How the Web works, and why you should care (Part I).
In today’s post we will be discussing how the web actually works, and why you , the business manager, should actually care. This short article could easily be a 10 volume encyclopedia if we delved into too many details. Furthermore, I would have to go take up a PhD in computer science before I could even write the half of it. There is that much to it.
Just to save some time (and get you to read the rest of this post!) I think I should answer the second question first, i.e. Why should I care?
You probably know all the buzzwords for internet technology. You can spew off terms like “TCP/IP”,”HTTP”, “SSL”, “HTML”,”ISP”, etc., etc., etc.! However, while you might get away with throwing around a few carefully selected buzzwords at a company social, when you are working with IT departments you really need to have some understanding of how the web works. If you are simply an end-user of the internet it is probably sufficient to know how to turn your computer on, open up Intenet Explorer and Microsoft Outlook, and start using the web. Not too much to it really. But if you are going to be utilizing internet technologies in order to build your company you need to know what technologies can help you, what the pluses and minuses of each technology are, and what other dependent technologies are required for their use. Even if you rely upon the recommendations of your IT department or your IT consulting firm, it is still a wise idea to know enough so that you can make wise decisions on their recommendations. After all, you’re in charge. The company’s success is in your hands, not theirs. You wll be the primary recipient of the rewards of success or the consequences of failure.
The Internet - A Network of Networks
The first thing you should know about the world wide web is that it is NOT the internet. The internet is actually the physical network of computers and devices that are connected together, and communicate together around the world. Its origins can be traced back to the late 1960’s when the first computer networks were linked together through ARPANET between UCLA and SRI International. By the early 1980’s it had grown to be an international collection of educational and government computer networks. By the late 1980’s the TCP/IP protocol was developed and commercial computer networks were allowed to join, and the internet has been booming ever since.
Network protocols, such as TCP/IP, are the low-level language that computers use to talk to each other. There are others, such as IPX/SPX (Netware Networks) and AppleTalk. TCP/IP is actually a suite of languanges that are commonly used for the internet. The backbone of the suite is the IP Address. Each computer which is connected to the internet must have a unique number in order to differentiate itself from other computers. The IP Address is a set of 4 numbers which can have up to 3 digits for each number. Each number is separated by a dot (.), and looks like XXX.XXX.XXX.XXX. Most of these numbers are available for use on the internet, but some ranges are reserved for use in internal networks, such as 10.0.0.0 - 10.255.255.255.    There are approximately 4.3 billion possible IP addresses. As you might imagine, the world is quickly running out of these ip addresses.
Most computers are not directly connected to the internet, but rather are part of a network that is connected to the internet. You must go through an Internet Service Provider (ISP). For example, you may have a small wireless home network of computers at your house. The individual computers all are assigned a private ip address, such as 10.0.0.11, 10.0.0.12, etc. They talk to to your wireless router. Your wireless router is usually hooked up to a cable or DSL modem, which in turn directly connects to your ISP, such as Time Warner, or Verizon. Your wireless router is assigned an ip address from the list of your provider’s available public ip addresses by using the Dynamic Host Configuration Protocol (DHCP). DHCP is one of the network protocols that is part of the TCP/IP suite of network protocols. In the days of dial-up phone modems it really helped on conserving public ip addresses.  When someone disconnected from their dial-up connection, the public ip address would be released, and would be available to give to another computer dialing in. Now, with all the broadband connections that are available at home, and on mobile devices and cellphones, your connection is always on whether you are using your computer or not, so the public ip address is never released. Anyhow, when you ask for a web page or ask for anything on the internet, your wireless router acts as a proxy. By utilizing Network Address Translation (NAT) (Another member of the TCP/IP protocol suite) your wireless router passes on your request for the internet resource using its public ip address, and then when it gets a response it forwards it on to your computer that has a private ip address. It “translates” for you, and for every computer in your house. Instead of having to have one public ip address for each computer on your home network, it only needs one.
Now the world wide web is actually a bunch of computer servers that are connected to the internet network that serve web pages through either the HTTP or HTTPS network protocols. Again, these are sub-protocols of the TCP/IP suite of network protocols.  When you type in URL into your browser your browser makes a request to the web server to give you a particular page that it is hosting. The web server responds to your browser, and the browser displays the results. HTTP is the normal protocol used. HTTPS is a secure encrypted protocol that is often used by online banking systems, and other web servers that host sensitive data that you don’t want intercepted by some hacker.
Now the web server has a public ip address, and if you typed it in to your browser the website would still work. Google’s web server has a public ip address, and if you type http://74.125.45.100/ into your browser, Google will appear.  Typing http://www.google.com only works because www.google.com is registered with a Domain Name System (DNS). A DNS Server keeps an entry in its records for every domain name, and what the public ip address is for the internet server that it corresponds to. DNS is yet another sub-protocol of the TCP/IP suite.
Email and FTP do not use the HTTP or HTTPS protocols. Rather they make use of other TCP/IP protocols such as POP3, SMTP, and FTP. If you use a browser to get your email from a hotmail email account you are indeed using HTTP or HTTPS to access the hotmail web server. However, the hotmail web server uses the SMTP and POP3 protocols in the background in order to access hotmail’s dedicated email servers. If you are using MS Outlook, the program accesses the email servers directly, and uses the SMTP and POP3 protocols to do so.
Summary
There are many great articles on internet infrastructure. I would suggest the How Internet Infrastructure Works on howstuffworks.com. In the next blog post, I will discuss how web servers operate. Please check back soon!
