Which layer is responsible for maintaining end-to-end connections and ensuring packets are delivered?

Which layer is responsible for maintaining end-to-end connections and ensuring packets are delivered?

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

Answer: (A)

The transport layer handles end-to-end connections and reliable delivery. It establishes and manages the connection between the sending and receiving hosts, breaks data into segments, and ensures those segments arrive correctly and in order. This layer provides reliability through mechanisms like error detection, retransmission, sequencing, and flow control (as seen in TCP). The network layer, by contrast, focuses on routing packets across multiple networks; the data link layer handles communication between adjacent nodes on a single link; and the physical layer deals with the actual electrical or optical signaling. Because end-to-end reliability and connection management are the hallmarks of the transport layer, it is the correct choice.

The transport layer handles end-to-end connections and reliable delivery. It establishes and manages the connection between the sending and receiving hosts, breaks data into segments, and ensures those segments arrive correctly and in order. This layer provides reliability through mechanisms like error detection, retransmission, sequencing, and flow control (as seen in TCP). The network layer, by contrast, focuses on routing packets across multiple networks; the data link layer handles communication between adjacent nodes on a single link; and the physical layer deals with the actual electrical or optical signaling. Because end-to-end reliability and connection management are the hallmarks of the transport layer, it is the correct choice.