Il documento esplora il concetto di peer-to-peer (P2P) come architettura di rete distribuita, analizzando vantaggi, debolezze, questioni legali e di sicurezza. Si discute dell'evoluzione storica del P2P, diverse architetture di rete e le applicazioni in ambito di condivisione file e potenza computazionale. Infine, si considerano gli sviluppi futuri, evidenziando problemi tecnici e normativi che ne limitano l'adozione.

1. Università degli Studi di Trento
Facoltà di Economia
Corso di Laurea Specialistica in Net-Economy
Corso di Telecomunicazioni
Nicola Cerami

2. Index
 What is P2P and  Security and
History Privacy issues
 Architecture of  Economic issues
P2P systems  Applications of
 Advantages and use
weaknesses of  Future
P2P Networks developments
 Legal issues
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3. What is Peer-to-Peer-1
 Is any distribuited network architecture
composed of partecipants that make a portion
of their resources, such as:
 Processing power
 Disk storage
 Network bandwith
 Directly available to other network
partecipants
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4. What is Peer-to-Peer-2
 Each Peer (usually workstation) has
equivalent capabilities and responsabilities
 Peer are both suppliers and consumers of
resources, in contrast to the traditional client-
server model
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5. What is Peer-to-Peer-3
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6. What is Peer-to-Peer-4
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7. History
 1999: first software dedicated to P2P is
Napster (Fanning)
 Spread broadband and ADSL Flat increasingly
accessible
 A growing success
 Today, huge numer of P2P Systems
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8. Architecture of P2P
systems
1. Centralized architecture
2. Distributed architecture, or pure
3. Mixed or hybrid architecture
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9. Centralized
Networks
 Using on the one hand central server(s) or
bootstrapping mechanisms (e.g. eDonkey
network).
 Central Server:
 Makes communicating between peers
 Controls the interaction between clients
 Contains no data
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10. Distributed
Architecture
 There is no central server managing the
network
 Peers act as equals, merging the roles of
clients and server
 Many access points
 P2P systems for file sharing using this
architecture often
 You must install software P2P (e.g Gnutella
protocol, Freenet protocol)
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11. Hybrid P2P Networks
 Mix of centralized architecture and decentralized
architecture
 Distribute their clients into two groups:
 Clients nodes
 Overlay nodes
 Tipically, 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 (e.g. Gnutella
protocol).
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12. Advantages and weaknesses
of P2P Networks
Advantages Weaknesses
 All clients provide  Not guarantee the
resources (Bandwidth, quality of service
Storage space,  It is not easy to
Computing power) retrieve information of
 Ease of administration interest
 Not require major  Reliability Data
infrastructure  Security
 Extreme tolerance in  Legal issues
the event of failure
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13. Legal issues-1
 The legal framework of reference is appointed
to regulate the c.d. copyright
 Italian law:
 Act 22 Aprile 1941, n. 633 amended several
times
 Dilemma law not legal P2P systems
 Art. 171: “anyone who is punisched does not
qualify, for any purpose and in any form”
 Limit of the law illegal file sharing
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14. Legal issues-2
 European level
 Directive 2001/29/CE of the European
Parlament and Council (May 2001)
 Telecom package approved by the European
Parlament (Nov 2009)
 Sarkozy’s Doctrine
 United States
 Copyright: Title 17 of the Unites States Code
 Violations  Federal crimes
 Exceptions  educational and scientific
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purposes 14

15. Security issues
 Fundamental use of antivirus, firewall,
cleaning log files and removal of infectious
agents (virus, spyware, trojan, malware).
 Attacks that a client can be, for example:
 Using file sharing systems
 Sharing an area of your disk
 It allows free access to certain ports on your
computer
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16. Privacy issues
 Protecting sensitive data (personal, business)
throught the adoption of:
 A network of anonymous
 Install SW such as PeerGuardian
 Encryption and obfuscation protocol
 A proxy for connection of the client’s real IP
mask
 ect..
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17. Economic issues -1
 New ways to access resources SW and HW
 Strongly dependent on the market that
produces use-value
 A study commissioned by the Dutch
goverment(2009):
“P2P Systems are good for the economy”
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18. Economic issues -2
 New ethnic workers (knowledge workers)
 Used to solve management problems, improve
communication between companies but also
within the same
 Greater sharing of know-how
 Faster data trasmission than traditional
networks (client-server)
 Less server overload
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COMPETITIVE ADVANTAGE 18

