2.  A hub is a central connecting device in a network.  Each node is connected directly to the hub.  They receive a data packet from one node and send that data packet to all nodes on the network.  This created a lot of unnecessary network traffic, as most of the nodes will ignore the data because it is not addressed to them.  A better type of hub is called a switch.

3.  A switch is an intelligent hub that only sends data to a specific node  The switch looks at the address of the data packet and sends it to that address.  A switch reduces the volume of traffic on a network compared to a hub.

4.  A router is a very intelligent hub that directs (routes) data packets to and from other networks.  A router maintains a table of the available routes and their conditions.  It uses this table to determine the best route for a given data packet.  Routers are often used to connect to the Internet.

5.  A bridge is a device to link two similar networks.  It often connects networks that use the same protocol such as Ethernet.  A bridge examines each data packet on a network and forwards any data packets addressed to a connected network.

6.  A gateway is a link between two different types of networks.  It converts different protocols and transfers data between the two networks.  For example, a gateway could be used to convert a TCP/IP packet to an IPX packet.  A gateway acts as the door between the networks.  All the data must pass through the gateway to reach the other network.  Gateways are not necessarily separate devices but rather are often pieces of software running on servers or in routers.

7.  A repeater is used to rebuild a fading signal to its original strength and shape before transmitting it onwards.  For example, the data sent along a UTP cable becomes unreadable after about 100 metres.  A repeater would be installed every 100 metres to rebuild the signal.

8.  A network interface card (NIC, pronounced ‘nick’) is an expansion card that allows a device to be connected to a network  NICs are installed into servers, workstations and some other devices.  Each device must have a driver to communicate on the network.  A NIC is usually given a unique address so that it can be identified on the network.  Most NICs require a network cable connection and have connectors on the card for different types of cables.