Explain the use of the following network connectivity devices: (a) Network interface card (b) Hub (c) Intelligent hub (d) Bridge (e) Repeater (g) Modem (f) LAN switch

​Explain the use of the following network connectivity devices: (a) Network interface card (b) Hub (c) Intelligent hub (d) Bridge (e) Repeater (g) Modem (f) LAN switch

• (a) network interface card is a printed circuit board that is A inserted on the motherboard of the computer in order to provide a physical link between the computer and the network cabling. It has several ports that allow connections to different cable terminator types.
• (b) A hub is a concentrator that has many ports for cables from different nodes to plug in as a means of interconnecting them on the network. A hub receives a signal from a network node, amplifies it and repeats/broadcasts it to the other nodes on the network.
• (c) An intelligent hub keeps information about the computers on the network in a small database called a management information base (MIB), and uses that information to manage the way computers communicate in the network.
• (d) A bridge is a networking device that divides a network into segments in order to try and control the broadcast domain on the entire network. The bridge reduces network traffic by limiting broadcasts to take place only in the segment where the destination computer is located.
• (e) A repeater is simply a signal amplifier. It cleans, amplifies and broadcasts a signal to make sure that signal loss is avoided on the network. A repeater is usually placed at the point of signal attenuation in the network.
• (f) A LAN switch creates point to point links between communicating nodes on a network. Data is switched from source to destination; hence, no broadcasts occur on the network. This reduces network traffic to a great extent and gives better quality of service on the network.
• (g) A modem is a device that converts computer data signals into a format that is suitable for transmission over communication links to distant computers. It does this through a process called modulation, where the low power message signal is used to vary either the frequency or amplitude of a high power carrier signal that is capable of travelling over long distances in the medium. At the destination, a modem demodulates the carrier signal and retrieves the message.