Critical Internet infrastructure

Critical Internet infrastructure is a collective term for all hardware and software systems that constitute essential components in the operation of the Internet.
Physical transmission lines of all types, such as wired, fiber optic and microwave links, along with routing equipment, the accompanying critical software services like the Domain Name System (DNS), Email, website hosting, authentication and authorization, storage systems, and database servers are considered critical Internet components. If any of these systems and services were to be interrupted for a significant period of time "[t]he Internet...as we know it would collapse".