Why is UDP over IP needed if it does not guarantee delivery?

UDP (User Datagram Protocol) over IP is used despite the lack of delivery guarantees for several reasons:

• Minimal latency and overhead. UDP does not establish a connection or confirm receipt, which reduces delays and network load.
• Protocol simplicity. This allows UDP to be used for applications where speed and simplicity are important, such as streaming video, audio, online gaming.
• Application-level control. Some applications implement their own mechanisms for delivery control and error correction, using UDP as a transport.
• Support for broadcast and multicast messages. UDP allows data to be sent to multiple recipients simultaneously, which is difficult to implement with TCP.

Thus, UDP is needed for scenarios where speed and efficiency are more important than guaranteed delivery of each packet.