The internet is basically the grand physical structure that connects all sorts of devices together into a grand network of networks, TCP/IP is the magic that makes makes the fact of computer-to-computer connection possible. Trying to imagine internet-based communication without TCP/IP is like trying to imagine sending a Wii to your grandmother in California without a single piece of information on the postal package.
TCP/IP stands for Transmission Control Protocol / Internet Protocol. In the internet protocol suite, TCP/IP represents the standards adopted by those smart internet engineers to get computers sending, routing and assembling data across an incredibly complex network in a reliable and consistent way. Think of it as the computer equivalent of the rules governing the physical transmission of goods via the USPS (you have to have a stamp, you have to have an address in a certain form, packages have to be a certain size, etc), except computers don't have minds, so the protocols exist as a standard set of applications and interfaces...
The Address: IP
IP is the most basic internet protocol (a "network protocol"), and it enables your computer to locate, send to and receive from other machines on the internet. How is this done, exactly? Well, from the transmission side, the an IP header is the last thing added to a packet (see TCP below), and this header includes the most basic addressing information necessary for data transmission across a network: the destination address of the machine to which you want to send data, and the address of your machine. Unlike TCP, IP does not check if a real connection exists between machines, and it does not include support for breaking down and serializing/ordering data packets. IP simply supports the most basic components of data navigation across a network. IP data is primarily interpreted by the IP router (see below).
Address verification/disassembly and assembly: TCP
The higher level transmission issues are handled by TCP, a "transport protocol". TCP includes baked-in support for establishing a real connection between applications on different machines (a three way handshake that initiates a "full duplex" communication between computers until it is terminated by either party). It also handles the complexities involved with breaking large data sets into small packets of data and sending them across a variegated network where the packets will likely not be received in the order sent. Thus, the TCP header will include information pertaining to the real connection between machines as well as information about individual packets. The TCP information is processed by applications on your computer and on the web server.
TCP also includes information about the sending and receiving ports involved in the transmission. More on ports at some other point perhaps.
Packet Routing: IP Routers
Like the USPS with its processing centers , you're going to have to have some kind of a third party involved in handling the packets sent from one machine to another; and that's the job of an IP Router (or network of routers) to which packages are actually sent and from which packages are finally received. Again like the USPS, routers identify sending and receiving machines by means of addresses. IP addresses consist of four numbers, separated by periods, each ranging from 0 to 255 (since each number must be represented in a single computer byte). On the world wide web (to be covered in another article), IP addresses are represented by domain names which are registered and actively translated into IP addresses by a Domain Name Server (DNS) process.
That's the absolute basics of the whole thing. Next time we'll look at the nature of the things you can put "in" (or on) those packages which is defined by further protocols.
Resources
The W3Schools Resource
A guy who seems to know a lot about this
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