Network topologies define how devices are connected in a network. There are five basic network topologies: bus, star, ring, mesh, and hybrid. The bus topology connects all devices to a single cable or backbone. The star topology connects all devices to a central device like a hub or switch. The ring topology connects devices in a closed loop so that data travels from one device to the next. The mesh topology fully interconnects all devices for redundancy. The hybrid topology combines two or more topologies to balance reliability and flexibility.