Indira Gandhi National Open University (IGNOU) 2005 Diploma Computer Applications CS09 Data Communications and Networking - - Question Paper

ADCA / MCA (II Yr)
Term-End exam

December, 2005

CS09 : Data Communications and Networking

Time: three hours
Maximum Marks: 75

Note : ques. No. one is compulsory. ans any 3 ques. from the rest.
1. (a) In most network, the datalink layer handles transmission eror by requesting damaged frames to be transmitted. If the probability of frames being damaged is P, what is the mean number of transmissions needed to send a frame if acknowledgements are never lost. (6)

(b) what are wavelength division multiplexing. (4)

(c) If the bit string 0111101111101111110 is bit stuffed. what is the output string ? Illustrate. (2)

(d) discuss the concept of transparent bridges. Where are they used ? (5)

(e) Make diagrams of manchester coding and differential manchester coding of bit stream : 100110010. (4)

(f) ans the subsequent ques. with respect to Internet congestion control algorithm :
(i) discuss all the parameters used in the algorithm. (3)
(ii) Plot the congestion window as a function of the transmission number and discuss the function of the algorithm. (6)

2. (a) Why does UDD exist ? Would it not have been enough to just let user processes send raw IP packets ? (5)

(b) A channel has a bit rate of four kbps and a propagation delay of 20 msec- For what range of frame sizes does stop and wait provide an efficiency ol at lowest 50% ? (5)

(c) discuss the functioning of broadband and baseband coaxial cable. (5)

3. (a) What is the difference ranging from p-persistent, non peristent and 1-persistent CSMA ? (6)

(b) Measurement of a Slotted ALPHA channel with an infinite number of users indicates that 10% of slots are idle. (4)
(i) What is the channel load G ?
(ii) What is the throughput ?

(c) List IEEE 802.5 standards for token ring and differentiate. (5)

4. (a) What do you understand by Quality of Service parameters ? List any live QoS parameters of tansport layer. (5)

(b) Make the diagram oI TCP header and discuss its different fields. (5)

(c) What is congestion ? what are leaky bucket algorithm used for congestion control. (5)

5. (a) explain the functioning of Reverse Address Resolution Protocol. (5)

(b) calculate a multicast spanning tree for router C in the subnet beneath for a group with members at routers A, B, C, D, E, F, J and K. (5)
-----DIAGRAM-----

(C) Make the diagram of IPv6 header and discuss its different fields. (5)

6. (a) Is fragmentation needed in concatenated virtual circuit internets or only in datagram segments ? discuss. (2)

(b) A new virtual circuit is being set up in all ATM network. ranging from the source and destination hosts lie 3 ATM switches. How many messages will be sent to establish the circuit ? (3)

(c) Differentiate ranging from broadcast routing and multicast routing. (5)

(d) ans the subsequent ques. :
(i) 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 ?
(2) (ii) The protocol field used in IPv4 header is not current in the fixed IPv6 header, Why not ? (3)

Earning:   Approval pending.