Computer Networks

At the Network Layer, the Protocol Data Unit (PDU) is called a Packet or Datagram. This layer is responsible for routing and forwarding packets across networks.

The Protocol Data Unit (PDU) at the Transport Layer is called a Segment. Frames are at the Data Link Layer, Bits at the Physical Layer, and Packets at the Network Layer.

In a Peer-to-Peer network model, all devices share resources directly without relying on a central server, unlike Client-Server networks where a central server manages resources. Cloud Networks and Circuit Switching do not describe this resource-sharing model.

At the Data Link Layer of the OSI model, the Protocol Data Unit (PDU) is called a Frame. Segments are PDUs at the Transport Layer, Packets at the Network Layer, and Bits at the Physical Layer.

Network Architecture defines the design and communication structure of a network, including how devices are interconnected and how data flows between them. It encompasses the arrangement and interaction of network components rather than physical device design or cable types.

A ring topology connects each device to exactly two other devices, forming a closed loop. This allows data to travel in one or both directions around the ring.

MODEM stands for Modulator-Demodulator, which is a device that modulates digital signals into analog for transmission and demodulates incoming analog signals back into digital form. Option A correctly reflects this full form.

Tree topology combines characteristics of star and bus topologies, where groups of star-configured networks are connected to a linear bus backbone, making it suitable for hierarchical network structures.

A proxy server acts as an intermediary between a client and the internet, primarily processing client requests for web pages by forwarding them and returning the responses. This helps with caching, filtering, and anonymity.

In a star topology, each computer is directly connected to a central computer or hub, making option B the correct answer. Other topologies like bus, ring, and node do not have this direct central connection.

Both a modem and a network card are used for internet connectivity. A modem modulates and demodulates signals for internet access, while a network card (NIC) allows a device to connect to a network, including the internet.

An Ethernet cable is used to connect a printer directly to a network, allowing it to communicate with multiple devices over the network. USB, Serial, and Firewire connections are typically used for direct connections to a single computer, not for network connectivity.

A switch improves network efficiency by using MAC addresses to forward data only to the intended device, unlike a hub which broadcasts data to all connected devices. This targeted forwarding reduces unnecessary traffic and collisions.

In a bus topology, all devices are connected to a single communication line (bus), sharing the same transmission medium. This allows all devices to receive the data sent over the bus, making option B correct.

In a star topology, all devices are connected to a central hub or switch, which acts as a common connection point for all nodes. This central device manages and controls the network traffic.

In a mesh topology, every device is connected directly to every other device, providing high redundancy and reliability because multiple paths exist for data transmission.

A modem (short for modulator-demodulator) converts digital signals from a computer into analogue signals for transmission over phone lines and vice versa, enabling communication between digital devices over analogue infrastructure.

Full-Duplex communication allows data to be sent and received simultaneously, just like a telephone call where both parties can talk and listen at the same time. Simplex is one-way only, Half-Duplex allows two-way communication but not simultaneously, and Asynchronous refers to timing of data transmission, not duplex mode.

A MAN (Metropolitan Area Network) typically connects devices within a city, covering a larger area than a LAN but smaller than a WAN. This makes option C the correct answer.

All three types of cables—optical fiber, coaxial, and twisted pair—are commonly used in wired networks depending on the application and network requirements. Therefore, 'All of the above' is the correct answer.

Half-Duplex communication allows data transmission in both directions, but only one direction at a time, similar to how a walkie-talkie operates. Full-Duplex allows simultaneous two-way communication, Simplex is one-way only, and Synchronous refers to timing, not directionality.

A mesh topology requires each computer to be connected to every other computer, resulting in the most extensive cabling compared to star, bus, or ring topologies.

Multiple users can access a mainframe through terminals, which are input/output devices connected to the mainframe. Terminals allow users to interact with the mainframe remotely. Options like 'Cluster Server frame' are not standard terms for mainframe access.

MAN stands for Metropolitan Area Network, which is a type of network that covers a larger geographic area than a Local Area Network (LAN) but smaller than a Wide Area Network (WAN).

A LAN (Local Area Network) is a data communication system confined to a limited geographic area such as a building, plant, campus, or nearby buildings, making it the correct choice.