Telecommunications and IT is full of confusing terms and acronyms. To make life easier, we’ve created this useful glossary of the most often used terms.

Asymmetric Digital Subscriber Line (ADSL)

ADSL is a technology for transmitting digital information at a high bandwidth on existing phone lines to homes and businesses. Unlike dialup phone service, ADSL provides continuously-available, "always on" connection. ADSL is asymmetric in that it uses most of the channel to transmit downstream to the user and only a small part to receive information from the user. ADSL simultaneously accommodates analogue (voice) information on the same line. ADSL is generally offered at downstream data rates up to 24 Mbps.


Each Internet Service Provider has major high speed lines or a series of connections that form their network infrastructure. These connections could be viewed as motorways for internet traffic with junctions where traffic can join the rest of the network. The size (bandwidth) of connections varies depending on the provider.

This term can also be used when describing high bandwidth links (e.g. fibre) between data cabinets on a LAN.


Describes how much data you can send through an Ethernet connection and is usually measured in bits-per-second. As a rule, increased bandwidth equals faster internet connections.


In telecommunications, broadband is wide bandwidth data transmission with an ability to simultaneously transport multiple signals and traffic types. The medium can be coaxial cable, optical fibre, twisted pair, DSL local telephone networks or wireless broadband (wireless broadband includes Mobile broadband).


Most often used to refer to having a server that belongs to one person or group physically located on an internet connected network. We offer co-location web server hosting providing a secure high speed internet connection for mission critical hosting applications.

Customer Premises Equipment (CPE)

Customer Premises Equipment refers to hardware located at the premises of a customer such as broadband internet routers, VoIP base stations, telephone handsets or other customised hardware.

Data Encryption Standard (DES)

Data Encryption Standard is a widely used method of data encryption that uses a 40-bit and 56-bit key to encrypt and decrypt data. DES and Triple-DES are used as encryption algorithms by S/MIME.

Domain Name Server (DNS)

DNS is used to map names to IP addresses and vice versa. Domain Name Servers maintain central lists of domain name/IP addresses and map the domain names in your internet requests to other servers on the internet until the specified web site is found.

Digital Suscriber Line (DSL)

Digital Suscriber Line (DSL) is a communications medium used to transfer digital signals. See ADSL, Broadband, FTTC, FTTP, SDSL.

Dynamic IP

This term is used to describe how an IP address is automatically assigned to computers as and when needed. Unlike static IP addresses, the IP address is temporary e.g. when you connect to your ISP using a dial up connection, your PC or router will be automatically assigned an IP address whilst you are online.


Ethernet is the most widely installed local area network (LAN) technology. Ethernet is a link layer protocol in the TCP/IP stack, describing how networked devices can format data for transmission to other network devices on the same network segment, and how to put that data out on the network connection. It touches both Layer 1 (the physical layer) and Layer 2 (the data link layer) on the OSI network protocol model. Ethernet defines two units of transmission, packet and frame. The frame includes not just the "payload" of data being transmitted but also addressing information identifying the physical "Media Access Control" (MAC) addresses of both sender and receiver, VLAN tagging and quality of service information, and error-correction information to detect problems in transmission. Each frame is wrapped in a packet, which affixes several bytes of information used in establishing the connection and marking where the frame starts.

Ethernet First Mile (EFM)

This is a copper wires based service that delivers connectivity via an uncontended part of the network. Available in either dual or quad configurations. Speeds are dependent on distance from the exchange like broadband, but are uncontended and are supported by a comprehensive service level agreement, guaranteeing both speed and connectivity.


A firewall is a combination of hardware and software that secures access to and from the LAN. There are three main types of firewall architecture - Stateful Inspection, Proxy based and Packet Filtering. The former provides the highest level of access control. Firewalls can also be used to secure internal network resources from internal network users too.

Fibre to the Cabinet (FTTC)

FTTC stands for Fibre to the Cabinet. It’s one of two ways in which next-gen fibre optic broadband is being delivered to homes and businesses in the UK. FTTC in a nutshell is much easier and cheaper to deliver en masse than its counterpart, FTTP or Fibre to the Premises as it utilised existing copper wires from the premises to the cabinet.

Fibre to the Premises (FTTP)

FTTP stands for Fibre to the Premises. It’s one of two ways in which next-gen fibre optic broadband is being delivered to homes and businesses in the UK. FTTP is more expensive than its counterpart, FTTC as it utilised fibre cabling from the premises to the cabinet.

Gemini Generic Ethernet Access (GEA)

This service takes the FTTC service from being positioned within the DSL 'best effort' network into the managed network, with other more expensive products like EFM and Leased Lines, which are supported by a comprehensive service level agreement, guaranteeing both speed and connectivity.

Geographic Number

A Geographic Number is a number with a 01 or 02 dialling code relating to a specific geographic area.

Gigabit (Gbps)

In data communications, a gigabit is one billion bits, or 1,000,000,000 (that is, 109) bits. It's commonly used for measuring the amount of data that is transferred in a second between two telecommunication points. For example, Gigabit Ethernet is a high-speed form of Ethernet (a local area network technology) that can provide data transfer rates of about 1 gigabit per second. Gigabits per second is usually shortened to Gbps.

Gigabyte (GB)

A Gigabyte (GB) has been a common unit of capacity mesurement for data storage, however in recent years this has been superceeded but Terabytes (TB) which is now the more common unit of storage capacity mesurement especially for hard disk drives (HDDs) and solid-state drives (SSDs). this term can also be used a a unit of mesurement for usage e.g. download limit on a broadband or mobile data connection.

