Networks, Internet and Protocols
A data network is a collection of nodes (computers, smartphones, and various junctions such as routers) 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). The world’s largest WAN you're well familiar with: 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 by the sender, and then reassembled by the receiver.
The packets are sent separately through the network (i.e. the telephone lines, which they used at the time), with an address for 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 they fit 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.
What’s ingenious about this system is that it allows many data packets to share the same lines at the same time, unlike 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 and Internet Explorer of the 90s, or today's Chrome, Brave, Safari and Firefox.
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 60s, 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 (like 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 anarchy and chaos, and computers too need to follow an agreed-upon set of rules so they can communicate and exchange data with each other.
Such a ruleset is what's called a communication protocol.
Communication protocols control the transfer of data between two points (for example computers) in a network. Following protocols is necessary for both the software and the hardware of the computers that communicate with each other, as well as network devices like a router and a switch.
Network equipment, clients and servers
Wonder what that is?
A local network can thus be connected wirelessly or via a switch, which in turn is connected to the Internet via a router. Over the 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 protocol (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 like Chrome or Firefox.
- 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.
- 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 (www). TCP/IP, on the other hand, ecompasses the rules of Internet communication as a whole.
Here's how it works: