2.1 PREAMBLE This course is introduced to make students learn the ...

raggedsquadNetworking and Communications

Oct 30, 2013 (3 years and 9 months ago)

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2.1 PREAMBLE


This course is introduced to make students learn the need for connecting the computers where the resources
available are scarce when compared to the demand; these resources include filename servers, printer servers,
communication servers &

application servers etc. There is therefore a need to know how these isolated resources
can be interconnected for resource sharing. Thus a basic fundamental course on computer networks is required at
undergraduate level. After the completion of this co
urse the student is exposed to the fundamental knowledge on
LAN, WAN, MAN and Internet. Regarding various protocols, models like OSI and TCP/IP, and the Transport
related protocols. In detail about Data link, Network, Transport and Application layers. Brie
fly about DNS (Domain
Name system), Electronic mail, and the World Wide Web.


2.2 PREREQUISITES


A student must have undergone a course in STLD, Data communication. Basic knowledge of programming
language like C is highly desirable. A course in OS is also

recommended.


2.3 SYLLABUS


2.3.1 UNIT I


2.3.1.1 Objective


At the end of this unit student is exposed to knowledge of OSI, TCP/IP, and Other networks models. Examples of
networks like Novell Netware, Arpanet, Internet and Network Topologies LAN, WAN an
d MAN.


2.3.1.2 Syllabus


OSI, TCP/IP and other networks models, Examples of Networks: Novell Networks, Arpanet, Internet, Network
topologies LAN, WAN and MAN.


2.3.2 UNIT II


2.3.2.1 Objective Physical Layer


To expose the students to Transmission media c
opper, twisted pair wirelesses switching and encoding asynchronous
communications, Narrow band, Broad band ISDN and ATM.


2.3.2.2 Syllabus


Physical Layer

Transmission media copper, twisted pair wireless, switching and encoding asynchronous
communications; Narrow band, broad band ISDN and ATM.


2.3.3 UNIT III


2.3.3.1 Objective Data link Layer


This unit emphasizes on Design issues, Framing, Error detection

& correction, CRC, Elementary protocol

stop &
wait, and sliding window, slip, and Data link layer in HDLC, Internet, and ATM.


2.3.3.2 Syllabus


Data link layer

Design issues, framing, error detection and correction, CRC, Elementary Protocol
-
stop and wai
t,
Sliding Window, Slip, Data link layer in HDLC, Internet, and ATM.


2.3.4 UNIT IV


2.3.4.1 Objective Medium Access sub Layer


At the end of this unit student acquires knowledge on ALOHA, MAC Addresses, Carrier sense Multiple Access,
IEEE


802, X,
Standard Ethernet, Wireless LANs, Bridges.


2.3.4.2 Syllabus


Medium Access sub Layer ALOHA
, MAC addresses, Carrier sense multiple access. IEEE 802.X Standard
Ethernet, wireless LANS. Bridges


2.3.5 UNIT V


2.3.5.1 Objective Network Layer


At the end of
this unit student is exposed to knowledge of virtual circuit & datagram subnets, Routing algorithm
short path routing, Flooding, Hierarchical routing, Broad cast, multicast, and Distance vector routing.


2.3.5.2 Syllabus


Network Layer
Virtual circuit and
Datagram subnets
-
Routing algorithm shortest path routing, Flooding,
Hierarchical routing, Broad cast, Multi cast, Distance vector routing.


2.3.6 UNIT VI


2.3.6.1 Objective


The objective is to furnish details on Dynamic routing


Broad cast routing, Rotar
y for mobility, Congestion.
Control algorithm, General principles of congestion, prevention policies, Internet working, The network layer in the
Internet and the ATM networks.


2.3.6.2 Syllabus


Dynamic routing


Broadcast routing, Rotary for mobility, Co
ngestion Control Algorithms


General Principles


of
Congestion prevention policies. Internet working: The Network layer in the Internet and in the ATM Networks.


2.3.7 UNIT VII


2.3.7.1 Objective


At the end of this unit the student is exposed to knowled
ge of Transport services, Connection management, TCP,
UDP Protocols, ATM AAL Layer protocols.


2.3.7.2 Syllabus


Transport Layer
Transport Services, Connection management, TCP and UDP protocols; ATM AAL Layer
Protocols.


2.3.8 UNIT VIII


2.3.8.1 Objective

On completion of this unit the student gains knowledge of Network security, Domain Name System, SNMP,
Electronic mail, The world web and multimedia.

2.3.8.2 Syllabus

Application Layer
Network Security, Domain name system, SNMP, Electronic Mail; the World Wide WEB, Multi Media.

2.4 SUGGESTED BOOKS


2.4.1 TEXT BOOKS


T1.

Computer Networks


Andrew S Tanenbaum, 4th Edition. Pearson Education/PHI

T2.

Data Communications and Networking


Beh
rouz A. Forouzan.Third Edition TMH


2.4.2 REFERENCES


R1.

An Engineering Approach to Computer Networks
-

S.Keshav, Pearson Education, 2nd Edition

R2.

Understanding communications and Networks, W.A. Shay, Thomson, 3rd Edition

R3.

Data communication networks

end edition by Alberta Leon Garcia university of Toronto and Indrawidiaia

R4.

Data communication and networking by Achyut S Godbale CGO of Apam Technologies.

R5.

Data network design by Spchm


3
rd

Edition

R6.

Computer Networks


M Anandamurugan

R7.

Comput
er Networks: Protocols, Standard and Interface II edition

R8.

Compute Network and distributed processing: Software Technologies Architecture Martin.

R9.

Data Communication and Computer Network ISRD Group.

R10.

Computer Networks: Principles, Technologies and Protocols for Network Design


Notalia Olifer, Victor
Olifer


2.5 WEBSITES


1.

www.acm.org.dl

2.

www.cs.wisc.edu

3.

www.umiacs.umd.edu

4.

www.ittg.ernet.in

5.

www.tcpipguide.com

6.

www.compnetworking.com














Lectu
re
N
o

Topics in JNTU
Syllab
us

Sub Topics

Suggested
B
ooks

UNIT

I

Introduction

1

Introduction



Uses of computer
networks



Network hardware
network software,
connection less service.