19. Applications of use
 Often used for file sharing:
 More Applications: Napster, Gnutella, FastTrack,
BitTorrent, Direct Connect, eDonkey, Kademila,
etc.
 Also widely used on mobile technology:
SymTorrent, Direct Connect Torrent, MobileDC,
etc.
 Sharing computational power:
 HW mainly shared resources for problem
solving or complex calculations
 Examples: SETI@Home, GIMPS,
18/04/2010 Distributed.net, FightAIDS@Home. 19

20. Future developments -1
Use innovative P2P  P2P TV
 For the diffusion of high data streams generated in
real time
 Using trasmission bandwidth of individual users
 Not require server performance
 Requires that individual users are provided with
high bandwidth connections in both reception and
trasmission (saturation bandwidth provided by the
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21. Future developments -2
 The Server serves as the index, synchronizes the
various users sharing the bandwidth and provides
the data flow and initial users share
 So, although in practice a server, after supplying
the initial data flow and have put in
communication the various users, the server is
not interested in the communication becomes
totally P2P systems
 Large companies are experimenting with the
possibility of offering paid content
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22. Future developments -3
Limits on the dissemination P2PTV
Systems are:
 Technical problems (diffusion
asymmetrical Internet lines, ADSL)
 Reliability problems
 Legal issues
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23. Future developments -4
Simulator epidemic protocols
 University of Bologna is experimenting with
new P2P applications simulator edpidemic
protocols for the study of issues of scale and
dynamism that characterize the moderm
information systems
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24. Future developments -5
 There protocols are able to put in
communication between their various
terminals. Such protocols are characterized by
large scale and high dynamics.
 The simulator is built from components that
enable rapid prototyping of communication
protocols by combining different data blocks
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25. Future developments -6
Using P2P Networks for mobile technologies
 System devised by TerraNet AB (Swedish
company)
 Allows:
 Local phone calls and send messages (2-20
km)
 Make calls to anyone with Internet access
TerraNet
 VoIP calls free long distance
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26. Future developments -7
 TerraNet integrated with technology every
type of mobile device becomes a wireless
communication
 It works via P2P wireless network (mesh
network) and no need for base stations,
antenna installations or infrastructure
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27. Future developments -8
Benefits Weaknesses
 For areas of the world  Phone companies
where you make obviously do not like
expensive trasmission the idea
infrastructure (Africa,  Political issues
South America, etc)
 Elimination
communications costs
 Greater privacy
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28. Conclusions -1
Network congestion and bandwidth
throlling
 Phenomenon increasingly attributed to P2P
systems
 Many provider have chosen to use the
bandwidth throlling:
 System that cuts the available bandwidth, especially
when using P2P systems
 Often the users knows nothing!
 For example Fastweb, Vodafone (mobile), Alice e
Tiscali
18/04/2010  Less opposed P2P systems  Libero e Tele2 28

29. Conclusions -2
 But the new version of uTorrent apparently
meets the needs of the ISP.
 uTorrent :
 Limiting network congestion, thus helping
Internet Provider
 The concept consists of a uTP: magnification
Bittorrent protocol
 uTP allow clients to automatically find any
blocks of the network (rule bandwidth
requirements and improves the connections)
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30. Conclusions -3
 Version of uTorrent with uTP is still in beta (Nov,
2009) but already is showing positive results
 Good thing for us users
 Providers would no longer decide on the bandwidth
limitation!
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31. Web Bibliography
1. http://en.wikipedia.org/wiki/Peer_to_peer
2. http://it.wikipedia.org/wiki/P2P_TV
3. http://it.wikipedia.org/wiki/Legge_italiana_sul_peer-to-peer
4. http://www.p2pitalia.com/
5. http://www.lastampa.it/redazione/cmsSezioni/economia/200805articoli/32454gira
ta.asp
6. http://www.megalab.it/4061/il-peer-to-peer-fa-bene-all-economia
7. http://setiathome.berkeley.edu/
8. http://www.mersenne.org/
9. http://www.distributed.net/
10. http://fightaidsathome.scripps.edu/
11. http://www.cs.unibo.it/bison/
12. http://www.terranet.se/index.php?option=com_content&task=category&sectionid
=9&id=18&Itemid=51
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32. Bibliography
 G. Pascuzzi, Il diritto dell’era digitale. Tecnologie
informatiche e regole privatistiche, II edizione, Il
Mulino, Bologna, 2006
 Shapiro e Varian, Information Rules. A strategic Guide
to the Network Economy. I edizione, Etas, Novembre
1999.
 Slide Corso Telecomunicazioni (dott. Zorat)
 Slide Corso Diritto Privato dell’Informatica (dott.
Caso)
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