ADSL (Asymmetric Digital Subscriber Line)

stands for “Asymmetric Digital Subscriber Line”. ADSL is also known as broadband.

Available in download speeds of up to 24Mb but the upload speed is always much lower, hence “asymmetric”. ADSL lines are much faster than 56k dial-up lines.

An always-on, high-bandwidth connection to the internet that uses existing telephone lines, while allowing them to be used for simultaneous voice calls. ADSL is available in a number of bandwidths, and the amount of data actually transmitted is partly determined by the contention ratio, i.e. the number of other users sharing the same bandwidth.

Also the bandwidth coming in is greater than the bandwidth going out, hence the term ‘asymmetric’. A Symmetric Digital Subscriber Line (SDSL) connection has equal bandwidth in each direction, and will be more suitable for organisations hosting well-used servers in-house.


A connection to the internet that is permanently available and ready for use. By contrast a typical modem connection needs to be manually initiated each time you wish to use it.

Application Service provider (ASP)

A company that ‘rents’ access to software and services that a company might otherwise purchase and configure for themselves. Web ‘hosting’ is the most common service offered by ASPs although they also offer more complex services such as shopping carts or payment systems. A future role for ASPs may be to rent typical office software on a pay-as-you go basis.


The rate at which data can move along a connection. Higher bandwidth allows for faster access to email, file downloads, and website browsing.


Client-side refers to any processing or activity that takes place on a user’s computer rather than on the server-side (often referred to as the ‘backend’). Client-side applications are generally more powerful and offer a better user experience than server-side applications (generally accessed via a web interface). However server-side applications are always up-to-date, and can be accessed from almost any computer. With the spread of high-speed internet access the different between client-side and server-side applications will tend to decrease.

Domain Name

A domain name represents the ‘space’ on the internet at which your organisation exists. You will tend to receive email at (@) your organisation’s domain name. Any servers you have online will tend to be identified by your domain name, prefixed by a ‘host’ name, most often ‘www’. These servers will have fixed and unique Internet Protocol (IP) addresses, which map to the host name. Thus ‘www’ is the host name for the webserver, and is the address of that server. Like a telephone number these allow them to be directly reached. (For instance the IP address for is With broadband you can have fixed IP addresses (which tends to cost more) or a dynamic (variable) IP address. Even if you have fixed IP addresses you may choose to have dynamic IP addresses on your local network, but if you host servers that need to be externally accessible by a changing audience they will need to have fixed IP addresses.

EDI (Electronic Data Interchange)

A way of structuring purchasing-related data such that orders between two organisations can be exchanged and processed with the minimum of human intervention.


Encoding of information to prevent unauthorised access. Data moving across the internet between a most web browsers and certain webservers can be encrypted using Secure Sockets Layer (SSL).

Extensive Markup Language (XML)

XML allows data to be stored in ways that it can be flexibly combined and re-combined, searched, sorted and exchanged. In XML data is marked up with semantic tags that indicate, in human readable form, the nature and measure of that information, for instance that it is a last name, or a price in a specific currency. In future the majority of data-driven products are likely to be based on, or interchangeable with, XML data.


A firewall is a system for restricting unauthorised access to resources on your servers or on your network. Firewalls also log attempted accesses to help you further secure your network. They can take the form of a dedicated box or a server running firewall software at the gateway into your network. Firewalls can also be run on individual users’ computers.


An internal document and information sharing system built using web technologies, primarily a webserver but often including shared task and contact management, and calendaring. An extranet is an intranet that is externally accessible by clients, partners or suppliers.


ISDN (Integrated Services Digital Network)

A way of sending data over a digital connection between a computer and a remote network using a standard telephone line. A basic ISDN connection moves data about twice as quickly as a fast modem. Like phone calls ISDN calls are billed based on time connected.


A company offering access to the internet, typically over a dialup modem or ISDN connection, ADSL, or leased line.

ISPs often offer web site hosting and other services such as domain name management.

LAN (Local Area Network)

A network of computers and other devices (including ‘routers’ and printers) that are in the same geographical location. Connections are typically made over Ethernet, but can be made using wireless technologies. A WAN (Wide Area Network) connects two or more ‘local area’ networks that are geographically separate.


Slower internet connections, typically below 500 kilobits per second, generally made over a modem connection.