T1
-
Ch1

2

OSI, TCP/IP



The OSI reference model.



The TCP/IP reference
model.



The comparison of the
OSI, TCP reference
model

T1
-
Ch1, T2
-

Ch2

3

Network Models



Novell Netware,



The ARPA NET



INTERNET

T1
-
Ch1

4

Examples of
Network .(Contd..)




X
-
25 Network



Frame Relay

T1
-
Ch1

5

Examples of
Network




Broad Band


ISDN



ATM Reference model

T1
-
Ch1

6

Network
Topologies



WAN, LAN, MAN

T1ch1

UNIT

II Physical Layer

7

Physical Layer



The theoretical basis for
data communication,



Transmission media
magnetic media

T1
-
Ch2, T2
-
Ch2

8

Twisted pair



Twisted pair,
Base band
co
-
axial cable



Fiber optics

T1
-
Ch2, T2
-
Ch7

9

Wireless
communication



Fiber optic network



Electronic spectrum,
Microwave transmission,
Radio Transmission

T1
-
Ch2, T2
-
Ch7

10

Narrow band



Broad band. ISDN and
ATM

T1
-
Ch2

11

Switching &
Asynchronous
communication



Switching, The switch
Hierarchy, Cross bar
switch, space division
switch

T1
-
Ch2

UNIT

III Data Link Layer

12

Data Link Layer



Design Issues, Error
Detection

T1
-
Ch3

13

Error Correction



Error Correction. Error
Detecting codes

T1
-
Ch3

14

Elementary Data
Link protocol



An unrestricted simple
protocol.



A simplex stop


and


wait protocol.

T1
-
Ch3, T1
-
Ch2

15

Sliding window


A one bit sliding window
T1
-
Ch3

protocols

protocol



A protocol using Go back
N



A protocol using selective
repeate.

16

Example Data
Link Layer



HDLC, SLIP, ATM,

T1
-
Ch3

UNIT

IV Medium Access Sub Layer

17

Medium Access
sub Layer



The Channel Allocation
problem.



Static channel Allocation
in LANs & MANs.



Dynamic Channel
Allocation problem

T1
-
Ch2, T2
-
Ch14

18

Multiple Access
Protocols



ALOHA, Slotted ALOHA



CSMA, CSMA with
collision Detection

T1
-
Ch4, T2
-
Ch13

19

Carrier sense
multiple access



Collision


Free protocols



A bit
-
map protocols



Binary count down



Limited contention
protocols

T1
-
Ch4

20

MAC Addresses



MACA and MACAW



GSM,

CDPD, CDMA

T1
-
Ch4, T2
-
Ch14

21

IEE 802 x
standard Ether net



IEEE 802, 802.3 cab lines



Manchester encoding
802.3



MAC sub layer

T1
-
Ch4, T2
-
Ch1.5

22

IEE standard
Ethernet (Contd.)




802.3 LANs



IEEE standard 802.4



Token bus

T1
-
Ch4

23

IEE standard
Ethernet




IEEE standard 802.5:
Token Rings Sub Layer



Comparison of 802.3,
802.4 & 802.5

T1
-
Ch4

24

BRIDGES



Bridges from 802. x to
802.y



Transparent bridge
Spanning Tree Bridge

T1
-
Ch4

25

Bridges, Wire less
LANs



Source Routing Bridges



Remote Bridges



comparison of
802
Bridges



High
-

Speed LANs



FDDI Fast Ethernet



HIPPI


T1
-
Ch4

UNIT

V Network Layer

26

Network Layer



Network Layer


Design Issues




Internal Organization of
the network layer



Comparison of UC & DC.

T1
-
Ch5








27

Routing Algorithm

(Contd..)



The
Optimality principle
shortest path routing,
Flooding

T1
-
Ch5

28

Routing Algorithm




Distance vector Routing



Link


state Routing

T1
-
Ch5

29

Hierarchical
Routing (Contd..)



Routing for mobile host,

T1
-
Ch2

30

Hierarchical
Routing



Broad cast routing



Multi
cast routing

T1
-
Ch4p

UNIT

VI

Dynamic Routing

31

Congestion



Congestion control
algorithms



General Principles of
Congestion control
algorithm

T1
-
Ch5

32

Congestion
Prevention
Policies



Congestion prevention
policies



Traffic Shopping



The Leaky Bucket
Algorithm



Token Bucket Algorithm

T1
-
Ch5

33

Intel Net working.
(Contd..)



Congestion control in
virtual circuit subnet



Choke packets



Weighted for queuing.



Hope


by hope choke
packets



Load shedding

T1
-
Ch5

34

Intel Net working



Internetworking



Concatenated

virtual
circuit



Tunnelling



Inter network Routing.

T1
-
Ch5

35

Fragmentation



Fragmentation.



Fire walls

T1
-
Ch5

36

Network Layer in
the Internet.
(Contd.)



The network Layer in the
Internet



The IP protocol, IP
Address, subnets

T1
-
Ch5

37

Network Layer in
the Internet



Internet control protocols



The address Resolution
Protocols



The reverse Address
Resolution Protocol

T1
-
Ch5

UNIT
-
VII Transport Layer

38

Transport Layer



Transport Services



Elements of Transport
protocols

T1
-
Ch6

39

Berkley Sockets
connection


Addressing



Establishing a connection
T1
-
Ch6

management

and Releasing

40

A simple transport
Protocol



The example of service
primitives



The example of Transport
entity



The example as a Finite
state machine

T1
-
Ch6

41

TCP

(Contd.)



The Internet Transport
protocols (TCP & UDP)



The TCP service model.



The TCP segment



TCP connection
management.

T1
-
Ch6

42

TCP




TCP Transmission Policy



TCP Congestion control



TCP Timer management

T1
-
Ch6

43

UDP



Wireless UDP & TCP

T1
-
Ch6

44

ATM: AAL Layer
Protocol. (Contd..)



