Transport layer
transport
The Transport layer
The tcp layer
transport
TCP and UDP are transport layer protocols; the OSI layer is layer 4 (transport)
transport
Transport layer TCP/IP Protocols are TCP and UDP
tcp is the transport control protocol and ip is the internet protocol. tcp is concerned with guaranteed delivery of packets from source to destination, while ip is the protocol used to actually deliver packets. tcp is located at layer 4 of the osi model, or the transport layer. ip is located at layer 3 of the osi model, or the network layer. check out the video tutorials in the link below.
Network Interface Layer
What do you mean with "TCP/IP programs"? Any program that communicates over the Internet uses TCP/IP protocols. I want to say that activities of TCP/IP protocols should be manipulate.
signaling
TCP/IP protocols are implemented by software, except for the bottom physical layer, which is implemented in hardware.