Network assessment testing for this analysis was performed with MyConnection Server and the Access Series Quality Assessment Point appliance. Connection tests were performed every 15 minutes over several days to capture network capacity and performance over time and during both peak activity periods and low activity period.
The Fig. 1 graph below clearly shows that at about 4pm GMT (10am CST) throughput drops dramatically. At about 4am (12 hours later) the capacity is restored to full throughput. Throughput drops from a clean and consistent 8Mbps to less than 1Mbps. This a classic ‘rush hour’ symptom — during peak hours when users are most active, the network is over utilized and cannot handle traffic.
Fig. 1 MCS report shows a classic over utilized network scenario, capacity drops during daytime hours.
The drop is especially serious because it is not only resulting in increased latency, in addition it causes a significant amount of dropped data.
The lost data correlates exactly to the drop in throughput and is ultimately the result of the congestion.
Fig. 2 The lost data correlates almost exactly to the drop in throughput shown in Fig. 1.
The big question and most difficult question is to determine where the congestion and the packet loss is occurring. The logical next step is to examine the route of the connection to see if that provides any clues. Fig. 3 below shows that the only hop that consistently shows packet loss is 188.8.131.52.
Fig. 3 MCS report shows the network route, with packet loss occurring in hop 7.
A network route test during the non-prime time hours shows a clean route with no packet loss.
Fig. 4 The route test above shows no data loss.
In conclusion, this network connection shows a classic over-utilization pattern. The device at hop 7 should be reviewed further to determine the cause of packet loss occurring at that hop.