PEER TO PEER COMPUTING

(1)

PEER TO PEER COMPUTING

Meenu Chandel*

ABSTRACT

This research paper is written to describe Peer-to-Peer systems built around Integration of

technologies from the Peer-to-Peer. Peer to Peer is a good technology that provides large source of

geographical resource and also provides structured and secured resource. By using this technology,

researcher and scientist try to create solution for faster data processing and omit the geographical

limitations.

(2)

GE-IJER(Dec 2013)

ISSN:2321-1717

GE-International Journal of Engineering Research

www.gejournal.net 2

INTRODUCTION

Peer means a host computer. When many hosts are connected through internet to share files,

computing capabilities, networks, bandwidth and storage, it calls peer to peer networking

system.

The term “peer-to-peer” (P2P) refers to a class of systems and applications that employ

distributed resources to perform a function in a decentralized manner. With the pervasive

deployment of computers, P2P is increasingly receiving attention in research, product

development, and investment circles. Some of the benefits of a P2P approach include:

improving scalability by avoiding dependency on centralized points; eliminating the need for

costly infrastructure by enabling direct communication among clients; and enabling resource

aggregation.

Peer to peer networks first made their apparition in the late 70's early 80's with USENET and

FidoNet. At that time there was a strong need for decentralization in network architecture. On

the Internet, peer-to-peer (referred to as P2P) is a type of transient Internet network that

allows a group of computer users with the same networking program to connect with each

other and directly access files from one another's hard drives.

In the Peer-to-Peer model all computers, or nodes, share resources. Opposed to the

client/server model, all clients on the P2P model share resources including bandwidth,

computing capability, and data. As the number of clients increase so does the capability of

the network. While in the client/server model more users would decrease the efficiency of the

network.

Peer-to-peer (abbreviated to P2P) refers to a computer network in which each computer in the

network can act as a client or server for the other computers in the network, allowing shared

access to files and peripherals without the need for a central server. P2P networks can be set

up in the home, a business or over the Internet. Each network type requires all computers in

the network to use the same or a compatible program to connect to each other and access files

and other resources found on the other computer. P2P networks can used for sharing content

such as audio, video, data or anything in digital format.

Peer-to-peer is a very easy to use network. It really facilitates team work and the way it is

designed makes it real secure due to the fact that all the data are shared among many peers.

Also, Peer-to-Peer is a communications model in which each party has the same capabilities

and either party can initiate a communication session. Other models with which it might be

(3)

In a client/server network architecture all the data are stored in a server. If something happens

to the server there is a risk of loss of data. In the client/server model the server program

responds to requests from a client program, and the peer-to-peer model either of the two

devices involded (client) can initiate a communication session.

The first peer-to-peer application was the file sharing system Napster, originally released in 1999. The concept has inspired new structures and philosophies in many areas of human

interaction. Peer-to-peer networking is not restricted to technology; it also covers social

(4)

GE-IJER(Dec 2013)

ISSN:2321-1717

ARCHITECTURE OF P2P SYSTEMS

Peer-to-peer systems often implement an abstract overlay network, built at Application

Layer, on top of the native or physical network topology. Such overlays are used for indexing

and peer discovery and make the P2P system independent from the physical network

topology. Content is typically exchanged directly over the underlying Internet (IP)

network. Anonymous peer-to-peer systems are an exception, and implement extra routing

layers to obscure the identity of the source or destination of queries.

The P2P overlay network consists of all the participating peers as network nodes. There are

links between any two nodes that know each other: i.e. if a participating peer knows the

location of another peer in the P2P network, then there is a directed edge from the former

node to the latter in the overlay network. Based on how the nodes in the overlay network are

linked to each other, we can classify the P2P networks as unstructured or structured.

In structured peer-to-peer networks, peers (and, sometimes, resources) are organized

following specific criteria and algorithms, which lead to overlays with specific topologies and

properties. They typically use distributed hash table-based (DHT) indexing, such as in

the Chord system (MIT).[2]

Unstructured peer-to-peer networks do not impose any structure on the overlay networks.

