The operating point

The operating point n is the desired number of packets to reside in the bottleneck queue. n should greater than zero; the intuition behind this decision is that an operating point equal to zero would lead to underutilization of the available bandwidth because the queues are always empty, i.e., no queueing is tolerated. Instead, the goal is to provide a small amount of queuing so that a packet is always available for forwarding over the bottleneck link. For example, if we choose n to be 1, then we expect a session to maintain 1 packet in the bottleneck queue, i.e., our ideal or desired congestion window would be one packet above the bandwidth delay product (BWDP) of the network.