Header Logo
Home   Hardware   Software   Storage   Networks   Internet   Mobile   Web 2.0   Cloud   Big Data   Green   Quantum   Security   DSE Regs   HOT!
The Internet


It may seem strange to have a section here on the Internet. After all, the topic is as vast as the largest computer network in the world, and you clearly know at least something about it already if you are sitting at a computer and reading this page! This section is therefore limited to the practical knowledge required to connect a computer to the Internet, to at least the start of the process of creating a website, and to Internet censorship.

Readers unfamiliar with computer networking are encouraged to read the networking section before this one. The cloud computing and Web 2.0 sections should additionally be consulted for coverageof Internet developments. The security page also contains information on firewalls and antivirus software.


The Internet is an example of an "internetwork", or in other words an interconnection of two or more networks to enable communications and resource exchange. The Internet started out in the 1960s as an internetwork of a number of early US military and academic networks. In the 1990s it then grew to also incorporate an increasing number of domestic and commercial business networks, and to become the largest internetwork in the world. More information on the history of the Internet can be found here.

The Internet is based on the client-server model (as discussed in the networking section), in which a large number of permanently interconnected server or "host" computers provide connectivity and services to an even larger number of usually only temporarily-connected clients. The direct network linkages between key Internet servers are referred to as the Internet's "backbone" as they are the route across which most Internet communications travel. You can access some Internet backbone maps here.

All of the networks that form part of the public Internet share an open network communications standard called IP (Internet Protocol). Any computing device that can use the IP communications standard and that has suitable wired or wireless connection facilities (see below) can connect to Internet resources (such as the world-wide web and e-mail) as an Internet client.

At least today, most Internet clients are desktop or laptop personal computers (although they are rapidly being joined by tablets, smartphone and all manner of other cloud-access devices). In order to connect to the Internet, these client computers require an account with an Internet Service Provider (ISP). An ISP runs at least one server that acts as an Internet "Point of Presence" (PoP), and through which its customers obtain access to other Internet servers via the Internet backbones, and including those servers on which websites are hosted.

The following illustration provides a simple topological representation of the Internet, with nine Internet host (server) computers permanently interconnected. In order to send an e-mail message, "User A" can use their PC as a client to connect to a host that is their Internet Service Provider. Their message is then communicated between the permanently interconnected hosts, and picked up by "User B" next time they connect to their own Internet Service Provider.

Internet topology 01


There are a number of technologies that may be employed to allow computers to connect to the Internet. Such connections may be individual (for example where they are used to directly connect just one personal computer), or shared (where they allow a number of users of a local area network to make use of the same Internet connection).

Most computers connect to the Internet directly or indirectly using the wired telephone network. Three possible means of connection are available to do this known as dial-up, leased-line and DSL (or "broadband"). In most countries broadband is now by far the most popular of these. However, for individuals who live too far from a telephone exchange, a dial-up connection may still provide their only means of obtaining a fixed-line connection to the Internet. Most dial-up connections are limited to 56kbs (56 kilobits per second). This equates to around 7 kilobytes per second, meaning that even under ideal conditions it will take approaching three minutes to communicate 1MB of information. For sending e-mails and accessing largely text-based websites this can be perfectly sufficient. However, for richer multimedia surfing (such as downloading music or video content) dial-up is not really practical.

Most medium and larger companies connect to the Internet over the telephone network using their own leased-line direct connection to an Internet Point of Presence. Such lines are rented from telecoms providers, do not have a telephone number, and establish a permanent connection between the Internet Point of Presence and the organization's local area network(s). This therefore permits all computers on the organization's network(s) access to the Internet. A typical speed for a single leased line in the UK is two megabits per second for both upload and download.

Having noted the existence of dial-up and leased-line Internet connections, for most individuals and small and medium-sized companies DSL or "broadband" is the dominant Internet connection technology. DSL stands for "digital subscriber line", and transmits digital data over a telephone line by using frequencies not used by voice traffic. DSL is commonly marketed as broadband. DSL is also available in two variants known as ADSL and SDSL.

