1018 |
|
|
1019 |
Currently, trust in Peer-to-Peer systems is based on \emph{reputation}. Current repuation methods focus either |
Currently, trust in Peer-to-Peer systems is based on \emph{reputation}. Current repuation methods focus either |
1020 |
on the semantic properties, or data management properties of the trust model. Some research has been |
on the semantic properties, or data management properties of the trust model. Some research has been |
1021 |
done on reputation models in Peer-to-Peer systems, such as \cite{aberer01trust}. Implementations |
done on reputation models in Peer-to-Peer systems, such as \cite{aberer01trust}, \cite{cornelli02reputableservents}. |
1022 |
include Advogato \cite{advogatourl}. None of the current proposals or implementations based on reputation address trust |
Implementations include Advogato \cite{advogatourl}. None of the current proposals or implementations |
1023 |
in a trustworthy way. |
based on reputation address trust in a reliable way. |
1024 |
|
|
1025 |
Optimal solution for trust in Peer-to-Peer systems would be certificate based security methods. |
Optimal solution for trust in Peer-to-Peer systems would be certificate based security methods. |
1026 |
Quite recently, widely used Public Key Infrastructure (PKI) has been deployed in distributed |
Quite recently, widely used Public Key Infrastructure (PKI) has been deployed in distributed |
1248 |
|
|
1249 |
|
|
1250 |
|
|
1251 |
\cite{crespo02semanticoverlay} |
|
1252 |
Locality \cite{keleher-02-p2p} |
Locality \cite{keleher-02-p2p} |
1253 |
|
|
1254 |
|
|
1286 |
While it is expected that web-like searches can be layered on top of tightly structured overlay, much |
While it is expected that web-like searches can be layered on top of tightly structured overlay, much |
1287 |
more research is required to make indexing and searching more efficient. |
more research is required to make indexing and searching more efficient. |
1288 |
|
|
|
\cite{ramanathan02goodpeers} |
|
1289 |
|
|
1290 |
Improve Freenet performance with small worlds \cite{zhang02using} |
Improve Freenet performance with small worlds \cite{zhang02using} |
1291 |
|
|
1353 |
|
|
1354 |
\section{Miscellaneous problems in Peer-to-Peer} |
\section{Miscellaneous problems in Peer-to-Peer} |
1355 |
|
|
1356 |
\subsection{Frameworks} |
In this section we discuss miscellaneous problems related to Peer-to-Peer systems. |
|
|
|
|
\cite{zhao03api} |
|
|
\cite{frise02p2pframework} |
|
|
\cite{babaoglu02anthill} |
|
|
\cite{rhea03benchmarks} |
|
|
|
|
|
\subsection{Social behaviour} |
|
|
\cite{cornelli02reputableservents} |
|
|
\cite{oram01harnessingpower} |
|
|
\cite{golle01incentivesp2p} |
|
|
|
|
|
Notes from from \cite{hearn02mojonation} |
|
|
|
|
|
1) Attack resistance |
|
|
2) malicious nodes |
|
|
3) mutual distrust |
|
|
4) motivation to cooperate |
|
1357 |
|
|
1358 |
|
\subsection{Programming guidelines and benchmarks} |
1359 |
|
|
1360 |
|
All existing Peer-to-Peer systems have rather different interfaces even they common points and |
1361 |
|
components. More important, all existing Peer-to-Peer systems incompatible with each other. One |
1362 |
|
of the most important area of future research is to create common programming abstractions, i.e. |
1363 |
|
interfaces, design patters and frameworks. Also, equal benchmarks are needed for comparing |
1364 |
|
different algorithms. Recently, there have been few proposals towards common programming |
1365 |
|
guidelines. This list includes \cite{zhao03api}, \cite{frise02p2pframework}, \cite{babaoglu02anthill}. |
1366 |
|
Early experiments with Peer-to-Peer benchmarking include \cite{ratnasamy02routing} and \cite{rhea03benchmarks}. |
1367 |
|
|
1368 |
\subsection{Usage patterns} |
\subsection{Social behaviour} |
|
\cite{saroiu02measurementstudyp2p} |
|
|
\cite{krishnamurthy01earlymeasurements} |
|
|
|
|
|
Research on *usage patterns* haven't been done. However, there have been some research |
|
|
focusing on file popularity in in www and p2p networks: file popularity follows the zipf/harmonical distribution) |
|
1369 |
|
|
1370 |
|
Very frequent assumption in Peer-to-Peer systems is that peers are willing to cooperate. Another belief |
1371 |
|
is that all peers would behave equally, i.e. all peers both consume resources and contributes resources. |
1372 |
|
However, these assumptions are not true as several studies show peers rather consume than contribute and |
1373 |
|
and peers are unwilling to cooperate \cite{saroiu02measurementstudyp2p}, \cite{oram01harnessingpower}, |
1374 |
|
\cite{hearn02mojonation}. |
1375 |
|
|
1376 |
|
Somewhat surprisingly little research has been in this area, especiaclly when considering |
1377 |
|
the possible impact of this \emph{unwanted socical behaviour} to performance of Peer-to-Peer |
1378 |
|
system. However, problem is addressed by Golle et al. \cite{golle01incentivesp2p}. Some |
1379 |
|
research has been focused on semantic properties of the overlay in order to increase |
1380 |
|
cooperation among participating peers \cite{crespo02semanticoverlay}. Ramanathan et al. |
1381 |
|
\cite{ramanathan02goodpeers} and Bernstein et al. \cite{bernstein03selection} use |
1382 |
|
empirical metrics and decision trees when teaching peers to make better decisions |
1383 |
|
when contacting other peers in Peer-to-Peer system. Alpine is an example of |
1384 |
|
Peer-to-Peer system, which uses empirical metrics for peer selection. |
1385 |
|
|
1386 |
|
|
1387 |
|
\subsection{Simulating the Peer-to-Peer system} |
1388 |
|
|
1389 |
|
Very little research has been done on simulating the global Peer-to-Peer system. Presumably, this |
1390 |
|
is due to complex nature of Peer-to-Peer system, which makes comprehensive simulations very |
1391 |
|
diffucult. Floyd et al. has been studying the simulation of the Internet in \cite{504642}. Authors |
1392 |
|
state that simulating the Internet is very challenging task, because of Internet's heterogeneity |
1393 |
|
and rapid change. Obviously, these factors exist also in Peer-to-Peer system even with higher |
1394 |
|
rates. |
1395 |
|
|
1396 |
|
As long as global simulations of Peer-to-Peer systems are lacking, we cannot we make any further |
1397 |
|
analysis e.g., on usage patterns in Peer-to-Peer systems. Presumedly, however, we can assume that |
1398 |
|
queries follow the Zipf-like distributions both in the Internet and in Peer-to-Peer systems. |
1399 |
|
|
1400 |
\section{Summary} |
\section{Summary} |
1401 |
|
|