Cisco QoS FAQ: Congestion Avoidance Through Drop Policies Q1. Describe the function of the congestion window in TCP, and how it is changed as a result of packet loss. Answer: The TCP congestion window, or CWND, is one of two windowing mechanisms that limit TCP senders. CWND can be split in half as a result of packet loss, slowing the sending rate. CWND can also be slammed … [Read more...]