As we all know, computers are a combination of hardware (computers, monitors and modems/routers) and software applications or programs (word processing, spreadsheet/accounting programs, etc.).
The same goes for networking: Both hardware and software are involved—and the heart of the networking software, which is built in to your computer, is TCP/IP...the international standardized guidelines for network communications. (TCP/IP stands for Transmission Control Protocol/Internet Protocol.)
Stacked in your favor.
TCP/IP is organized in layers or stacks. You'll sometimes also hear the layers referred to as the protocol suite. Each layer of the stack has a special function, and each plays a role in handling your data, processing it through the entire stack, and sending it on its way. To where? To an identical TCP/IP protocol suite at the computer to which your data is headed. These layers work together seamlessly and instantly whenever you send data from your computer to another across a network, especially on the Internet.
TCP/IP: It comes standard!
When you buy a computer, a TCP/IP stack is already inside and operable, so you don't have to install one. Your actual software might not be identical to somebody else's, but they both work identically because they're following the same RFCs (Request for Commands), which is more or less the bible of TCP/IP protocols. (Rumor has it you can even swap out your TCP/IP software for another...but that's like switching engines in your car. You pretty much have to know what you're doing and why.)
How your messages are routed.
TCP/IP breaks down your message (in its data form, because it is all electronic data) into packets and sends them out into the network. It also adds headers to the message, which provide instructions (to the network and the destination computer) for special handling. On the receiving end (and along the way), TCP/IP reads the headers, handles the instructions and data appropriately, and puts the message back together again.
When you send a message from your computer to another computer, the electronic data goes through the TCP/IP stack, from top to bottom. When it reaches the other computer, it goes through that stack from bottom to top, translated and manipulated for reading at each step.
The layers within the suite.
TCP/IP is complex, of course, and there is no practical reason for the everyday computer user to know all the details. Still, a grasp of the technology behind your computer usage is pretty fascinating. So, here is a simple overview of the names of the layers in the stack and the protocols (or function) within each one.
And guess what? You'll find a protocol for determining your IP addresses here—after all, that's what helps your data requests find their way to your computer, and not someone else's.
The TCP/IP layers...and protocols.
There are specific protocols or other instructional/directional functions in each layer. Depending on the type of message you send, your computer will mostly likely use something from each layer, but it doesn't use all of the protocols. Here are the different layers and just some of the embedded protocols and functions:
- Layer 1—Physical
- Standards for wires, cables and radio waves
- Layer 2—Data Link
- Protocols that work with network hardware, Ethernet and VPNs
- Layer 3—Internet
- IP (Internet Protocol)
- IPv6 (Internet Protocol Version 6)
- ARP (Address Resolution Protocol)
- RARP (Reverse Address Resolution Protocol)
- ICMP (Internet Control Message Protocol)
- IPSec (IP Security Protocols)
- L2TP (Layer 2 Tunneling Protocol)
- CIDR (Classless Inter-Domain Routing)
- Layer 4—Transport
- TCP (Transmission Control Protocol)
- UDP (User Diagram Protocol)
- Layer 5—Application
- DNS (Domain Name Service)
- FTP (File Transfer Protocol)
- HTTP (HyperText Transfer Protocol)
- SMTP (Simple Mail Transfer Protocol)
- POP3 (Post Office Protocol Version 3)
- ...and many more
Again, the greatest news is that this all happens seamlessly, rather instantly, and doesn't require you to configure each message for sending. Imagine if it did! We'd have to know all the protocols and their functions, and program them to work for us.
Thank goodness for the many Internet associations and organizations that have figured this all out (including TCP/IP) for everyone who uses a computer.