Structure of the ATM
Adaption Layer



AALI, AAL2, AAL3/4,
AAL 5,

T1
-
Ch6

45

ATM: AAL Layer
Protocol



Comparison of AAL
protocols



performance Issues

T1
-
Ch6

UNIT

VIII Application Layer

46

Application Layer



Network Security



Traditional Cryptography



Substitution cipher



Transposition ciphers



Two fundamental
cryptography principles

T1
-
Ch7

47

Network Security

(Contd.)



Secret


Key Algorithms



DES, DES chaining



Breaking DES



Public Key Algorithm

T1
-
Ch7

48

Network Security

(Contd.)



The RSA Algorithm



Other
public key
Algorithm



Authentication protocols

T1
-
Ch8

49

Network Security




Establishing shared key
Authentication using Key
heroes



Authentication using
public key cryptography.

T1
-
Ch7

50

DNS

(Contd..)



The Domain Name
system



The DNS Name space



Resource
Records

T1
-
Ch7

51

DNS




Name Servers



SNMP, SMI, MIB



The Stamp Protocol

T1
-
Ch7

52

Electronic Mail



Electronic mail



Architecture & service

T1
-
Ch7



The user Agent



MIME



Message Transfer



SMTP



Email Privacy

53

The World Wide
Web



The World Wide Web



The client
side, The server
side



HTTP protocol



The URL, HTML

T1
-
Ch7

54

www, security



Java, Security

T1
-
Ch7

55

Multimedia



Audio, Video, Analog
System



Digital System



Entropy Encoding



Source Encoding

T1
-
Ch7



















2.7 REVIEW QUESTIONS


2.7.1 UNIT I


1.

Explain the various uses of computer networks

2.

Explain in detail about various protocol hierarchies

3.

Write about design issues for layers

4.

What is the functionality of various service primitives

5.

Explain the architecture of Internet in detail

6.

Wi
th a neat diagram explain ATM virtual circuit


2.7.2 UNIT II


1.

What is the meaning of transmission media and explain different types of transmission media

2.

Explain the Co


Axial Cable with neat diagram

3.

What is the meaning of switching and

explain the different types of switching techniques with neat diagram.

4.

What is the main variation between the Narrow


Band and Broad


Band

5.

Explain the General model of the ATM switch


2.7.3 UNIT III


1.

Explain in detail error detection and
correction

2.

Explain in detail error detecting codes

3.

Explain in detail the elementary data link protocols

4.

Explain in detail the HDLC protocol

5.

Wit ha neat diagram explain the data link layer in Internet


2.7.4 UNIT IV


1.

Explain in detail the wa
velength division multiple access protocols

2.

Explain in detail the exponential back off algorithm

3.

Explain the performance of the Ethernet

4.

Compare and explain SLIP and PPP

5.

Explain in detail 802.11 frame structure


2.7.5 UNIT V


1.

Explain the

store and forward packet switching

2.

Explain the various services provided to the Transport layer

3.

Explain the difference between connection oriented and connectionless


Service

4.

Explain the functionality of shortest path routing

5.

Explain the routing done in Broadcast routing


2.7.6 UNIT VI


1.

Explain in detail congestion prevention policies

2.

Explain briefly about load shedding

3.

Explain in detail about connectionless internetworking

4.

Explain the routing done in Interior gatew
ay protocol

5.

Explain the routing done in Exterior gateway protocol


2.7.7 UNIT VII


1.

Explain in detail the flow control and buffering

2.

Explain the functionality of various service primitives

3.

Explain in detail about the Remote procedure call in UDP

4.

Explain in detail the TCP segment header

5.

Explain how congestion control is done in TCP


2.7.8 UNIT VIII


1.

Explain in detail about the authentication protocols to be provided for network security

2.

Explain in detail about the SNMP model

3.

Explain

the message format in E
-
Mail

4.

Explain the client side and server side scripting in detail

5.

Explain the methods used for data compression




2.8. QUESTION BANK


2.8.1 UNIT I


1.

a)

Write any four reasons for using layered protocols?




b)

List two ways in which the OSI reference model and the TCP/IP reference model are the same



and list in which they differ








c)

Which is the principle difference between CO communication and CL communication?

(Feb 08, Nov 07, Feb 07,
( Mar 06)

2.

a)

Briefly explain about the TCP/IP reference model






b)

Compare and contrast OSI and TCP/IP reference model


(Feb 08, Nov 07, Feb 07, Mar 06, Nov 05)

3.

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?






(Nov’08)

4)

a)

Define the following terms




i)

Computer Network



ii)


Peer Process



iii)

Protocol




iv)

Interface


b)

Discuss various network applications and goals in detail?






(
Nov 08)

5.

a)

Explain problems of the TCP/IP model and protocols?


b)

With a neat diagram explain ARPANET design?








(Nov 08)

6.

a)

List two advantages and t
wo disadvantages of having International standards for network protocols


(Feb 08, Nov 07, Feb 07, Nov 06, ( Mar 06)


b)

With a neat diagram, explain the functionality

of layers, protocols and Interfaces


(Nov 08, Nov 07, Nov 06)

7.

Two networks each provide a reliable connection oriented service. One of them offers a reliable byte stream

and the other offers a reliable message stream. Are they identical?






(Feb 08)

8.

a)

Draw and explain in detail about ISO
-
OSI reference
model






b)

Refer to Question number 2(b)

(Nov 07, Feb 07,Mar 06, Nov 05)

9.

a)

Write short notes on interfaces, services and protocols of ISO layers?




b)

Refer to question 5(a)


(Feb 07, Mar 06, Nov 05)

10.

An alternative to LAN is simply a big t
ime sharing system with terminals for all users. Give two


advantages of a client server system using a LAN







(T1
-
Ch1)

11.

What does “negotiation” mean when discussing network protocols? Give an example












(T1
-
Ch1)

12.

What is

the main difference between TCP and UDP







(T1
-
Ch1)

13

Why does ATM use small, fixed length cells

.








(T1
-
Ch1)

14.