Peers in these networks connect in an ad-hoc fashion.[3] Ideally, unstructured P2P systems

would have absolutely no centralized system, but in practice there are several types of

unstructured systems with various degrees of centralization. Three categories can easily be

seen.

In pure peer-to-peer systems the entire network consists solely of equipotent peers. There is

only one routing layer, as there are no preferred nodes with any special infrastructure

function.

Hybrid peer-to-peer systems allow such infrastructure nodes to exist, often called super

nodes.[4]

In centralized peer-to-peer systems, a central server is used for indexing functions and to

bootstrap the entire system. Although this has similarities with a structured architecture, the

connections between peers are not determined by any algorithm.

A pure P2P network does not have the notion of clients or servers but only equal peer nodes

that simultaneously function as both "clients" and "servers" to the other nodes on the

network. This model of network arrangement differs from the client–server model where

(5)

Structur Structure efficientl rare. Suc common of consis analogou term DH structure Distribu Distribut

lookup s

participat DHTs fo distribute Unstruc An unstr Such net copy exis P2P netw be floode main dis Popular c

to find th

then it is

a peer an

has the d

and henc

red systems ed P2P netw

ly route a se

ch a guarante

type of st

stent hashing

us to a traditi

HT is commo

implemente

ted hash tab ted hash tabl

service simil

ting node ca

orm an infr

ed networks

ctured syste ructured P2P

tworks can b

sting links o

work, if a pe

ed through t

sadvantage w

content is lik

he same thin

highly unlik

nd the conten

desired data.

ce such netw

works employ

earch to som

ee necessitat

tructured P2

g is used to

ional hash's

only used to

ed on top of

bles

les (DHTs) a

lar to a hash

an efficiently

rastructure t

that use DH

Distributed

ems

P network is

be easily co

of another no

eer wants to

the network

with such n

kely to be av

ng. But if a p

kely that sea

nt managed

Flooding al

orks typicall

y a globally

me peer that

tes a more st

2P network

assign owne

assignment

o refer to th

a structured

are a class o

h table: (key

y retrieve the

that can be

HTs

d hash tables

s formed wh

onstructed as

ode and then

find a desir

k to find as

networks is

vailable at se

peer is lookin

arch will be

by it, there i

lso causes a

ly have very

y consistent p

has the desi

tructured pat

is the dist

ership of ea

of each key

he structured

overlay.[6]

f decentraliz

y, value) pa

e value assoc

used to bu

s

hen the ove

s a new pee

n form its ow

ed piece of

many peers

that the qu

everal peers

ng for rare d

successful.

is no guaran

high amoun

y poor search

protocol to

ired file, eve

ttern of over

tributed (DH

ch file to a

to a particu

d overlay, in

zed distribut

airs are store

ciated with a

uild peer-to

erlay links ar

er that wants

wn links over

data in the n

as possible

ueries may

and any pee

data shared b

Since there

ntee that floo

nt of signall

h.

ensure that

en if the file

rlay links. By

HT), in whi

particular p

ular array slo

n practice, D

ted systems t

ed in the D

a given key.

o-peer netwo

re establishe

s to join the

r time. In an

network, the

e that share

not always

er searching

by only a few

is no correla

oding will fin

ing traffic in

any node ca

e is extremel

y far the mo

ich a varian

peer, in a wa

ot. Though th

DHT is a dat

that provide

DHT, and an

orks. Notab

ed arbitrarily

e network ca

n unstructure

e query has t

the data. Th

be resolve

for it is likel

w other peer

ation betwee

nd a peer th

(6)

GE-IJER(Dec 2013)

ISSN:2321-1717

Advantages

In P2P networks, clients provide resources, which may include bandwidth, storage space, and

computing power. This property is one of the major advantages of using P2P networks

because it makes the setup and running costs very small for the original content distributor.

As nodes arrive and demand on the system increases, the total capacity of the system also

increases, and the likelihood of failure decreases. If one peer on the network fails to function

properly, the whole network is not compromised or damaged.

1. P2P networks of today have seen an enormous increase of their security and file

verification mechanism.

2. It is easy to install and so is the configuration of computers on this network,

3. All the resources and contents are shared by all the peers, unlike server-client architecture

where Server shares all the contents and resources.