Operating system (OS)

The ‘guts’ of a computer, which manages files, allows for input (keyboards and mice) and output (video and audio), and provides common services to applications (such as internet access). Common personal computer operating systems include Microsoft Windows, Apple MacOS, and Unix. Applications are created and ‘compiled’ for particular operating systems, and even the experience of using the web varies between operating systems.

OS (see Operating System) Performance

The responsiveness of a web site to requests for pages. Performance encompasses webserver and network speed, as well as the speed and accuracy with which the page displays in the user’s browser.



An operating system, like Windows or MacOS, though in fact considerably older. It has been extensively developed upon elsewhere including Sun Microsystem’s Solaris, Apple’s MacOS X, and the ‘open source’ Linux (properly known as GNU/Linux) that has been adopted by IBM among others. Unix has traditionally been used on workstations and servers, and much of the early development of internet protocols and applications was done on Unix platforms, including the first webserver and browser.

VPN (Virtual Private Network)

A ‘wide area network’ that uses connections over public telecommunications infrastructure (including the internet) while retaining private communication using encryption and other techniques.

Active Channel

Active Channel is frequently updated information residing on a Web server. Users can subscribe to the channel if they have a CDF (Channel Definition Language) capable browser (e.g. Internet Explorer)


A name that points to another name. Aliases are used to make the original name easier to remember or to protect the site’s identity.

Audio Streaming

Audio Streaming is the process of providing audio content on a web site. This takes up a large amount of bandwidth, especially if you get a lot of visitors at your site. Some hosts do not allow audio or video streaming because of this.

Availability (Uptime)

Refers to the amount of time within a 24 hour period a system is active or available for servicing requests. For example, if a hosting company says it is available 99.9% of the time, they are claiming that your web site will up all the time except for about 8 seconds each day. Over the course of a year, in this example, the hosting company is claiming that your site will only be unavailable (couldn’t surf to it) for 48 minutes.


Backbone is a high-speed line or series of connections that forms a major pathway within a network. The term is relative as a backbone in a small network will likely be much smaller than many non-backbone lines in a large network. In general, the better the backbone of the hosting company, the better the availability of the web sites that run on their computers.

Back ups

The backing up of data on servers to prevent the loss of data should something happen to the server. If you think you may need to restore old data in case of a disaster, it may make sense to choose regular backups. The fresh approach to communications


This is the client software that displays (interprets) the HTML code it receives from the server. All browsers work slightly different and one may not display the pages correctly if the code was developed exclusively for another browser. Today the two main browsers are Microsoft Internet Explorer and Netscape.


C+ and C++ are programming languages. Some hosting companies provide access to C+ and C++ class libraries if your web site contains these types of program modules. Once your web site has been constructed, you will know whether access to C+ or C++ will be required.

CGI (Common Gateway Interface)

A CGI is a program that translates data from a web server and then displays that data on a web page or in an email. CGI involves the transfer of data between a server and a CGI program (called a script). This allows HTML pages to interact with other programming applications. These scripts make web pages interactive. Page counters, forms, guest books, random text/images and other features can be driven by CGI scripts.


Co-location means housing a web server that you own in the secure facilities of a hosting provider.

Control Panel

An online package of tools permitting easy site management and editing. It is a very important feature to have. By having your own control panel, you can maintain basic information about your site, mail boxes, etc.


A cookie is a message given to a Web browser by a Web server. The browser stores the message in a text file called cookie.txt. The message is then sent back to the server each time the browser requests a page from the server. The main purpose of cookies is to identify users and possibly prepare customised Web pages for them.


Database Support

If your web site will leverage a database to store information, database support by the hosting company will be required. After you have developed your web site, you will know which database will be required. Some commonly used database programs are SQL Server, MySQL, Access, Oracle, and FoxPro.

Data Transfer

This is the amount of data that is transferred from an account as visitors view the pages of the web site. If you have a web site with lots of video, audio, and images that gets many visitors per day, you would have to make sure that you choose a hosting package that will allow large amounts of data to be transferred. As a general rule, 500 MB of data transfer is equivalent to 20,000 page views.

Dedicated Server

The hosting company provides you with an entire hosting setup including your own server hardware that only you can use. This means a much faster loading time for your site because the entire computer is “dedicated” to running the server software. A dedicated server makes sense for web sites that require higher availability and higher data transfer rates.

Disk Space

This indicates the amount of disk space that will be available to you on the server to hold your web site files. Normally because HTML files are small, a web site (unless it has extensive graphics or database functionality) will be small, as low as 1 or 2 MB in most cases.