Describe the network types, topologies and switching






(T1
-
Ch1)

15

Explain the difference between
LAN, MAN and WAN






(T1
-
Ch1)

16.

Explain the various protocol hierarchies










(T1
-
Ch1)

17.

Explain in detail about wireless networks









(T1
-
Ch1)

18.

Explain the difference between Internetworking and Internet









19.

Explain in detail about Internet, ATM and Ethernet









(T1
-
Ch1)

20

Which of the OSI layers handles each of the following


a)

Dividing the transmitted bit stream into frames


b)

Determining which route

through the subnet to use







(T1
-
Ch1)

21.

What are the responsibilities of the Data link layer in the Internet model?





(T2
-
Ch2)

22.

What are the responsibilities of the network layer in the Internet model?






(T2
-
Ch2)

23

What are the responsibilities of the Transport layer in the Internet model?





(T2
-
Ch2)

24.

Does the Novell Netware architecture look more like X.25or like the Internet? Explain your answer


(T1
-
Ch1)

25)

Do TPDU’s encapsulate packets or the other

way around? Discuss.




(T1
-
Ch1)

2. 8.2 UNIT II


1.

a)

Compare point
-
to
-
point channels with broadcast channels with suitbleexamples


b)

A collection of 5 routers is to be collected in a point
-
to
-
point subnet. Between each pair of routers,



th
e designers may put a high speed line , a low speed line, or no line. If it takes 100 msec of



computer time to generate and inspect each topology, how long will it take to inspect all of them




to find the one that best matches the expected load








(Nov 08)

2.

Television channels are 6 MHz, wide. How many bits/sec can be sent if four level digital signals


are used. Assume a noise less channel










(Nov 08)

3.

a)

Discuss in detail about Time division switches



b)

With a
neat diagram explain ISDN system with a PBX for use in large businesses




(Nov 08)

4.

a)

Discuss in detail about asynchronous communication


b)

Explain in detail about broad band ISDN









(Nov 08)

5.

What signal to noise ratio is ne
eded to put a T1 carrier on a 50 KHz line





(
T1
-
Ch2)

6.

A regional Telephone company has 10 million subscribers. Each of their telephone is connected to a

Central office by a copper twisted pair. The average length of these twisted pairs is 10 Km. H
ow much is the
copper in the local loops worth? Assume that the cross section of each strand is a circle 1 mm in diameter, the
specific gravity of copper is 9.0, and that copper sells for 3 dollars per Kilogram





(T1
-
Ch2)

7.

A cable TV system has
100 commercial channels, all of them alternating programs which advertising


is this more like TDM or like FDM?









(T1
-
Ch2)

8.

Give an advantage and disadvantage of NT12 ( as opposed to NT1 and NT2) in an ISDN network












(T1
-
C
h2 )

9.

Compare the maximum data rate of a noiseless 4
-
KHz channel using

a.

Analog encoding with 2 bits per sample

b.

The T1 PCM system











(T1
-
Ch2)

10.

Does time division switching necessarily introduce a maximum delay at each switching sta
ge? If so


what is it












(T1
-
Ch2)

11.

In the space division switch of fig 2.39 (a), what is the smallest number of existing connections, that can block a
new outgoing call?










(T1
-
Ch2)

12.

How many bits of RAM buffer does a time switch interchanger need if the input line samples are 10 bits and


there are 80 input lines?












(T1
-
Ch2)



13.

What is the percent overhead on a T1 carrier; that is, what percent of the 1.544 Mbps
are not delivered to


the end user













(T1
-
Ch2)

14.

What is the difference if any, between the demodulator part of a modem and the coder part of a codec?













(T1
-
Ch2)

15.

a)

What are the three major switching meth
ods


b)

What are the two types of switches used in circuit switching







(T2
-
Ch8)

16.

a)

What is crosspoint in a crossbar switch


b)

What is the limiting factor in a crossbar switch? How does a multistage switch alleviate the problem











(T2
-
Ch8)

17.

a)

How is blocking related to crossbar switch


b)

How is blocking related to Multistage switch







(T2
-
Ch8)

18.

a)

Compare TSI and TDM bus


b)

What is the function of the control unit in a TSI and a TDM bus?


19.

How is spac
e division switching superior to time division switching?






(T2
-
Ch8)

20.

How is time division switching superior to space division switching?





(T2
-
Ch8)

21.

What is the form of a signal in twisted pair cable and coaxial cable? How does this
differ from the signal in
fiber optic cable?












(T2
-
Ch8)

22.

Three packet switching networks each contain n nodes. The first network has a star topology with a central
switch, the second is aring, and the third is fully interconnected, with a
wire from every node to every other
node. What are the best, average, and worst case transmission paths in hops?






(T1
-
Ch2)

23.

How many cross points do the switches of

fig 2
-
39(a), what is the smallest number of existing connections that
can block a new outgoing call?









(T1
-
Ch2)

24.

Does time division switching necessarily introduce a minimum delay at each switching stage? If so, What is it?















(T1
-
Ch2)


2.8.3 UNIT III


1.

a)

Briefly Explain about DLL design issues?








(Feb 08, Nov 07)


b)

If the bit string 0111101111101111110 is bit stuffed. What is the output of the string



(Feb 08, Nov 07, Nov 06)

2.

Explain in detail about e
lementary DLL protocols







(Feb 08, Nov 05)

3.

a)

What is the remainder obtained by dividing x
7
+x
5
+1 by the generator x
3
+1





b)

Frames of 1000 bits are sent over a 1Mbps satellite channel. Acknowledgements are always piggy




backed onto data frames. The headers are very short three bit sequence numbers are used what is
the




maximum achievable channel utilization for



i)

Stop
-
and
-
Wait



ii)

Go back n



iii)

Selective repeat









(Feb 08, Nov
06, Mar 06)

4
.

a)

Mentioning the advantages and disadvantages, explain the sliding window protocol using Go back n



and selective repeat protocol


b)

Draw and explain about HDLC protocol frame format






(Feb 08, Feb 07, Nov 05)

5

a)

A 4
-
Mbps token rin
g has a token holding timer value of 10nm sec. What is the longest frame that can


be sent on this ring?


b)

In a token ring the sender removes the frame. What modifications to the system would be needed to


have the receiver re
move the frame instead, and what would the consequences be?




