I am facing this problem. Any info will be appreciated An ECN flow forcibly dropped packet is retransmiited due to timeout. This packet is marked with CE bit. Due to timeout cwnd is 1. Now TCP code in NS is supposed to reduce cwnd to 1/2 after receiving ECE Acks. My ECN flow stops after receiving ECE Acks. Is it due to cwnd<1 or any other problem?. rupinder makkar [email protected]