In recent years, the P2P (peer to peer) application has been the main research focus and has been gaining popularity for the download of large sized content such as multimedia resources. A great deal of P2P users, especially young students, have started to operate in broadband and campus networks. P2P applications then have a critical problem because they consume too much network bandwidth, causing trouble for other applications such as mail, news, search engines as well as E-commerce (Electronic Commerce). Thus, how to facilitate the side-effects of P2P applications will be one of the most important research topics for network or E-commerce managers. In this paper, merging technology and management, we propose a comprehensive scheme to the problem above. This scheme consists of P2P traffic control, P2P port blockage, P2P download incentive measure and improvement of P2P data piece selection. An example of a BT (BitTorrent) download shows that the scheme can not only reduce average access time and increase download speed when compared with the existing BT peer selection process with randomly selected peers. In a word, the scheme can help to insure less infection of E-commerce from P2P applications.