UDP packets are not transmitted directly to the ‘true’ IP address of the receiving device, but are transmitted with a specific device allocated IP multicast address. The operation of UDP protocol is so simple. When the application layer invokes UDP, the following operations are performed by UDP:
Encapsulates the data of users into datagrams. Forwards these datagrams to the IP layer for the transmission. On the other side, these datagrams are then forwarded to UDP from the IP layer. Then UDP removes the data from the datagram and forwards to the upper application layer.