The World of Peer-to-Peer (P2P)/Networks and Protocols/eDonkey

eDonkey

eDonkey the original client for the eDonkey network (also known as eDonkey2000 network or eD2k), was created and managed by MetaMachines (Sam Yagan and Jed McCaleh) based on the city of new York. It had a stable P2P community and the protocol was older than BitTorrent it was created in 2002 shortly after the closing of Napster and competed with the FastTrack network. In June of 2005, the entertainment industry gained a victory in the Supreme Court (USA) that stated that every file-sharing developer could be sued for copyright infringement if they induced such behavior. In September 2005 the Recording Industry Association of America (RIAA) sent several commercial P2P developer cease and desist letters including to MetaMachines and with no funds to battle the interpretation of the Supreme Court decision, Sam Yagan conceded defeat as he testified to the United States Senate Judiciary Committee.

"...I am not here as an active participant in the future of P2P, but rather as one who has thrown in his towel and with no interest in replaying past issues..."
--Sam Yagan

On September 11, 2006 users could not get the eDonkey2000 client software, in September 12, 2006 MetaMachines settles for $30 Million (US) and the agreement closes any avenue MetaMachines had in dealing with any P2P technology in the future...

The eDonkey networks is centralized (as it depends on serves) to provide decentralized sharing of content (not stored on the servers), there are still many software implementations that support the network the most popular is eMule.

Protocol

"The eMule Protocol Specification" ( http://sourceforge.net/project/showfiles.php?group_id=53489&package_id=145950 ) by Yoram Kulbak and Danny Bickson DANSS (Distributed Algorithms, Networking and Secure Systems) Lab - School of Computer Science and Engineering - The Hebrew University of Jerusalem, Israel - January 20, 2005, PDF document provided by the Emule Project.

Kademlia

Started as the Overnet project by Jed McCaleb, the creator of eDonkey2000 to overcome the need of servers. Overnet implemented the Kademlia algorithm. In late 2006, Overnet and all Overnet-owned resources were taken down as a result of legal actions from the RIAA and others. However, since the core of Overnet is decentralized, Overnet clients are still able to function with limited functionality.

The KadC library (http://kadc.sourceforge.net/ ) provides an OpenSource C library to publishing and retrieving records in Kademlia-based Distributed Hash Tables.

A some what old paper named Kademlia: A Peer-to-peer Information System Based on the XOR Metric by Petar Maymounkov and David Mazières can also be a source of information about the protocol.

The network is now known as Kademlia and is supported by many of the implementations of the old eDonkey/Overnet clients, especially by the eMule project. Kademlia is a research effort to implement a full-featured peer-to-peer system based on the XOR metric routing. Of special interest are the objectives for efficient data storage and query; anonymity; network, content and user security and authentication.

eMule content database

eMule mascot.

( http://content.emule-project.net/ ) a service provided by the eMule project team for the eDonkey2000 and Kad network users, to make free content available for download and easy to find. The content database has been on line since around new years 2004.

Software Implementations

eMule ( http://www.emule-project.net/ ) a filesharing software implementation based on the eDonkey2000 network but offers more features than the standard client, open source C++/MFC and windows only, licensed under GPL ( http://sourceforge.net/projects/emule/ )
Xmod ( http://savannah.nongnu.org/projects/x-mod/ ) The Xmod is a Project is based on the eMule Client, OpenSource under the GPL.
xMule ( http://www.xmule.ws/ ), the X11 Mule, intended to bring a clone of eMule to virtually all the major Unix platforms, with a particular emphasis on Linux. C++ using wxWidgets for the GUI released as OpenSource under the GPL.
MLdonkey ( http://mldonkey.sourceforge.net ) is a multi-platform, multi-network P2P implementation. It supports several large networks such as eDonkey, Overnet, Kademlia, Bittorrent, Gnutella (Bearshare, Limewire, etc.), Gnutella2 (Shareaza), or Fasttrack (Kazaa, Imesh, Grobster). Networks can be enabled or disabled. Searches are performed in parallel on all enabled networks. For some networks, each file can be downloaded from multiple clients concurrently.
AMule ( http://www.amule.org/wiki/ ) this project is based on the eMule Client, using also C++ but also wxWidgets and crypto++. Opensource under the GPL, currently supports Linux, FreeBSD, OpenBSD, Windows, MacOS X and X-Box on both 32 and 64 bit computers.
eMule Bowlfish ( http://pwp.netcabo.pt/DeepSea/ ), another eMule based project that aims to provide an restricted Network solution.
Hydranode ( http://hydranode.com/ ) a modular, plugin-driven peer-to-peer client framework which is designed with true multi-network downloads in mind (Support for eDonkey2000 and Bittorrent networks). OpenSource under the GPL, supports Linux and Windows.
Shareaza ( multi-protocol, referenced on the Gnutella section )