Cisco Certified Network Associate (CCNA) Practice Exam

Which TCP/IP layer represents the core of the TCP/IP architecture?

1. Network Layer

2. Data Link Layer

3. Transport Layer

4. Application Layer

The correct answer is: Transport Layer

The correct answer is the Transport Layer, which plays a crucial role in the TCP/IP architecture by providing the means for communication between applications on different hosts. This layer is responsible for ensuring reliable data transfer through mechanisms such as error detection, flow control, and connection management. At the Transport Layer, protocols like TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) operate. TCP is particularly noted for its reliability, offering features that ensure data arrives accurately and in the correct order, which is essential for applications that require high fidelity in data transmission, such as file transfers and web browsing. UDP, on the other hand, offers a connectionless service that reduces overhead, making it suitable for applications that need speed over reliability, like streaming services or online gaming. This layer serves as an intermediary between the Application Layer, where user-facing apps operate, and the Network Layer, which focuses on routing data packets across various networks. By enabling different applications to communicate effectively and managing how data is sent and received over the network, the Transport Layer acts as a core element of the TCP/IP stack, ensuring that even with varied network conditions, the end-user experiences seamless data communication. The other layers, while essential as well, primarily support functions that make the Transport Layer