Unit 2: Competency-Based Questions
The Computer Networks unit heavily features case-study based questions. You will typically be given a scenario of an organization setting up a new campus network, and you will have to make engineering decisions based on the concepts learned in Chapters 6-8.
Case Study Type Questions
Question 2.1 Tech Vidya is an educational NGO that is setting up its new central campus in Delhi. They have 4 main buildings: Administrative Block (Admin), Computer Science Block (CS), Library, and Science Block (Science).
The distances between the buildings are:
- Admin to CS: 50 meters
- Admin to Library: 150 meters
- CS to Library: 70 meters
- CS to Science: 60 meters
- Library to Science: 120 meters
The number of computers expected in each building:
- Admin: 30
- CS: 150
- Library: 20
- Science: 60
Based on the above specifications, answer the following questions:
a) Suggest the most appropriate building to house the server. Provide a reason for your choice. Answer: The Computer Science (CS) block. Reason: In network design, the server should ideally be placed in the building with the maximum number of computers (150 computers). This minimizes network traffic on the main backbone cables connecting other buildings, ensuring faster response times for the majority of users.
b) Suggest the cable layout design (topology) for connecting all the buildings to the server. Draw a simple diagram or describe it. Answer: A Star Topology spanning out from the Server in the CS block. Description: Connect Admin, Library, and Science blocks directly to the main switch/server located in the CS block.
Admin Block <----(50m)----> CS Block (SERVER)
| \
(70m) (60m)
| \
Library Science Block
c) Suggest the placement of the following network devices with justification:
- (i) Repeater
- (ii) Hub/Switch
Answer:
- (i) Repeater: None of the distances between the buildings in the star layout exceed 100 meters (the typical limit for unshielded twisted pair cables without signal loss). However, if they were connecting Admin to Library directly (150m), a repeater would be needed after 100m. In the suggested star layout, no repeater is strictly necessary.
- (ii) Hub/Switch: A switch should be placed in every building (Admin, CS, Library, Science) to connect all the individual computers within that building together.
d) Suggest the best wired medium to connect the buildings together to ensure high-speed data transfer. Answer: Fiber-Optic Cable. Reason: It provides very high bandwidth, immunity to electromagnetic interference, and is ideal for connecting building backbones over moderate distances.
2. Differentiate / Concept Based Questions
Question 2.2 Differentiate between HTTP and HTTPS protocols. Why is HTTPS preferred for banking websites? Answer: HTTP transmits data across the web in plain, readable text. HTTPS is its secure version; it uses encryption to scramble data during transmission. Banking websites prefer HTTPS to ensure that sensitive user data (like passwords, account numbers, PINs) cannot be intercepted and read by hackers while travelling across the network.
Question 2.3 Your friend is setting up a cyber cafe and wants all computers to share the same internet connection effectively without causing unnecessary broadcast traffic. Should he buy a Hub or a Switch? Give a reason. Answer: He should buy a Switch. Reason: A Hub is a dumb device that broadcasts incoming data to all its ports, leading to heavy network congestion and security risks. A Switch is intelligent; it learns the MAC addresses of connected devices and forwards data packets only to the specific port where the destination device is connected, thereby reducing traffic.
Question 2.4 Write down the expanded forms of:
- SMTP: Simple Mail Transfer Protocol
- VoIP: Voice over Internet Protocol
- ARPANET: Advanced Research Projects Agency Network
- MAC: Media Access Control