Peer-to-Peer file sharing system

Project Background

This P2P file sharing system project is the first project for the University of Melbourne’s COMP90015 Distributed System Subject. This system is using a hybrid client/server and peer-to-peer architecture. In this architecture there are two components:

Index Server : a process that acts as a server, to manage an index of files and IP addresses of file sharers
Peer : a process that acts as both a client to an Index Server, and as a server for sharing file data with other Peers

Key technologies

Java
Concurrency
TCP/IP Connection
Distributed System

Server

The Server accepts TCP connections and uses a request-per-connection session protocol as defined in Server.java. The session consists of a welcome message, an authentication step, and then a single request using a request-reply protocol.

WelcomeMsg : sent by the server as the first message on any new connection
AuthenticateRequest : sent by the client to request authentication
AuthenticateReply : sent by the server in response to a AuthenticateRequest

Following the handshake, a single request can be made, using one of the following messages:

ShareRequest : allows the Peer to provide the Index Server with details of a file to index
DropShareRequest : allows the Peer to request the Index Server to remove the details of a file that it previously indexed
SearchRequest : allows the Peer to search for files on the Index Server
LookupRequest : allows the Peer to obtain a list of Peers that are sharing a given file

Each of the requests above has an accompanying reply message from the Server.

The server can be run locally or deployed to run on a cloud server. You can specify the IP address and port number of the server when you start the server. If you don’t, the default IP address is localhost and the port number is 3200.

Peer

The Peer uses a terminal text GUI that is best run in a UNIX/Linux terminal. When the application runs the h key can be pressed for help on using the application.

In the peer GUI, there are range of features that users can operate:

File Share : allows the Peer to share a file in the local computer
Search : allows the Peer to search files that have been shared by other peers
Config : allows the Peer to config the server’s IP address that they want to connect
Download : allows the Peer to download the files that was searched

Key achievement

The final score for this project was 9.5/10. The system was able to successfully share a one or two gigabyte sized video while successfully downloading and playing it within the allotted time.