Use windows explorer to check the total MB of your site while it is still on your development machine. Then perhaps double your sites current size so that you have room to grow. When you check the total MB of your site don’t forget to include the total MB of your graphics files.

A good rule of thumb is to assume approx. 50 KB per page (1 MB = 1000 KB, 1 GB = 1000 MB).

Domain Parking

This is the option to ‘park’ your domain name without actually having your web site up and running. This is a nice option if you want to acquire a domain name for your web site well ahead of having the web site itself designed and constructed.


Domain Name

This is the unique name that identifies an Internet site. Domain Names always have 2 or more parts, separated by dots. Technically, the domain name is a name that identifies an IP address. To most of us, it simply means Because the Internet is based on IP addresses, not domain names, web servers depend on a Domain Name System (DNS) to translate domain names into IP addresses. Simply stated, domain names allow people to find your web site by name rather than by its numerical (IP) address.


Domain Name System (DNS)

A model for tracking other machines (that contain web sites) and their numeric IP addresses. It translates domain names (for example, into a numerical IP address). When a computer is referred to by name, a domain name server puts that name into the numeric IP address assigned to that computer. So when you buy a domain, say, it does not become accessible until it gets assigned an IP address from a hosting company. Once the IP address is assigned, a cross-reference record (DNS record) is created that points your domain name to the numeric IP address.


Email POP Account

POP (Post Office Protocol)is an actual e-mail account on your web host’s e-mail server. Think of each POP account as a unique email address. You should know exactly how many email accounts are required to meet your specific needs.


File Transfer Protocol (FTP)

A way of transferring files (uploading and downloading) across the Internet. Most web sites are uploaded to the Internet by means of an FTP program. This is how the web site you create on your computer at home is transferred (uploaded) to the Internet. Some software, such as Microsoft Front Page, does not require use of an FTP program but the use of most other HTML editors requites the use of and FTP Program.


Host (Name Server)

When you hear the term “host” in the Internet world, it is referring to an Internet company that has the required servers and software to connect domain names to (IP) Internet Protocol numbers so that your site can be viewed by the public when they type your domain in their browser window. Basically this is where you house your site, and you usually have to pay a monthly or annual fee for this service.

Host Platform

This is the platform of the hosting providers’ servers. Hosting companies typically have hosting platforms based upon Windows 2000 (Win2K), Windows NT or Linux. If you have a basic web site that does not make use of server side applications such as a database then you do not need to worry which platform is used.


Hypertext Transport Protocol (HTTP)

The protocol for transferring hypertext files across the Internet. It requires a HTTP client program on one end, and an HTTP server program on the other end. HTTP is the most important protocol used in the World Wide Web (WWW). You see it every time you type a web site in your browser.

IP Address

A unique number used to specify hosts and networks. Internet Protocol (IP) numbers are used for identifying machines that are connected to the Internet. They are sometimes called a dotted quad and are unique numbers consisting of 4 parts separated by dots, They would look something like this Every machine that is on the Internet has a unique IP number – if a machine does not have an IP number, it is not really on the Internet. Most machines also have one or more Domain Names that are easier for people to remember.

Internet Service Provider (ISP)

A company or institution that provides access to the Internet in some form, usually for money. They will usually allow users to dial up through a modem, DSL, or cable connection to view the information on the Internet Access is via SLIP, PPP, or TCP/IP. Picking your ISP is an important decision but has more to do with how you access the Internet rather than which host you choose.

Post Office Protocol (POP)

This is a method of retrieving e-mail from an e-mail server. Most e-mail applications (sometimes called an e-mail client) use the POP protocol, although some can use the newer IMAP (Internet Message Access Protocol).

Root Server

A machine that has the software and data needed to locate name servers that contain authoritative data for the top-level domains.


A computer, or software package, that provides a specific kind of service to client software running on other computers. The term can refer to a particular piece of software, such as a WWW or HTTP server, or to the machine on which the software is running. A single server machine could have several different server software packages running on it, thus providing many different servers to clients on the network. More specifically, a server is a computer that manages and shares network resources.

Simple Mail Transfer Protocol (SMTP)

The main protocol used to send electronic mail on the Internet. Most Internet email is sent and received using SMTP. SMTP consists of a set of rules for how a program sending mail and a program receiving mail should interact.

Secure Socket Layer (SSL)

A protocol designed to enable encrypted, authenticated communications across the Internet. It is used mostly (but not exclusively) in communications between web browsers and web servers. URL’s that begin with “https” indicate that an SSL connection will be used. SSL provides 3 important things: Privacy, Authentication, and Message Integrity.


