Which protocol is considered connection-oriented and ensures reliable data delivery?
Correct Answer: A
Detailed Explanation: Transmission Control Protocol (TCP) is a transport-layer protocol known for being connection-oriented, which means it establishes a reliable connection between the source and destination before data is transmitted. TCP is designed to provide error-free delivery of data packets across networks by implementing mechanisms for flow control, error detection, and retransmission. The connection-oriented nature of TCP means that before any data is sent, a handshake process takes place between the communicating devices. This process, commonly known as the three-way handshake, involves the exchange of SYN, SYN-ACK, and ACK packets. This handshake ensures that both the sender and receiver are ready for communication and agree upon initial parameters such as sequence numbers, which are crucial for maintaining data order and integrity. Once the connection is established, TCP guarantees that data is delivered reliably by using sequence numbers to track each segment of data transmitted. If any segment is lost or arrives out of order, the protocol detects the anomaly and requests a retransmission. This mechanism ensures that data is reassembled in the correct order at the destination. Moreover, TCP uses acknowledgment packets to confirm successful data reception, and its congestion control algorithms adjust the data transmission rate to prevent network congestion. Flow control is another important aspect of TCP. It uses a sliding window technique that allows the sender to transmit multiple segments before needing an acknowledgment, while also ensuring that the receiver is not overwhelmed by data faster than it can process. This dynamic adjustment helps maintain an optimal data flow rate even in variable network conditions. In contrast, protocols like UDP (User Datagram Protocol) are connectionless and do not provide the reliability mechanisms inherent to TCP. UDP does not establish a connection before sending data and does not confirm whether packets reach their destination. As a result, UDP is faster and more efficient for applications that require minimal delay, such as streaming or online gaming, but it does not guarantee data integrity or order. TCP’s reliability comes at the cost of additional overhead due to the control packets required for establishing, maintaining, and terminating a connection, as well as the processing needed for error-checking and retransmissions. However, for applications where data integrity and accuracy are critical—such as file transfers, web browsing, and email—TCP is the preferred protocol. For network professionals, understanding TCP is essential, not only because it is one of the core protocols in the Internet protocol suite but also because it influences the performance and reliability of many network applications. Knowing the differences between TCP and UDP, along with how TCP achieves reliability through mechanisms like the three-way handshake, flow control, and congestion management, is fundamental for designing, troubleshooting, and securing networks. In summary, TCP is the connection-oriented protocol that ensures reliable data delivery by establishing a secure, negotiated connection between endpoints and employing robust mechanisms for error detection, data sequencing, and congestion control. This makes it indispensable for many of the critical applications and services that rely on consistent, error-free communication.
This CCNA practice question helps students prepare for Cisco networking certification exams by testing knowledge of network fundamentals, routing, switching, and network security concepts.