[AI] Peer-to-Peer (P2P)

vishnu ramchandani vishnuhappy at yahoo.com
Mon Feb 18 03:38:09 EST 2008

Peer-to-Peer (P2P)
contributor : Baskar P (an employee of MphasiS
Software Services)
What is Peer-to-Peer architecture?
Often referred to simply as peer-to-peer, or
abbreviated P2P, peer-to-peer architecture is a type
of network in which each workstation has equivalent
capabilities and responsibilities. This differs from
client/server architectures where some computers are
dedicated to serving the others. Peer-to-peer networks
are generally simpler but they usually do not offer
the same performance under heavy loads. The P2P
network itself relies on computing power at the ends
of a connection rather than from within the network
P2P is often mistakenly used as as a term to describe
one user linking with another user to transfer
information and files through the use of a common P2P
client to download MP3s, videos, images, games and
other software. This, however, is only one type of P2P
networking. Generally, P2P networks are used for
sharing files, but a  P2P network can also mean Grid
Computing or Instant messaging.

What are its types?
Peer-to-peer networks come in three flavors. The
category classification is based on the network and
• Collaborative Computing
Also referred to as distributed computing, it combines
the idle or unused CPU processing power and/or free
disk space of many computers in the network.
Collaborative computing is most popular with science
and biotech organizations where intense computer
processing is required. Examples of distributed
computing can be found at GRID.ORG where United
Devices is hosting virtual screening for cancer
research on the Grid MP platform. This project has
evolved into the largest computational chemistry
project in history. United Devices has harnessed the
power of more than 2,000,000 PCs around the world to
generate more than 100 teraflops of power. Most
distributed computing networks are created by users
volunteering their unused computing resources to
contribute to public interest research projects.
• Instant Messaging
One very common form of P2P networking is Instant
Messaging (IM) where software applications, such as
MSN Messenger or AOL Instant Messenger, for example,
allow users to chat via text messages in real-time.
While most vendors offer a free version of their IM
software others have begun to focus on enterprise
versions of IM software as business and corporations
have moved towards implementing IM as a standard
communications tool for business.
• Affinity Communities
Affinity communities is the group of P2P networks that
is based around file-sharing and became widely known
and talked about due to the public legal issues
surrounding the direct file sharing group, Napster.
Affinity Communities are based on users collaborating
and searching other user's computers for information
and files.
Further Info:
How Peer-to-peer File-sharing Clients Work:-
Once you have downloaded and installed a P2P client,
if you are connected to the Internet you can launch
the utility and you are then logged into a central
indexing server. This central server indexes all users
who are currently online connected to the server. This
server does not host any files for downloading. The
P2P client will contain an area where you can search
for a specific file. The utility queries the index
server to find other connected users with the file you
are looking for. When a match is found the central
server will tell you where to find the requested file.
You can then choose a result from the search query and
your utility when then attempt to establish a
connection with the computer hosting the file you have
requested. If a successful connection is made, you
will begin downloading the file. Once the file
download is complete the connection will be broken.
A second model of P2P clients works in the same way
but without a central indexing server.  In this
scenario the P2P software simply seeks out other
Internet users using the same program and informs them
of your presence online, building a large network of
computers as more users install and use the software.
P2P Security Concerns:-
One major concern of using P2P architecture in the
workplace is, of course, network security. Security
concerns stem from the architecture itself. Today we
find most blocking and routing handles by a specific
server within network, but the P2P architecture has no
single fixed server responsible for routing and
requests. The first step in securing your P2P network
is to adopt a strict usage policy within the
workplace. In securing your network against attacks
and viruses there are two main strategies where focus
is on controlling the network access or the focus is
put on controlling the files. A protocol-based
approach is where system administrators use a software
or hardware solution to watch for and block intrusive
network traffic being received through the P2P
clients. A second method of protection is a software
solution which would provide file surveillance to
actively search for files based on their type, their
name, their signature or even their content.
P2P at Work:-
P2P is not only popular with home users but many small
business have come to rely on this cost-effective
solution for sharing files with co-workers and
clients. P2P promotes the ease of working together
when you're not physically located in the same office.
In just seconds updated files and data can be shared
with peers and confidential files can be blocked for
security. Additionally, companies can also block
access to Internet music and video files to assist in
maintaining a work-oriented P2P network. Not only does
this keep the company free and clear from legal issues
regarding music downloading and sharing but it also
keeps the corporate bandwidth usage down.
What is its usefulness?
An important goal in peer-to-peer networks is that all
clients provide resources, including bandwidth,
storage space, and computing power. Thus, as nodes
arrive and demand on the system increases, the total
capacity of the system also increases. This is not
true of a client-server architecture with a fixed set
of servers, in which adding more clients could mean
slower data transfer for all users.
The distributed nature of peer-to-peer networks also
increases robustness in case of failures by
replicating data over multiple peers, and -- in pure
P2P systems -- by enabling peers to find the data
without relying on a centralized index server. In the
latter case, there is no single point of failure in
the system.
When the term peer-to-peer was used to describe the
Napster network, it implied that the peer protocol was
important, but, in reality, the great achievement of
Napster was the empowerment of the peers (i.e., the
fringes of the network) in association with a central
index, which made it fast and efficient to locate
available content. The peer protocol was just a common
way to achieve this.
While the original Napster network was a P2P network,
the newest version of Napster has no connection to P2P
networking at all. The 2008 version of Napster is a
subscription based service which allows you to
download music files legally.

Further References
All About Peer-To-Peer Architecture: 

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