They provide basic management capabilities, while nonintelligent hubs do not. On a large district network, this is a desirable feature. On smaller networks, it is not as necessary. Switches are electronics that allow you break up one large network into smaller functional pieces or hook up smaller networks into a large one. They are used to speed up a network that has a great deal of data traffic on it.
Routers are devices that connect networks to other networks.
They select what data will go outside the network and what data will stay inside the network. In a large network, several routers might create a path for network traffic to follow to get to a specified destination. A router of some kind is needed for Internet access from a local area network. A router is also used to hook up dissimilar network protocols. If you have a large 10BaseT network and you want to connect a few users on an old token ring network, you can put a router in between them.