Question

Which OSI layer is responsible for end-to-end communication?

• A. Transport
• B. Network
• C. Data Link
• D. Physical

Hint:

A good way to remember the distinction: The Network layer gets the packet from the source computer to the destination computer. The Transport layer gets the packet from the correct application (e.g., your web browser) on the source computer to the correct application (e.g., the web server) on the destination computer.

Answer 1

The Correct Option is A

Let's review the responsibilities of the lower layers of the OSI model:
(D) Physical Layer (Layer 1): Deals with the physical transmission of raw bits over a medium.
(C) Data Link Layer (Layer 2): Responsible for node-to-node (or hop-to-hop) delivery of data frames between two directly connected devices. It handles framing and physical addressing (MAC addresses).
(B) Network Layer (Layer 3): Responsible for host-to-host delivery of packets across different networks. It handles logical addressing (IP addresses) and routing.
(A) Transport Layer (Layer 4): This is the first true end-to-end layer. It is responsible for process-to-process communication between the source and destination hosts. It provides services like segmentation, flow control, error control, and connection management (e.g., TCP and UDP). It ensures that data from an application on one machine gets to the correct application on the destination machine, providing a complete end-to-end communication channel.
Therefore, the Transport Layer is responsible for end-to-end communication.