BE EXTC Mumbai university Sem VII REV DEC 2007-2012

1. CCN Module : V: Packet Switching Networks ( 25 Marks ) By Kamal Rochlani
N.B: Questions printed in different color were asked in Mumbai University exams.
 Network Services & internal network Operation
(Q: 1) What is packet Switching? 5
(Q:2) What do you mean by Network Service? Explain in detail. 6
(Q:3) Explain the following Network Services:
A. Connectionless Network Service ( CLNS)
B. Connection Oriented Service (CONS)
OR
Compare: CLNS & CONS. 5 / 10
(Q:4) Why does the internet use a connectionless network service? 5
(Q:5) What is the difference between Network layer delivery & transport layer delivery? 5
 Packet Network Topology
(Q:6) Write short note on: Packet Network Topology. 5
 Connectionless Packet switching ( Datagram)
(Q:7) Write short note on : Connectionless Packet Switching (Datagram). 08
 Virtual Circuit Packet Switching
(Q:8) Write short note on : Virtual Circuit Packet Switching . 08
(Q:9) Consider a multistage switch that consists of N inputs grouped into N/n groups of n input lines. Each of first stage
switch consists of n X k array of crosspoints.
i. For N= 32, compare the number of crosspoints required by a non blocking sitch ith n=16 & repeat for n=8.
ii. For N=16, n=4, k=2 find the maximum number of connections that can be supported at any time. 10
(Q:10) Define the following parameters for a switching network:
N= number of hops between two given end systems
L= message length in bits
B= data rate, in bits per second (bps), on all link
P = fixed packet size, in bits
H= Overhead ( header) in bits per packet
S= call setup time ( circuit switching or virtual circuit) in seconds
D= Propagation Delay per hop in seconds
For N=4,L=3200,B=9600,P=1024,H=16,S=0.2,D=0.001, Compute the end to end delay for circuit switching, virtual
circuit packet switching & datagram packet switching. Assume that there are no acknowledgements. Ignore
processing delay at the nodes. 10
(Q:11) Using the example network given in fig. give the virtual circuit tables for all the switches after each of the following
connections is established . Assume that the sequence of connections is cumulative ; i.e the first connection is still
up when the second connection is established and so on. Also assume that VCI assignment always picks the lowest
unused VCI on each link, starting with 0.

2. BE EXTC SEM VII -2- CCN QB By Kamal Rochlani
i. Host A connects to Host B.
ii. Host C connects to Host G.
iii. Host E connects to Host I.
iv. Host D connects to Host B.
v. Host F connects to Host J.
vi. Host H connects to Host A. 10
 Routing in Packet Networks
(Q:12) What is routing? Also explain what is routing algorithms? Give properties of routing algorithms. Also write goals of
routing algorithm. 8
 Routing Algorithm Classification
(Q:13) What are different types of routing algorithm? Explain in detail. 10
OR
Explain: Fixed routing & Random Routing 06
 Routing Table
(Q:14) for the following example, draw the routing table for each node: 1, 2 , 3 ,4 , 5 & 6. 10

3. BE EXTC SEM VII -3- CCN QB By Kamal Rochlani
 Link state Vs Distance Vector Routing
(Q:15 )Write short note on : Distance Vector Routing. 5
(Q:16) Explain count-to-infinity problem with the help of an example. It is drawback of which algorithm? 5
(Q:17) Write short note on : Link state Routing 5
(Q:18) Compare: Link state Routing & Distance Vector Routing. 5
 Hierarchical Routing
(Q:19) Write short note on : Hierarchical Routing 5
 Shortest Path & Other routing Algorithms
(Q:20) Give flooding algorithm. 5
(Q:21) Write short note on : Flow based Routing 5
 Dijkstra’s Algorithms
 Bellman-Ford Algorithms
(Q:22) Write short note on Dijkstra’s algorithm 10
(Q:23) Write short note on Bellman-Ford algorithm 10
(Q:24) What is the essential difference between Dijkstra’s algorithm & Bellman-Ford algorithm? Explain these algorithms.
10
(Q:25) Write the dijkstra’s algorithm. Find the shortest path to detination node 6 using dijkstra’s algorithm. Will Bellman-
Ford yield same solution? Why or why Not? 10

4. BE EXTC SEM VII -4- CCN QB By Kamal Rochlani
(Q:26) Find the shortest path from node 1 to every other node for the graph given as shown in figure using Bellman-ford &
Dijkstra’s algorithm. 10
(Q:27)Find the shortest path from source node 1 to every other node for the graph given below. Using Dijkstra’s algorithm.
Give routing table & also generate shortest path tree. 06
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