Introduction Kad

The Kad network, short for kademilia is a a peer-to-peer network which implements the Kademlia P2P overlay protocol. The majority of users on the Kad Network are also connected to servers on the eDonkey network, and Kad Network clients typically query known nodes on the eDonkey network in order to find an initial node on the Kad network.

Overview

The kad network uses UDP to

• find sources for ed2k hashes,
• search for ed2k hashes based on keywords in the file name
• find comments and ratings on files (hashes)
• provide buddy services for firewalled (low ID) nodes.
• store locations, comments and (keywords out of) filenames.

Note that kad is not used to actually transfer the file in the ed2l network.

Kad gui

There is a KAd screen in the officiel client. This is mainly used for debug purposes. All al user should see is that the peers turn from yellow (unknown) to green (4 succes connects). If all peers in kad go red(ish) something is likely worng with the udp communication

bootstrap

You need to know first some clients to get into the network. This can be down by downloading a nodes.dat files or (simpler) starting a download via the servers and then boostrap kad with the clients found there.

search

Kad uses the hash of the first word you look for as key where to look in the kad network. SO in general is is better to look for "Moviename the" than "the Moviename".

internal working

All lookups and searches are done form the local client. No searches are ofloaded to other clients.

external links

• Distributed hash table
• [1] Kademlia: A Peer-to-peer Information System (pdf)

Based on the XOR Metric