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How many types of Networking Devices?

Answer: Networking Devices

Networks are connected by using some types of devices such as hubs, repeaters, switches, bridges,
routers and gateways. It is very important to know the basic function of these devices in order to decide upon the device that is to be used for a particular purpose.

1. Hub :

A hub works in the physical layer of the OSI model. Hub  is a non‐intelligent device, and has no decision making capability. Hub basically takes the input data from one of the ports and broadcast the information to all the other ports connected to the network.

There are two types of hub :

(i) Active hub : Active hub regenerate, concentrate and  strengthen the signals before sending them to their destinations.
(ii) Passive hub : Passive hub simple broadcast the signals.

2. Repeater :

A repeater is a device similar to the hub, but has  additional features. It also works in the physical layer. The repeaters are used in places where amplification of input signal is necessary. It regenerates the input signal, and amplifies only the desirable signal. Hence, the noise component of the signal is eliminated. It is also called as active hub.

The repeaters are useful for long distance transmission.

One common problem between the repeaters and the hubs are that only one transmission can take place on the network at a particular time. If multiple devices transmit data simultaneously, there will be data collision.

3. Switch :

A switch is an intelligent device that works in the data link layer. The term intelligent refers to the decision making capacity of the switch. It has knowledge of the MAC addresses of the ports in the network. It establishes a link between the sender and the receiver based on the MAC addresses. Simultaneous data transfer is possible in a switch. Switch does not divide bandwidth. A switch is a secure device, because it sends information only to the desired destinations, and also certain security features such as firewalls can be implemented in the switches.

4. Bridge :

A bridge is also a device which works in the data link layer, but is more primitive when compared to a switch. Initial bridges were used to connect only 2 LAN’s, but the most recent ones perform similar operation as the switches. It also works on the principle of transfer of information using the MAC addresses of the ports. When bridging is used, each time the device has to be connected to the internet. A bridge alone cannot be used to connect to the internet. It has no knowledge of the IP addresses used in the internet.

5. Router :

Router connects two different LANs. Router works in the network layer. Route send the on the basis of IP addresses. Routers are similar to bridges but there are some additional features, which routers provide such as ability to filter messages and forward them to different location based on various criteria. Routers are used to find the best route for data packets to travel in the network. The process of finding the path is called as routing. The information about the best route is stored in the table called as routing table.

There are two types of routers :
(i) Static router : In static router, users need to specify the routing path.
(ii) Dynamic router : Dynamic router determine the routing path automatically by using
different algorithms.

6. Gateway :

A gateway is a software or hardware device is used to connect two or more networks of dissimilar types. The gateways are useful for communication between different network architecture with different protocol. Gateway is also called as protocol converter. Gateway accept the packet formatted for one protocol and convert it to a packet formatted for another protocol.

7. Network interface card (NIC) :

A network interface card (NIC) is a computer hardware component that allows a computer to connect to a network. NICs may be used for both wired and wireless connections. A NIC is also known as a network interface controller (NIC), network interface controller card, expansion card, computer circuit board, network card, LAN card, network adapter or network adapter card (NAC).