Performance of AQM Routers in the Presence of New TCP Variants

In this paper, we study the performance of active queue management algorithms for packet queueing in Internet routers in the presence of new versions of the TCP congestion control mechanism. In particular, we compare the performance of tail drop, adaptive RED, AVQ, PI, REM and AN-AQM queueing in four TCP cases: (i) the classic New Reno protocol, (ii) the Sack protocol, (iii) the Fack protocol, (iv) the Cubic protocol. Apparently, the application of Fack and Cubic versions of TCP have (with some exceptions) minor impact on the basic performance characteristics (throughput and delay) of the router´s queueing mechanism. However, application of Cubic TCP has often a positive impact on the stability of the router´s queue size. As for the inter-flow fairness for different TCPs, the results are not univocal - both fairness improvement and degradation can be observed depending on the network congestion level.