Rajiv Gandhi Proudyogiki Vishwavidyalaya 2007-3rd Sem M.C.A Computer Aplications .(ester) , .-., - Question Paper

MCA-305(N)
M.C.A.(Third Semester) EXAMINATION, Nov.-Dec.,2007
(New Course)
COMPUTER NETWORKS
[MCA-305(N)]
Time : 3 Hours
Maximum Marks : 100
Minimum Pass Marks : 40

Note : There are 5 Units. Attempt any 1 ques. from every Unit.

Unit - I

1.(a) explain and compare protocols and services in the situation on layered network architecture.
(b) Differentiate ranging from the subsequent :
(i) Broad band ISDN and narrow band ISDN
(ii) Differential PCM and normal PCM

Or

2.(a) What is not-persistent CSMA/CD ? Consider building a CSMA/CD network running at one Gbps over a
one km cable with no repeaters. The signal speed in the cable is 200000 km/sec. What is minimum
frame size ?
(b) Consider the delay of pure ALHOA vs slotted ALOHA at low load. Which 1 is less ? discuss
your ans.

Unit - II

3.(a) Assuming a send window of K, deduce the minimum range of sequence nos. (frame identifiers)
needed with every of the subsequent fault control schemes :
(i) Selective repeat
(ii) Goback-n
(b) In system 16 binary messages 0000 through 1111 are to be transmitted over a data line. every
message is to be protected by a 3-bit CRC generated using the polynomial x3 + x2 + 1:
(i) Derive three check bits for every of the 3 messages:
(1) 0000
(2) 0001
(3) 0010
(ii) Show a single bit fault and a double bit fault in a transmitted code word are detected at
the receiver assuming the transmitted message is 1111.
4.(a) discuss the principle of operation of a CRC fault detection scheme. If the provided message is
'1010001101' and predefined patter is '110101' then :
(i) generate the transmitted message at the transmitter.
(ii) the received message is checked for correctness at the receiver.

(b) Consider an fault free 64 kbpx satellite channel used to send 512 byte data frames in one
direction with very short acknowledgement coming back the open way. What is the maximum
throughput for window sizes of 1,7,15 and 127 ?

Unit - III

5.(a) define the frame format of IEEE 802.4 standards.
(b) Derive an expression for the utilization and worst case access delay of FDDI ring network in
terms of the ring latency and target token rotation timer setting.
Or
6.(a) Differentiate ranging from 802.3,802.4 and 802.5.
(b) A bridge ranging from 802.3 LAN and 802.4 LAN has a issue with intermittent memory errors.
Can this issue reason undetected errors with transmitted frames or will all these be caught
by frame checksum ?

Unit - IV

7.(a) define distance vector routing algorithm. What is count to infinity issue ?
(b) Compare the subsequent :
(i) Virtual circuit and Datagram service
(ii) Open loop and Closed loop congestion control
(iii) Static and Dynamic routing
Or
8.(a) discuss leaky bucket algorithm in congestion control.
(b) With a neat diagram discuss Bellman-Ford routing algorithm for routing packets.

Unit - V

9.(a) discuss DNS. How many levels can a DNS have ? Also discuss domain, tag and full qualified
domain name.
(b) discuss the concept of SNMP ?
Or
10.(a) discuss the Architecture of www. Also describe client, server, URL, cookies.
(b) discuss cryptography. elaborate its different components ?

Earning:   Approval pending.