Congestion only applies to Azerbaijan traffic
The following graph shows the number of sessions coming from inside Azerbaijan (green) vs outside the country (blue). The TCP retransmissions are only taking place in sessions from inside Azerbaijan (black). Traffic from outside the country (blue) is not affected (red).
Traffic inside Azerbaijan
A careful look into Azerbaijan Internet infrastructure shows that two largest players Azertelecom and Delta Telecom control the traffic upstreams of the country. Our test confirm that all ASNs connected via Delta Telecom are affected.
Modelling of TCP Retransmissions under normal circumstances
13 December 2013
In order to model what is a normal behaviour in the traffic coming from Azerbaijan we have collected statistics of the number of TCP Retransmissions that take place every minute.
The graph shows that under normal circumstances we should receive no more than between 1-4 retransmissions per second (~50-200 retransmissions/minute). During the times of congestion we receive at least 200 retransmission per second (~12000 retransmissions/minute).