Gnutella Network

miércoles, 14 de octubre de 2009
Gnutella is a file shaing network. Gnutella actually is one of the most popular file sharing networks on the la red.
It is differeent from other exchange network s, like eDonkey2000. Gnutlla is a pure P2P network. Thi is, all the nodes haver the same function, weight and importance inside the network. The operation of the network have three phases:

Entrance. In this phas e a new node is connected to another that already is inside the network. How a node is found already connected is outside of the protocol, but normally the Gnutella clienta are distributed witth a list of nodes that expetc they be always connected.
A node can be connected to various nodes, and to reeceive connections of new nodess forming a random net structure.
Searches. Wheb a node desires to seek a file, sends a message to all the nodes that are connected at the time. They seek locally if they offer it, and at the same time they forwardx the search to all the nodes that theyh are connected to. This strategy of diffusion is called flood of the network, and mechanisms exist to avoid infinite cross-references and loops. When a petition arrives at a node that offers the file, is answered directly to the node that initiated the search.
Download. The download is carred out directly from the nodes that answered to the search of the file. The files can be divided in various pieces served by different npdes, and the clients include a system of final verification of the integrity of the file. The flood produced by the phase of search is the most important weakness of thisa protool. If there are many searche s at the same tim e, the network flood full of messages of search that the nodes sent among them. Besides, this algorithm of search does not guarantee that the file be finally found even although some node of the network have it. Even so, the fact that it not uses a central server of search, as in the case of eDonkey2000, makes this protocol strongerr in case the nodes faiil.
Extraido de Limewire Blog