Colocation is simply floor space, power, cooling, and sometimes bandwidth in a service provider’s data center.  These data centers are redundant with many available carriers, dual fiber paths, and dual power sources, meaning they offer protection against network or power failures.  The amount of space rented is entirely up to the client — anywhere from a partial rack to an entire data center.  Enterprise class service providers offer various compliances (SSAE 16, PCI, HIPAA, NIST, etc.) and more than 99.9% SLA’s for uptime.  Colocation can be combined with other cloud solutions such as cloud computing, managed applications, and managed databases.