Statistical estimation of TCP packet loss rate from sampled ACK packets

The appearance of various quality-sensitive applications has greatly changed the requirements for network management. To manage the quality of these applications, monitoring of individual traffic flows, as well as aggregated traffic statistics, has become more important. Since per-flow monitoring involves a high processing cost, especially in emerging high-speed links, packet sampling techniques have been attracting considerable attention. However, existing sampling techniques, such as NetFlow and sFlow, have mainly targeted traffic volume monitoring and there has been little discussion on the monitoring of quality indexes including packet loss rate. In this paper, we propose a method to estimate the TCP packet loss rate from sampled packets. The proposed method detects packet loss events by monitoring duplicate ACK events induced by a TCP receiver indicating the loss events. Since only a portion of packet loss events can be detected from the sampled packets, the correct packet loss rate is estimated by means of statistical approximation. Simulation results show that the proposed method accurately estimates the TCP packet loss rate from 10% of sampled packets.