(Feb 08)

6.

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





(Nov 08)

7.

Explain in detail the two data link Protocols widely used in the Internet






(Nov 08)

8.

a)

Discuss the use of hamming code to correct burst errors?


b)

Explain sliding window
protocol using Go back n. What are its advantages and disadvantages?













(Nov 08)

9.

The following data fragment occurs in the middle of a data stream for which the character stuffing



Algorithm described in the text is used

DLE, STX,

A, DLE, B, DLE, ETX. What is the output after


Stuffing













(Nov 07, Mar 06)

10.

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?













(Nov 07, Mar 06)

11.

a)

Data link protocols almost always put the CRC in a trailer, rather than in a header why?


b)

What is SLIP? What are the disadvantage
s of it








(Nov 07, Nov 05)

12.


Draw and explain point to point protocol









(Feb 07)

13.

Write different types of LCP packets that are defined in RFC 1661






(Feb 07, Mar 06)

14

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 me
thods are used


i) Character count


ii) Flag bytes with bit stuffing


iii) Starting and ending flag bytes, with bit stuffing






(T1
-
Ch1)

15.

The following data fragment occurs in the middle of a data stream for which the byte stuffing algorithm



descri
bed in the text is used A B ESC C ESC FLAG FLAG D. What is the output after stuffing











(T1
-
Ch1)

12.

When bit stuffing is used, is it possible for the loss






(T1
-
Ch1)

13.

Can you think of any circumstances under which an open loop control migh
t be preferable to the feed back


type protocols discussed









(T1
-
Ch1)

14.

An 8
-
bit byte with binary value 10101111 is to be encoded using an even
-
parity Hamming code. what is the


binary value after encoding







(T1
-
Ch1)

15.

A 12
-

bit Hamming code whose hexadecimal value is 0xE4F arrives at a receiver. What was the original


Value in hexadecimal? Assume that not more than 1 bit is in error




(T1
-
Ch1)

16.

A channel has a bit rate of 4 Kbps and a propagation delay of 20msec. For what range of frame sizes does


stop
-
and
-
wait give an efficiency of at least 50 percent





(T1
-
Ch1)

17.

Imagine a sliding window protocol using so many bits for sequence numbers

that wraparound never



occurs. What relations must hold among the four window edges and the window size, which is constant


and the same for both the sender and the receiver





(T1
-
Ch1)

18.

a)

In HDLC, what is bit stuffing and why is it needed



b
)

Name the types of HDLC frames, and give a brief description of each


(T2
-
Ch11)


19.

A 12
-

bit Hamming code whose hexadecimal value is 0xE4F arrives at a receiver. What was the original


Value in hexadecimal?

Assume that not more than 1 bit is in error




(T1
-
Ch1)

20.

A channel has a bit rate of 4 Kbps and a propagation delay of 20msec. For what range of frame sizes does


stop
-
and
-
wait give an efficiency of at least 50 percent





(T1
-
Ch1)

21.

Imagine a s
liding window protocol using so many bits for sequence numbers that wraparound never



occurs. What relations must hold among the four window edges and the window size, which is constant


and the same for both the sender and the receiver





(T1
-
Ch1)

2
2.

a)

In HDLC, what is bit stuffing and why is it needed



b)

Name the types of HDLC frames, and give a brief description of each



(T2
-
Ch11)

23.

Stop and Wait ARQ has two control variables S and R. what are their functions




(T1
-
Ch1)

24.

How does Go
back N ARQ differ from Selective Repeat ARQ?






(T1
-
Ch1)

25.

Discuss the size of the selective repeat ARQ sliding window at both the sender site and the receiver site












(T1
-
Ch1)

2.8.4 UNIT IV


1.

a)

Explain in detail the operation of slotted
ALOHA?








b)

Consider the delay of pure ALOHA versus slotted ALOHA at low load. Which one is less?



Explain your answer











(Feb 08, Mar 06)

2.

a)

Explain the static channel allocation in LANs and MANs








b)

Explain five

key assumptions in Dynamic channel Allocation in LANs and MANs










(Feb 08, Nov 08,Feb 07, Mar 06)

3.

a)

Discuss about MAC addresses?


b)

Explain about a bit map collision free protocol








(Nov 08)

4.

a)

Discuss a
bout five key assumptions in case of Dynamic channel allocation in LANs and WANs


b)

Discuss in detail the working of a token bus?







(Nov 08)

5.

a)

Explain how the token ring is maintained in detail?


b)

Does the use of a wire c
entre have any influence on the performance of a token ring




(Nov 08)

6.

a)

What is the prime difference between a token bus and a token ring


b)

A large population of ALOHA users manage to generate 50 requests/sec, Including both o
riginals and


retransmissions. Time is slotted in the units of 40 msec



i)

What is the chance of success on the 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






(Nov 08)

7.

Explain the multiple access protocol using which the stations are aware about their transmissions as



Soon as they detect a collision?








(Nov 07/Feb 07/Nov 06/Mar 06)

8.

a)

Exp
lain the binary exponential Back off algorithm


b)

Write about 802.3 performances










(Nov 07)

9.

a)

What is bridge? Explain the operation of a LAN bridge from 802.3 to 802.4













(Nov 07/Feb 07/Mar 06)


b)

Explain the operation o
f a transparent bridge







(Nov 07/Feb 07/ Mar 06)

10.

Compare Pure ALOHA and slotted ALOHA in detail






(Feb 07, Nov 06, Mar 06)


11.

a)

What is collision free protocol? Explain binary count down protocol


b)

Explain in detail Adaptive
free walk Protocol








(Feb 07)

12.

Measurements of a slotted ALOHA channel with an infinite number of users show that 10 percent of the


Slots are idle.


a)

What is the channel load G


b)

What is the throughput


c)

Is the channel under loaded

or overloaded









(Nov 06, Mar 06)

13.

