CBSE Class 12 Computer Science Computer Network Case Study Questions Set 01

Case Study 1. BAJAJ AUTO LTD is planning to start offices in four major cities of India. Its head office in Kolkata will be in three locations named Sales Office, Head Office and HRD Office. The company's regional offices are in New Delhi, Kanpur and Jaipur. A rough layout is shown below.

From	To	Distance
Head Office	Sales Office	300 m
Head Office	HRD Office	150 m
Head Office	New Delhi Office	1500 km
Head Office	Kanpur Office	1200 km
Head Office	Jaipur Office	1700 km

Office	Number of computers
Head Office	250
Sales Office	50
HRD Office	75
New Delhi Office	150
Kanpur Office	100
Jaipur Office	60

(i) Suggest the network type (out of LAN, MAN, WAN) for connecting each of the following sets of offices: (a) Head Office and Sales Office (b) Head Office and New Delhi Office
(ii) Which device out of MODEM, Switch/Hub and Repeater will you suggest for connecting all the computers within each office?
(iii) Suggest a cable/wiring layout for connecting the company's local offices in Kolkata.
(iv) Name the communication medium you will suggest for connecting the local offices in Kolkata for fast communication.

Answer:
(i) (a) Head Office and Sales Office are 300 m apart in the same city campus: LAN. (b) Head Office (Kolkata) and New Delhi Office are 1500 km apart in different cities: WAN.
(ii) Switch/Hub. It connects all the computers inside one office into a LAN; a switch is better because it sends data only to the intended computer.
(iii) A star layout with the Head Office (250 computers) at the centre, connected to the Sales Office (300 m) and the HRD Office (150 m). Because both links are longer than about 100 m, a repeater should be placed on each of them.

(iv) Optical fibre cable, because it gives the highest speed and is free from electrical interference.
In simple words: Offices in the same city are joined as a LAN and offices in different cities as a WAN; use switches inside offices and fibre for fast links.

Case Study 2. Knowledge Supplement Organisation has set up its new centre at Mangalore for its office and web-based activities. It has four blocks of buildings as shown below.

Blocks	Centre-to-centre distance
A to B	50 m
B to C	150 m
C to D	25 m
A to D	170 m
B to D	125 m
A to C	90 m

Block	Number of computers
A	25
B	150
C	60
D	20

(i) Suggest a cable layout of connections between the blocks, and the topology.
(ii) Suggest the most suitable block to house the server of this organisation, with a suitable reason.
(iii) Suggest the placement of the following devices with justification: (a) Repeater (b) Hub/Switch
(iv) The organisation plans to link its front office, situated in the city in a hilly region where a cable connection is not feasible. Suggest an economical way to connect it with reasonably high speed.

Answer:
(i) Star topology with Block B (the server block) at the centre, connected to Block A (50 m), Block C (150 m) and Block D (125 m):

(The layout with the shortest total cable, A–B, A–C and C–D = 165 m, is also accepted, but the star layout keeps every block one hop from the server.)
(ii) Block B, because it has the maximum number of computers (150). Most of the traffic then stays within one block, which reduces network traffic between blocks.
(iii) (a) Repeater: on the links B–C (150 m) and B–D (125 m), since these distances are too long for the signal to stay strong. No repeater is needed on A–B (50 m). (b) Hub/Switch: one in each block, to connect the computers within that block.
(iv) Radio waves (a wireless radio or microwave link). No cable has to be laid over the hills, and it is economical while giving reasonable speed.
In simple words: Put the server where most computers are, a switch in every block, repeaters on long links, and use radio waves where cables cannot reach.

Case Study 3. G.R.K. International Inc. is planning to connect its Bengaluru office setup with its Head Office in Delhi. The Bengaluru office is spread over an area of about 1 square kilometre and has three blocks: Human Resources, Academics and Administration. As a network expert, suggest answers to the queries (i) to (v).

Between	Shortest distance
Human Resources and Administration	200 m
Human Resources and Academics	60 m
Academics and Administration	150 m
Delhi Head Office and Bengaluru Office Setup	2000 km

Block	Number of computers
Human Resources	55
Administration	60
Academics	200
Delhi Head Office	30

(i) Suggest the network type (out of LAN, MAN, WAN) for connecting each of the following sets of offices: (a) Delhi Head Office and Administration Office (b) Human Resources Office and Academics Office
(ii) Which device out of MODEM, Switch/Hub and Repeater will you suggest for connecting all the computers within each block?
(iii) Suggest a cable/wiring layout among the blocks within the Bengaluru office setup.
(iv) Suggest the most suitable block in the Bengaluru office setup to host the server, with a suitable reason.
(v) Suggest the most suitable medium to provide secure, fast and reliable data connectivity between the Delhi Head Office and the Bengaluru office setup.

Answer:
(i) (a) Delhi Head Office and the Administration block are about 2000 km apart in different cities: WAN. (b) Human Resources and Academics are 60 m apart in the same campus: LAN.
(ii) Switch/Hub, to connect the computers within each block.
(iii) A star layout with Academics (the server block) at the centre, connected to Human Resources (60 m) and Administration (150 m), with a repeater on the 150 m link:

(iv) Academics block, because it has the maximum number of computers (200), so most data traffic stays within that block.
(v) A satellite (microwave) link, which covers the 2000 km distance reliably. A leased optical fibre line taken from a service provider is also a fast and secure choice.
In simple words: Within the campus use a LAN with the server in Academics; between Delhi and Bengaluru use a WAN link over satellite or leased fibre.