set
-
2 aug 2008)

7
. (a) Compare and contrast SLIP and PPP.

(b) Draw and explain HDL
C frame format. [8+8] (set
-
3)(
Nov 2010
)

8
.
Briefly, explain about the DLL design issues.

(Dec
-
2011
-

set
-
1)





Unit
-
4


THEOERITICAL QUESTIONS


1
. What is a token? Discuss the protocol of token

ring LAN in general. Discuss with

example how priority is implemented in a token ring LAN? [16]


(
Feb

2008
(set1)
(set
-
2)
)

2
. (a) Consider the delay of pure ALOHA versus slotted ALOHA at lo
w load. Which

one
is less? Explain your answer


3
. Write short notes on:

(a) Ethernet

(b) Wireless LAN

(c) Source routing bridge

(d) Remote bridges. [4_4=16]
(set2)(
Nov
-
2009
)

4
. (a) What is pure ALOHA and slotted ALOHA? Mention the advantages of
slotted
ALO
HA? (
Nov 2009
Set
-
3)

5. (a) What is the need for wireless communication? Discuss about various portions

of
spectrum used for transmitting information?

(b) What is done if the cells arriving at two or more input lines at a ATM switch

want to go to the same

output port

in the same cycle? [8+8](
Set
-
2
)
(
Feb

2008)

6
. (a) What is pure ALOHA and slotted ALOHA? Mention the advantages of slotted

ALOHA?

(b) A seven
-
story office building has 15 adjacent offices per floor. Each office

contains a wall socket for a termi
nal in the front wall, so the sockets from a

rectangular grid in the vertical plane, with a separation of 4 m between sockets,

both horizontally and vertically. Assuming that it is feasible to run a straight

cable between any pair of sockets, horizontally,

vertically, or diagonally, how

many meters of cable are needed to connect all sockets using

i. a star configuration with a single router in middle?

ii. an 802.3 LAN?

iii. a ring network (without a wire center )? [6+10
]? (Set
-
3

feb 2008
)

7
. (a) What is the

prime difference between a token bus and a token ring?

(b) A large population of ALOHA users manages to generate 50 requests/sec,

including both originals and retransmissions. Time is slotted in the units of

40 msec.

i. What is the chance of success on th
e first attempt?

ii. What is the probability of exactly k collisions and then a success?

iii. What is the expected number of transmission attempts needed? [4+12](
Set
-
4

Feb

2008)

8
. What is congestion? How does it differ from flow control? Discuss about the

general
principles of congestion? Briefly discuss about polici
es that affect congestion. [16](
Set
-
1

aug 2008)

9
. (a) What is Broadcasting? With an example, explain about Reverse path for
-

warding

(b) With an example, explain mul
ticast Routing Algorithm. [
8+8](
Set
-
2

aug 2008)

10
. (a) With an example, explain Hierarchical Routing Algorithm.

(b) With an example, explain multicast Routing Algorithm. [8+8]
(
Set
-
3

aug 2008)

11
. (a) Write short notes on:

i. Choke packet

ii. Load shedding

iii. Jitter control.

(b)
With an example, explain any one adaptive routing algorithm. [8+8](
Set

4 aug
-
2008)

12
. (a) Discuss about MAC addresses?

(b) Explain about a bit
-
map collision free protocol? [8+8](
Set

1
nov

200
8
)

13
. (a) What is collision free protocols? Explain Binary coun
t down protocol.

(b) Explain in detail, Adaptive fr
ee walk protocol. [8+8] (Set
-
3

Nov 2009
)

14
. (a) Explain the operation of source Routing Bridges.

(b) Compare and contrast Transparent and Source routing bridges. [8+8]




(Set
-
1,2 Nov 2010
)

15
. (a) What is meant by contention systems.

(b) Explain CSMA/CD protocol.

(Dec 2011 set3,4)









Unit
-
5

THEOERITICAL QUESTIONS


1
. (a) Network layer can provide either connection oriented service or connection less

service. Which one you prefer. Justify your answer

(b) Defi
ne Virtual circuit and Datagram. Compare Virtual circuit subnet with

Dat
agram Subnet.

.(set
-
1)(feb
-
2008)

(c) Is Virtual circuit same as Physical connection. Comment. [5+8+3]
(
Set

4
Feb

2008
)

2.

(a) Explain the working of Distance vector routing algorithm with the help of an

example.

(b) What is Count to Infnity problem? Suggest

solution for it. [10+6]
(set1)
(
Nov
-
2009
)

3. (a) What is Multicasting? How is it diferent from broadcasting? How do you

construct a multicast tree? Explain with an example.

(b) What are the applications of multicasting. [10+6]
(set2)(nov2009)

4
. (a) Any V.C.

subnet delivers packets in order, but why Datagram subnet fails to

deliver
packets in order.

(b) For request
-
reply type of service which one is preferred connection oriented

Service/connection

less service. Why?

(c) Among VC Subnet and datagram subnet, wh
ich one maintains state informa
-

tion and why? [6+5+5]
(
set
-
30(nov
-
2009)

5. (a) The major problem with Distance vector algorithm is count to infinity. How

exchange of complete path from router to Destination instead of delay, helps

in solving count to infin
ity problem.

