I tested a line for its link quality with iperf. The measured speed (UDP port 9005) was 96Mbps, which is fine, because both servers are connected with 100Mbps to the internet. On the other hand the datagram loss rate was shown to be 3.3-3.7%, which I found a little too much. Using a high-speed transfer protocol I recorded the packets on both sides with tcpdump. Than I calculated the packet loss - average 0.25%. Have anyone an explanation, where this big difference may be coming from? What is an acceptable packet loss in your opinion?