Date Added: Jan 2012
Many two-layer hierarchy unstructured Peer-To-Peer (P2P) systems, comprising of superpeers and ordinary peers improved the performance of large scale P2P systems. The construction and maintenance of the superpeer overlay network play an important role in improving the performance P2P systems. One efficient method of constructing the superpeer overlay network is based on notion of Perfect Difference Networks (PDN).The construction and maintenance of network in this method is controlled by single bootstrap server. Such network is prone to single-point failures. The number of registration requests lost before getting up the failed bootstrap server and the delay in adding new peer to the network gets increased.