ADSL stands for "asymmetric digital subscriber line", and has a faster download speed from the Internet than its upload speed to the Internet. For example, first generation ADSL connections offer a theoretical 8 megabits per second download speed coupled with a 488 kilobits per second upload speed. As the majority of Internet users do more content downloading than uploading, the differences in download and upload speed makes relatively little difference to them (and indeed most broadband users are probably unaware that they have a different download and upload speed). However, the differences in download and upload speeds become more critical if large-scale online data transfers and back-ups are necessary, or if there is a need for high quality video conferencing (where two-way high speed communications are hence required). While 8 megabits per second remains the theoretical maximum download speed for ADSL, this rises to 12 megabits per second for a standard called ADSL2, and 24 megabits per second for ADSL2+. This said, at least in the UK, availability of ADSL2 and ADSL2+ remains somewhat limited.

SDSL (symmetric digital subscriber line) offers equal upload and download speeds. At least in the UK, it also requires new SDSL wiring, and typically costs at least five times as much as ADSL (BT SDSL Broadband prices, for example, start at 170/a month plus VAT and connection). SDSL is hence currently being targeted at companies that want improved Internet connectivity but cannot afford far more expensive dedicated leased lines.

For a guide to UK broadband services, you may like to visit BroadbandDeals.co.uk or BroadbandGenie.co.uk.


An ADSL broadband service has to be purchased for a specific telephone line. Not all phone lines are suitable, and few fully support the highest potential speeds on the market due to the quality of the legacy cabling and the distance of the socket from the exchange (which needs to be no more than around 5km). Physical modifications are required at the telephone exchange to enable the service to operate. Once these are completed, a single DSL modem is connected to a telephone socket. Microfilters also need to be inserted between the phone socket and any telephones on the line to prevent crossover (interference) between the data and voice services.

DSL modems are usually external to a computer and connected to it via either a USB or Ethernet (UTP) port, or else wirelessly by Wi-Fi. For wired connections, the use of an Ethernet connection is preferable for maximum performance if download speeds of over 4 megabits per second are available. Many DSL modems are also network switches and/or wireless access points, enabling the Internet connection to be shared between many users (and as discussed in more detail in the networking section).

When selecting either an ADSL or SDSL service, several factors need to be considered. As discussed above, both download and upload speeds should ideally be taken into account, although in practice most users only realistically have a choice of download speed, and this is often limited in practice by the quality of their telephone line. As an aside, it should be noted that DSL and other network speeds are measured in megabits per second, and not megabytes (which are 8 times larger). Many commentators (including some IT journalists who should know better!) freely talk about "eight megabyte broadband services", when they really mean 8 megabits ADSL. OK. Pet rant over!

Alongside upload and download speeds, the most critical factor to get right in choosing a DSL service is the monthly download limit. Many cheaper broadband packages limit users to one or a few gigabytes of downloaded data a month, or else charge for any download beyond this limit. The extent to which this matters depends on what the Internet connection is going to be used for, with users who regularly download video content being the most likely to have the highest monthly download requirements.

Different ADSL and SDSL packages also have different "contention ratios". This is a measure of how many users share parts of the same network infrastructure. In the UK, ADSL contention ratios are typically between 10:1 and 50:1.

A contention ratio of say 50:1 means that 50 users share the same ADSL infrastructure. In turn this means that an 8 megabit ADSL service with a 50:1 contention ratio actually shares the 8 megabit download bandwidth amongst 50 subscribers. On the basis that they are all unlikely to be downloading at the same time, this is not a problem. However, lower contention ratios are inevitably preferable (and the reason, along with download/upload speed symmetry, that large companies are prepared to pay substantially for on-the-face-of-it slower two megabit leased line Internet connections that have a "private" contention ratio of 1:1).

In practice, whether the contention ratio on a DSL service actually matters depends on how many users on a particular local telephone exchange actually have broadband and what they use it for. So, if all of your neighbours have broadband and live on YouTube and BBC iPlayer, then paying a little more for an ADSL service with a lower contention ratio may be worth it. However, if you are the only ADSL subscriber in the immediate area, then whether your service is contended 10:1 or 50:1 becomes irrelevant, as whilst your bandwidth is potentially shared, in practice no other "sharers" actually exist. Of course today being in the later position is increasingly unlikely, making contention ratios a bigger and bigger issue, particularly at busy times of day.


