Networking Fundamentals Pt.1
| Network make-up | Endpoint & network devices | Physical network | Logical network data |
What is a network?
A network, in the technological sense, is made up of a collection of endpoint devices (laptops, desktops, smartphones, smart-TVs, etc…). These devices are connected together in a certain way to allow the passage of network data to take place. The way these devices are physically or wirelessly connected to one another is referred to as the “Network Topology”. You can think of a network topology as a map or blueprint that is used to show or plan how a network is going to be built or connected, but for now that is not our topic.
You can also think of a network as a train track, and the data that passes through as the train itself — without the existence of train tracks (the network infrastructure) there is no way the train will be able to make the journey from it’s origin (Point A) to it’s destination/endpoint (Point B).
For example when you opened this page the web-browser on your device acted as a client and requested specific data to be sent over the network, this data was sent over a huge network (the Internet) — after a successful request has been made the web-server acted as a server and delivered the data requested by your web-browser to it’s final destination or endpoint. Furthermore, you can also say that the server (while receiving the request) was at that point in time an endpoint device as well.
Now that you have a clear definition on what a network is and what it’s made of, we can move on to describe the two important and fundamental parts/sides of a network the physical (endpoint & network devices) & logical (network data) sides.
The physical side of a network consists of endpoint devices and network devices. Broadly speaking, a network device is any device that is able to communicate to other devices on a network through its built-in “NIC” (Network Interface Card/Controller). Usually a “NIC” is either soldered onto your motherboard with an Ethernet port or Wireless antenna sticking out the back (or both) or is connected to the motherboard into your “PCI” or “PCI-e” slots. Bottom line, is that these Network devices/components are physical in nature and consist of routers, mobile/cell towers, switches/bridges, hubs, Ethernet cables, RJ45 connectors, etc… Such is the nature of the physical side of a network.
On the other hand, the logical side of a network, or what I’d like to personally refer to as the “abstract” side, generally consists of the network data that we cannot see and touch. Eventually, this data makes its way to (or from) the wire or the endpoint device itself (the physical part).
To put it simply, the data traveling in the wire and inside your computer is logical in nature and thus why I refer to it as the abstract. Another way to look at it would be that that the logical part (abstract) is the software-base of network communication. This part of network communication is the part you should be concerned about the most as an ethical hacker. You can think of this part as the control panel inside a train without which you cannot control, steer, and stop a train.
Furthermore, the logical side of a network consists of data that is broken down and divided into layers (OSI & TCP/IP Models) — each layer is responsible for a specific but also very important task. In addition, almost every layer is known for its own protocols that have a small role to play, but also come together to accomplish the main role of successful delivery or communication that networks are built to accomplish.
For example, IP or “Internet Protocol” is the most popular protocol out there and it belongs to layer 3 (Network layer) of the OSI model. Almost anyone who hasn’t been living under a rock has heard of it. IP is responsible for network addressing which enables network routing. Another protocol would be TCP “ or “Transmission Control Protocol”. We will dive into more detail about these protocols in part 2 of this article.
As promised, I’ve tried my best to make the above fundamentals as clear as day. However, if you‘re having any trouble fully understanding the above simple concepts, do not be troubled. Things will start to come together as we move on. Also, don’t be shy to re-read the article or even do a quick and dandy google search to clear up any details you have not absorbed. Finally, don’t forget to:
Try Harder!
Now that you’ve had a sneak peak of what’s to come in part 2 of this article I hope you will be joining me in the next one. Cheers!
~Any1