Detailed information regarding your Web site, including the number of hits, the source of those hits, most popular pages and amount of data transferred, as well as other useful information.


Telephone or e-mail technical support provided by the hosting company to their customers. When there’s a problem with your site, e-mail or database etc, you want to be able to get an answer promptly by e-mail or on the phone. 24/7/365 support is important if your site is an e-commerce site with a lot of daily visitors.


This is a set of communications protocols to connect hosts on the Internet.


A computer operating system designed to be used by many people at the same time (it is multi-user) and has TCP/IP built-in. It is the most common operating system for servers on the Internet.

Uniform Resource Locator (URL)

The standard way to give the address of any resource on the Internet that is part of the World Wide Web (WWW).

Unique IP Address

Obtaining a unique IP address (see IP Address) provides a one-to-one relationship between your domain name ( and an IP address.

Video Streaming

The process of providing video data or content via a web page.

Virtual Server

A virtual server is a web server which shares its resources with multiple users. It’s another way of saying that multiple web sites share the resources of one server.


Or 3rd generation is used in mobile, the 3G network is a newer version of older networks such as 2G and 2.5G, it uses newer technology which allows for higher speed data transfer.

Analogue line

The basic phone line – one line one number


Asynchronous Transfer Mode – The pipes that take data (and voice packets if using VoIP) over the internet from the exchange

Auxiliary line

Additional lines that can be added to an analogue connection. These lines will ring if the main line is busy.

Bit, byte, kilobyte etc.

Measurements of the amount of information in a message / communication between computers.

BT Openreach

The arm of BT who are the engineers that maintain the network.

BT Retail

Our competitors, the company that sells to customers and sends bills out

BT Wholesale

The arm of BT that owns and operates the physical network


Alternative networks to BT that offer us preferential rates which in turn means we can offer our customers substantial savings.


Call Data Record. A report produced by our suppliers showing calls that our customers have made.


A geographical area in which you can use your mobile phone

Cell site

An aerial that creates a cell, sometimes known as a mast.

Contention Ratio

The number of people who have access to your line at the same time, so if your contention ratio was 50:1 then at any one time 50 people could be using your line at the same time. The lower the ratio, the more likely you are to get near your advertised download speed.


Carrier Pre Selection. A service that allows service providers to select the network customers calls will be carried over. The instructions take effect at the exchange.


Digital Dial In. A digital service allowing customers to receive calls on the same digital line, but with their own direct number. This will sit on top of an existing number.

Digital line

A phone line that converts voice into a digital signal, 1’s and 0’s rather than as sound waves.


Receiving information on to your computer.


A way of making use of digital lines allowing many users to receive calls of the same type. All users share the same number. Must be managed by a phone system.

ICSTIS (Refer to Phone Pay Plus)

The body that regulates premium rate numbers


InDirect Acess. Allows customers calls to travel over a network that they are not physically wired to, for example a customer could connect to a network at the exchange.


Integrated Services Digital Network. The digital system that handles most standard digital lines. Is available in ISDN2 which can have 2, 4 or 6 channels or ISDN30 which can have between 8 and 30 channels.



Integrated Voice Response. A system that allows calls to be directed depending upon caller choices (press 1 for this dept, press 2 for that dept etc.)


Least Cost Routing. Allows us to send calls over different routes at different times to achieve call savings.


Multiple Subscriber Number. A digital service allowing customers to receive calls on the same digital line, but with their own direct number. These numbers are real numbers that exist on the exchange.


Voice and data transmissions are routed via different technical platforms. The aim of a next generation network is to combine both functions to provide integrated voice-data services. NGNs are based entirely on IP technology.


Number translation services 08 numbers, formally known as  NGN’s or non geographic numbers. NTS’s are not geographical numbers, they sit on top of “real” numbers but they are designed to identify a service and not a geographical location.


The Office of communications. The industry regulators who issue licences to operate and set pricing rules and industry policies.


The Office of the TELecoms Ombudsman. The body that deals with customer complaints and can fine companies for breaches of codes of conduct.

Peer to Peer (P2P)

A network of two or more computers connected as equal partners and able to share processing, control and access to data and peripherals

Phone Pay Plus

The body that regulates premium rate numbers


Public Switch Telephone Network. The network of wires, signals, and switches allowing one phone connect to another anywhere in the world.

