SCAP: Smart Caching inWireless Access Points to Improve P2P Streaming

The increasing number of wireless users in Internet P2P applications causes two new performance problems due to the requirement of uploading the downloaded traffic for other peers, limited bandwidth of wireless communications, and resource competition between the access point and wireless stations. First, an active P2P wireless user can significantly reduce the downloading throughput of other wireless users in the WLAN. Second, the slowdown of a P2P wireless user communication can also delay its relay and data sharing service for other dependent wired/wireless peers. In order to address these problems, in this paper, we propose an efficient caching mechanism called SCAP (Smart Caching in Access Points). Conducting intensive Internet measurements on representative P2P streaming applications, we observe a high percentage of duplicated data packets in successive downloading and uploading data streams. Through duplication detection and caching at the access point, these duplicated packets can be compressed so that the uploading traffic in the WLAN is significantly reduced. Our prototype-based experimental evaluation demonstrates that by effectively reducing the redundant P2P traffic in the WLAN, SCAP improves the throughput of the WLAN by up to 88% and reduces the response delay to other Internet users meanwhile.