Network Devices : A Layman’s Definition

Introduction

This is the very first post in networking, which will help us to dive in the ocean called network. I would be publishing a series of posts to explain the basic concepts of networking and then we would leap in the advance level of networks and internetworks.

Before learning about the network devices, lets first understand what are networks?

What are Networks?

Like we humans, computers also need to talk to each other for sharing information and resources. This results in establishment of a connection, to talk, which is called network or computer network or data network.
Well nobody can beat Wikipedia in definition, so let’s read what wiki says :

A computer network or data network is a digital telecommunications network which allows nodes to share resources. In computer networks, networked computing devices exchange data with each other using a data link. The connections between nodes are established using either cable media or wireless media.

Wikipedia

In the definition, nodes are nothing but the devices attached to the network and data link is the mode via which the nodes can communicate.
I hope there is no doubt about network.
Now let’s understand what are network devices?

Network Devices :-

The physical devices (nodes) which helps computer to communicate (talk) to each other are called network devices. In a network, the devices which receive or generate data are called hosts and the intermediate devices are called nodes/hops. There are different types of networking devices, which are listed as follows :-

• Network Hubs
• Network Bridge
• Network Switches
• Routers
• Network Gateways
• Modem
• Access Point
• Wifi Router
• Repeaters

Network Hubs :-

Network Hubs are the devices which are used to connect multiple nodes, so that they can form a network and exchange data. Here, that data travels in the form of data frame. In a hub, when a data frame is received in one port, then it replicates or we say repeats that data frame to all of its port (except the receiving port). As a result of this, all the node attached to this hub, receives the same data frame.

Bridge :-

A network bridge is a device which joins two physical segment (subnets) of a same network. It’s quite same like that of, a normal bridge which is connecting two roads over a river. This device is very decisive like a traffic controller. When a packet arrives in one of its port then it makes a decision, to forward or to drop. This decision is made based on the entries in its MAC (Media Access Control) address table; if the entry of the MAC address is present for that data frame, then only bridge would allow it to pass else it would drop it

Network Switches :-

A network switch is the combination of a network hub and a network bridge, but in a smatter way. That means, a switch can perform packet forwarding and bridging at the same time. In other words, when a data frame arrives in one of the ports of the switch, then it makes a decision to forward it or drop it. If the answer is to forward then to which port. Switch’s MAC address table is little bit different from that of a bridge, it keep the MAC entries along with the port(of the switch) it is attached to. That way it forwards the data frame to that specific port and not to all of its port.

Routers :-

Routers are very intelligent device that makes routing decisions. We can say that routers are the backbone of “The Internet”. If routers are removed then data won’t be able to reach the destination. Like switch, router maintains a routing table. The routing table contains the route/path (IPs of its next hops and what IP addresses they have) which is explicitly configured by the Network Administrator. By default, all the internal data frames are dropped by router, because router doesn’t understand the MAC address in which the internal network (intranet) operates.

Network Gateways :-

Network gateways are the devices which combines two different networks with different protocols (set of rules), also known as protocol converters. We can say that routers are special case of network gateway. Unlike router, gateways are more complex networking devices which provides system or network interoperability, due to this reason they are generally the perimeter (at the entry and exit of the network) devices. In home, broadband routers are the gateways; in a company, a firewall can be the gateway.

Modems :-

Modems, also called as modulator and de-modulator, are the device that modulates one or more carrier waves to encode data/information and demodulates the carrier wave to decode that data/information. This phenomenon is quite similar to a transport system, where the passengers are the data/information and the transports (bus, train, aircrafts, etc.) are the carrier waves. The goal of the modems is to provide the cheapest way to send and receive data/information, like the telephone lines. In home, the modem performs the task of a router, gateway and sometimes also as a wifi access point (which is also called as wifi routers).

Access Points :-

Wireless access point, which is commonly known as access points, are the devices which allows wireless (or WI-FI) devices to connect with a wired network. In simple terms, it is a device which converts the wired signal to a wireless form so that people with different kinds of devices (smartphone, laptops, tablets, etc.) can access the internet (network). It is different form the hotspot which people commonly use to transfer data quickly.

Wi-Fi Routers :-

Wi-Fi Routers are the device which is the combination of a router and an access point or a router, an access point, a gateway and a modem. That means, this device can perform routing, switching, giving a gateway to the data/information and granting access to the wireless devices. Generally home Wi-Fi routers are the combination of a router, an access point, a gateway and a modem.

Repeaters :-

Repeaters are the devices which amplifies the original signal like an amplifier of a public-address system (PA system). This device is used where the signal requires to travel a longer distance (more than its capability). Repeaters can be both wired and wireless, if it is wireless then we call it as a range extender.

Conclusion:-

All devices in networking have there own role. In industry environment, every device is a separate unit e.g., router, network switch, network gateways etc. But when it comes to home usage, we use every role on a single unit e.g., WiFi Router. Hence the home devices has a lower capability than the industrial devices.