The eMule Project

1
The eMule Project

• Prepared by
• Emre Aydemir Arif Çanakoglu
• CMPE 473 Project

2
Outline

• Introduction
• Protocol
• TCP Protocol
• Client Server Communication
• Client Client Communication
• UDP Protocol
• Client Server Communication
• Client Client Communication

3
Introduction

• P2P file sharing application
• Extended from eDonkey protocol
• Based on both TCP and UDP
• Client Side
• Open source
• Server Side

4
eMule Network Diagram
Picture from www.emule-project.com
5
Protocol

• TCP Communication
• Client Server
• Client - Client
• UDP Communication
• Client Server
• Client - Client

6
Client Server Protocol

• Login Process
• Connection startup
• File Search
• Callback Mechanism

7
Login Process
LowID
HighID
8
Connection startup

• Client sends shared file list
• Server provides
• Server status
• List of servers
• Source lists

9
File Search

• Search for a file
• Get list of sources

10
Callback Mechanism

• Access from highId client to lowId client

11
Client Client Protocol

• Handshaking
• File requests
• Upload Queue Operations
• Data Transfer

12
Handshaking

• Initial message for connection
• Symmetric

13
File Requests

• Checks whether source supplies the file
• Gets available list of sources

14
Upload Queue Operations

• Upload Request
• Start Transfer
• Enter upload queue
• Reaching Top of Upload Queue
• Request part
• Cancel Transfer

15
Data Transfer

• Transfer of file parts
• eMule supports compression

16
Client Server UDP Communication

• UDP is used for
• Server status checks
• Enhanced file search
• Enhanced file-source searches
• Optional

17
Client-Client UDP Communication

• Used in checking position in source queue

18
Application

• Queue Management
• Credit System
• Download part ordering
• Corrupted download recovery

19

• Thank you...