Thank you for the opportunity to help you with your question!
TCP/IP (Transmission Control Protocol/Internet Protocol) is the basic communication language or protocol of the Internet. It can also be used as a communications protocol in a private network (either an intranet or an extranet). When you are set up with direct access to the Internet, your computer is provided with a copy of the TCP/IP program just as every other computer that you may send messages to or get information from also has a copy of TCP/IP.
Forouzan, B. A. (2002). TCP/IP protocol suite. McGraw-Hill, Inc..
Please let me know if you need any clarification. I'm always happy to answer your questions.