Wireless connections to the Internet come in two forms: those that actually involve a direct wireless link between a client computer and their Internet Service Provider, and those that are a wireless network extension of a DSL or leased line wired connection. The latter allow computing devices such as laptops and mobile computers equipped with WiFi wireless networking to connect to the Internet when they are in reach of a wireless access point (and again as discussed in the networking section).

Households or companies that have DSL Internet connections either terminated in a wireless access point, or connected to a local area network that includes a wireless access point, are not in any real sense purchasing wireless Internet access from their ISP (whatever the marketing may say!). However, where such a facility is offered as a "wireless hotspot" free or for a fee in a public location (such as a cafe or hotel lobby) then this point is more open to debate. Indeed, if the forthcoming 802.11y Wi-Fi standard really does manage to boost outdoor range from around 100m to 5000m, opportunities will start to exist for Internet Service Providers to sell direct WiFi wireless Internet access to households and companies.

Direct wireless connections using so termed mobile broadband have recently also started to become widely available. These mostly make use of 3G mobile phone networks to provide a direct and high speed wireless connection to a mobile Internet service provider. To use mobile broadband you need to have a contract or a pay-as-you-go account with a mobile broadband provider. This will include a SIM card with its own mobile phone number and a mobile broadband modem. This usually comes in the form of a USB stick known as a dongle.

mobile broadhand dongle image

A mobile broadband dongle has a slot for the SIM card and can be thought of as a data-only mobile phone. Most dongles automatically install connection software when they are first inserted. This is then run each time you want to connect to the Internet. The mobile broadband software will also keep track of your data usage and will allow you to send and receive texts on your mobile broadband phone number.

At least in the UK, in good reception areas mobile broadband can now be as fast as that actually obtainable with a wired broadband connection, with theoretical connection speeds of 3.6 and even 7.2Mbps, and actual speeds of several Mbps. Not least due to some excellent pay-as-you-go contract options, for some people with moderate Internet usage mobile broadband is therefore already a viable an alternative to a wired broadband connection. There is lots of good information on mobile broadband to be found at Mobile Broadband Genie, with some good comparison tables of current UK offerings also available on BroadbandExpert.com. To learn more about wireless broadband you can also watch the following video:

As detailed in the networking section, Internet connectivity using a wireless technology known as WiMax is now also becoming a possibility. WiMax offers a wireless connection at above DSL/broadband speeds for both fixed and mobile devices. Users require an account with a WiMax provider, together with a WiMax base station or adapter connected to their desktop or laptop PC, or indeed incorporated into their mobile computing device.


Whilst many individuals are happy to use Web 2.0 resources to publish their own content on the world-wide web (or indeed not to publish content at all), most businesses now require their own website to compete in the modern world. The creation of a website can be very simple or very complex, involving as it does a potentially large number of technical as well as aesthetic and conceptual decisions in addition to content creation. For those wanting a fairly straight-forward site -- or who indeed want a complex one but are happy to live within a number of design and other constraints -- then a number of cloud services (such as Google Sites and Moonfruit) allow anybody to create a new website in minutes using online tools. (For a list of such providers, please see the cloud computing directory). Sites created and hosted using these online website builders can be very good indeed. However, for those wanting total control over a complex website, the steps required to get up-and-running are usually roughly as follows:

Making hosting arrangements
A website has to live somewhere, and this means on a disk on a server with a permanent connection to the Internet. This server can be one of an organization's or even an individual's own computers with ideally at least an SDSL and or a leased-line Internet connection. However, most websites are hosted on servers run by companies that specialise in web hosting, and which allow their customers to run a reliable website at a reasonable cost. This site, for example, is hosted by Easily.co.uk. You can search for a good hosting deal by visting HostingObserver.com.

When choosing a hosting service, several factors need to be considered alongside price. One is the storage "webspace" on offer, although today most hosting packages offer a significant amount of webspace (usually several gigabytes), and hence only those wishing to host a lot of media files on their website have to pay too much attention to the webspace supplied. However, what is far more critical for most users is the amount of data transfer included with their hosting package and the cost per gigabyte incurred for additional traffic. Transferring data over the Internet is not free, and can become significantly expensive if a website becomes popular.

