How demultiplexing works host receives IP datagrams o each datagram has source 32 bits IP address,destination IP address source port dest port o each datagram carries 1 transport-layer segment other header fields o each segment has source, destination port number host uses IP addresses port application numbers to direct segment to data appropriate socket (message) TCP/UDP segment format Transport Layer 3-9 Transport Layer 3-9 How demultiplexing works  host receives IP datagrams  each datagram has source IP address, destination IP address  each datagram carries 1 transport-layer segment  each segment has source, destination port number  host uses IP addresses & port numbers to direct segment to appropriate socket source port # dest port # 32 bits application data (message) other header fields TCP/UDP segment format