What exactly is TCP/IP?


I am starting out in IT and am about to complete A+ cert course. I understand that TCP/IP is a foundation element of the internet and is implemented with many other protocols. I would like to know exactly what it’s function is tho. What does it do, how long has it been around, and how it work in tandem with other protocols? I’ve tried researching it but always end up reading a bunch of high level tech jargon.

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If you think of the information as a letter being sent the application drafts the letter and then it get’s all packed up and ready to send but you need to know where it is going. TCP/IP is essentially the address and return address information and then DNS allows names to be converted to the numbers etc.

TCP and IP are both separate but tightly coupled protocols used as the basis of the Internet.

IP is used to deliver packets of information between two devices. The IP packet header includes the source and destination addresses, which tell the routers where to route the packet. However, this protocol doesn’t contain any information on where to direct the packet inside the device (which program should get it) or how it relates to other packets, and has no mechanism to detect packet loss.

TCP is used to establish a “conversation” between two programs. A TCP packet’s source and destination ports are used to identify the conversation between two programs, so the devices themselves know where to route them. The packets are numbered sequentially, so that the receivers on both ends know how to order them and how to join them into a single stream of data, as well as detect when a packet was lost along the way, so they could ask for that packet again.

Internet Protocol (IP) controls how data packets are routed over the internet to get to their destination.

Transmission control protocol (TCP) handles establishing a connection between two devices to pass data back and forth and detecting things like packet loss and retransmitting if needed.

Other protocols like http then build on top of TCP/IP.

There are some alternatives to TCP like UDP that run on top of IP for different types of connection but TCP is by far the most common.

There is also a MAC layer (media access control) that runs under all of this that handles the physical link between two devices. This will get replaced each hop along the network. E.g. the MAC layer for WiFi is very different to the one for wired ethernet but the IP layer and above are the same on both.

TCP and IP are two different things, which are often used together.

At the lower levels, you have things like Ethernet and Wi-Fi which allow your computer to communicate to a device next to them- one connected by wires in the case of Ethernet or within radio range in the case of Wi-Fi.

The Internet Protocol, or IP is the system that lets you use all the computers connected together as a relay to forward a message from your computer to any other computer connected to the Internet even if it’s not directly connected to your computer.

The problem is that in this giant relay around the world, sometimes messages get lost or arrive out of order. The transmission control protocol, or TCP is a procedure built on top of IP that you and the computer you’re communicating with can use to try to find order in that chaos. It’s got the rules for how to tell the other computer how many messages you’re sending and what order they’re supposed to be arranged in, and the rules for when you should retry sending a message in case it got lost. It makes an Internet connection seem more reliable than it really is.

Others have already answered the question adequately I suppose, but just thought of pointing out that you may also want to lookup up others like arp, udp, smtp, icmp, rtcp, sctp… You can basically run Wireshark or a similar tool and go from there (also maybe YouTube wap, that’s a very important protocol to learn in college ;-))