We’re going to talk about popular network devices and hardware in this post so you need be already familiar with various types of media and network connections. The most basic hardware used in a network are: NIC (Network Interface Card), Hub, Switch and Router. So stay tuned.
Network Interface Card (NIC)
The network interface card or NIC is an expansion card that you install on of your computer slots. This is the client-side piece of hardware that provides an Ethernet port so that you can connect a computer to a network through a cable.
All of the workstations in a Local Area Network (LAN) typically need at least one of these cards.
Fiber-optics with LC type connector and twisted pair cables with RJ45 connector can connect to NIC interfaces. This depends on which type NIC is installed on your device.
The NIC card is working in layer 2 of the OSI model and as mentioned before, it has a pre-defined MAC address which is a unique address for every NIC card. Read more about MAC address.
HUB is a device that connects all segments in a local network together. Its job is to get the data through one incoming cable and broadcast a copy of that data to all other devices.
As mentioned before, since hub only uses broadcast transmission, if one computer in the network sends data, all other computers will receive it. Better said, all ports on a hub belong to one broadcast domain.
The point is that all other computers will drop the received packets except the computer with the same destination MAC address that the packet is destined to. HUB is the central point of access in a Star topology network.
Like Hub, a switch also connects network segments together but with one big difference.
When a switch receives a piece of data an any of its ports, it doesn’t send a copy of it to other ports. Switch knows which client is connected to which port so it sends the data only to the client which is supposed to receive it.
The switch increases the efficiency of a network to its maximum level because the amount of redundant traffic on the network is eliminated. So to say, unlike a hub, there’s no wasted bandwidth when using a switch in the network.
A Switches works in Data link layer (Layer 2). They are able to find destination MAC address (If sender & receiver located in the same broadcast domain).
A Routers, as the name stands for, is a pathfinder in the network. It’s job is to find the best path from source to destination. This device is usually used in the backbone of a network. Other segments or departments in a network have one or more connection with this device.
Routers are layer 3 devices which means they are able to read Network layer information and determine the shortest path by reading the destination IP addresses from within the packet.
Later, we’ll see how Switches and Routers can do their job. It’s both interesting and also very important for a network engineer to have an in-depth knowledge about the functionality of these devices.