Packet loss and congestion state in TCP Veno

One sender-side enhancement of TCP, called Veno TCP, was recently proposed to mainly eliminate TCP´s suffering in wireless environments. Real experiments verified that TCP Veno indeed works effectively and harmoniously in wire/wireless networks. In this paper, we revisit packet loss distinguishing scheme, which is borrowed from Vegas TCP and adopted in Veno TCP. Our simulation results demonstrate that in networks with light or moderate cross traffic, loss distinguishing between congestion loss and random loss does work well, while in networks with heavy cross traffic, misinterpreting congestion loss as random loss is very high. However, this superior erroneous loss type judgment does not affect Veno behavior negatively, which is quite different from our intuition. Veno´s overall window evolution is still comparable with Reno´s and thus continues to work harmoniously with Reno in wired networks. Such observed dilemma pushes us to rethink two fundamental aspects in system control theory - the congestion signal monitored and according to the actions performed. Further study on Veno is still being explored.