Quiz: Computer Networking Fundamentals — 21 questions

1. Which classification correctly matches each network type with its geographic coverage?

A. LAN covers a local area, MAN a metropolitan area, and WAN a wide area

B. LAN covers a metropolitan area, MAN a wide area, and WAN a local area

C. LAN covers a wide area, MAN a local area, and WAN a metropolitan area

D. LAN covers a local area, MAN a wide area, and WAN a metropolitan area

Answer: (A)

Explanation

A LAN covers a limited local area, a MAN covers a metropolitan area, and a WAN covers a wide geographic area. The other classifications assign these coverage categories to the wrong network types.

2. A device must forward packets between two different networks; which device performs this function at the Network layer?

A. A hub

B. A modem

C. A switch

D. A router

Answer: (D)

Explanation

A router operates at the Network layer and forwards packets between different networks through routing decisions. A switch forwards frames within the Data Link layer using MAC addresses.

3. Why is optical fiber well suited to high-volume communication over long distances?

A. It transmits electrical signals and requires frequent signal regeneration

B. It carries data through magnetic fields and supports short-range connections

C. It uses radio waves and avoids the need for any transmission medium

D. It transmits light signals and provides high bandwidth over long distances

Answer: (D)

Explanation

Optical fiber carries data as light signals and offers high bandwidth over long distances. Copper cables, rather than optical fiber, are associated with electrical signal transmission.

4. A communication system allows both participants to transmit, but each must wait while the other is sending. Which mode is this?

A. Half-duplex communication

B. Simplex communication

C. Broadcast communication

D. Full-duplex communication

Answer: (A)

Explanation

Half-duplex communication supports transmission in both directions, but not at the same time. Full-duplex communication allows simultaneous transmission and reception, while simplex communication is one-way.

5. Which OSI layer provides end-to-end delivery between communicating hosts?

A. The Network layer

B. The Session layer

C. The Transport layer

D. The Application layer

Answer: (C)

Explanation

The Transport layer provides end-to-end delivery between hosts. The Application layer supports network applications and protocols such as HTTP, FTP, DNS, and SMTP, while the Network layer handles packet routing.

6. Which statement correctly distinguishes TCP from UDP?

A. TCP and UDP are both connection-oriented, but TCP uses faster addressing mechanisms.

B. TCP is connection-oriented and reliable, whereas UDP is connectionless and lacks the same reliability mechanisms.

C. TCP and UDP are both connectionless, but UDP provides stronger delivery guarantees.

D. TCP is connectionless and unreliable, whereas UDP is connection-oriented and reliable.

Answer: (B)

Explanation

TCP establishes a connection and provides reliability mechanisms, whereas UDP is connectionless and does not provide equivalent reliability mechanisms. Treating UDP as connection-oriented reverses the defining distinction between the two protocols.

7. A packet has length $L=12{,}000$ bits and is sent over a link with transmission rate $R=6$ Mbps. What is its transmission delay?

A. $0.5$ milliseconds

B. $72$ milliseconds

C. $2$ milliseconds

D. $6$ milliseconds

Answer: (C)

Explanation

Using $T_t=\frac{L}{R}$ gives $\frac{12{,}000}{6{,}000{,}000}=0.002$ seconds, or $2$ milliseconds. The distance and signal speed would instead be relevant to propagation delay.

8. A network connects computers across several buildings on one university campus, while another connects offices in different countries; how are they typically classified?

A. The campus network is a WAN, and the international network is a LAN

B. Both networks are generally classified as LANs because they connect organizational devices

C. Both networks are generally classified as MANs because they connect multiple sites

D. The campus network is a LAN, and the international network is a WAN

Answer: (D)

Explanation

A network within a building or campus is commonly a LAN, whereas a network spanning cities or countries is typically a WAN. A MAN is associated with coverage across a metropolitan area rather than a campus or international region.

9. Which device operates at the Data Link layer and forwards frames using MAC addresses?

A. A hub

B. A modem

C. A router

D. A switch

Answer: (D)

Explanation

A switch operates at the Data Link layer and uses MAC addresses to forward frames. A router instead operates at the Network layer and makes forwarding decisions between networks using logical addressing.

10. Which function is included in the rules established by a network protocol?

A. Specifying data format, addressing, error checking, and delivery

B. Providing electrical power to every device connected to the network

C. Replacing all intermediary devices with a single central computer

D. Converting every transmitted signal into a printed document

Answer: (A)

Explanation

Network protocols define how data is formatted, exchanged, checked for errors, addressed, and delivered. They do not supply power or perform physical document production.

