  P2P system rely on voluntary allocation of resources by its members due to
absence of any central controlling authority. This resource allocation can be
viewed as classical control problem where feedback is the amount of resource
received, which controls the output i.e. the amount of resources shared back to
the network by the node. The motivation behind the use of control system in
resource allocation is to exploit already existing tools in control theory to
improve the overall allocation process and thereby solving the problem of
freeriding and whitewashing in the network. At the outset, we have derived the
transfer function to model the P2P system. Subsequently, through the simulation
results we have shown that transfer function was able to provide optimal value
of resource sharing for the peers during the normal as well as high degree of
overloading in the network. Thereafter we verified the accuracy of the transfer
function derived by comparing its output with the simulated P2P network. To
demonstrate how control system reduces free riding it has been shown through
simulations how the control systems penalizes the nodes indulging in different
levels of freeriding. Our proposed control system shows considerable gain over
existing state of art algorithm. This improvement is achieved through PI action
of controller. Since low reputation peers usually subvert reputation system by
whitewashing. We propose and substantiate a technique modifying transfer
function such that systems' sluggishness becomes adaptive in such a way that it
encourage genuine new comers to enter network and discourages member peers to
whitewash.
