DOEACC Society 2006 DOEACC B Level - B2.4 Data Communication and Computer Networks ( ) - Question Paper

C) Network Layer
D) Application Layer
B2.4-R3 Page two of five July, 2006
2. every statement beneath is either actual or FALSE. select the most improper one
and ENTER in the “tear-off” sheet attached to the ques. paper, subsequent
instructions therein. (1 x 10)
2.1 The cells used in Mobile Communications are triangular in shape.
2.2 X.25 is based on virtual circuit.
2.3 2 commonly used data link layer standards are RS-232-C and its successor RS-449.
2.4 PCM is not a common digital modulation method.
2.5 The ATM cells are 64 bytes long.
2.6 IP is a best-effort connectionless protocol.
2.7 The most popular network system in the PC world is Novell Netware.
2.8 The remote controls of TVs, VCRs and Stereo use Radio waves.
2.9 A new development in the communication satellite world is development of low cost
microstations, sometimes called VSATs (Very Small Aperture Terminals).
2.10 Routing and switching in frame relay are performed by the data link layer.
3. Match words and phrases in column X with the nearest related meaning/
word(s)/phrase(s) in column Y. Enter your selection in the “tear-off” ans sheet
attached to the ques. paper, subsequent instructions therein. (1 x 10)
X Y
3.1 Total Internal Reflection A. A simplex protocol
3.2 Cryptography B. Stop and wait protocol
3.3 Echo suppressor C. Fiber optics
3.4 Codec D. Security
3.5 Go back n E. Telephone System
3.6 Multiple access protocols F. Local loop
3.7 Logical Link Control G. Sliding window protocols
3.8 Polling H. IEEE 802.3
3.9 Firewall I. IEEE 802.4
3.10 Flow control & buffering J. Frame Relay
K. Pure ALOHA
L. IEEE 802.2
M. Satellite Networks
N. Internetworking
O. Transport Layer
B2.4-R3 Page three of five July, 2006
4. every statement beneath has a blank space to fit 1 of the word(s) or phrase(s) in
the list beneath. Enter your option in the “tear-off” ans sheet attached to the
ques. paper, subsequent instructions therein. (1 x 10)
A. Cryptography B. HDLC C. Modem
D. Star topology E. Analog Signal F. Framing
G. Distributed queue dual bus H. CDPD I. Routing Algorithm
J. Congestion K. Circuit L. SNA
M. one MHz N. Diffraction grating O. CDMA
P. Traffic shaping Q. Crash Recovery R. Management info
base
4.1 ________ is 1 of the data link layer design problems.
4.2 ________ is IEEE standard 802.6.
4.3 ________ is a packet switched digital datagram service.
4.4 ________ is that past of the Network Layer software responsible for deciding which
output line an incoming packet should be transmitted on.
4.5 When too many packets are current in the subnet, performance degrades this situation
is called ________.
4.6 In WDM, an optical system uses a(n) ________.
4.7 ________, avoids time synchronization issue and also the channel allocation
problem.
4.8 ________ is an approach to congestion management.
4.9 ________ is an element of transport protocol.
4.10 The collection of all possible objects in a network is provided in a data structure called the
________.
B2.4-R3 Page four of five July, 2006
PART TWO
(Answer any 4 questions)
5.
a) discuss with the help of a neat labelled diagram the B-ISDN ATM reference Model.
b) discuss with the help of a neat labelled diagram the ISO-OSI Model and the function of
its different layers.
c) elaborate the various classes of addresses used in IPv4? List their ranges in dotted
decimal notation.
(5+5+5)
6.
a) With respect to transmission media, compare Fiber Optics and Copper Wire.
b) discuss the concept of framing with respect to Data Link Layer.
c) Briefly discuss the High-Level Data Link Control (HDLC) protocols with neat labelled
diagrams.
(5+5+5)
7.
a) Compare the IEEE standards 802.2, 802.3, 802.4, 802.5 and 802.6 briefly.
b) discuss the difference ranging from pure ALOHA and slotted ALOHA and draw diagrams for
them.
c) What is high speed LANs? define briefly the different kinds of High-speed LANs used
in computer communication networking.
(5+5+5)
8.
a) discuss the concept of IP protocols and addresses, subnets and Internet Control
Protocols for the network layer in the Internet.
b) elaborate Routing Algorithms? discuss flooding, the optimality principle and shortest
path routing.
c) What basic functions does a communication satellite perform? provide a good cause why
up-link and down-link frequencies are not identical. Why are earth dish antenna are
generally parabolic in shape?
(5+5+5)
9. Write short notes on any three:
a) GSM
b) SONET
c) Novell Netware
d) Firewalls
(3x5)
B2.4-R3 Page five of five July, 2006

Earning:   Approval pending.