In an infinite population slotted ALOHA system, the mean number of slots a station waits between a


Collision and its retransmission is 4. Plot the delay versus throughput curve for this system




(M
ar 06)

14.

Briefly write about Network Layer design issues









(Nov 06)

15.

Draw and Explain 802.3 format










(Nov 06)

16.

A group of N stations share a 56
-
Kbps pure ALOHA channel. Each station outputs a 1000 bit frame On an
average o
f once every 100 sec, even if the previous one has not yet been sent. What is the maximum value of N.











(T1
-
Ch1)

17.

A large population of ALOHA users manages to generate 50 requests/sec, including both originals and


retransmissions. Time is s
lotted in units of 40 msec

a)

what is the chance of success on first attempt

b)

what is the probability of exactly k collisions and then a success

c)

what is the expected number of transmission attempts needed





(T1
-
Ch1)

18.

How long does a station s, has to wait in the worst cases before it can start retransmitting its frame over a


LAN that uses


a)

the basic bit map protocol

b)

Mok and Wards protocol with permuting virtual station numbers?





T1
-
Ch1)

19.

What is the b
aud rate of the standard 10 Mbps Ethernet?






(T1
-
Ch1)

20.

An IP packet to be transmitted by Ethernet is 60 bytes long, including all its headers. If LLc is not used,


is padding needed in the Ethernet frame, and if so, how many bytes?





(T1
-
Ch1)

21.

Name two networks that allow frames to be packed back
-

to
-
back. Why is this feature worth having














(T1
-
Ch1)

22.

An 802.16 network has a channel width of 20 MHz. How many bits per second can be sent to a


subscriber station












(T1
-
Ch1)

23.

Give two reasons why networks might use an error correcting code instead of error detection and



retransmission












(T1
-
Ch1)

24.

Ten thousand airline reservation stations are competing for the use of a single slotted ALOHA channel.


the avera
ge station makes 18 requests per hour. A slot is 125 µsec. what is the approximate total channel


load













(T1
-
Ch1)

25.

Imagine two LAN bridges, both connecting a pair of 802.4 networks. The first bridge is faced with 1000


512 bytes frames per second that must be forwarded. The second is faced with 200 4096 byte frames per


second. Which bridge do you think will need the faster CPU? Discuss.





(T1
-
Ch1)

2.8.5 UNIT V


1)

a)

Briefly discuss about concatenated virtual cir
cuits







b)

Briefly discuss about connectionless Internetworking






(Feb 08, Nov 07, Nov 06)


2)

a)

For hierarchical routing with 4800 routers, what region and cluster sizes should be chosen to minimize



the size of routing table

for a three level hierarchy







(
Feb 08, Mar 06)


b)

Compute multicast spanning tree for router c in the subnet below for a group with member at routers



A, B, C, D, E, F, I and k.

3)

a)

What are the problems that caused the demise of distan
ce vector routing? Explain the algorithm that



replaced it










b)

With an example, explain the distance vector routing algorithm










(Feb 08, Nov 07, Feb 07, Mar 06)

4)

a)

What is non adaptive routing. Explain any two non adaptive routing alg
orithms


b)

Define route. Why routing algorithm is required, routes can be predetermined and use them when



required or routes can be determined when needed and use them immediately. First method is



proactive

and second method is reactive. Which one is preferred for wired networks? Justify your



answer













(Nov 08)

5)

What are the services provided by Network layer to the Transport layer. Explain







6)

Give three examples of
protocol parameters that might be negotiated when a connection is set up


(Nov 07)

7)

Are there any circumstances when a virtual circuit service will ( or at least should) deliver packets out of


order. Explain













(Nov 07)

8)

Assuming th
at all the routers and hosts are working properly and that all software in both is free of all errors. Is
there any chance, however small, that a packet will be delivered to the wrong destination?














(Nov 07)

9)

A network uses a token
bucket scheme for traffic shaping. A new token is put into the bucket every 5µsec.
What is the maximum sustainable net data rate









(Nov 07)

10)

A computer on a 6 Mbps network is regulated by a token bucket. The token bucket is filled at a rate of

1 Mbps.
It is initially filled to capacity with 8 mega bits. How long can the computer transmit at full 6 Mbps.










(Nov 07, Mar 06)

11)

A datagram subnet allows routers to drop packets whenever they need to. The probability of a router
discarding a packet is p. consider the case of a source host connected to the source router, which is connected to
the destination router an
d then to the destination host. If either of the router discards the packet, the source host
eventually times out and tries again. If the host
-
router and router
-

router lines are counted as hops. What is the
mean number of


i)

hops a packet makes per tra
nsmission


ii)

transmissions a packet makes


iii)

hops required per received packet










(Nov 07)


12)

Briefly discuss about the congestion control in VC subnets







(Nov 07, Mar 06)

13)

Explain about count to infinity problem? What

is split horizon hack?






(Feb 07, Mar 06)

14)

With an example explain Hierarchical routing algorithm







(Feb 07, Mar 06)

15)

With an example explain Multicast routing algorithm








(Mar 06)

16)

What is flooding? What are the variations of flooding








(Nov 06)

17)

What is routing algorithm? What are the classifications of it? What is optimality principle? With an example
explain shortest path routing algorithm











(No
v 06)

18)

Briefly write about Network layer design issues









(Nov 06)

19)

Compare and contrast datagram versus virtual circuit subnets








(Nov 06)



20)

Consider the network ignoring the weights on the lines. Suppose that it use
s flooding as the routing algorithm. If
a packet sent by A to D has a maximum hop count of 3, list all the routers it will take.also list how many hops
worth of bandwidth it consumes






(T1
-
Ch5)

21)

Give a simple heuristic for finding two paths throu
gh a network from a given source to a given destination that
can survive the loss of any communication line. The routers are considered reliable enough, so it is not
necessary to worry about the possibility of router crashes








(T1
-
Ch5)

22)

Looking
at the subnet, how many packets are generated by a broadcast from B, using


a)

reverse path forwarding?


b)

the sink tree?












