Packet drops have a great impact in the RTT variation and the throughput experienced by some TCP applications. However, using packet drops is the primary way TCP uses to discover the bandwidth available in order to proceed with its packet transmissions. A different approach is used by SmoothTCP-q, where ICMP-SQ messages are sent to the SmoothTCP-q sender every time a threshold is reached in the queue size of the router. In this mechanism, SmoothTCPq tries to avoid packet drops since it is not necessary anymore to overload the router queue to discover the network bandwidth. Consequently, it is important to have some way to determine the queue threshold and evaluate its effect on SmoothTCP-q. This paper briefly describes SmoothTCP-q and presents a simple model for this relationship that can be used to evaluate whether or not there will be packet drops in a SmoothTCP-q connection.