What is a Data Center?
A data center is an electronic infrastructure filled with computer systems and hardware. These large facilities are used in areas such as telecommunications or information storage, and are highly protected by firewalls and other security measures to reduce downtime as much as possible. Basically everything needed to allow a continued flow of operations is contained within a data center. ISPs (Internet Services Providers) usually run an maintain data centers, used to host servers for customers looking to pay for such services. Cogent is an example of one of these ISPs, and is an example of a Tier 1 data center.
There are 4 types of data centers, ranging from tier 1, and increasing in complexity until reaching tier 4. Each tier increases in the amount of uptime that is likely from that data center. Most ISPs use a tier 1 system, as higher tiers such as 4 are used for urgent operations or situations that might be critically endangering if the system was to experience any issues causing downtime.