[Gzz-commits] gzz/Documentation/misc/hemppah-progradu mastert...

[Hermanni Hyytiälä]

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Module name:    gzz
Changes by:     Hermanni Hyytiälä <address@hidden>      03/03/21 11:23:01

Modified files:
        Documentation/misc/hemppah-progradu: masterthesis.tex 

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http://savannah.gnu.org/cgi-bin/viewcvs/gzz/gzz/Documentation/misc/hemppah-progradu/masterthesis.tex.diff?tr1=1.172&tr2=1.173&r1=text&r2=text

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Index: gzz/Documentation/misc/hemppah-progradu/masterthesis.tex
diff -u gzz/Documentation/misc/hemppah-progradu/masterthesis.tex:1.172 
gzz/Documentation/misc/hemppah-progradu/masterthesis.tex:1.173
--- gzz/Documentation/misc/hemppah-progradu/masterthesis.tex:1.172      Fri Mar 
21 10:32:46 2003
+++ gzz/Documentation/misc/hemppah-progradu/masterthesis.tex    Fri Mar 21 
11:23:01 2003
@@ -820,27 +820,25 @@
 
 \chapter{Open Problems in Peer-to-Peer}
 
-In this chapter, we discuss open problems in Peer-to-Peer research. We describe
-the open problems and their proposed solutions. Then, we list all issues in
-tables. Note that the open problems list considered here is not meant
+In this chapter, we discuss open problems in Peer-to-Peer research.
+Note that the open problems list considered here is not meant
 to be an exhaustive survey of \emph{all} open problems in Peer-to-Peer domain; 
-we focus our attention to security, scalability, usability and performance 
issues
-only.
+we focus our attention to some security, scalability, usability and 
performance related
+issues only.
 
 \section{Overview}
 
 Partly due to the non-maturity of modern Peer-to-Peer technology, there are 
several
-open problems to be solved. The most severe problems are related to 
performance, scalability, usability
-and security. Also, many techniques developed for traditional distributed
-systems may no longer apply with Peer-to-Peer systems. Therefore, new 
solutions are 
-needed to make Peer-to-Peer systems more secure and efficient.
-
-Both the loosely structured and the tightly structured approach have their own 
specific problems. 
-Since Gnutella \cite{gnutellaurl} was first introduced 
-to the public, researchers' main concern has been the scalability problem of 
loosely structured 
-systems. However, people often misunderstand the scalability problem of the 
loosely structured 
-approach; \emph{the network overlay} of loosely structured systems is 
scalable, but the \emph{data lookup model} is not. 
-The main concern of the tightly structured system is to make overlay's data 
lookup process 
+open problems to be solved. Also, many techniques developed for traditional 
distributed
+systems may no longer apply with Peer-to-Peer systems, e.g., load balancing 
techiques \cite{byers03dhtbalancing}. 
+
+Different problem apply to both the loosely structured and the tightly 
structured approach have their own specific problems. 
+Since the introduction of Gnutella \cite{gnutellaurl}, the main concern has 
been the scalability problem of loosely structured 
+systems. However, the scalability problem of the loosely structured is often 
misunderstood; 
+\emph{the network overlay} of loosely structured systems is scalable, but the 
\emph{data lookup model} is not as
+the data lookup process creates lot of extra network traffic (e.g., 
\cite{yang02improvingsearch}). 
+
+In tightly structured system the main concern is to make overlay's data lookup 
process 
 more fault tolerant against hostile attacks. Other key problems in tightly 
structured 
 systems are the lack of keyword searches, support for heterogeneous peers and 
load balancing
 \cite{balakrishanarticle03lookupp2p}.
@@ -861,9 +859,9 @@
 currently there are no realizable techniques for this task. Partial solutions 
for the Sybil attack is to replicate
 and fragment data items randomly among several participating peers. However, 
this suggestion assumes that two different 
 remote entities are actually different; Sybil attacks are still possible and 
therefore would need centralized 
-authority for reliable authentication. As the author argues in 
\cite{douceur02sybil}, without centralized authority, 
+authority for reliable authentication. Without centralized authority, 
 Sybil attacks are always possible in a Peer-to-Peer system except under 
extreme and unrealistic assumptions of 
-resource parity and coordination among entities.
+resource parity and coordination among entities \cite{douceur02sybil}.
  
 In the Fail-stop attack model, cited in \cite{naor03simpledht}, a faulty peer 
is deleted from the Peer-to-Peer system.
 The reason for the faultiness of a peer can be a software failure or a hostile 
attack.