A room in the Telecity colocation centre in Aubervilliers, a suburb of Paris

A colocation centre (collocation center) ("colo") or carrier hotel is a type of data center where multiple customers locate network, server and storage gear and interconnect to a variety of telecommunications and other network service provider(s) with a minimum of cost and complexity. An Internet hosting service is a service that runs Internet servers allowing organizations and individuals to serve content to the Internet or in newbie terms a way for you A virtual private server ( VPS, also referred to as Virtual Dedicated Server or VDS) is a method of partitioning a physical server computer into multiple A free web hosting service is a Web hosting service that A shared web hosting service or virtual hosting service or derive host refers to a Web hosting service where many websites reside on one Web server Clustered hosting technology is designed to eliminate the problems inherent with typical Shared hosting infrastructures Weblog software (also called blog software or blogware) is a category of software which consists of a specialised form of Content Management Systems A guild hosting or clan hosting service is a specialized type of Web hosting service designed to support online gaming communities generally referred to as An image hosting service allows individuals to upload Images to an Internet website A video sharing service allows individuals to Upload Video clips to an Internet website A wiki farm is a server or an array of servers that provides hosting for multiple Wikis Wiki farms are also known as "hosted wiki service A file hosting service, online file storage service, or online media center is an Internet hosting service specifically designed to host static content A remote online or managed backup service is a service that provides users with an online system for backing up and storing Computer files Managed backup providers A game server is a remotely or locally run server used by Game clients to play multiplayer games. A DNS hosting service is a service that runs Domain Name System servers An email hosting service is an Internet hosting service that runs Email servers Aubervilliers is a commune in the northeastern suburbs of Paris, France. Paris (ˈpærɨs in English; in French) is the Capital of France and the country's largest city A data center is a facility used to house computer systems and associated components such as telecommunications and storage systems

Increasingly organizations are recognizing the benefits of colocating their mission-critical equipment within a data centre. Colocation is becoming popular because of the time and cost savings a company can realize as result of using shared data centre infrastructure. Significant benefits of scale (large power and mechanical systems) result in large colocation facilities, typically 4500 to 9500 square metres (roughly 50000 to 100000 square feet). With IT and communications facilities in safe, secure hands, telecommunications, internet, ASP and content providers, as well as enterprises, enjoy less latency and the freedom to focus on their core business. An application service provider (ASP is a business that provides computer-based services to customers over a network

Additionally, customers reduce their traffic back-haul costs and free up their internal networks for other uses. Moreover, by outsourcing network traffic to a colocation service provider with greater bandwidth capacity, web site access speeds should improve considerably. In Computer networking and Computer science, digital bandwidth or just bandwidth is the capacity for a given system to transfer data over a connection

Major types of colocation customers are:

• Web commerce companies, who use the facilities for a safe environment and cost-effective, redundant connections to the Internet
• Major enterprises, who use the facility for disaster avoidance, offsite data backup and business continuity
• Telecommunication companies, who use the facilities to interexchange traffic with other telecommunications companies and access to potential clients

Most network access point facilities provide colocation. The four Network Access Points (NAPs were defined under the U

Building

A typical server rack, commonly seen in colocation.

• Fire protection systems, including passive and active active design elements, as well as implementation of fire prevention programs in operations. Fire protection is the study and practice of mitigating the unwanted effects of Fires ref>NFPA Fire Protection Handbook pg Passive fire protection (PFP is an integral component of the three components of structural Fire protection and fire safety in a Building. Active fire protection (AFP is an integral part of Fire protection. Fire safety refers to precautions that are taken to prevent or reduce the likelihood of a Fire that may result in death injury or property damage alert those in a structure Smoke detectors are usually installed to provide early warning of a developing fire by detecting particles generated by smoldering components prior to the development of flame. A smoke detector is a device that detects Smoke and issues an Alarm. This allows investigation, interruption of power, and manual fire suppression using hand held fire extinguishers before the fire grows to a large size. A fire sprinkler system is often provided to control a full scale fire if it develops. A fire sprinkler system is an Active fire protection measure consisting of a water supply providing adequate pressure and flowrate to a water distribution piping system Clean agent fire suppression gaseous systems are sometimes installed to suppress a fire earlier than the fire sprinkler system. Gaseous fire suppression is a term to describe the use of inert Gases and chemical agents to extinguish a Fire. Passive fire protection elements include the installation of fire walls around the space, so a fire can be restricted to a portion of the facility for a limited time in the event of the failure of the active fire protection systems, or if they are not installed. A firewall is an integrated collection of security measures designed to prevent unauthorized electronic access to a networked computer system
• 19-inch racks for data equipment and servers, 23-inch racks for telecom equipment.
• Cabinets and cages for physical access control over tenants' equipment.
• Overhead cable rack (tray) and fiberguide, power cables usually on separate rack from data.
• Air conditioning is used to control the temperature and humidity in the space. The term air conditioning refers to the cooling and dehumidification of indoor air for Thermal comfort. ASHRAE recommends a temperature range of 20–25 °C and humidity range of 40–60% as optimal for electronic equipmemt conditions. The American Society of Heating Refrigerating and Air Conditioning Engineers ( ASHRAE; pronounced 'ash'-'ray' is an international technical society for all individuals The electrical power used by the electronic equipment is converted to heat, which is rejected to the ambient air in the data center space. Unless the heat is removed, the ambient temperature will rise, resulting in electronic equipment malfunction. By controlling the space air temperature, the server components at the board level are kept within the manufacturer's specified temperature/humidity range. Air conditioning systems help control space humidity within acceptable parameters by cooling the return space air below the dew point. Humidity is the amount of water vapor in the air In daily language the term "humidity" is normally taken to mean Relative humidity. The dew point (sometimes spelled dewpoint) is the Temperature to which a given parcel of Air must be cooled at constant Barometric pressure, Too much humidity and water may begin to condense on internal components. Condensation is the change of the physical state of aggregation (or simply state of matter from gaseous phase into liquid phase In case of a dry atmosphere, ancillary humidification systems may add water vapor to the space if the space humidy is too low, which can result in static electricity discharge problems which may damage components. Electrostatics is the branch of Science that deals with the Phenomena arising from what seems to be stationary Electric charges Since Classical
• Low-impedance electrical ground. In Electrical engineering, the term ground or earth has several meanings depending on the specific application areas
• Few, if any, windows.

