Difference between a distributed and a decentralized network

Question

I thought I knew the difference but now I got myself a little bit confused and I'm not sure anymore. So I thought I could ask you. Can a distributed network be centralized and also de-centralized? Or does a distributed network always means that there is no central node? I thought that a distributed network is also decentralized but after research I doubt that now.

I hope someone can help me thank you!

Answer 1

First take a look at this description about distributed system:

A distributed system is a network that consists of autonomous computers that are connected using a distribution middleware. They help in sharing different resources and capabilities to provide users with a single and integrated coherent network. (Distributed System)

And also this, about decentralized system:

"A decentralized system is one which requires multiple parties to make their own independent decisions" In such a decentralized system, there is no single centralized authority that makes decisions on behalf of all the parties. Instead each party, also called a peer, makes local autonomous decisions towards its individual goals which may possibly conflict with those of other peers. Peers directly interact with each other and share information or provide service to other peers. (Decentralization)

But let me provide a simple example.

A distributed chat system has several servers. Each client connects to one of these servers and servers then pass data between each other to give a proper result to the user and also deliver the message to another user (who btw is also connected to this distributed system). So this could easily be done with a single server, but what about the load balancing and resources? Few reason we go for distributed designs are

1. resource sharing
2. scalability
3. high-availability

While in same example, a chat system that is decentralized, relies on its own users to make peer to peer connections to each other and then send message. Each node has all the logic to serve the messaging service and to send messages. There is no middle-ware in charge of delivering messages or persisting them.