June 2010 Edition
Computer Science Department, University of Cape Town
| MSc-IT Study Material June 2010 Edition Computer Science Department, University of Cape Town |
The traditional information distribution model for the Internet is the client-server model, an individual client requests information from a server. The peer to peer model replaces this with a notion of equal peers between which information is transferred. In recent years, peer to peer technology has become better known because of its use to facilitate the sharing of copyrighted material which those using the P2P networks do not have a license to distribute, such as music or videos.
In some P2P networks, a server is employed to keep information on the individual peers and the files that they are sharing. This is used to locate files data on the P2P network, as well as to improve the network's efficiency.These P2P networks are sometimes referred to as hybrid P2P network. eDonkey is an example of such a hybrid system.
Read up more about the BitTorrent P2P System. A good place to start is here.
Although P2P applications have received a lot of negative comments from such organizations as the RIAA and the MPAA, P2P remains a legitimate method of data distribution. Much free-software is currently distributed using P2P methods, such as OpenOffice.org, as are other publicly available materials, such as out-of-copyright books, or media still within copyright but licenced for such distribution (such as much of the media licensed under one of the Creative Commons licenses), public-funded media such as those produced by the BBC in the UK.
Some of the advantages of P2P network include the following:
Higher Shared Bandwidth: P2P attempts to share the total available bandwidth to each peer equitably among all the peers. This effectively means that the total available bandwidth can be made use of. Compare to the client-server model where the servers bandwidth is a limiting factor. Ultimately, the P2P model encourages better use of available network resources.
Scalability: The availability and bandwidth available to share a file depends on how many peers are interested in it. The more interest there is, the more bandwidth is available. Contrast this to the client-server model which often suffers from degrading performance as the number of connected clients increases (i.e. the more interest there is). On the other extreme, unpopular files are automatically discarded from the P2P network as the number of peers sharing it is reduced.
Disadvantages of P2P network include:
Control: There is no central server that oversees the operation of the network. As such, there is little control. Managing the sharing of files could be problematic. This also encourages the sharing of questionable material such as pirated music.
As mentioned earlier, P2P is often seen as a technology that enables illegal activity. As a result of this, many P2P protocol become low-priority technologies for most companies or service provider.
Do you think that there is a place for P2P networks and technologies? Under what scenario or restriction do you think a P2P network should operate?
Read up on the legal controversy with P2P. What are your opinions on it? Do you think that it should be automatically assumed that P2P network mostly provides links to pirated material?
Have a look at other P2P networks such as Direct Connect ++ (DC++), WinMX, GnuTella and eDonkey. Compare and contrast how each network operates.