11. Which layer is responsible for routing packets between networks?

A. The Physical layer

B. The Transport layer

C. The Network layer

D. The Data Link layer

Answer: (C)

Explanation

The Network layer routes packets between networks using logical addressing. The Data Link layer handles frames and MAC addressing, while the Physical layer transmits raw bits.

12. A communication system sends signals through a copper cable rather than through open space. How is its medium classified?

A. Unguided media, because the signal travels between separate devices

B. Simplex media, because the cable determines the communication direction

C. Intermediary media, because the cable forwards data between networks

D. Guided media, because the signal follows a physical transmission path

Answer: (D)

Explanation

Guided media carry signals through a physical path, including cables such as twisted-pair and coaxial cable. Unguided media propagate signals through free space without a physical guiding path.

13. A signal travels across a link of distance $d=2000$ km at propagation speed $s=2\times10^8$ m/s. What is the propagation delay?

A. $100$ milliseconds

B. $10$ milliseconds

C. $400$ milliseconds

D. $1$ millisecond

Answer: (B)

Explanation

Using $T_p=\frac{d}{s}$, convert $2000$ km to $2\times10^6$ m and calculate $\frac{2\times10^6}{2\times10^8}=0.01$ seconds, or $10$ milliseconds. Packet length and transmission rate determine transmission delay rather than propagation delay.

14. What does a hub do when it receives an incoming signal?

A. It forwards the frame using the destination MAC address

B. It converts the signal for the transmission medium

C. It routes the packet toward another network

D. It broadcasts the signal to its connected ports

Answer: (D)

Explanation

A hub operates at the Physical layer and broadcasts an incoming signal to its ports. A switch, rather than a hub, uses MAC addresses to forward frames selectively.

15. What is data communication?

A. The storage of information in a device without transmitting it

B. The exchange of data between devices through a transmission medium

C. The analysis and modification of information within a single device

D. The installation of software that controls a device's internal operations

Answer: (B)

Explanation

Data communication is the exchange of data between devices using a transmission medium. Changing or analyzing data within one device is data processing rather than data communication.

16. Which expression represents the total nodal delay for a packet traveling through a network node?

A. $T=T_t+T_p-T_{pr}+T_q$

B. $T=T_t+T_p+T_{pr}+T_q$

C. $T=T_t+T_p+T_{pr}-T_q$

D. $T=T_t-T_p+T_{pr}+T_q$

Answer: (B)

Explanation

Total nodal delay combines transmission, propagation, processing, and queuing delays by adding all four components. Subtracting one component would incorrectly reduce the measured time rather than represent the complete delay.

17. Which delivery method establishes a dedicated path before transmission and retains it for the communication session?

A. Datagram switching

B. Circuit switching

C. Broadcast forwarding

D. Packet switching

Answer: (B)

Explanation

Circuit switching reserves a dedicated path before communication begins and keeps that path for the session. Packet switching instead sends packets through shared links without requiring one continuously reserved path.

18. What best defines a computer network?

A. A transmission cable that carries signals between two connected devices

B. A single device that processes data within its own internal components

C. A collection of programs that manages files and applications on one computer

D. A set of interconnected devices that communicate and share data through links

Answer: (D)

Explanation

A computer network consists of multiple interconnected devices that communicate and share data through communication links. A communication link is merely the connection between devices, not the complete network.

19. A router receives a data packet and sends it toward its destination, while a laptop creates the message. How are these devices classified?

A. Both devices are intermediary devices because they handle network data

B. The router is an end device, and the laptop is an intermediary device

C. Both devices are end devices because they participate in communication

D. The router is an intermediary device, and the laptop is an end device

Answer: (D)

Explanation

Intermediary devices connect networks and forward data, whereas end devices generate or consume data. The router forwards the packet, while the laptop creates the message.

20. How does packet switching deliver data across a network?

A. It sends the complete message through a fixed circuit

B. It establishes a logical connection before every transmission

C. It divides data into packets forwarded through shared links

D. It reserves one physical path for the entire session

Answer: (C)

Explanation

Packet switching divides data into packets that can be forwarded independently through shared network links. Reserving a dedicated path for the whole session describes circuit switching.

21. How many layers does the OSI reference model contain?

A. Four layers

B. Five layers

C. Seven layers

D. Three layers

Answer: (C)

Explanation

The OSI reference model is organized into seven layers, from Physical through Application. The smaller layer counts are associated with practical TCP/IP model groupings rather than the OSI structure.