(T1
-
Ch5)

23)

Give two example applications for which connection oriented service is appropriate also give two examples

for
which the connectionless service is best









(T1
-
Ch5)

24)

Give three examples of protocol parameters that might be negotiated when a connection is setup















(T1
-
Ch5)

25)

Consider the subnet. Distance vector routing is
used, and the following vectors have just come into router C:
from B: (5,0,8,12,6,2); from D: (16,12,6,0,9,10); and from E(7,6,3,9,0,4). The measured delays to B, D and E
are 6, 3 and 5 respectively. What is C’s new routing table? Give both the outgoing li
ne to use and the expected
delay.














(T1
-
Ch5)



2.8.6 UNIT VI


1.

a)

Explain congestion? How do we control the same? Which packets are used practically for this



Purpose? At what layer it is done? What is the difference between f
low control and congestion control














(Feb 08)

2.

a)

Imagine a generalized n
-
army problem, in which the agreement of any two of the armies is sufficient




for victory. Does a protocol exists that allow blue to win?





b)

Suppose that the clock driven scheme for generating initial sequence numbers is used with a 15 bit



wide clock counter. The clock ticks once every 100 msec, and the maximum packet life time is 60 sec.



how often need resynchronization takes place



i)


in the worst case



ii)

when the data consumes 240 sequence numbers/min






(Feb 08, Nov 06, Mar 06)


c)

Why does the maximum packet lifetime, T, have to be large enough to ensure that not only the



Packet, but also its acknowledgements,

have vanished





(Feb 08, Nov 06, Mar 06)

3.

a)

Briefly discuss ICMP








b)

Discuss the two styles of Internetworking










(Feb 08, Feb 07,(Mar 06)

4.

a)

what is meant by contention systems


b)

Explain CSMA/CD protocol


c)

Explain any one col
lision free protocol








(Feb 08)

5.

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





(Feb 08)

6.

a)

What is the format of cell in ATM


b)

Compare permanent VC with
switched VC in ATM


c)

How fixed size cells increased the speed of switching







(Nov 08)


7.

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 congestion window? What happens if bandwidth is




limited













(Nov 08)

8.

Briefly discuss about Internet work routing









(Nov 07, Mar 06)

9.

Brief
ly discuss about fragmentation










(N0v 07, Mar 06)

10.

What is tunnelling? When it is used? Is it used in wireless LANs?




(Nov 07, Nov 06, Mar 06)

11.

What is three bears problem? Write short notes on CIDR







(Nov 07)

12.

Briefly discuss about connectionless Internet working







(Nov 07, Feb 07)

13.

Draw, explain the IPV6 header format









(Feb 07)

14.

With an example explain the address resolution protocol







(Nov 06, Mar 06)

15.

Is fragmentation needed in concatenated virtual circuit internets, or only in datagram systems?














(T1
-
Ch1)



16.

Tunnelling through a concatenated virtual circuit subnet is straight forward: the multi protocol router at one end
just sets u
p a virtual circuit to the other end and passes packets thorough it. Can tunnelling be used in datagram
subnets? If so,how?









(T1
-
Ch1)

17.

A class B network on the internet has a subnet mask of 255.255.240.0. What is the maximum number of

hosts

per subnet?












(T1
-
Ch1)

18.

Describe a way to do reassembly of IP fragments at the destination






(T1
-
Ch1)

19.

IPv6 uses 16
-
byte addresses. If a block of 1 billion addresses is to allocate every picoseconds, how long will


the

address last?












(T1
-
Ch1)

20.

The protocol field used in the IPv4 header is not present in the fixed IPv6 header. Why not?














(T1
-
Ch1)

21.

When the IPv6 protocol is introduced, does the ARP protocol have to be changed? If so, are

the changes


conceptual or technical?











(T1
-
Ch1)

22.

ARP and RARP both map addresses from one space to another. In this respect they are similar. However, their
implementations are fundamentally different. In what major way do they differ?














(T1
-
Ch1)

23.

Suppose that instead of using 16 bits for the network part of a class B address, 20 bits has been used. How many
class B networks would there have been.








(T1
-
Ch1)

24.

In both IP and ATM, the checksum covers only the head
er and not the data. Why do you suppose the design
was chosen?












(T1
-
Ch1)

25.

Convert the IP address whose hexadecimal representation is C22F1582 to dotted decimal notations














(T1
-
Ch1)


2.8.7 UNIT VII


1.

a)

Give the format of a

TCP segment and UDP segment. Explain when UDP is preferred to TCP


b)

What are blocking call primitives and non blocking primitives





(Feb 08)


2.

a)

Define the following terms



i)

option negotiation



ii)

transport quality



iii)

transport

service user



iv)

transport service provider


b)

Explain four protocol scenarios for releasing a connection






(Feb 08)

3.

a)

Draw and explain the structure of the ATM adaption layer


b)

Briefly discuss about TCP timer management







(Feb 08, Feb 07)

4.

a)

Explain the techniques for controlling packet lifetime


b)

What is forbidden region? Explain how sequence numbers are given to TP
-
DUS




(Nov 08)

5.

a)

What are the different flags in TCP segment? Explain eac
h of them


b)

How TCP uses sliding window to achieve flow control






(Nov 08)

6.

a)

Why pseudo header is used in computing TCP checksum


b)

Explain how TCP controls congestion








(Nov 08)

7.

a)

Explain how service differentiation can be achieved using types of service field


b)

The IP header checksum only verifies the integrity of the IP header. Discuss the pros and cons of doing
the checksum on the header part versus on the entire packet


c)

Identify the range of IPv6 addresses spanned by class A, class Band class C




(Nov 08)

8.

a)

Explain Berkley socket primitives for TCP


b)


Briefly explain the concept of addressing in TL







(NOV 07)

9.

What is Nagales algo
rithm? Explain the problem of silly window syndrome. Suggest a solution to


this problem











(Nov 07)

10.

Draw and explain AAL1 cell format, header and trailers







(Nov 07)

11.

a)

Briefly discuss about TCP connection Management


b)

Refer to

question number 1(b)








(Feb 07, ( Mar 06)

12.

