Controlling the flow of network traffic to avoid undesired delay in the transmission of timing sensitive packets is disclosed. A plurality of packets to be transmitted via a network transmission path is monitored. A time at which a timing sensitive packet will become available for transmission via the network transmission path is anticipated. The plurality of packets is controlled in light of the anticipated time so that packets other than the timing sensitive packet will not occupy the network transmission path at a time associated with the anticipated time. Approximating a maximum data transmission rate associated with a network transmission path by sending and analyzing receipt of a series of test packets is disclosed. Approximating a buffer size of a buffer associated with a network transmission path by sending and analyzing receipt of a series of test packets is disclosed.