Provider, Server, Hosting

Servers
This is a computer that runs a software programme controlling access and providing the functions required by network users. In principle, a server carries out requests from network users, providing people with speed, efficiency and thus increased productivity. A server optimises system performance and dispenses with peer to peer connections. Instead of having to wade through files on numerous other computers, the server holds all data which can be accessed by all connected to it. Centrally stored data is available instantly and simultaneously to all authorised network users, whatever their location. Basically a server is a powerful computer which carries out numerous requests at an incredible speed and automatically optimizing user productivity. This system also forms the basis of Internet access.

Internet providers
Obviously it would be impossible to connect each and every computer directly with cables. This is where an Internet Access Provider (IAP) comes in. This is a company which provides access to the Internet and the actual hardware to connect some type of dedicated data line from its network source to your computer. It also provides and manages the send & receive data stream. Most Internet providers generally hire space on their server for web site storage. A modem is required for Internet access.

Modems
In simple terms, a modem is a device which allows your computer to communicate with other computers via a communications link. A modem converts computer data into the format used on the communications connection and the remote modem converts that transmission back into data. Modems vary in shape, size and type, depending on the connection system. Some are integrated into the computer, others have an external connection to the computer. Connection to the Internet may be made via a modem for a standard telephone, cable network, DSL (Digital Subscriber Line) or a wireless system. Broadband is a term often heard regarding Internet access and simply means high speed Internet access.

Routers
In order to cope with the immense number of message transfers, the network contains a substantial number of switching points called routers. A router is a computer which communicates with more than one network running software to allow it to move data between networks Routers receive messages and direct or “route” them along the correct networks to the desired destinations. So-called routing protocols have been devised in order for large networks with many sub-networks to automatically recognize where the various networks are and move data automatically between them.

Web Hosting
To have a web site on the Internet, you need a web server but owning one is very expensive. This problem is solved by a web host. Instead of you having to fathom out how all the technology works, a web hosting company will do it for you and rent you space for your web site on the company’s web server. So effectively your web host provides Internet space for your web site and also those of others. This costs a great deal less buying a server and you still retain control over the construction and configuration of your individual web site. 

Domain Name
A domain name is your web address, allowing access to your web site. It is often referred to as URL (Uniform Resource Locator) which describes the address for any document on the Internet. The name should be simple and easy to remember to make it readily accessible to all wishing to visit it. Domain names are usually coupled with e-mail accounts and end with .com (commerce), .net (network), .org (organization) or very often the official abbreviation for a specific country. 


WLAN
Wireless local-area network is a local-area network which uses radio waves instead of wires to communicate data, providing opportunities for new applications and increased network flexibility. WLAN users can access networks and information from far beyond the walls of their usual static location, which may still have a wired system. But wireless LANs may also simply provide a connection between the basic wired network and various users with access to information on that network. This is of enormous benefit to all kinds of employees who are not tied to a desk and who can use hand-held or notebook computers. For example: hospital staff, external auditors, construction-site managers, network managers, warehouse managers, teachers and their students – the list is endless. The huge expansion of the Internet and its online services and today’s reliance on networking make WLAN an ideal tool for sharing data in all spheres. And although wireless LAN hardware may be more expensive than wired systems, the ease and speed with which a WLAN system can be installed - no pulling cables or installing unsightly conduits – usually more than offset an additional cost of hardware.

There are various technology options for WLAN solutions:
Spread Spectrum is the most common, using a wideband radio frequency technique. It is considered very efficient, reliable and secure. It uses more bandwidth than narrowband transmissions but produces a louder, more easily detected signal provided that the receiver is tuned to the correct frequency. Otherwise the signal appears like background noise. 
Narrowband
This is a radio system which transmits and receives on a specific radio frequency, keeping the signal as narrow as possible. Cross-talk between communication channels is avoided by coordinating different users on different channel frequencies. It’s similar to a telephone line, in as much as one private phone user cannot listen in to a conversation made by another private user. A radio receiver filters out all signals except those on its designated frequency.
Frequency-Hopping Spread Spectrum Technology
FHSS uses a narrowband carrier that changes frequency in a pattern recognized by the transmitter and receiver. Effectively, correctly synchronization maintains a single logical channel. To an unintended receiver, FHSS appears as a short-duration impulse noise. 


ISDN 
Integrated Services Digital Network provides digital data service over traditional analogue telephone lines. It was intended to be the solution for providing faster Internet connection in comparison to the slow data delivery of traditional modems. But it lost out to cable modems and DSL (digital subscriber lines), which do the same. ISDN sends and receives data at rates of up to 128Kpbs and carries voice and data transmission on the same line. The installation requires the telephone company to set up a network interface device which has to be wired to the analogue telephone line. An ISDN adapter has to be installed in the computer together with the appropriate software. A connector plugs into the adapter at one end and into the telephone line at the other. The computer uses the ISDN line instead of a dial-up modem.
But it took some time to cure technological teething problems, despite the fact that development started back in the early 1980s. Installation was problematic and service expensive. At one time ISDN was thought to be the all-embracing answer to problems such as solution voice-data integration, image handling and live collaboration. It has never lived up to those expectations but nevertheless is still a good solution for users in remote places where DSL and cable modems are not available.


ADSL
Asymmetric Digital Subscriber Line, often referred to as broadband, is a technology allowing you to enjoy very fast Internet access. It provides connection speeds of up to 20 times the speed of a standard dial-up installation. There are no dial-up charges, no second phone line is required and the major benefit is that the Internet connection is always on. So there are savings on telephone charges - both on calls and line rental and large amounts of data can be downloaded very quickly. Also, despite the fact that you may have only one line, you can still use the telephone and Internet at the same time. This has the obvious advantage of not missing calls while online, as both voice and data can be transferred at the same time. 
ADSL functions by placing a splitter on the existing telephone line to enable multi-frequency communication. This splits a telephone line signal into two separate channels, one for voice and one for data. 


Wi-Fi
Wireless Fidelity, is a general term used to refer to a product or service using any type of 802.11 technology. Wi-Fi networks operate in the unlicensed radio bands - 2.4 and 5 GHz, with an 11 Mbps (802.11b) or 54 Mbps (802.11a) data rate, respectively. 
Wi-Fi-enabled devices, such as notebook computers or PDAs, can send and receive data over-the-air from any location equipped with Wi-Fi access. This functions by means of access points installed within a Wi-Fi location that transmit an RF signal to Wi-Fi enabled devices sited within range of the access point. 
To simplify: WiFi is also a local-area network (LAN) that uses high frequency radio signals to transmit and receive data over distances of a hundred to a few hundred feet.
With unencrypted Wi-Fi, e-mail, every password and every Webpage can be read by any other user on that Wi-Fi network. That means that only secure (encrypted) e-mails should be sent and a password or confidential information should never be entered on a Webpage over Wi-Fi unless it is a secure connection.

Cable modem
A cable modem connects a computer system to the Internet using the cable TV network. Cable Internet technology allows for much faster data transfer rates of millions of bits per second. However, that bandwidth is usually divided amongst all subscribers within a defined area and the effective transfer rate, though still fast, is much slower per individual user. A cable modem Internet connection is always on and dialling up unnecessary. If the computer is turned on, all you need do is click the e-mail or Internet icon to connect. A modem gets its name from the words modulate and demodulate. That is to say it is a device which modulates and demodulates a signal between an analogue network (e.g. a phone) and a digital end device (e.g. a computer). The early cable modems did the same, but with a cable TV signal. These days however, many cable Internet service providers are changing to a fully digital network for everything, including TV signals. So the term cable “modem” will soon be replaced by the correct term – “cable terminal device”.