Peer to Peer The Network

introduction

The peer to peer, abbreviated to « P2P »,is a set of techniques used to establish a data exchange system with multiple users together.Unlike generally accepted ideas, the peer-to-peer is not just for the exchange of music, videos and software. Many companies or social networks make daily use of it and in various ways.

introduction

A few examples of using P2P: Flash technology developed by Adobe Systems now

integrates a P2P system for exchanging video streams.

The microblogging platform Twitter uses the P2P for updates.

The Free Jamendo music distributor sends its 36,000 albums through the BitTorrent P2P network.

The BOINC* distributed computing platform is based on P2P to access additional computing power, four times more than the most powerful supercomputers with one objective, to advance science, economics, art, etc.

*BOINC acronym for Berkeley Open Infrastructure for Network Computing is a distributed computing platform developed by the University of Berkeley,

The advantage of a "peer-to-peer”system is having a network without costly servers and which provides expansive bandwidth between users to centralize and make files available.Exchanges are transferred directly from one computer to another.Unfortunately, although the peer-to-peer is an inexpensive tool for commissioning, it is too quickly assimilated with piracy and illegality.

The Architecture of p2p networks: “The centralized network”

There are several types of P2P network.First type: the centralized network, which relies on one or many servers allowing all users contact with each other, identifying each of them (name, IP address) and all shared resources available using an indexing system called the distributed hash table (DHT: Distributed Hash Table).

The Architecture of p2p networks: “The centralized network”

The distributed hash table theoretically prevents the multiplication of unnecessary files. In simplified terms, this technique allows you to associate a unique identifier (hash) for each pair, each keyword and each file based on its content and not its name.The advantage of the centralized network architecture is to provide a comprehensive overview of the network. In return, this network is now less used (except for certain private networks), and just turn off the server to destroy the P2P network.

The Architecture of P2P networks: “The distributed network”

The distributed network is not based on any server.Every PC user plays the role of a client / server. They are connected together to relay PC to PC queries.The technique of the distributed hash table is still used to avoid duplicates.However, it is now users that support the server role to ensure proper functioning of hash tables.

The Architecture of p2p networks: “The distributed network”

Unlike the centralized network (left), the distributed network, also known as a decentralized network, is not based on any server.Each client user automatically becomes a server.

The Architecture of P2P networks: “The distributed network”

The advantage of this type of architecture is that it provides a robust network because each PC can be transformed into a client / server, the loss of one or more of them will not be enough to stop the network.However traffic is more important and file search will take much more time, every request is sent to every user, and each of them does the same.

The Architecture of P2P networks: “The hybrid network (Static & Dynamic)”

The hybrid system is a little more complex to implement and combines both centralized and distributed networks.This type of network uses several servers, they are numerous enough not to result in the loss of the network in case of the loss or shutdown of a server (in theory).In this way, each server is connected to other servers on the model of the distributed architecture.If a user looks for a file not indexed by the server to which it is attached, then it passes the request to another server.This allows you to benefit from better bandwidth by reducing traffic requests.

The Architecture of P2P networks: “The hybrid network (Static & Dynamic)”

Hybrid networks are networks which are not completely centralized,not completely distributed

The Architecture of p2p networks: “The hybrid network (Static & Dynamic)”

Two types of hybrid networks exist: static and dynamic hybrid networks. In the first case, the client PC can become a server if the

user wishes. It is on this type of network that eDonkey works.

In the second case, the client software can automatically become a server under certain conditions. It’s notably the case of Limewire, GNUtella and Fasttrack.

The client software

In general, P2P allows each user who downloaded the data he wants to become a server automatically in turn, and then serve other users.But to avoid any constraints on the size of the shared file and the bandwidth of the source, the latest P2P software supports multi-source transfer.This can download the same file in parallel from all existing sources and, as a result, increase download speed.For this, each shared file is first divided into multiple blocks.But thanks to the hash table, P2P software detects blocks on each source to identify which source has been chosen according to the missing blocks.

The client software

Developed by Bram Cohen, BitTorrent is based on the multi-source download. But unlike P2P, the BitTorrent network first allows each user, or even, (soon to become) server to share files even before downloading them in full.The Torrent is characterized by the leechers (people who download and share files blocks with other users), and the seeders who have an entire file to share. This set of leechers and seeders is called swarm.

The client software

Peer to Peer The Network

https://www.youtube.com/watch?v=C5UWEWcGJgs

Thank you for your attention and have fun on P2P networks