Complex sentence: Flat networks are designed to reduce the number of routers and switches on a computer network by connecting the devices to a single switch instead of separate switches, or by using network hubs rather than switches to connect devices to each other.
Split into simpler sentences: Flat networks are designed to reduce the number of routers and switches on a computer network by connecting the devices to a single switch instead of separate switches. Some such networks may use network hubs or a mixture of hubs and switches, rather than switches and routers, to connect devices to each other.