How demultiplexing works host receives IP 32 bits datagrams source port dest port each datagram has source IP address, other header fields destination IP address each datagram carries one transport-layer application segment data each segment has (payload) source,destination port number host uses IP addresses TCP/UDP segment format port numbers to direct segment to appropriate socket 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 one transport-layer segment  each segment has source, destination port number  host uses IP addresses & port numbers to direct segment to appropriate soc ket source port # dest port # 32 bits application data (payload) other header fields TCP/UDP segment format