Search This Blog

Pages

Friday, January 6, 2012

P2P Software

The word P2P means peer-to-peer computing software or workloads among peers. They are very easy, equally privileged, equipotent participants in the application. They are said to form a peer-to-peer network of nodes. It make's a portion of their resources, such as processing power, disk storage or network bandwidth, directly available to other network participants, without the need for central coordination by servers or stable hosts. Peers are both suppliers and consumers  of resources, in contrast to the traditional client–server model where only servers supply , and clients consume . All these kind of software plays a vital role in work performance. The peer-to-peer application structure was popularized by file sharing systems like Napster. The concept has inspired new
 structures and philosophies in many areas of human interaction. Peer-to-peer networking is not restricted to technology,
but covers also social processes with a peer-to-peer dynamic. In such context, social peer-to-peer processes are currently
emerging throughout society. P2P has two way to define.
Structured P2P and un Structured P2P .
Structured P2P networks employ a globally consistent protocol to ensure that any node can efficiently route a search to some
 peer that has the desired file, even if the file is extremely rare. Such a guarantee necessitates a more structured pattern of overlay links. frostwire 4.20.9 can downloaded for P2P computing.
By far the most common type of structured P2P network is the distributed hash table (DHT), in which a variant of consistent hashing is
used to assign ownership of each file to a particular peer, in a way analogous to a traditional hash table's assignment of each key to a
particular array slot. The another one is an unstructured P2P network.
An unstructured P2P network is  is formed when the overlay links are established arbitrarily. Such networks can be easily constructed as a
new peer that wants to join the network can copy existing links of another node and then form its own links over time. In an unstructured
P2P network, if a peer wants to find a desired piece of data in the network, the query has to be flooded through the network to find as
many peers as possible that share the data. The main disadvantage with such networks is that the queries may not always be resolved.
 Popular content is likely to be available at several peers and any peer searching for it is likely to find the same thing. But if a peer is
 looking for rare data shared by only a few other peers, then it is highly unlikely that search will be successful. Since there is no correlation
between a peer and the content managed by it, there is no guarantee that flooding will find a peer that has the desired data.
Flooding also causes a high amount of signaling traffic in the network and hence such networks typically have very poor search efficiency.
 Many of the popular P2P networks are unstructured.
In pure P2P networks: Peers act as equals, merging the roles of clients and server. In such networks, there is no central server managing the network, neither is there a central router. Some examples of pure P2P Application Layer networks designed for peer-to-peer file sharing are gnutella (pre v0.4) and Freenet.
There also exist hybrid P2P systems, which distribute their clients into two groups: client nodes and overlay nodes. Typically, each client is able to act according to the momentary need of the network and can become part of the respective overlay network used to coordinate the P2P structure. This division between normal and 'better' nodes is done in order to address the scaling problems on early pure P2P networks. As examples for such networks can be named modern implementations of gnutella (after v0.4) and Gnutella2.
Another type of hybrid P2P network are networks using on the one hand central server or bootstrapping mechanisms, on the other hand P2P
for their data transfers. These networks are in general called 'centralized networks' because of their lack of ability to work without their
central server(s). An example for such a network is the eDonkey network (often also called eD2k).

No comments:

Post a Comment