Based on the clockwise property of parameterized curves and the general Nyquist criterion of stability, a conjecture on the stability of the Internet congestion control algorithm with diverse propagation delays is proved. A more general stability criterion is also provided. The new criterion preserves the elegancy of the conjecture being decentralized and locally implemented: each end system needs knowledge only of its own round-trip delay, but enlarges the stability region of control gains and admissible communication delays. (C) 2004 Elsevier Ltd. All rights reserved.