``SCAP: Smart Caching in wireless Access Points to Improving P2P streaming"  
 
Enhua Tan, Lei Guo, Songqing Chen, and Xiaodong Zhang

Proceedings of the 27th International Conference on Distributed Computing 
Systems (ICDCS'07), Toronto Canada, June 25-29, 2007.  

Abstract

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 
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.