A fiber-optic link is a physical network path that carries data as pulses of light through glass or plastic fibers. It is used for high-speed, low-latency communication between switches, routers, data centers, and telecom sites.
In cyber security, fiber matters because it is part of the infrastructure an attacker may target or a defender may rely on. A damaged or removed fiber route can disrupt service, break redundant paths, and force traffic onto slower or less secure alternatives. Fiber can also be tapped with specialized equipment, so sensitive traffic is usually encrypted even when the physical medium is hard to access. Defenders reduce risk by using route diversity, physical protection, inventory of leased circuits, and tested failover plans.