Internet Protocol (IP) Address

Also sometimes called a dotted quad. It is a unique number consisting of 4 parts separated by dots e.g. 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 Protocol Security (IPSec)

A standard for security at the network or packet processing layer of network communication. IPSec essentially encrypts data to create secure data transmissions across private and public networks such as the internet and allows companies to implement VPNs (Virtual Private Networks) across the internet as a cost effective alternative to dedicated connections.

Integrated Services Digital Network (ISDN)

Stands for "Integrated Services Digital Network." ISDN is a telecommunications technology that enables the transmission of digital data over standard phone lines. It can be used for voice calls as well as data transfers.

Local Area Network (LAN)

These are networks of computers that are local to the immediate area, usually the same building or floor of a building. LANs allow files, information and resources to be shared or stored centrally for all users that have a connection to it.

Leased Line

This is a fibre based service that delivers the best connectivity via a managed part of the network. Leased Lines offer a flexible option with uncontended speeds from 10Mbps-1Gbps and are supported by a comprehensive service level agreement, guaranteeing both speed and connectivity.

Megabit (Mb)

A measure, representing 1 million bits, generally used to express the speed per second of telecommunications services and equipment. A bit is the smallest unit used to express digital information.

Multi-Protocol Label Switching (MPLS)

MPLS is a way to speed up the flow of traffic on a network by making better use of available network paths. It designates the proper path for each function so that the opportunities for bottlenecks within the network are minimized.

Network Address Translation (NAT)

NAT is the translation of an IP address used within one network to a different IP address known within another network. Typically a company maps its local inside network addresses to one or more global outside IP addresses and unmaps the global IP addresses on incoming packets back into local IP addresses. This helps ensure network security since each outgoing or incoming request must go through a translation process that also provides the opportunity to qualify or authenticate the request or match it to a previous request. NAT also conserves the number of global IP addresses that a company needs by letting a company use a single IP address to communicate with the world. NAT is also a feature of most routers and firewalls.

Network Operating Centre (NOC)

Network operating centre is a central location for monitoring and maintaining a network.

Packet Internet Groper (PING)

This is a command that can be used to check if communication can be established between two devices. The information that is returned includes how long it takes for the data to make the journey, how many hops across the internet (or router path) it took and how much of the traffic gets through.

Point of Presence (POP)

Point of presence usually means a city or location where an Internet Service Provider provides local access to connect to the internet using dial up phone lines and leased lines. We currently have almost 50 POPs in the UK alone.

Public Switched Telephone Network (PSTN)

This is the world's collection of interconnected voice oriented public telephone networks, both commercial and government owned.

Remote Authentication Dial-In User Service (RADIUS)

Remote authentication dial-in user service is a client/server protocol and software that enables remote access servers (RAS), to communicate with a central server to authenticate dial-in users and authorise their access to the network. RADIUS allows a company to maintain user profiles in a database that all remote servers can share and allows a company to set up a remote access policy that can be applied at a single administered network point.


A router is a piece of hardware that essentially connects two or more networks together. Routers forward packets of data between networks based on network layer information, or in other words, it looks at the destination addresses of the packets passing through it and decides which route to send them on.


No phone line, just a small satellite dish pointed at the sky.

For some customers standard broadband is either not available, to slow or to unreliable that Satellite broadband is the only connectivity option. Satellite broadband can help with download speeds of up to 20Mbps and an upstream of up to 10Mbps. A package can be specifically designed for you depending on your monthly downloads as with satellite connectivity the download limit is strictly enforced and could expensive option for the heavy downloader.

Software as a Service (SaaS)

SaaS is typically accessed by users using a thin client via a web browser. SaaS has become a common delivery model for many business applications, including office & messaging software, payroll processing software, DBMS software, management software, CAD software, development software

Session Initiation Protocol (SIP)

SIP is a signalling protocol used for establishing sessions in an IP network. A session could be a simple two-way telephone call or it could be a collaborative multi-media conference session. The ability to establish these sessions means that a host of innovative services become possible, such as voice enriched e-commerce, web page click-to-dial, Instant Messaging with buddy lists, and IP Centrex services.

Symmetric Digital Subscriber Line (SDSL)

This is a DSL service that transmits and receives data at the same speed in both directions.

Secure Sockets Layer (SSL)

Secure sockets layer is a protocol designed by Netscape Communications to enable encrypted, authenticated communications across the internet. SSL is used mostly (but not exclusively) in communications between web browsers and web servers. URLs that begin with “https” indicate that an SSL connection will be used. SSL provides 3 important things: privacy, authentication and message integrity.

Static IP

Static IP is the term used to describe a PC or network device that has a permanent IP address as opposed to a dynamic IP address.

Transmission Control Protocol/Internet Protocol (TCP/IP)

Common names for the suite of protocols developed to support and unify the construction of worldwide internetworks such as the internet. TCP and IP are the best known protocols in the suite.

Triple DES

Triple DES is an enhanced version of DES that allows for more security than DES alone, triple DES uses three keys and encrypts three times – hence ‘triple’.

Virtual Private Network (VPN)

This usually refers to a network in which some of the parts are connected using the public internet, but the data sent across the internet is encrypted, so the entire network is "virtually" private.

Wide Area Network (WAN)

This is a geographically dispersed network.

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