Why does software mention TCP or TCP/IP when it means just IP?

Question

When I configure a network interface in Windows to have a static address, I have to go to TCP/IP settings. In this TCP/IP settings dialog I can set IP, subnet and gateway, which are IP- and route-settings. I can set resolver, and WINS settings, which are local network configuration settings. None of these have anything to do with TCP, apart from the fact that TCP (like UDP, GRE, ICMP, etc.) probably need IP to work.

Another example is the *NIX utility tcpdump, which shows traffic that is observed by a specific interface. tcpdump may be configured to only show TCP traffic, but by default it will show all IP traffic, like TCP, UDP, GRE, ICMP..

I think there are probably other examples out there, but these two I have seen the most.

Why is TCP or TCP/IP mentioned when it's actually only about IP? Why specifically TCP and not for example HTTP/TCP/IP or UDP/IP?

Answer 1

It is actually referring to the Internet Protocol Suite, which includes IP, TCP, UDP etc as well other protocols. As TCP and IP are the most commonly used protocols, and provide transport for many other Internet Protocol Suite protocols, it is sometimes referred to as TCP/IP, but it is referring to the entire suite of protocols. The protocol stack inside the OS is named the TCP/IP stack, but also supports other protocols.

Interestingly, the precursor to TCP - Transmission Control Program, combined both the Internet layer and Transport layer into a single protocol They were later split into separate protocols to provide more flexibility.