What Is Colocation?

Colocation (often spelled as "collocation" or "co-location") is the provisioning or use of space and/or bandwidth in a data center for lease by customers.

Customers install servers or telecommunications equipment in the leased space. Typically, the leased space consists of rackspace in the form of full cabinets or a portion of a cabinet measured in Rack Units or RU (1RU comprises 1.75 vertical inches of space). Larger spaces, such as a caged portion of one room or private rooms or suites are sometimes offered for lease.

Customers typically connect to the Internet using bandwidth leased by the facility at a predetermined cost and transfer rate (also known as a "contracted rate"). At certain colocation facilities, customers may also provision their own bandwidth through a carrier of their choosing (facilities that allow this are called "carrier neutral"). Colocated customers using the facility's bandwidth usually experience a significant bandwidth cost savings.

Colocation has several advantages for the customer. In contrast to managed hosting, in which the customer is provided service through equipment owned by the ISP, customers use their own equipment in the leased space. Additionally, colocation facilities provide an environment of security and redundancy. Security is achieved through the use of physical measures, including locking cabinets, keyed access to the server room and video surveillance. Non-physical security measures include network monitoring and bandwidth auditing. Redundancy is achieved through the facility's use of UPS and/or generator systems to negate the effects of on-the-grid power outages, the facility's provisioning of several on-net connections through distinct carriers and the facility's integration of load-balancing or firewall technologies within its network. This blend of security and redundancy makes colocation an ideal solution for customers seeking a stable platform for mission-critical applications.