ALCCS
NOTE:
· Question 1 is compulsory and
carries 28 marks. Answer any FOUR questions from the rest. Marks are indicated against each question.
· Parts of a question should be
answered at the same place.
Q.1 a. Differentiate
(i) LAN and WAN
(ii) Monolithic and structured protocols.
b. Explain the working of TCP/IP
model.
c. What signal to noise ratio is required to put
T1 carrier on 50 kHz line?
d. For the binary data 01101001, plot different
digital shift keying modulated wave form and explain the same.
e. Explain the working of CSMA/CA and CSMA/CD
protocol.
f. Why data encryption is required in
networks? Also explain in brief about
DES.
g.
Write a note on World Wide Web. (7
4)
Q.2 a. Explain the functions performed by each
layer in a ISO-OSI reference model with the help of a neat diagram.
b. Explain different types of multiplexing
techniques.
c. Using
CRC a bit stream 1101011011 is to be transmitted. If the generator polynomial
is 1+X3+X4, find the transmitted code. Explain decoding
procedure by adding single bit error in the received code. (6+6+6)
Q.3 a. Explain ALOHA and
slotted ALOHA protocol. Compare the efficiency in each case.
b. Write a brief note on working of the following
(Any ONE):
(i) SNMP
(ii) Electronic mail
(iii) FTP
c. Suppose a group of N stations share a 56 kbps
pure ALOHA channel. Each station outputs 1000 bit frame on an average of once
every 100 sec, even if the previous one has not yet been sent (e.g. the
stations can buffer outgoing frames). What is the maximum value of N? (8+6+4)
Q.4 a. Discuss Markov chain model and explain M/G/1 queues.
b. Explain token ring protocol and obtain the
expressions for its throughput in different cases.
c. T1 carrier has a channel capacity of 1.544 ×106
bits / sec. If 3000 km long T1 trunk is used to transmit 64 byte frames using
Go – back – N protocol. How many bits the sequence number should be if the
propagation speed is 6 s/km. (6+8+4)
Q.5 a. Explain the working of Stop-and-Wait ARQ and
Go-Back-N ARQ protocol.
b. Explain the working of distance vector routing
algorithm.
c. In a network with 720 IMPs, find the number of
table entries required for one, two and three level hierarchy. (8+6+4)
Q.6 a. Explain IPv4 header format with the help of a
neat diagram. State four major improvements of IPv6 over IPv4.
b. Explain the working of User Datagram Protocol.
c. Using Dijkstra algorithm to find the shortest
path from A to D. (8+6+4)
Q.7 a. Explain how the connection is released in a
TCP.
b. Explain the working of RSA algorithm.
c. Encode the 5 symbols, s0, s1,
s2, s3, and s4, generated by a digital source
with probabilities of occurrence of 0.4, 0.1, 0.25, 0.05 and 0.2. (6+6+6)