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Web Hosting - The Internet and How It Works
In one sense, detailing the statement in the title would require at least a book. In another sense, it can't be fully explained at all, since there's no central authority that designs or implements the highly distributed entity called The Internet.
But the basics can certainly be outlined, simply and briefly. And it's in the interest of any novice web site owner to have some idea of how their tree fits into that gigantic forest, full of complex paths, that is called the Internet.
The analogy to a forest is not far off. Every computer is a single plant, sometimes a little bush sometimes a mighty tree. A percentage, to be sure, are weeds we could do without. In networking terminology, the individual plants are called 'nodes' and each one has a domain name and IP address. Connecting those nodes are paths.
The Internet, taken in total, is just the collection of all those plants and the pieces that allow for their interconnections - all the nodes and the paths between them.
Servers and clients (desktop computers, laptops, PDAs, cell phones and more) make up the most visible parts of the Internet. They store information and programs that make the data accessible. But behind the scenes there are vitally important components - both hardware and software - that make the entire mesh possible and useful.
Though there's no single central authority, database, or computer that creates the World Wide Web, it's nonetheless true that not all computers are equal. There is a hierarchy. That hierarchy starts with a tree with many branches: the domain system.
Designators like .com, .net, .org, and so forth are familiar to everyone now. Those basic names are stored inside a relatively small number of specialized systems maintained by a few non-profit organizations. They form something called the TLD, the Top Level Domains. From there, company networks and others form what are called the Second Level Domains, such as Microsoft.com.
That's further sub-divided into www.Microsoft.com which is, technically, a sub-domain but is sometimes mis-named 'a host' or a domain. A host is the name for one specific computer. That host name may or may not be, for example, 'www' and usually isn't. The domain is the name without the 'www' in front. Finally, at the bottom of the pyramid, are the individual hosts (usually servers) that provide actual information and the means to share it.
Those hosts (along with other hardware and software that enable communication, such as routers) form a network. The set of all those networks taken together is the physical aspect of the Internet.
There are less obvious aspects, too, that are essential. When you click on a URL (Uniform Resource Locator, such as http://www.microsoft.com) on a web page, your browser sends a request through the Internet to connect and get data. That request, and the data that is returned from the request, is divided up into packets (chunks of data wrapped in routing and control information).
That's one of the reasons you will often see your web page getting painted on the screen one section at a time. When the packets take too long to get where they're supposed to go, that's a 'timeout'. Suppose you request a set of names that are stored in a database. Those names, let's suppose get stored in order. But the packets they get shoved into for delivery can arrive at your computer in any order. They're then reassembled and displayed.
All those packets can be directed to the proper place because they're associated with a specified IP address, a numeric identifier that designates a host (a computer that 'hosts' data). But those numbers are hard to remember and work with, so names are layered on top, the so-called domain names we started out discussing.
Imagine the postal system (the Internet). Each home (domain name) has an address (IP address). Those who live in them (programs) send and receive letters (packets). The letters contain news (database data, email messages, images) that's of interest to the residents.
The Internet is very much the same.
