In OSI model match the following:
i. Physical layer - a. Dialog control & synchronization
ii. Data link layer - b. Synchronization of bits
iii. Session layer - c. Translation & compression,
iv. Presentation layer. - d. Error control & framing.

Question

In OSI model match the following: 
i. Physical layer - a. Dialog control & synchronization
ii. Data link layer - b. Synchronization of bits
iii. Session layer - c. Translation & compression, 
iv. Presentation layer. - d. Error control & framing.

Accepted Answer

The correct option is (1):
The OSI (Open Systems Interconnection) model is a conceptual framework that divides network communication into seven distinct layers, each with specific, defined responsibilities. This option correctly maps each layer to its primary function. The **Physical layer (i)** is the lowest layer and is solely responsible for the physical transmission of data bits over the communication medium, which includes **Synchronization of bits (b)** to ensure that the sender and receiver use the same clock for timing the bits. The **Data Link layer (ii)** is above the Physical layer and focuses on reliable node-to-node data transfer by organizing the raw bits into frames and providing **Error control & framing (d)** to detect and potentially correct transmission errors. The **Session layer (iii)** manages the communication session or 'dialog' between two applications, including establishing, managing, and terminating the connection, hence its role in **Dialog control & synchronization (a)**. Finally, the **Presentation layer (iv)** is concerned with the syntax and semantics of the information, handling data formatting functions like **Translation & compression (c)** to ensure application layers can understand the exchanged data.

The incorrect option is (2):
This option incorrectly pairs the layers with their functions. It assigns **Dialog control & synchronization (a)** to the Physical layer (i), while this is fundamentally the role of the Session layer. Similarly, **Translation & compression (c)** is incorrectly linked to the Data Link layer (ii), when it is a primary function of the Presentation layer. The match of Session layer (iii) to **Synchronization of bits (b)** is wrong because bit synchronization is a Layer 1 task, and Presentation layer (iv) to **Error control & framing (d)** is wrong because error control and framing belong to the Data Link layer.

The incorrect option is (3):
This choice completely mismatches several critical functions. It incorrectly attributes **Translation & compression (c)** to the Physical layer (i), which is a Layer 6 function. It then mistakenly links **Dialog control & synchronization (a)** to the Data Link layer (ii), which is the job of the Session layer. This option incorrectly assigns **Error control & framing (d)** to the Session layer (iii), even though it is the core responsibility of the Data Link layer. Finally, the Presentation layer (iv) is incorrectly matched with **Synchronization of bits (b)**, a Layer 1 function.

The incorrect option is (4):
This option also contains foundational errors in the OSI layer assignments. It incorrectly pairs the Physical layer (i) with **Error control & framing (d)**, which belongs to the Data Link layer. The Data Link layer (ii) is mistakenly matched with **Synchronization of bits (b)**, which is the function of the Physical layer. Furthermore, the Session layer (iii) is incorrectly associated with **Translation & compression (c)**, which should be handled by the Presentation layer. Lastly, the Presentation layer (iv) is wrongly assigned **Dialog control & synchronization (a)**, a function of the Session layer.