Computers attached to a network need to have their data mediated by a network device, and there are several kinds of network devices.
A hub is a device that connects multiple Ethernet or twisted pair devices together. By this connection, multiple devices can act as a single network segment. Hubs can either simply receive data transmitted from a device to one port and broadcast it out to the devices connected on all other ports, or they can perform the same receive-then-broadcast action but regenerate or boost the signal. Hubs are generally inexpensive and easy to manage; how-ever, they do not provide the best performance in high-traffic or latency- sensitive situations. Hubs have largely been replaced by switches, but many dedicated hubs still remain in use. Troubleshooting a hub is made easier by the use of status lights for the various ports.
A switch is a network hardware device that joins multiple computers together within the same LAN. Unlike a hub, switches forward packets to only the destination port based on MAC addresses. Because of this, they are slightly “smarter” than hubs, and are more common. Switches can also be connected to other switches, thus increasing the number of devices on a LAN without sacriﬁcing performance. Troubleshooting a switch is made easier by the use of status indicator lights on the various ports.
A router is a networking device that connects multiple networks that use the same protocols. Traffic from one network to another does not always have to travel between the same routers. On the Internet, for example, traffic is routed according to the best available path at the time. Troubleshooting a router is made easier by the use of status indicator lights on the various ports.