Physical security

Most colocation centres have high levels of physical security, and may be guarded continuously. They may employ closed-circuit television camera. CCTV cameras can produce images or recordings for Surveillance purposes and can be either video cameras or digital stills cameras

Some colocation facilities require that employees escort customers, especially if there are not individual locked cages/cabinets for each customer. In other facilities, a card access system may allow customers access into the building, and individual cages/cabinets have locks.

Power

Colocation facilities generally have generators that start automatically when utility power fails, usually running on diesel fuel. In Electricity generation, an electrical generator is a device that converts Mechanical energy to Electrical energy, generally using Electromagnetic A diesel engine is an Internal combustion engine which operates using the Diesel cycle (named after Dr These generators may have varying levels of redundancy, depending on how the facility is built.

Generators do not start instantaneously, so colocation facilities usually have battery backup systems. In many facilities, the operator of the facility provides large inverters to provide AC power from the batteries. In other cases, the customers may install smaller UPSes in their racks. An uninterruptible power supply ( UPS) also known as a continuous power supply ( CPS) or a battery backup is a device which maintains a continuous

Some customers choose to use equipment that is powered directly by 48VDC (nominal) battery banks. This may provide better energy efficiency, and may reduce the number of parts that can fail.

An alternative to batteries is a motor generator connected to a flywheel and diesel engine. A flywheel is a mechanical device with significant Moment of inertia used as a storage device for Rotational energy.

Many colocation facilities can provide A and B power feeds to customer equipment, and high end servers and telecommunications equipment often can have two power supplies installed.

Colocation facilities are sometimes connected to multiple sections of the utility power grid for additional reliability.

Cooling

The operator of a colocation facility generally provides air conditioning for the computer and telecommunications equipment in the building. The term air conditioning refers to the cooling and dehumidification of indoor air for Thermal comfort. The cooling system generally includes some degree of redundancy

In older facilities, the cooling system capacity often limits the amount of equipment that can operate in the building, more so than the available square footage.

Internal connections

Colocation facility owners have differing rules regarding cross connects between their customers. These rules may allow customers to run such connections at no charge, or allow customers to order such connections for a significant monthly fee. They may allow customers to order cross connects to carriers, but not to other customers.

Some colocation centres feature a "meet-me-room" where the different carriers housed in the centre can efficiently exchange data. A " meet me room " (MMR is a place within a Colocation center (or carrier hotel where multiple Telecommunications companies can physically connect to one

Most peering points sit in colocation centres. Peering is voluntary interconnection of administratively separate Internet networks for the purpose of exchanging traffic between the customers of each network

Because of the high concentration of servers inside larger colocation centres, most carriers will be interested in bringing direct connections to such buildings.

In many cases there will be a larger Internet Exchange hosted inside a colocation centre, where customers can connect for peering. An Internet exchange point ( IX or IXP) is a physical infrastructure that allows different Internet service providers (ISPs to exchange Internet

External connections

Colocation facilities generally have multiple locations for fiber optic cables to enter the building, to provide redundancy so that communications can continue if one bundle of cables is damaged.

References

External links

• Colocation at the Open Directory Project
• A Los Angeles 'Hotel' for Internet Carriers 19 February 2007 NPR story