4. P2P is more reliable as central dependency is eliminated. Failure of one peer doesn’t affect

the functioning of other peers. In case of Client –Server network, if server goes down whole

network gets affected.

5. There is no need for full-time System Administrator. Every user is the administrator of his

machine. User can control their shared resources.

6. The over-all cost of building and maintaining this type of network is comparatively very

less.

WEEKNEES

P2P networks, however, are more unreliable in sharing unpopular files because sharing files

in a P2P network requires that at least one node in the network has the requested data, and

that node must be able to connect to the node requesting the data.

1.In this network, the whole system is decentralized thus it is difficult to administer. That is

one person cannot determine the whole accessibility setting of whole network.

2.Securty in this system is very less viruses, spywares, trojans, etc malwares can easily

transmitted over this P-2-P architecture.

3.Data recovery or backup is very difficult. Each computer should have its own back-up

system

4.Lot of movies, music and other copyrighted files are transferred using this type of file

transfer. P2P is the technology used in torrents.

5.Harmful data can also be distributed on P2P networks by modifying files that are already

being distributed on the network.

(7)

Different applications of P2P networks enable users to share the computation power

(distributed systems), data (file-sharing), and bandwidth (using many nodes for transferring

data).

Instant Messaging

The first adopted usage of P2P applications was instant messengers. Back in the early days of

the internet, people used gopher and IRC servers for communication. These technologies

could only handle a certain number of users online at the same time, so there were delays for

communicating whenever the server was approaching its limits. However the use of P2P

changed the whole idea of IM. The bandwidth was shared between users, enabling faster and

more scalable communication.

File Sharing

The peer-to-peer file sharing era started with Napster and continued with much more

powerful applications such as Kazaa, Gnutella. These programs brought P2P into the

mainstream. Although some P2P file-sharing applications have stopped because of legal

issues, there is still a high demand in the industry. Now Napster has gone 'legit' and there are

new media P2P apps like Joost(P2P TV) arriving on the scene. We will discuss this more in

the next post.

Collaborative Community

Document sharing and collaboration is really important for a company. This issue has tried to

be solved by internal portals and collaboration servers. However the information has to be up

to date and with portals this wasn't always possible. Collaboration with P2P broke that

barrier, by using peoples computer resources instead of a centralized server.

Groove is a software with P2P capabilities which was acquired by Microsoft in April 2005.

Groove is now offering Microsoft Office based solutions, mainly using P2P for document

collaboration. It also allows the usage of instant messaging and integration with some video

conferencing solutions. It provides user and role based security, which is one of the most

important aspects of P2P for an organization. Groove is also a Äúrelay serverÄ? to enable

offline usage.

IP Telephony

Another major usage of P2P is IP telephony. IP telephony revolutionaries the way we use the

internet, enabling us to call anywhere in the world for free using our computers.

Skype is a good example of P2P usage in VoIP. It was acquired by eBay in 2005. Skype

(8)

GE-IJER(Dec 2013)

ISSN:2321-1717

CONCLUSION

In many ways Peer to Peer grid technology has proven that it is the best technology to work

over the internet on commerce, businesses, educations, science, researches, and many other

projects by eliminating the geographical and economical limitations of the resources. By

using this technology now, we can finish our projects in short time and without depending on

one main server or super computers. Still, we need to concentrate on security and privacy

issues and data losses through the internet connections. We can develop a great Peer to Peer

Grid computing by paying attention to find solutions for its issues. Peer to peer networks are

good to connect small number (around 10) of computer and places where high level of

security is not required. In case of business network where sensitive data can be present this

type of architecture is not advisable or preferred.

REFERENCES

1. http://www106.ibm.com/developerworks/library/gr-heritage/

2. http://www.bitd.clrc.ac.uk/Activity/CORAS;Presentation=PAPER;

3. http://www.bitd.clrc.ac.uk/Activity/iTRUST;Presentation=PAPER;;

4. http://www.googal.com

5. http://www.pervasive.iu.edu/researchptl.html

6. www.pree-to-peercomputing.com