— Millions of residential users are widely served by cable or DSL connections with modest upload bandwidth and relatively high download bandwidth. For the increasingly important and demanding P2P applications such as VoIP, BitTorrent, and Internet streaming, stable or high upload bandwidth is required. Inadequate upload bandwidth degrades the performance of these applications among residential users. On the other hand, our Internet measurements show that plenty of idle upload bandwidth (from 50% to 80%) is always available in a local residential network. Based on this observation, we propose a system prototype to Coordinate Upload Bandwidth Sharing (CUBS) among neighboring residential users. Specifically, the idle upload bandwidth of neighbors can be used upon a request from a demanding user. Since it has become a common practice to deploy wireless access points in a residential user’s home, we have built CUBS by leveraging the support from the wireless networks. In CUBS, to disco...