Peer-to-peer networks and how information is shared

P2p (peer-to-peer) networks consist of devices such as web servers or personal computers that participate with the same hierarchy in a communication between them. Each device (peer) can communicate with another device and there is no distinction between consumers and producers. Everyone participates in a global network.

Web server vs. p2p networks

In Fig. 1 you can see how a p2p network works. In it several computers located in different parts of the world communicate with others who share a resource of interest to both.

p2p network peer-to-peer
Figure 1. p2p network with computers connecting to each other

It has nothing to do with a centralized network. A web server works by sharing resources with the other devices in the system as can be seen in Fig. 2.

Figure 2. Centralized network, with a central computer (server)

The client is both a server

In a p2p network you are both a client (you request a resource) and a server (you host a resource that someone else may need). On the internet, p2p applications use p2p protocols that are based on the IP protocol.

Peer-to-peer networks can be used for file sharing, software distribution, electronic money (such as bitcoin), chat, distributed storage and so on.

Advantages of p2p networking

Among the advantages of this type of networks are:

  • Being decentralized entities, a computer, it is not possible for a failure in a computer to affect the rest of the network. In a system of a network one by much if a point fails, a server, the entire network fails.
  • The network is powered by resources shared by users. More resources can be obtained.
  • There is no administration in the absence of a central server.
  • They guarantee the freedom of their users. All devices have the same role.

Examples of Peer-to-peer networks

In a way it can be understood that the SMTP protocol for sending and receiving mail, can be an example of a p2p network. The domain name system can also enumerate multipleservers that are able to handle incoming email for a particular domain, increasing the reliability of the system.

Peers in file-sharing networks do not immediately know the IP addresses of other peers participating in the network and do not know which peers have which files (or parts of these files).

The files are identified by “hash” keys, which are basically fingerprints that allow the individualfiles to be uniquely identified. A file a hash fingerprint. Distributed hash tables (DHT) allow “peers” to discover which other peers are available to download all or part of a particular file.

Non-legal use

Websites like and use a kind of dictionary to identify files and share them. Files that are uploaded to these networks are often not legal. These are films, series, music, copyrighted and distributed in order to save the money it costs to acquire them. It is not a good idea to use this type of network since many times you download the file you are looking for but it comes with a parasite stuck in the form of a virus. If you use these sites protect your computer.

However, fingerprints of files can also be distributed via email, chat and social media, meaning there is no centralized system. There are also peer-to-peer networks that provide anonymity to participating peers.

Blockchain, a peer-to-peer network

As Blockchain technology emerges, immutable records can be established that are distributed across different computers to create a decentralized data network. Since these networks do not depend on a centralized computer with all the information, the risks of attacks in which all that data can be lost are reduced.  

You can see all the blocks in this direction: The blocks are going up but it is interesting to remember that they are all saved and that if you want to participate in the blockchain you can have access to the entire blockchain from its inception. All blocks have a unique hash value, a unique mince, so you can’t break the chain since the blocks are related to each other.

You can see all uncommitted strings at this address: Fig. 3 shows a comparison of one of the unconfirmed blocks of a transaction of more than  1700 BTC that equivalent at the time of making the capture to more than  63 million dollars. These uncommitted transactions have been sent to the network but have not been added to any blocks.

Figure 3. Summary of a bitcoin transaction

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