Networks, Internet and Protocols
A data network is a collection of nodes (computers, smartphones, and various junctions such as routers, connecting increasing types of devices such as vacuums, panel ovens and electrical switches to mention but a few) that are connected—either by cables or wirelessly—so they can communicate and share resources. Data is transferred over the data network in the form of bits.
There are several types of networks, for example local networks in a business or a home (LAN, Local Area Network) and networks that are spread geographically across several places (WAN, Wide Area Network). You're very familiar with the world’s largest WAN : the Internet.
The Internet traces its roots back to the research project ARPANET, which was initiated by the US Department of Defense's Advanced Research Projects Agency (ARPA) in 1966.
Back then, ARPANET made use of a new invention called packet switching. The idea is as simple as it is ingenious: Instead of needing a stable and uninterrupted connection for communication between two computers, the information was divided into small data packets at the sender’s end, and then reassembled by the receiver.
Internet packets are sent separately through the network (i.e. the telephone lines, which they used at the ARPANET time), with an address describing where they're going—much like several envelopes each containing a part of a construction set. The packets contain instructions for where they're going (like a package has an address and stamp) and where their content fits on reassembly.
The individual packets can take different routes and travel via different nodes—like post offices—that send them further along the lines where there is available capacity. Furthermore, the packets need not arrive in the correct order. The recipient puzzles it all together, filling in the blanks as numbered sequence packages arrive.
One ingenious aspect of this system is that it allows many data packets to share the same lines at the same time, not needing a continuous and uninterrupted connection like old telephone lines (so-called circuit switching). Packet switching was a breakthrough in network technology and the basis for today's TCP/IP system (which we'll return to shortly).
The first computers that were connected to the ARPANET in 1969 were situated at different American universities, but it soon expanded. Norway, for example, connected to the networks as early as 1973.
Internet and the World Wide Web
What do you associate with “the Internet"? Many think of it as whatever can be found through a browser—such as Netscape Navigator and Internet Explorer of the 1990s, or today's Chrome, Brave, Safari, Firefox and Vivaldi.
What we access through a browser is actually not the Internet itself, but more specifically the global network of hypertext documents—i.e. websites—known as the World Wide Web.
While the Internet originated in the 1960s, the World Wide Web was launched in 1991. It was developed by Tim Berners-Lee at the European research organisation CERN.
The World Wide Web uses so-called hypertext, with links that let us navigate between web pages with the help of domain names (such as datareisen.no), which make it easier to find web pages and other resources.
Therefore, the Web is not quite the same as the Internet, but is one of the Internet's services—alongside e-mail and file transfer, among other things.
HTTP, TCP/IP and other protocols
Sports and games need rules in order to avoid chaos, and computers too need to follow an agreed-upon set of rules so they can communicate and exchange data with one another.
Such rulesets are what's called communication protocols.
Communication protocols control the transfer of data between two points (for example computers, but increasingly other devices) in a network. Following protocols is necessary for both the software and the hardware of the computers and devices that communicate with each other, as well as network devices like routers and switches.
Network equipment, clients and servers
Wonder what that is?
A local network can thus be connected wirelessly or via a cable to a switch, which in turn is connected to the Internet via a router. Over a network, one can connect to various servers, for example servers related to domain names like datareisen.no or google.com.
Let's look at some of these protocols:
- HTTP: It is the HTTP (Hypertext Transfer Protocol) that makes it possible for a client computer to download a website from a server, so that the website can be displayed in a browser.
- SMTP: Another important protocol is SMTP (Simple Mail Transfer Protocol), for—you guessed it!—transferring emails.
- FTP: Historically, FTP (File Transfer Protocol) has been widely used for file transfer, but with developments in the HTTP protocol, HTTP has largely taken over this function, even when it comes to transferring other file formats than HTML (websites). For example, streaming services now typically use HTTP to transfer media content (audio and video). Streaming services typically transfer many smaller files, something HTTP is better suited for than FTP. When transferring large sets of data between networks, sometimes over the Internet, FTP is still in use in legacy systems. For new deployments, SFTP (SSH File Transfer Protocol) and HTTPS-based file transfer are generally preferred because they are much more secure.
- TCP/IP: Last but not least, we must mention TCP/IP (Transmission Control Protocol/Internet Protocol), which encompasses the basic rules of the Internet.
We mentioned TCP/IP earlier when we talked about packet switching. Today, packet switching is part of the TCP/IP protocol, which is actually a whole set of protocols for Internet communication (it's often referred to as the “Internet Protocol Suite”).
TCP/IP, along with HTTP, are the most important protocols to familiarise yourself with—and that's exactly what you can do through the box below.
How HTTP and TCP/IP work
HTTP is simply the framework for transferring information on the World Wide Web. TCP/IP, on the other hand, encompasses the rules of Internet communication as a whole.
Here's how it works: