A real-time voice application can tolerate occasional missing data and does not need delivery confirmation. Which transport protocol is the best fit according to the refresher?

### Why this is right Real-time voice is listed as a best-effort application. If the application can continue despite a lost packet, UDP avoids adding TCP's confirmation and retransmission mechanisms. ### The concept Best-effort delivery means the transport protocol does not promise that each packet will arrive, arrive in order, or be retransmitted when missing. UDP has a smaller and simpler header than TCP, leaving more room for payload in a packet. TCP is a better fit when reliable delivery matters, as with file transfers or email. A real-time application may prefer timely new data over waiting for missing data to be resent. ### The other options - **B. Transmission Control Protocol (TCP), because it retransmits every missing real-time packet.**: TCP supports retransmission, but the scenario says the application does not need it; retransmission is not a defining advantage for this use. - **C. Transmission Control Protocol (TCP), because its larger header increases the payload size.**: TCP has a larger header, which limits rather than increases the total payload size. - **D. User Datagram Protocol (UDP), because it creates an explicit reliable session.**: UDP does not explicitly create a session and does not provide TCP-style reliability. ### Terms - **UDP**: User Datagram Protocol. A transport protocol with a small, simple header and best-effort delivery. - **TCP**: Transmission Control Protocol. A transport protocol that supports reliable delivery through a session. - **Best-effort delivery**: Sending data without a guarantee of confirmation, ordering, or retransmission. - **Header**: Control information attached to data. - **Payload**: The application data carried inside a packet. - **Retransmission**: Sending data again when it is missing. ### Remember For delay-sensitive applications that can tolerate loss, best-effort UDP may fit better than reliable TCP.