A network topology is the arrangement of links and devices. Camera systems almost always use a star, with each camera on its own cable to a switch. Star topology isolates one failed cable, but it makes the switch a single point of failure.
Topology decides how a fault travels. On a star, one bad cable affects one camera. On a shared bus or ring, one break can affect many.
Star is the default
Each camera runs to a switch port, usually over PoE. Faults stay local, a camera can be power-cycled from the switch, and adding a camera means one new cable rather than a rework.
Multi-building sites and rings
Between buildings, a ring can add resilience because traffic can travel either way. Fiber between switches also removes the distance limit and the electrical ground difference that copper cannot cross.