P2P File Sharing (μTorrent)
Jeevan Mahtani, S3448872
S3448872@student.rmit.edu.au

Abstract. The purpose of this report is to identify the need for P2P file sharing applications. It also focuses on the risks and disadvantages that come along with P2P file sharing. It will then outline on one of the most commonly used P2P clients in the world that makes use of the Bittorrent Protocol which comes with a package of terminologies that are explained. The use of P2P software also tends to lead to an array of complications such as copyright infringement which will be talked about later on. 1. Introduction
We are living in an age where the advancement of technology can happen in the blink of an eye. The use of P2P applications have become part of the standard suite of PC applications.
With millions of users world-wide sharing music, video, software and pictures at their fingertips, it is no wonder why it is so commonly used today, compared to the traditional client/server file distribution system. However with that being taken into account, it comes with its disadvantages like copyright infringement issues, technical and security issues which will be covered further in this report. This report will also go to into the architecture and mechanics of the popular P2P file sharing client, uTorrent.

2. How does P2P file sharing work?

Firstly, in order to get around to the mechanics of P2P file sharing, we first have to understand what it is. It all started from the traditional method of file distribution using the client/server method. This meant that in order for files to be obtained, client computers would have to connect to a single dedicated server to in order to download files. As a dedicated server was a single source, this caused many delays in downloads and file sharing was done very slowly and became counterproductive. Thus the P2P(short for Peer-to-Peer)file sharing applications enables a client computer to act as both a client and server, assuming whatever role is efficient for the network. Files can be shared directly between systems on the network without the need of a central server. It is easy and inexpensive to set up. All that is needed is an internet connection and P2P file sharing client. It focuses on using the user’s storage, processing power and upload capacity. This is great in terms of scalability. It does not require the need to maintain a dedicated server as well as buying more storage space to contain files.

BittorentInc Co. is a world famous P2P file sharing system which focuses on sharing files through their Bittorent Protocol. A very famous client used by millions of users worldwide is μTorrent. This P2P application is owned by Bittorent, Inc and is a lightweight P2P file sharing system. It’s logo ‘μ’ stems from Greek alphabet and it stands for ‘micro’ in a unit prefix as the program is famous for using a very small amount of memory on a computer. Like other bittorrent clients, it uses the bittorrent protocol for sharing of files. A typical P2P system in the past like Napster, Kazaa and the likes ran on a centralized P2P system. This meant that it incorporated features from the client/server model in the sense that peers located their resources through the aid of a centralised server that acted as a task scheduler and coordinator for peers to establish direction connections to each other for the purpose of file sharing. It also operates on a client-server protocol over point-to-point TCP. There were some disadvantages to this model as the centralised server, like the client/server model, poses as a single point of failure if the routing tables are not available resulting in peers not being able to communicate and locate one another. The computing power and storage capabilities also need to be maintained in line with the increasing number of peers. μTorrent uses a Bittorrent protocol for their file sharing system. There are a few terms that come along with this protocol. All users have to do is download