Another concept you need to be familiar with to understand Blockchain is the concept of a P2p distributed network. This is the physical architecture that allows Blockchain to work and provides a blockchain with redundancy.
The P2P in P2P distributed network stands for peer to peer, indicating a network comprised of peers. What do I mean by that? The majority of computer networks in place right now are what is known as Server/Client networks.
In the picture below, the center square represents a server, with the boxes around it representing nodes (or in your case, the computer/tablet/phone you are reading this on). When you want to view a web page, you send a request from your node to a server. The server will then respond with the requested information.
While this works well, it does have some drawbacks. First off, since the server is central point of communication and the holder of all the information (webpages, databases, etc), if the server goes down, the network is essentially dead. This is the whole idea behind one of the more successful methods of cyber attack – the Denial of Service in which a server is targeted with more traffic than it can handle, shutting it down. You will often see it called a Distributed Denial of Server of DDoS as in order to hit the server with enough traffic to break it, hackers use multiple computers synced to deliver enough requests to the server all at the same time, overwhelming it. In other words, the attack is “distributed” across multiple computers.
Blockchain does not use a server client approach. Instead it uses a P2p or peer to peer network to function. In a peer to peer, the nodes (laptops, tablets, etc) all talk directly to each other. Instead of a server holding all the information, the data that makes up the blockchain is instead distributed across all the different nodes. So the more nodes that are part of the blockchain, the more copies of it that exist.
This works great for redundancy as even if you took out a couple of nodes in the network, it would still be able to function as normal. And as we will see a future lesson, even if you were able to hack in and corrupt the blockchain in one of the nodes, the fact that copies of it exist on all the other nodes protect it from corruption.
This architecture is also at the heart of philosophy around crypto-currencies like BitCoin. Unlike traditional banking systems that have centralized management, BitCoin is programmed with a deflationary policy that no one person (or group of person) can control. This is an interesting economic experiment unfurling before all of us. And I for one am curious to see how it plays out. While organizations like the Fed (in the United States) have done a relatively good job of keeping the US dollar strong, poor centralized economic management has spelled disaster in countries like Venezuela and Zimbabwe.
I’ll discuss more on the economic theory behind BitCoin in later lessons. It is enough for now for you to know that the P2P decentralized nature of the network is all part of the design in ensuring no one person can make such drastic changes.
If you want to learn more about networks and how they interact, here are some further resources:
https://www.khanacademy.org/computing/computer-science/internet-intro
https://www.techsoup.org/support/articles-and-how-tos/networking-101-concepts-and-definitions
http://www.tomshardware.com/reviews/local-area-network-wi-fi-wireless,3020.html
