CS Free MCQ Bank

[ Option C ]

ALOHA is a Random-Access Protocol used in computer networks for sharing a common communication channel.
It allows multiple users or stations to send data whenever they want, but collisions can occur if two or more stations send data at the same time.
Throughput means the rate of successful data transmission over a communication channel.

• G = The total transmission attempts per slot.
• e^−G = The probability that no other station transmits in the same slot, i.e., no collision.

OTHER RANDOM-ACCESS PROTOCOLS:

[ Option B ]

The OSI (Open Systems Interconnection) model has seven layers, with the Physical Layer at the bottom (Layer 1).
The physical layer main job is to send raw bits (0s and 1s) from one device to another through a physical medium like cables, radio waves, or fiber optics. It does not understand data, packets, or addresses, it only deals with electrical signals, light signals, or radio signals.

[ Option A ]

The Data Link Layer is responsible for Node-To-Node Delivery and ensures reliable communication over a physical link. It performs key functions such as Framing, Error Control, and MAC Addressing, all of which are essential for organizing data into frames, detecting, or correcting errors, and identifying devices on the network.

However, Congestion Control is typically not a function of the data link layer; it is primarily handled by higher layers such as the network or transport layer to manage traffic load and avoid network congestion.

[ Option A ]

[ Option A ]

Protocols such as SMTP (Simple Mail Transfer Protocol), HTTP (Hypertext Transfer Protocol), and FTP (File Transfer Protocol) operate at the Application Layer of the OSI and TCP/IP models. The application layer provides network services directly to end-user applications and manages communication between users and networks.
SMTP is responsible for email transmission, HTTP is used for accessing and transferring web pages, and FTP allows file transfers between systems.

[ Option D ]

Reliable data transfer means ensuring that data reaches the receiver without errors, without loss, and in the correct order.
Reliable data transfer is implemented by the Transport Layer in the OSI model. The transport layer is responsible for providing end-to-end communication services for applications. 
It ensures reliable delivery of data through mechanisms such as error detection and correction, flow control, segmentation, acknowledgment of received data, and retransmission of lost or corrupted segments. 
Protocols like TCP (Transmission Control Protocol) at this layer offer connection-oriented and reliable communication by managing data packets and maintaining the order and integrity of the data transmitted between sender and receiver.