Select Services

Services that customers can choose at a low cost that helps them to get more out of their telephony such as call diverting, holding and networked answering machines.

The last mile

The part of the network that runs from the exchange to customers premises. Despite the name the last mile can be over 100 miles long.

Tier 1 network

A network that is able to carry calls between the last mile at either end of the call without having to use the BT network


Sending information to someone / somewhere else from your computer.


Voice over Internet Protocol. Passing voice calls as data packets over the internet rather than the PSTN. Widely hailed as the future of telecoms, however, there is still some way to go before VoIP becomes a widely used and viable proposition.


Wholesale Line Rental. The ability for service providers such as daisy to buy line rental products off BT and in turn to sell line rental to our customers.


Bandwith how much data you can send through an internet connection. Generally, the higher the bandwidth, the faster the connection.


An internet service provider that has its own network and leases this network out to suppliers. Examples of carriers include BT, Cable&Wireless and Global Cross.


Contention ratio

Two network interfaces try to transmit data at the same time. Leased lines are uncontended (1:1), SDSL has a low contention (20:1, 15:1, 10:1) and ADSL usually has the highest contention ratio (20:1, 50:1). The lower the contention, the more stable a line is.


Certificate of Acceptance – to ‘COA’ something means to start billing (the service has gone live)


Carrier Pre-Select – where the customer’s phone call is routed through Daisy and we charge them for the call rather than BT



Data Centre or Data Centre Operations – you will hear ‘DCO’ in the context of, “I’m going to pass this to the DCO’ or ‘Pass it to the DC’


Domain Name Service. It is a service that can keep large number of machines’ IP addresses for huge network communication

Domain name

Domain name a unique name that identifies a site’s presence on the web. For example, is a domain name.

Dynamic IP

a temporary IP address for a computer. For example, a different IP address is assigned each time you connect to the internet. This is more secure than having a static IP.


Extranet a private network that shares information via internet protocols and is usually part of a company’s intranet. An extranet is usually used to share information with customers or suppliers.


a combination of hardware and software that secures access to and from the Local Area Network. A bit like a bouncer for your network.


Intranet a private network within a business, company or organisation, basically a mini-internet that is for internal use only.


IP stands for “internet protocol”. Provides features for addressing, type of-service specification and security.

IP address

a unique number consisting of four parts separated by dots, e.g. 123.456.789.0. Every machine connected to the internet has a unique IP address.


ISP stands for “internet service provider”. A company that provides access to the internet in some way. The ISP connects to its customers using a data transmission technology appropriate for delivering Internet Protocol packets or frames, such as dial-up, DSL, cable modem, wireless or dedicated high-speed lines



stands for “local area network”. Usually a group of computers in the same building, floor, etc that are connected to the same network. Allows data to be stored for all users connected to said network.

Leased line

Leased line a dedicated line that is rented for exclusive 24/7 use and provides a direct connection from a customer to their provider. Very stable due to the line being uncontended and exclusively for the company that has bought it.


Megastream Ethernet – any access solution placed on a 10Mbp/s, 100Mbp/s or 1Gbp/s bearer


Network any time you connect two or more computers together, you have a network. Two or more networks connected creates an internet.



Network Operations Centre – the department that monitors the network and notifies customers of any issues.


Operations Management Centre—same as the NOC


Point to Point – a leased line that goes from office-to-office, rather than office-to-internet


Standard leased line


stands for “point of presence”. A POP is the location where an ISP has local access to connect to the internet using leased lines.


Router a piece of hardware that connects two or more networks together.


Standard leased line.


SDSL is a fast and efficient way of ensuring your business broadband offers equal upload and download speeds.  SDSL stands for “Symmetric Digital Subscriber Line”. A line similar to ADSL, but unlike ADSL the upload and download speed are equal. A bit more stable than ADSL. Good for companies that send a lot of data as well as receiving it.


Server a computer or software package that provides a specific kind of service to client software running on other computers.


Spam is unsolicited junk e-mail from the internet. It is basically advertising sent to a large number of people who didn’t ask for it. It can clog up inboxes and a lot of spam contains harmful viruses. Maildefender prevents spam.

Static IP

Static IP a computer or network that has a permanent IP address that does not change, unlike a dynamic IP.


VPN stands for “virtual private network”. Refers to a network that can send private data across a network, The data is encrypted when sent across the internet, thus creating a “private network”. Useful for companies with more than one site who want to send sensitive information between them.


WAN stands for “wide area network”. A geographically dispersed network.


Glossary Ends