Question 56 of 367 from exam 200-301-CCNA: Implementing and Administering Cisco Solutions

Question 56 of 367 from exam 200-301-CCNA: Implementing and Administering Cisco Solutions


What are two benefits that the UDP protocol provide for application traffic? (Choose two.)



A. B. C. D. E.


The correct answers are A and E.

A. UDP traffic has lower overhead than TCP traffic: UDP (User Datagram Protocol) provides a connectionless protocol that operates on top of IP (Internet Protocol) without requiring a connection establishment, acknowledgement or error recovery mechanisms. Because of the lack of these features, the overhead of the UDP protocol is lower than that of TCP (Transmission Control Protocol). This means that UDP can transmit data faster than TCP, and it's more efficient for applications that do not require the reliability of a guaranteed data delivery, such as video and audio streaming, DNS (Domain Name System) resolution, or real-time multiplayer games.

E. The application can use checksums to verify the integrity of application data: UDP does not provide a built-in mechanism for error detection or correction. However, it does allow the application to perform its own error checking by including a checksum field in the UDP header. This field contains a value that is calculated by the application based on the data being sent. When the receiver receives the UDP datagram, it recalculates the checksum and compares it to the value in the UDP header. If they match, the data is assumed to be intact. If they don't match, the data is considered corrupted, and the receiver discards the packet. This way, the application can ensure the integrity of the data being transmitted without incurring the overhead of TCP's error detection and recovery mechanisms.

B. UDP provides a built-in recovery mechanism to retransmit lost packets: UDP does not provide any retransmission mechanism for lost packets. Once a packet is sent, it's up to the application to decide whether to resend it or not. This can be an advantage in applications where the loss of a few packets is not critical, but it can be a disadvantage in applications where the data needs to be transmitted reliably, such as file transfers or email.

C. The CTL field in the UDP packet header enables a three-way handshake to establish the connection: UDP does not have a connection establishment phase, so there is no three-way handshake as in TCP. The CTL (Control) field in the UDP header is used to indicate the type of data being transmitted, such as a query or a response, but it does not establish a connection.

D. UDP maintains the connection state to provide more stable connections than TCP: UDP does not maintain any connection state, unlike TCP, which uses a stateful protocol to ensure the reliability of the data transmission. UDP treats each datagram as an independent packet and does not keep track of whether it has been received or not. This makes UDP more lightweight but less reliable than TCP.