Sender: Multiplexing of UDP datagrams
UDP datagrams are received from multiple application programs
A single sequence of UDP datagrams is passed to the IP layer.
At the destination host the transport layer receives segments from the network layer.
Transport layer has the responsibility of delivering the data in these segment
Socket programming with “TCP and socket programming UDP” that process can have one or more socket
Transport layer in the receiving host does not actually deliver data directly to a process but instead to an intermediary socket.
Each socket has unique identifier the format of the identifier depends on wheather the socket is a UDP or TCP socket.
Directing the arriving segment’s data to the corresponding process socket, the transport layer in the middle.