Fundamentals
This first post will cover the basics of networking. I'm still learning, so everything I figure out along the way will end up here under the fundamentals tab. If you're a beginner too, you're in the right place, I'll try and explain these concepts as I understand them and as simply as I can.
What is a network?
A network is simply two or more connected devices used to share information. They use protocols to do this.
The internet is a network, your WiFi is a network, a network encompasses a wide range of things.
Networks are everywhere; public transport, AI datacentres and even McDonald's. As technology improves, networks become more complicated because we expect everything to just work. In reality we need new infrastructure, new techniques and sometimes even new technology.
The OSI model
The OSI (open systems interconnection model) is a way to help us understand how communication works between systems by structuring it into layers, from physical cables to applications.
The OSI layers are:
- 1.) Physical
- 2.) Data link
- 3.) Network
- 4.) Transport
- 5.) Session
- 6.) Presentation
- 7.) Application
Layer 3 is where the OSI puts routing and addressing which are the core components that allow networks to talk to each other.
Devices on a network
Devices on a network have a name and a fingerprint:
The Name (IP address): Can be changed.
The Fingerprint (MAC address): Built into hardware (though it can be spoofed).
We need both because MAC addresses are useful on local networks and as a permanent identifier while IP addresses change and are used across networks.
IPv4 and IPv6
Everything from fridges to doorbells is now online, we burned through the 4.3 billion IPv4 addresses and so we are slowly moving towards IPv6 while IPv4 continues to exist.
Our current infrastructure supports (and are built around) both, so IPv4 isn't going anywhere for a very long time.
Routing and Protocols
As previously mentioned, networks rely on protocols, protocols are basically the defined rules that devices agree on so they understand each other.
Protocols like OSPF (open shortest path first) and RIP (routing information protocol) are used to share information. They choose routes based on how busy a path is, reliability and speed.
Routing is how data figures out the best path across networks and without it, your device wouldn't be able to talk to anything outside of its network; not websites or anything else on the internet.
These are the basics that everything in networks sit on top of. Understanding what a network is, how devices identify themselves and how IPv4/IPv6 works is a solid place to start. Thanks for reading.