Glossary of Colocation and Data Centre terms
| ADSL | Asymmetric Digital Subscriber Line: DSL transforms an analogue telephone line into a high speed digital line. With ADSL, incoming and outgoing data speeds are different, download being faster than upload. |
| ASCII | American Standard Code for Information Interchange: A set of numbers representing all the normal characters to be found on the keyboard plus others. |
| ATM | Asynchronous Transfer Mode: the international CCITT standard for high speed, packet-switched networks that operate at digital transmission speeds above 1.544 Mbps. |
| Bit | A contraction of “binary digit”. The smallest unit of information that a computer can hold. A Bit can have only two states “on” or “off”, usually described as 1 or 0. Eight bits is equivalent to one byte. Four bits is sometimes called a nibble. |
| Bluetooth | A technology embedded in electronic devices to provide wireless connections over short distances. |
| Broadband | Telecoms systems capable of simultaneously supporting multiple information formats at high speeds such as voice, high-speed data services and video services on demand. See Connectivity. |
| BSI | British Standards Institute, the body responsible for the drawing up standards for equipment used in the UK. |
| Byte | A unit in the binary system. 8 bits equals one byte. One byte can represent one character in the alphabet. |
| Cable modem | Cable modem: a high speed modem allowing users to connect to a service provider through their local cable network to have an ‘always on’ connection to the Internet. |
| CILE | Call Information Logging Equipment. Equipment used to log call information for later analysis. |
| CLID | Calling Line Identity, where identity information from the device making a call is interpreted by the device answering the call. |
| Colocated Racks | Colocated Racks are generally in a common data hall or suite containing many racks in which the Customer’s equipment operates, sharing facilities such as power and cooling with other Customers. |
| Colocation | A colocation data centre (or data center) is an independently owned and operated building where multiple data or telecommunications carriers locate their connections next to one another, enabling customers in the building to interconnect to them with a minimum of cost and complexity. View alternative spellings for colocation (Collocation, Co-location, Co location, Colo, Co-lo, Co lo) |
| CoS | Class of Service: a term dividing the source traffic from a user into separate classes, each attracting its own quality of service indicators. |
| CPE | Customer Premises Equipment: communications equipment belonging to a carrier but located in a customer’s suite or rack, and where the customer pays for the power. In Lifeline House, only BT operates in this way. |
| CPS | Carrier Pre-Select: a service that allows connection to a network while retaining existing numbers. |
| Dark Fibre | Dark Fibre or Dark Fiber. is underground fibre available where a carrier has installed many fibre ways between buildings and has need for only some of them. The carrier makes them available to others on the basis that others provide all the equipment to light and terminate the fibres. See Dark Fibre. |
| Data Centre | A data centre (or data center) is a facility used to house computer or telecoms systems and associated components. It includes redundant or backup power supplies, redundant data and voice communications connections, environmental controls and security devices. See Facilities. |
| DNS | Domain Name Service: an internet protocol for relating service names to URLs to an IP address and vice versa. |
| DoS | Denial of Service. An electronic attack whose purpose is to prohibit the use of a program or an entire system by the target. |
| DSL | Digital Subscriber Line: transforms an analogue telephone line into a high speed digital line. |
| E1 | The European standard for digital transmission, carrying data at 2 Mbps. Many of the carriers in Lifeline House offer E1 connections to all parts of the world. See the Carrier List. |
| Ethernet | The most widely-installed LAN technology. Ethernet LAN uses Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol running over a coaxial cable or twisted pairs. 10BASE-T provides transmission speeds up to 10 Mbps. Fast Ethernet, or 100BASE-T10, provides transmission speeds up to 100 Mbps. See Internet Transit. |
| FTP | File Transfer Protocol: A way of sending files between computers. |
| Hexadecimal | A numbering system operating on a base of 16, rather than the normal 10. Numbers sequence 0,1,2,3,4,5,6,7,8,9,A,B,C, D,E,F. Hexadecimal is useful because 4 binary bits can describe 16 elements. |
| Internet | A world-wide network of computer networks in which users at any one computer can obtain files or information from any other computer. See Internet Transit. |
| Internet Telephony | See VoIP |
| IP | Internet Protocol: the method of sending information from one computer to another across the internet. |
| IP Address | Internet Protocol Address. A numeric address that is given to servers and users connected to the Internet. |
| IP PBX | Internet Protocol Private Branch eXchange: an Internet Protocol-enabled PBX which sends voice traffic over a data network instead of a traditional phone network. |
| IPSec VPN | A virtual private network (VPN) implementation based on the IPsec (Security Architecture for the IP Protocol, RFC2401) standard. |
| IP Telephony | See VoIP |
| ISDN | Integrated Services Digital Network: A fully digital telecommunications network access method which works over copper wires. Basic rate ISDN provides two 64 kbps information channels and a single 16 kbps control channel. Primary rate provides thirty 64 kbps information channels and a 64 kbps control channel. |
| ISP | Internet Service Provider: Point of access to the Internet. The ISP provides its customers with high-speed access to the Internet. See Carriers. |
| IPVPN | Internet Protocol Virtual Private Network: a way of using the internet to link up separate sites of an organisation. |
| IVR | Interactive Voice Response: a system that permits the voice control of computer systems, allowing the user to interact with a computer system. |
| JPEG | Joint Photographic Experts Group: An international standard for the compression of images. |
