  Peer-to-peer networks consist of thousands or millions of nodes that might
join and leave arbitrarily. The evaluation of new protocols in real
environments is many times practically impossible, especially at design and
testing stages. The purpose of this paper is to describe the implementation
aspects of a new Java based P2P simulator that has been developed to support
scalability in the evaluation of such P2P dynamic environments. Evolving the
functionality presented by previous solutions, we provide a friendly graphical
user interface through which the high-level theoretic researcher/designer of a
P2P system can easily construct an overlay with the desirable number of nodes
and evaluate its operations using a number of key distributions. Furthermore,
the simulator has built-in ability to produce statistics about the distributed
structure. Emphasis was given to the parametrical configuration of the
simulator. As a result the developed tool can be utilized in the simulation and
evaluation procedures of a variety of different protocols, with only few
changes in the Java code.
