A "Network" is a system where two or more computers are connected—either wired or wirelessly—to share hardware and software resources. Everything we hear about, use, and manage in the digital world is essentially built upon this fundamental definition.

So, how do these massive systems work in the background, and what components are they made of? In this first technical log, we will take a closer look at the foundations of network architecture and design classifications.

Core Network Components: Active and Passive Infrastructure

Network systems primarily consist of an infrastructure that connects devices together, and the communication devices that operate on top of it. To build a network, we need both hardware and software components.

We can divide the hardware into two main categories:

  • Passive Components: These are the structures that physically connect computers and transmit data without processing it. Cables, fiber optics, and patch panels fall into this group.
  • Active (Electronic) Devices: These are the hardware components that manage and route communication over the infrastructure. Devices like Hubs, Switches, Routers, and Repeaters work to ensure data reaches the correct destination.

On the software side, network operating systems, communication protocols, and network management applications keep the structure alive.

The Heart of the Network: Computers and Ethernet

Computers take on the biggest role in a network system. A network requires at least two computers to exist. These machines can take on different roles; some act as a Server (Web Server, File Server) providing resources, while others act as a Client accessing those resources.

The hardware standard developed to connect multiple computers within a local communication network is called Ethernet. Starting as a small office technology back in the day, Ethernet is now the undisputed champion of local area networks (LAN). However, connecting these local networks globally to form the massive structure we call the "Internet" is made possible through universal communication languages like TCP/IP.

Types of Networks by Geographical Distance

Network systems connect over different distances depending on their physical scope. We basically classify them into four categories:

LAN and WAN Logical Connection Diagram
Figure 1: Coverage areas of network types based on geographical distance.
  • 1. Personal Area Network (PAN): The smallest network type. It is a small-scale network where your personal digital devices connect, often using Bluetooth or Wi-Fi. It is the meeting point for your wireless mouse, phone, printer, and personal computer.
  • 2. Local Area Network (LAN): Connects end systems located within the same physical environment to edge routers. It is the network structure used for devices in close physical proximity, such as in our homes and corporate offices.
  • 3. Metropolitan Area Network (MAN): A system that encompasses multiple LANs, connecting them under a single umbrella across a larger area like a city. It is typically used in large enterprises, massive university campuses, or city-wide corporate connections.
  • 4. Wide Area Network (WAN): The most extensive network type. It is a large logical and physical network that enables communication by connecting LANs across different geographical regions. The "Internet" as we know it today is actually a massive WAN.

A Critical Step in Network Design: Classification and Security

One of the most important aspects of building a network system is "Classification". Proper classification paves the way for a healthy system by ensuring network security and order. In network engineering, we approach design in two dimensions:

  • Physical Topology: Determines which device connects to which, through which cables and switches, directly or indirectly. It is the physical map of the network.
  • Logical Topology: This is the brain of the operation. The logical design determines access privileges, Firewall rules, IP addressing, and data flow directions for the devices connected to the servers.

Conclusion

Various universal standards have been developed to ensure that network systems can communicate within such a diverse range of devices and structures in a specific order. The most well-known of these are the 7-layer OSI Reference Model, developed by the Open Systems Interconnection committee, and the TCP/IP Reference Model, developed by the US Department of Defense.

But how do devices from completely different brands understand each other using these rules? In our next technical log, we will take a much closer look at these communication protocols.