(b) What are the advantages of adaptive routing approach over non adaptive

routing. [10+6](feb 2008)(set
-
2)

6. (a) Consider an organization which has several branches in different cities of India.

How hierarchical routing can be used for routi
ng in such an organization.

(b) Explain how complexity of network layer and transport layer varies with type

of service provided. [10+6](set
-
3
Nov 2009
)

7
. (a) Briefly explain the concepts of Flow Control and Buffering.

(b) Imagine that a two
-
way handshake

rather than a three
-
way handshake were

used to set up connections. In other words, the third message was not required.

Are deadlocks now possible? Give an example or show that none exist. [8+8]

(
set
1,2,
4
Dec

20
11
)




Unit
-
6


THEOERITICAL QUESTIONS


1
. (a) What is the role played by threshold value in congestion control?

(b) Assume network with links having abundant bandwidth. What are the pros

and cons of using exponential increase and linear increase of c
ongestion win
-

dow? What happens if bandwidth is limited?
(set30(nov
-
2009)


2
. (a) How connections are setup and released in ATM?

(b) What is the Format of routing table in ATM? How it helps in routing cells?

[8+8]
(set
-
4)(nov
-
2009)

3. (a) How congestion is

controlled in V.C. subnets?

(b) What is Choke packet? How use of choke packets helps in congestion control?

[8+8](feb 2008)(set
-
2)

4
. Explain routing in mobile hosts. [16](set 3 Feb2008)
(set
-
4 feb 2008)

5
. (a) Briefly discuss ICMP.

(b)

explain Address res
olution protocol. [8+8]9set
-
1 aug 2008)


6. (a) Briefly discuss about connection less Internetworking.

(b) Explain firewalls, packet filter and a proxy in detail. [8+8]
,

7
. (a) Briefly discuss about the ways network can differ.

(b) Briefly discuss about I
P address classes and special IP

addresses. [8+8](set
-
3 Nov
2010
)

8
. (a) What is internet work routing? Explain interior gateway and exterior gateway

protocols.

(b) What is three bears problem? Write short notes on CIDR. [8+8]

(set
-
3, Dec 2011
)






Unit
-
7


THEOERITICAL QUESTIONS


1
. What are the services provided by Network layer to Transport layer. Explain. [16]
(set
-
10(feb 2008)

2
. (a) Network layer can provide both connection oriented service and conne
ction

less service. Similar is the case with Transport layer, then why two di_erent

layers are required.

(b) What are the Transport layers Quality of Service parameters? [8+8]
(set10(nov
-
2009)

3
. (a) What are the header fields in TCP segment header that are

related to only

data transfer? Explain?

(b) What are the header fields in TCP segment header that are required for con
-

nection establishment and release? Explain. [8+8]
(set20(nov 2009)

4. (a) In TCP Why three
-
way handshake is required for connection esta
blishment

and release.

(b) Why TCP is not suitable for request
-
reply type of transfers?

(c) As application developer under what circumstances you use TCP and under

what circumstances you use UDP? [6+5+5]
(set4)(nov 2009)

5
. (a) Why Pseudo header is used in
computing TCP Checksum?

(b) Explain how TCP controls congestion? ](set
-
2)(feb 2008)
(set
-
4 feb 2008)

6
. (a) What are the similarities and differences between Data Link layer and Transport
layer?

(b) Explain addressing at Transport layer? [6+10](set
-
3 feb200
8)

7
. (a) Draw and explain in detail the TCP Header.

(b) Briefly discuss TCP connection Manag
ement. [8+8](
set
-
1
,3

Nov 2010
)

8
. (a) Suppose that the TCP congestion window is set to 18K bytes and a timeout

occurs. How bit will the window be if the next four
transmission bursts are

all successful? Assume that the maximum segment size is 1 KB.


(c) Datagram fragmentation and reassembly are handled by IP and are invisible

to TCP. Does this mean that TCP does not have to worry about data arriving

in the wrong ord
er? [6+6+4 (
set
-
3
Dec 2011
)








Unit
-
8


THEOERITICAL QUESTIONS



1
. Explain in detail SNMP? [16]
(
Set1

Nov

2009)

2. Explain the architecture and services of

e mail system. [16]
(
Set2

Nov

2009)

3
. (a) What are the advantages of using e mail gateways?

(b) How SMTP protocol works? [8+8](set 3 nov 2009)

4. Explain how privacy is achieved in e
-
mail system? [16]
(
Set
-
3

Feb

2008)

5
. (a) What is Domain? Explain the Int
ernet domain space in the context of DNS.

(b) What is resource record? What is its format?

(c) What are the record types of DNS resource record? [6+5+5]
(Set
-
4 Feb 2008)

6
. (a) PGP does not support canonicalization as does PEM. Why not?

(b) Assuming that ev
eryone on the Internet used PGP, could a PGP message be

sent to an arbitrary Internet address and be decoded correctly by all con
-

cerned? Discuss your answer. [8+8](
Set
-
1

Aug

2008)

7
. (a) What is the difference between message confidentiality and message
integrity?

Can you have one without the other? Justify your answer
. (Set
-
1
,4

Nov 2010
)

8. (a) Explain in detail methods of DES chaining.

(b) Br
iefly discuss about IDEA. [8+8](
Set
-
2,
3

Dec 2011
)