For example, the initial price of a website hosting package may include 5GB of data transfer per year. This would be fine for site with say 2MB of content expected to be fully downloaded up to 2500 times. However, a site expecting tens or hundreds of thousands of downloads would clearly exceed a 5GB annual data transfer limit very quickly, with the cost of additional data transfer becoming a key consideration in selecting the hosting package. There are a lot of very low cost hosting packages on the market. However, these tend to provide large amounts of webspace (which is cheap for hosting companies to supply given the current price of hard disks) but very limited data transfer capacity (often well under one gigabyte) as this is costly to deliver.

When selecting a hosting package for a potentially very popular and/or business-critical website, the speed of the provider's own connection to an Internet backbone, as well as the physical security and resilience of their "server farm" should also be considered.

Registering a domain name.
Alongside hosting arrangements, a website will require the purchase of an Internet domain name -- or in other words a web address that users will type in to access the site. Domain names are very easy to purchase online from website hosting companies, although most ".com" and many other web addresses are no longer available. Domain names are rented (usually indirectly) for a certain period of years from the Internet registry organizations (such as Nominet in the UK) set up to manage them.

Creating the HTML, graphics and other files that will comprise the site.
A website is no more and no less that a number of data files. Most of these are usually text files written in the hypertext mark-up language (HTML), and image files in formats such as JPEG and GIF. Websites can be written either directly in a text editor, or else in a number of web authoring packages (including Microsoft Frontpage and Dreamweaver). There are some excellent guides to website creation available online, including those at www.4creatingawebsite.com and www.jessett.com.

Making any PSP e-commerce arrangements.
If a website will be used for e-commerce then it will need to have the facility to take credit cards or another form of online payment. This can be achieved by setting up an account with a payment service provider (PSP), such as Worldpay or Netbanx. Some PSPs, most notably Paypal, allow customers to set up "e-wallet" accounts that allow the exchange of funds online without directly using a credit card. A good source of further information on PSPs is PaymentMerchant.com.

Uploading the files to the site (via FTP).
Once a website has been created the data files of which it is comprised will need to be uploaded to the webspace on which it is being hosted. This is facilitated by a process called FTP (file transfer protocol), using a program such as WS FTP, or via the upload/FTP functionality of the web authoring package. Every time the website is updated, the altered content will again need uploading via FTP.

Registering with search engines.
Once the above stages have been completed a website will be live and will be fully operational. As it is found by the "crawler" programs that search the web for new content, its pages will also begin to appear in Internet search engines like Google. However, this process can be speeded and refined by registering the website with search engines to improve the likelihood of it being found by people searching the Internet. Such registration can be performed "manually" with every search engine, or via a search engine registration website. Some of these are free -- for example searchengineoptimising.com -- whilst others charge a fee. As with many things in life, you get what you pay for.

Setting up Analytical Tools
Businesses increasingly want not just to generate web traffic, but to be able to analyse it. This is now very effectively achieved via the use of the many Web 2.0 website analytical tools available. These monitor traffic to a website and provide reports on measures including the most popular pages on the site, time spent on pages, pages of entry, routes taken through the site, the geographic location of visitors, and the method of entry (for example directly, or from another site or search engine). Again there are both free and for a fee services available, with Google Analytics proving increasingly popular as it is free until very significant traffic levels are reached.

Businesses concerned that their website is always available to their customers may also wish to use external analytics tools to monitor the reliability of their site. To do this they can use the services available from a company like Aware Monitoring. These constantly check monitored websites for errors and slowdowns, and can also simulate visitor behaviour to monitor the reliability of logins and the completion of web forms so that those who run the site can receive instant alerts of problems.


Having discussed how to put content online, it is worth side-stepping briefly to consider how access to Internet content may sometimes be restricted on moral, legal, religious or political grounds. Internet censorship may be defined as preventing or hindering access to inappropriate online content. This may involve a regulator physically taking down a website, the blocking of the site's web address, or preventing the site from appearing in search engines. Blocks may be placed on specific websites or pages thereof, or else keyword blocking may be used to prevent access to certain types of content.

