A router is a more sophisticated network device than either a switch or a hub. Like hubs and switches, network routers are typically small, box-like pieces of equipment that multiple computers can connect to. Each features a number of "ports" the front or back that provide the connection points for these computers, a connection for electric power, and a number of LED lights to display device status. While routers, hubs and switches all share similiar physical appearance, routers differ substantially in their inner workings.
A switch is a small hardware device that joins multiple computers together within one local area network (LAN). Technically, network switches operate at layer two (Data Link Layer) of the OSI model. Network switches appear nearly identical to network hubs, but a switch generally contains more "intelligence" (and a slightly higher price tag) than a hub. Unlike hubs, network switches are capable of inspecting data packets as they are received, determining the source and destination device of that packet, and forwarding it appropriately. By delivering each message only to the connected device it was intended for, a network switch conserves network bandwidth and offers generally better performance than a hub.
A Hubis a small, simple, inexpensive network device that joins multiple computers together.
Most hubs manufactured today support the Ethernet standard. Non-Ethernet hubs (Token Ring, for example) also exist, but Ethernet is always used in home networking. Technically speaking, hubs operate as Layer 2 devices in the OSI model.
To join a group of computers with an Ethernet hub, one connects an Ethernet cable (that has an RJ-45 connector attached) into the hub, then connect the other end of the cable each computer's network interface card (NIC). Hubs also require external power and can be connected to other hubs, switches, or routers.
One good way to differentiate between Ethernet hubs is by the speed (data rate) they support.To know more: