Peer-to-peer networks are the foundation of the decentralized web. Today we dive into what P2P networks are, how they differ from the popular client-server model, and the advantages of decentralized file sharing in P2P networks.

The Client-Server Model

Today the predominant type of distributed application architecture is the client-server model. In this model, the client is the service requestor, and the server is the provider of the resource or service. The client usually doesn't provide any resources to the network. Some well-known examples of the client-server model are network printing, email, and the World Wide Web.

What is a Peer-to-Peer Network?

A peer-to-peer network, on the other hand, is a distributed application architecture where each participant (peer) acts as a node. All nodes are equal, and all contribute some processing power, bandwidth, or disk space to the network. A node can make requests as well as provide a resource or service. A well-known example of a peer-to-peer network is Napster, a digital audio file-sharing system.

Decentralized File Sharing

If there is no central intermediary receiving requests and returning resources, how does peer-to-peer file sharing work? In a client-server model, servers host files, and clients download the files from those central servers. In a P2P system, peers request and share files directly. This is commonly done through a DHT or Distributed Hash Table. Information like file names, hashes, and locations are all stored in the DHT. The hashes represent keys and act as unique identifiers that help identify a specific piece of data within the DHT.

When users want to share a file, they break it down into smaller blocks and distribute those blocks across nodes in the network. Then, when users want to download the file, they query the network with the help of the DHT to find the nodes that have stored these blocks. When they find the nodes, they connect to them directly and download the file.

Advantages of Peer-to-Peer Networks

The decentralized DHT structure makes P2P networks more scalable, secure, and fault-tolerant.

Scalable: As the number of network participants and requests increases, so does the ability to handle those requests.

Secure: The network is less susceptible to malicious attacks because there is no central server hosting the data.

Fault-Tolerant: Multiple copies of data spread across many nodes in the network means that even if a few nodes go down, there will be others to take on the responsibilities of those fallen nodes and maintain data availability.

Peer-to-Peer Networks Today

Today, P2P networks are gaining in popularity.

IPFS, or the InterPlanetary File System, is a peer-to-peer network and hypermedia protocol. When a file is stored on the network, it's split into smaller chunks, hashed, and given a CID or content identifier. When users request that file, they use the CID to locate it. Users can store graphics, audio, video, plain text, and hyperlinks on IPFS.

Blockchains, like Ethereum and Bitcoin, are also P2P networks. They use a distributed ledger to track transactions in a network without a central authority. The blockchain is tamper-proof and immutable, with many use cases - from storing ownership records to distributing cryptocurrencies.

In conclusion, peer-to-peer networks are a resilient and decentralized way to share and distribute files, collaborate with other users, and distribute compute power and resources.

Interested in learning more about the decentralized web? Check out our posts on content addressing and DWeb principles on our blog.