Given that the Internet is so open -- with virtually anybody being able to add content -- some forms of censorship are arguably a good thing. The question almost certainly is not whether the Internet should be censored, but who gets to decide what content is inappropriate and what control those being censored potentially have over their regulators.

Internet censorship may usefully be divided into a range of categories. Very common is individual self-censorship, such as that which occurs when parents use web filtering to prevent their children accessing pornography, gambling sites, chat rooms, and other content they consider inappropriate for their young. The fact that so many people use and indeed pay for these kinds of parental controls at the very least suggests that a lot of people consider it important that the Internet is censored to some degree.

Next comes the censorship of illegal content. Whilst laws differ between nations, most countries agree on certain types of inappropriate content -- and which include images of child sexual abuse and material that may incite racial hatred. Organizations such as INHOPE (the International Association of Internet Hotlines) and the UK's IWF (Internet Watch Foundation) exist to monitor such illegal content, as well as to provide a mechanism for people to report it and to facilitate its removal by regulators. Evidence also suggests a growing need for such censorship. For example, in April 2008 the IWF reported that there were 2,755 publicly available sites worldwide trading images of child sex abuse, the removal of which would be seen as a good thing across all nations.

Next comes government censorship. In 2006, the French free press association Reporters Without Borders published a list of 13 "enemies of the Internet" who heavily censor Internet content. The list comprises Belarus, China, Cuba, Egypt, Iran, North Korea, Saudi Arabia, Syria, Tunisia, Turkmenistan, Uzbekistan and Vietnam, with for example China censoring content concerning Tibetan independence, Taiwanese independence, police brutality, the 1989 Tiananmen Square protests, freedom of speech, democracy, pornography, some international news, and some religions -- including the Roman Catholic Church.

A final category is censorship by Internet Service Providers (ISPs). Because, as noted above, broadband connections are contended (with users sharing the available bandwidth capacity), many ISPs have policies to "throttle" the speed of some users' connections if they start to download so much content that is may impact detrimentally on others. This has always been contentious. However, in April 2008 it became far more so when an argument erupted in the UK between ISPs and the BBC due to the success of the corporation's iPlayer video service. According to the ISPs, tens of millions of television programme downloads will require hundreds of millions of pounds of network upgrades, which they believe the BBC should pay for. The BBC is, however, having none of it, and the possibility of the ISPs throttling access to iPlayer has hence being raised. The BBC has suggested that video content providers should communicate to their users any ISPs who cap access to their content, with this debate only likely to intensify as more and more video content is placed online.


This section of ExplainingComputers.com has provided a brief introduction to the internetworking model of the Internet, an overview of methods of Internet connection -- and in particular DSL or "broadband" connectivity -- a rudimentary discussion of the stages involved in creating a website, and the thorny issue of Internet censorship. This said, whilst these issues are important, none of them are the driving force of the continuing Internet Revolution.

Ten years ago getting online -- whether that involved establishing a connection with an Internet Service Provider or publishing a website -- was culturally the big issue. But today both of these are increasingly the norm. Even getting a faster Internet connection is no longer a really significant deal.

The initial 10-20 times speed improvement marketed to and enjoyed by many in the move from dial-up to DSL/broadband was rightfully heralded as the Next Big Thing. However, the speed improvements realised over the past few years -- as 512 kilobit broadband packages have been replaced by sixteen times faster 8 megabit offerings -- have been met with far less of a fanfare (even though they have made practical Internet video services like YouTube). Future speed improvements are now almost guaranteed to receive even less attention. The fact is that for the majority the Internet is just now there and works like any other utility, and will now technically at least be only be noticed in its occasional irritating absence.

For most individuals and organizations, today's and tomorrow's key Internet developments will involve new and richer means of connection between people, between organizations, between software applications and other computing resources, and between minds. Cloud computing and Web 2.0 are therefore where the Internet Revolution is now at will remain for some time to come.

Hardware image

The Internet is the combined internetwork of the majority of other computer networks
in the world.


Mobile Broadband

logo line
Twit Link