1755 |
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|
1756 |
In this chapter we evaluate Fenfire in Peer-to-Peer environment. |
In this chapter we evaluate Fenfire in Peer-to-Peer environment. |
1757 |
We start by giving a problem overview when considering Fenfire in Peer-to-Peer |
We start by giving a problem overview when considering Fenfire in Peer-to-Peer |
1758 |
environment. We define Fenfire's objectives and special needs. Finally, we |
environment. Then, we define Fenfire's objectives and special needs in Peer-to-Peer |
1759 |
evaluate different peer-to-peer approaches with regard to Fenfire, and propose |
environment. Finally, we evaluate different peer-to-peer approaches with regard |
1760 |
initial algorihms for obtaining Fenfire specific data from Peer-to-Peer overlay |
to Fenfire, and propose initial algorihms for obtaining Fenfire specific data |
1761 |
network. |
from Peer-to-Peer overlay network. |
1762 |
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1763 |
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In the following sections, we don't respond to security issues. We assume |
|
|
that either system has a reliable techique for identifying invidual entities, or |
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there are no hostile entities in the system. |
|
1764 |
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1765 |
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|
1766 |
\section{Problem overview} |
\section{Problem overview} |
1767 |
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|
1768 |
As already mentioned in chapter 4, xanalogical document is a ''virtual |
As already mentioned in chapter 4, xanalogical document is a ''virtual |
1769 |
file'', in which parts of the document (i.e. scroll blocks) are fetched from a |
file'', in which parts of the document are fetched from a |
1770 |
\emph{global} data repository. Thus, system implementing xanalogical model \emph{must} |
\emph{global} data repository. Thus, system implementing xanalogical model \emph{must} |
1771 |
support global data lookups efficiently in order to assemble a ''virtual file'' |
support global data lookups efficiently in order to assemble a ''virtual file'' |
1772 |
from fragments of data. |
from fragments of data. |
1773 |
|
|
1774 |
In the xanalogical storage model, each fragment of data is identified by a globally |
In the xanalogical storage model, each fragment of data is identified by a globally |
1775 |
unique identifier. As we discussed already in chapter 4, Fenfire's Storm design |
unique identifier. In Fenfire, data fragments are scroll blocks of Storm storage module. |
1776 |
|
As we discussed already in chapter 4, Fenfire's Storm design |
1777 |
uses SHA-1 \footnote{SHA-1 is considered a collision free hash function. Therefore, it is |
uses SHA-1 \footnote{SHA-1 is considered a collision free hash function. Therefore, it is |
1778 |
very unlikely that two different Storm scroll blocks would have same identifier.} |
very unlikely that two different Storm scroll blocks would have same identifier.} |
1779 |
\cite{fips-sha-1} hash over the contents of a block for creating globally unique |
\cite{fips-sha-1} hash over the contents of a scroll block for creating globally unique |
1780 |
identifiers. In our scenario, fragments of data is distributed throughout the Peer-to-Peer |
identifiers for each scroll block. In our scenario, fragments of data is distributed |
1781 |
overlay. Moreover, our task is to locate and fetch (i.e. obtain) \emph{all} |
throughout the Peer-to-Peer overlay. Our task is to locate and fetch |
1782 |
Storm scroll blocks, associated to a specific ''virtual file'', from Peer-to-Peer |
(i.e. obtain) \emph{all} Storm scroll blocks, associated to a specific ''virtual |
1783 |
overlay as efficiently as possible. In addition to \emph{direct} scroll block obtaining using |
file'', from Peer-to-Peer overlay as efficiently as possible. In addition to |
1784 |
globally unique identifier of Storm block, we also must support \emph{indirect} obtaining of |
\emph{direct} scroll block obtaining using globally unique identifier of Storm block, |
1785 |
Storm scroll block using pointer blocks. |
we also must support \emph{indirect} obtaining of Storm scroll block using pointer blocks. |
1786 |
|
|
1787 |
We have decided to use Peer-to-Peer network as a Fenfire's communication layer. For |
Some research regarding to these problem has been made by Lukka et al. |
1788 |
motivations and discussion, see \cite{lukka02freenetguids, fallenstein03storm}. |
\cite{lukka02freenetguids}. Authors' work is mainly based on insight of implementing |
1789 |
This paper's focus, however, is to evaluate existing Peer-to-Peer systems and their |
xanalogical model in Peer-to-Peer enviroment with globally unique identifiers. Lukka et al. |
1790 |
applicably with regard to Fenfire's requirements. Anyhow, it must be feasible to perform |
use Freenet \cite{clarke00freenet} as a example Peer-to-Peer system supporting |
1791 |
efficient lookups to locate parts of the document from the global repository based on |
globally unique identifiers. This thesis presented here extends their work by |
1792 |
block's identifier. To be more specific, Fenfire's Storm module has to support \emph{global scale} |
evaluating different Peer-to-Peer approaches more extensively to Fenfire's needs. |
1793 |
data lookup to locate and fetch scroll blocks by using \emph{location-independent} |
Additionally, related to non-xanalogical hypermedia systems, Thompson and de Roure |
1794 |
identifiers. |
\cite{thompson01hypermedia} have studied locating documents and links in Peer-to-Peer |
1795 |
|
environment. Bouving \cite{bouvin02openhypermedia} has done initial work regarding |
1796 |
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|
1797 |
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|
1798 |
|
In the following sections, we don't respond to security issues. We assume |
1799 |
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that either system has a reliable techique for identifying invidual entities, or |
1800 |
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there are no hostile entities in the system. |
1801 |
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|
1802 |
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1803 |
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|
\cite{thompson01hypermedia} |
|
1804 |
\cite{wiil02p2phypertext} |
\cite{wiil02p2phypertext} |
1805 |
\cite{bouvin02openhypermedia} |
|
1806 |
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1807 |
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|
1808 |
\section{Objectives} |
\section{Objectives} |