Web Hosting - When Changing Web Hosts Nearly everyone will want to change to a new web host at some point. It may involve just changing out old hardware for new. It usually means finding an entirely new web hosting company. When faced with that decision there are a number of issues to be considered. Swapping hardware and/or software is a fairly straightforward decision. There are two possible scenarios. Either you maintain your own hardware and software at a facility managed by others, or you are considering upgrading to newer (usually more expensive) systems maintained by others. In either case, it's simply a matter of estimating the cost and the short-term impact versus the long-term benefits. If the system(s) you currently use are short on capacity, sooner or later you'll be sufficiently motivated to make the change. Either the hardware will become unreliable or loaded to the point you'll be forced to migrate, or your needs will expand enough to justify the effort and expense of moving. Similar considerations apply to the scenario in which you rely on the web hosting company for everything, and want to find someone else to rely on. Regrettably, that's a very common situation. Many web hosting companies provide systems and staff that sooner or later fall below an acceptable level. Most people make the decision to change based on emotion. That's not entirely bad. Emotions incent you to take action. But you need to keep a cool head, too, in order to calculate your long-range self-interest. Bearing some minor inconveniences from time to time is usually worth the trade off. When it begins to affect your site to the point you're losing visitors, it's time to make a change. To get a more objective handle on when that point is reached, reach for some numbers. Maintain, or get from the hosting company, a factual report about availability and current usage. If the server is down so much, or so heavily loaded, that it drives your visitors away, it's time to take action. There are other less easily quantifiable but equally important factors, as well. You will at some point need to communicate with one or more persons who help maintain your site. Even if you do all your own server, database and web site maintenance, someone behind the scenes is helping to keep things running smoothly. That's called 'infrastructure'. If the road you drive on has potholes, it's not enough that you can fix your own car. In terms of network bandwidth and availability, server capacity, disk space, security and a whole array of other aspects, the web hosting company has to have competent people who care (and are allowed) to do the job well. When the company's people fall down - because of incompetence, lack of resources or absence of a culture of excellence - or for any other reason - your web site suffers. This issue more than any other is what drives people to seek another web hosting company. Even if you choose well at the outset, things can change. Management changes, staff changes and companies are taken over by other companies. Sometimes, it isn't simply a matter of swapping out an unreliable piece of hardware or software. When it's time to swap out people, you look for the same aspect: doing the job required.
Web Hosting - Redundancy and Failover Among the more useful innovations in computing, actually invented decades ago, are the twin ideas of redundancy and failover. These fancy words name very common sense concepts. When one computer (or part) fails, switch to another. Doing that seamlessly and quickly versus slowly with disruption defines one difference between good hosting and bad. Network redundancy is the most widely used example. The Internet is just that, an inter-connected set of networks. Between and within networks are paths that make possible page requests, file transfers and data movement from one spot (called a 'node') to the next. If you have two or more paths between a user's computer and the server, one becoming unavailable is not much of a problem. Closing one street is not so bad, if you can drive down another just as easily. Of course, there's the catch: 'just as easily'. When one path fails, the total load (the amount of data requested and by how many within what time frame) doesn't change. Now the same number of 'cars' are using fewer 'roads'. That can lead to traffic jams. A very different, but related, phenomenon occurs when there suddenly become more 'cars', as happens in a massively widespread virus attack, for example. Then, a large number of useless and destructive programs are running around flooding the network. Making the situation worse, at a certain point, parts of the networks may shut down to prevent further spread, producing more 'cars' on now-fewer 'roads'. A related form of redundancy and failover can be carried out with servers, which are in essence the 'end-nodes' of a network path. Servers can fail because of a hard drive failure, motherboard overheating, memory malfunction, operating system bug, web server software overload or any of a hundred other causes. Whatever the cause, when two or more servers are configured so that another can take up the slack from one that's failed, that is redundancy. That is more difficult to achieve than network redundancy, but it is still very common. Not as common as it should be, since many times a failed server is just re-booted or replaced or repaired with another piece of hardware. But, more sophisticated web hosting companies will have such redundancy in place. And that's one lesson for anyone considering which web hosting company may offer superior service over another (similarly priced) company. Look at which company can offer competent assistance when things fail, as they always do sooner or later. One company may have a habit of simply re-booting. Others may have redundant disk arrays. Hardware containing multiple disk drives to which the server has access allows for one or more drives to fail without bringing the system down. The failed drive is replaced and no one but the administrator is even aware there was a problem. Still other companies may have still more sophisticated systems in place. Failover servers that take up the load of a crashed computer, without the end-user seeing anything are possible. In fact, in better installations, they're the norm. When they're in place, the user has at most only to refresh his or her browser and, bingo, everything is fine. The more a web site owner knows about redundancy and failover, the better he or she can understand why things go wrong, and what options are available when they do. That knowledge can lead to better choices for a better web site experience.