Web, Internet...same thing (choo choo)
“Web, Internet, same thing”. I’ve heard that a few times. It’s not actually true, but I let it slip. Until now.
Firstly, The Internet came first. And by years.
By how much actually depends on what you define as ‘starting’, but here’s some rough years:
- 1969 ARPANET sends it’s first data; it was effectively the first interconnected network (or network of networks – linking two different networks)
- Early-mid 1980s. What we think of as The Internet was taking shape and being used. It evolved from ARPANET and others.
- 1991. The World Wide Web started, it was ‘text’ based (from memory!). It took off in 1993 with the graphical browser (Mosaic)
BTW, I’d recommend this excellent book on the early days of the Internet.
So, how is the Web and Internet related? Think of it this way:
- The Internet is like the railway network – the rails, signals, switches, stations.
- The Web is one of the types of trains that use it.
The same railway lines can be used for carrying people, iron ore, cattle, grain and oil etc. All with different types of ‘carriage’. It can also have steam, electric and diesel trains on it – even those little hand-pumped ‘carts’ work.
Again, it’s an analogy, so don’t overthink it. But it does have further uses.
The Web (equivalent to say, passenger trains) is like a service that runs on the Internet (railway network). Email, Facebook, Spotify and so on are other train/service types##.
Split that Train into Carriages
What follows is a core and important Internet concept.
Our ‘train’ in fact can be thought of having two main parts:
- A header (the locomotive)
- The content (the carriages)
Again, these may are my terms, but you’ll see they hopefully make sense.
Unlike a real train, the carriages on an Internet transmission can be separated and go via different train lines to their destination.
The header keeps track of how many carriages there should be and it what order they should be in (packets is the technical correct term for ‘carriage’ here).
These packets can arrive – at the other end – and be out of order…but the header will enable them to be reassembled correctly, by the receiving system. If a packet doesn’t arrive or is damaged, the receiving system can ask for it to be re-sent (nice!)
In fact the Internet, like the railways, uses Switches. And Routes.
Now, say you live in Melbourne and request a web page from Sydney. Some of the many, small packets – that make up the web page content – could start flowing down to you, via a main fibre optic link from Sydney to Melbourne.
But then that link suddenly becomes busy or develops a fault; after it’s sent the first lot of packets. The underlying Internet technologies know there’s a route between Sydney and Adelaide, plus one from Adelaide to Melbourne. The rest of your packets are sent down those links. This happens very fast. Very, very fast. It’s unlikely you’ll even notice.
Your device gets the packets for that web page, puts them back in the correct order and shows you the web page. Or plays you the song. Or starts that interactive web conference, enabling you to work from home.
## Some things like Facebook, YouTube and Netflix are apps on your phone, but may be actually using the Web behind the scenes. Others may be using different Internet ‘services’.