| Kbps | Kilobits per second: a measure of data transmission. |
| KBps | Kilobytes per second: a measure of data transmission. 1 megabyte = 8 megabits. |
| KWh | KiloWatt Hour: One thousand Watt Hours (see Watt Hour).The standard unit of charging for electricity. A 1KW load consumes 1 KWh in 1 hour. See Contracts. |
| LAN | Local Area Network: a high speed communications network covering a small geographical area. |
| Leased Lines | A point-to-point physical connection between two sites, leased from a network operator. |
| MAN | Metropolitan Area Network: a high speed communications network covering an area larger than a LAN and smaller than a WAN. |
| Mbps | Megabits per second: a measure of data transmission. |
| MBps | Megabytes per second: a measure of data transmission. 1 megabyte = 8 megabits. |
| MPEG | Moving Pictures Expert Group:. An international standard for video compression. |
| MPLS | Multi-Protocol Label Switching: a labelling standard to manage traffic based on priority and service plans. It works with (IP) Internet Protocol, (ATM) Asynchronous Transport Mode, and frame relay network protocols. |
| NOC | Network Operating Centre: a manned operation from which a communications network is monitored and controlled on a 24-hour basis. |
| Octal | A numbering system operating on a base of 8 rather than the normal 10. Numbers are sequenced 0,1,2,3,4,5,6,7. Octal is useful because 3 binary bits can describe 8 elements. |
| Packet Switching | The method of moving data on the Internet. In a packet switching network, the data from a machine is broken into sections. Sections of data from different sources are directed along different routes. Thus many people can use the same lines at the same time. See Connectivity. |
| PBX | Private Branch eXchange: a private telephone network within an organisation allowing users to share external telephone lines instead of having a dedicated external line for every telephone. |
| Pixel | Pixel: a definition of the number of elements in an image. On this website, images are a max of 100dpi; The main template is 620×200 pixels; the Feature images are 333×240 pixels; the GooglePlaces image is 90×90 pixels; carrier logos are typically 45 to 65 pixels high in gif or jpg; partners page logos are typically 60 to 65 pixels high. |
| PoP | Point of Presence: a point of connection to a service provider’s network. The more POP’s in a carrier neutral colocation data centre, the more choice of carriers. See the Carrier List. |
| PSTN | Public Switched Telephone Network: a national wired telephone network. |
| POTS | Plain Old Telephone System: a term used for a voice telephone system with no enhancements |
| Power Factor | A measure between 0 and 1 of the relationship between the electrical power used to do useful work and the power used to create and destroy electrical or magnetic fields in an ac electrical system. A measure of 1 indicates all the power is being used to do useful work. See Electrical Power. |
| Private Suite | Customers in a data centre will frequently take a long-term private suite to gain privacy and complete control of operations. |
| QoS | Quality of Service: The quality of communications services delivered to a customer. Different classes of information require different qualities. For example, voice requires a higher QoS than data. Measurements include parameters such as jitter, loss and end-to-end delay. |
| Router | A device or setup that finds the best route between any two networks, even if there are multiple networks to traverse. Remote sites can be connected using routers. |
| SDSL | Symmetric Digital Subscriber Line. A high-speed internet connection where the upload and download speeds match. |
| SDH | Synchronous Digital Hierarchy: a standard for transmitting and receiving digital information over optical networks. |
| SIP | Session Initiation Protocol: used to set up varying communications sessions on the Internet, such as telephony, event notification and instant messaging. |
| SMTP | Simple Mail Transfer Protocol: a protocol used to send and receive email. |
| Spam | Something ubiquitous and undesired, from the canned meat product purchased from US suppliers by the British government during WWII and popularised by Mr Montague Python, now meaning unsolicited and unwanted emails. |
| SSL VPN | SSL VPN (Secure Sockets Layer Virtual Private Network) is a specific type of VPN that runs on Secure Socket Layers technology. |
| TCP/IP | Transmission Control Protocol/Internet Protocol: The protocols on which the Internet is based. TCP guarantees that every byte sent from one port arrives at the other in the same order and without duplication or loss. IP assigns local IP addresses to physical network addresses. See Internet Transit. |
| Three Phase Power | Three separate power outputs from a single source. There is a phase difference of 120° between any two of the three voltages and currents. See Electrical Power |
| UPS | Uninterruptible Power Supply: Equipment providing no-break power supply for the duration of the reserves of its batteries in the event of failure of the primary source of power. See Electrical Power |
| VPLS | Virtual Private LAN Service: provides Ethernet based multipoint to multipoint communication |
| Virtual LAN | Virtual Local Area Network: A logical rather than a physical LAN comprising workgroups drawn together regardless of each member’s physical location. |
| VoIP | Voice over Internet Protocol: a method of transmitting voice calls over the internet. See Internet Transit |
| VPN | Virtual Private Network: a private network that uses the public telecoms infrastructure. |
| WATT HOUR | Electrical power measured in terms of time. One watt hour of electricity is equal to one watt of power being consumed for one hour. (A one-watt light operated for one hour would consume one watt hour of electricity.) See Contracts and KWh |
| WAN | Wide Area Network: A network covering large geographic distances. WANs operate at slower speeds and with higher delays than networks that operate over shorter distances. |
Colocation Spellings
Leading on from our Glossary of terms, we thought it might also be useful to provide some information about the different spellings of colocation, as this can also be confusing. Click here to view the various spellings of Colocation.
