Information Technology Reference
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chains is found on the basis of the existing knowledge about the peer net-
work, and attempts are made to establish a connection between the node that
sends out the request and the node at the end of the best chain in order to
obtain the desired resource. In the course of establishing this connection, it is
not a concern if the credibility of the node at the end of the best chain is lower
than a certain threshold value, which would make it seem less trustworthy.
It is sufficient to ensure that the most reliable peer among all the available
peers is chosen. The degree of truthfulness for certain P2P nodes is calcu-
lated using their credibility. After a destination is selected for downloading,
the desired resource can then be downloaded from that node.
When the requesting node's attempt to download a resource from the des-
tination node is successful, the credibility between the starting node and the
destination node is increased. On the other hand, if the transaction is not
successful the credibility between nodes is decreased. Such updating is the
most critical phase in our model because it is efficient and self-adjusting.
4.3 The Resource Chain Model (RCM)
4.3.1 assumptions
In order to simplify the explanation of our model [4,5], we would like to
make the following assumptions. The number of neighbors is eight, and the
length of the search is eight. This means that the longest requesting length is
eight. A record of a node's neighbors is maintained in a list called the neigh-
bor list. The nodes are ordered on the basis of their credibility; the higher
a node's credibility, the higher the position it holds. In addition to these
assumptions, we assume that we have a formula to evaluate the relationship
between the nodes. For 0 <
i
< 9, Ni = Neighbor (N0, 1). This means that the
distance between nodes N
i
and N0 is 1.
4.3.2 Working the rCM
Consider a node N0 that seeks to know where it can download File X in
the peer network. Since N0 is only aware of a limited number of nodes by
virtue of their being its neighbors, it transmits the request for file X to all of
its neighbors. We assume that those nodes that already know the node that
hosts File X will send a reply to N0 without sending out any more forward-
ing requests. Here, we assume that N1, N2, N3, and N4 know the location of
the node that hosts File X. Further, we assume that we have new nodes that
are previously unknown to node N0. They will forward N0's request for file
X to their neighbors. Here, we assume that N5, N6, N7, and N8 do not know
the location of the node that hosts File X. Therefore, they forward the request
