The ideas of this paper are firmly grounded in the concept of Application Level Framing (ALF) . The ALF principle states that networking mechanisms should be coordinated with application-level objectives. As explained above, however, C-to-C applications present unique challenges because these objectives involve interstream tradeoffs for flows that do not share a complete end-to-end path. The actions of heterogeneous protocols distributed among a cluster of devices must be coordinated to incorporate application-specific knowledge. In essence, we are extending the ALF concept to the idea of adapting protocol behavior to reflect application-level semantics. This idea is also well expressed in a position paper by Padmanabhan .