Question 1

Which layer ensures that data is in a format that the receiving application can understand?

Accepted Answer

Presentation Layer. The Presentation Layer formats the data so that it can be presented to the application layer. It manages the abstract syntax and ensures compatibility between different data formats used by various systems. This layer is also responsible for converting data into a standard network format.

Question 2

Flow control and segmentation are primary functions of which OSI layer?

Accepted Answer

Transport Layer. The Transport Layer breaks down large pieces of data into smaller segments for easier transmission. It implements flow control to prevent the sender from overwhelming the receiver with too much data. This layer ensures that the data arrives in the correct sequence at the destination.

Question 3

Which layer of the OSI model is the only one that can interact directly with the physical transmission medium?

Accepted Answer

Physical Layer. The Physical Layer manages the actual transmission of unstructured raw bitstreams over a physical medium. It handles the electrical, optical, and radio signals that represent the data. No other layer communicates directly with the physical cables or wireless signals.

Question 4

At which layer do 'Routers' operate to connect different networks?

Accepted Answer

Layer 3. Routers operate at the Network Layer (Layer 3) to determine the best path for data packets across networks. They use routing tables and IP addresses to forward traffic between different IP subnets. Routers are essential for the functioning of the global Internet.

Question 5

Which layer provides the mechanism for 'Dialogue Control' and synchronization?

Accepted Answer

Session Layer. The Session Layer establishes and manages the connections between applications on different devices. It allows for half-duplex or full-duplex communication modes through dialogue control. Synchronization points are used to recover from failures during long data transfers.

Question 6

Which of the following protocols is found at the Application Layer of the OSI model?

Accepted Answer

HTTP. HTTP (Hypertext Transfer Protocol) is an application-level protocol used for accessing and transferring web pages. It provides the rules for how web browsers and servers communicate. Other common application protocols include DNS, DHCP, and Telnet.

Question 7

The term 'Bit' is the data unit used at which layer of the OSI model?

Accepted Answer

Physical Layer. At the Physical Layer, data is viewed as a stream of individual bits (0s and 1s). These bits are converted into physical signals like light pulses or voltage changes for transmission. As data moves up the layers, these bits are organized into larger structures.

Question 8

Which layer is responsible for adding 'Source and Destination MAC addresses' to a frame?

Accepted Answer

Data Link Layer. The Data Link Layer adds a header to the data containing the physical MAC addresses of the sender and the next hop receiver. This physical address is hard-coded into the network interface card (NIC). MAC addresses are used for local delivery within a single segment.

Question 9

Error control through 'Cyclic Redundancy Check' (CRC) is primarily a function of which layer?

Accepted Answer

Data Link Layer. The Data Link Layer adds a trailer to each frame that contains a CRC or checksum for error detection. If the receiving device detects an error, it may request a retransmission of the frame. This ensures the integrity of data across the local physical link.

Question 10

Which layer of the OSI model is often described as the 'End-to-End' layer?

Accepted Answer

Transport Layer. The Transport Layer is considered 'end-to-end' because it creates a logical connection between the source and destination applications. Unlike lower layers that deal with intermediate hops, the transport layer focuses on the complete journey of the message. it ensures that the entire message is reconstructed correctly at the receiving end.

OSI Model — Set 2