If all links in the Internet were to provide the reliable delivery service, would the TCP reliable delivery



Service be completely redundant? Why or why not







(Feb 07)

13.

what

are some of the services that a data link layer protocol can offer to the NL? Which of these data link


layer services have corresponding services in IP? In TCP?






(Feb 07)

14.

Give a potential advantage when Nagales algorithm is used on a badly
congested network


(Nov 06, ( Mar 06)

15.

Are deadlocks possible with the transport entity? If so, how? Suggest a solution to overcome the


deadlock











(Nov 06, ( Mar 06)

16

Draw and explain in detail TCP header









( Mar 06)

17

a)

Can AA
L1 handle messages shorter than 40 bytes using the scheme with the pointer field?



Explain your answer?










b)

AAL ¾ allows multiple sessions to be multiplexexd onto a single virtual circuit. Give an example of a



situation in whic
h that has no value. Assume that one virtual circuit has sufficient bandwidth to carry all



the traffic











(Nov 06)

18

What is the payload size of the maximum length message that fits in a single AAL 3/4 cell


b)

Briefly discuss the differen
ce between AAL protocols







( Nov 06)


19

Why does UDP exist? Would it not have been enough to just let user processes send raw IP packets













( Nov 06)

20.

Imagine that a two way handshake rather than a three way handshake were used to set up connections. In

other words, the third message were not required. Are deadlocks now possible? Give an example or show that
none exist








(T1
-
Ch6)

21.

Datagram fragm
entation 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 order


(T1
-
Ch6)

22.

In a network that has a maximum TPDU size of 128 bytes, a maximum TPDU lifetime of 30 sec, and
an 8 bit sequence number , what is the maximum data rate per connection


(T1
-
Ch6)

23 A TCP machine is sending windows of 65,535 bytes ov
er 1
-
Gbps channel that has a 10 msec one way delay.
What is the maximum throughput achievable? What is the line efficiency?

(T1
-
Ch6)

24)

Suppose that the TCP congestion window is set to 18K bytes and a timeout occurs. How big the window


will be if the ne
xt four transmission bursts are all successful? Assume that the maximum packet size is 1KB








(T1
-
Ch6)

25)

For each event that can potentially occur in the transport entity, tell whether it is legal or or not when


the user is sleeping in sending state






(T1
-
Ch6)



2.8.8 UNIT VIII



1)

a)

What is public key cryptography? Explain with an example



b)

Explain Diffie
-

Hellman key exchange authentication protocol




(Feb 08, Feb 07, Nov 06)

2)

a)

Explain in detail methods of DES chaining


b)

Briefly discuss about IDEA








(Feb 08, Nov 06)

3)

a)

What is crypt analysis? Briefly discuss about substitution chipper, transposition chippers and one time



Pads


b)

Explain any one secret key algorithm







(Feb 08, Nov 0
7, ( Mar 06)

4)

a)

What is MOSPF? Discuss briefly about Multicast backbone


b)

What is ADSL? Draw, explain the ADSL as the local distribution network




(Feb 08,( Mar 06)

5

a)

with the help of a diagram explain the encryption model


b)

What is th
e role of key secrecy and algorithm secrecy in security?


c)

What are the approaches for crypt analysis








(Nov 08)

6

a)

What is security? What is network security? What is information security? How network security and




Information securities are related?


b)

What are the pros and cons of providing security?


c)

Who are the people who cause security problems







(Nov 08)

7

a)

In E
-
Mail system, where the E
-
Mail messages are shared and why?


b)

E
xplain any browser of your choice









(Nov 08)

8

Explain in detail DES











(Nov 08)

9.

What is SNMP? Briefly discuss the SNMP model components






(Nov 07, Nov 06)

10.

a)

What is e
-
mail? Brief
ly discuss about the user agent


b)

What is the role of SMI in network management








(Feb 07)

11.

a)

What is a key distribution center ? what is a certificate authority?


b)

In what way does a public key encrypted message digest provide a be
tter digital signature than using




public key encrypted message










(Feb 07)

12.

a)

What is DNS? Briefly discuss DNS Namespace


b)

Explain, in detail principal DNS resource record types






(Nov 06, Feb 07)

13.

Explain any two com
pression techniques









(Feb 07)

14.

Explain the built in HTTP request methods








( Mar 06)

15.

How do you make an image clickable in HTML? Give an example






(Mar 06)

16.

a)

PGP does not support canonicalization as does PEM. Why

not





b)

Assuming that every one on the Internet used PGP, could a PGP message be sent to an arbitrary Internet




address and be decoded correctly by all concerned? Discuss your answer





(Mar 06)

17.

Explain the hardware architecture of vid
eo server






(Nov 07)

18.

Draw and explain the video on demand protocol stack






(Mar 06)

19.

Suppose that a message has been encrypted using DES in ciphertext block chaining mode. One bit of a

ciphertext in block C, is accidentally transf
ormed from a 0 to a 1 during transmission. How much plain text


will be garbled as a result










(T1
-
Ch7)


20.

Design an attack on DES based on the knowledge that the plain text consists exclusively of uppercase


ASCII letters, plus space, comma,
period, semicolon, carriage return, and line feed. Nothing is known


about the plain text parity bits







(T1
-
Ch7)

21.

Using the RSA public key cryptosystem with a =1,b=2 etc


a) If p=7 and q=11, list five legal values for d.


b) If p=13, q=31 an
d d=7, find e


c) Using p=5, q=11, and d=27, find e and encrypt “abcdefghij”


22.

The Diffie


Hellman algorithm is being used to establish a secret key between Alice and Bob. Alice sends



Bob (719,3,191). Bob responds with (543). Alice’s secret number,
x is 16. What is the secret key?













(T1
-
Ch7)

23.

Consider the quoted

printable MIME encoding scheme. Mention a problem not discussed in the text and


Propose a solution











(T1
-
Ch7)

24.

Give two reasons why PGP compresses messages








(T1
-
Ch7)

25.

When web pages are sent out , they are prefixed by MIME headers. Why?



(T1
-
Ch7)