Controlling Internet queue dynamics using recursively identified models

Data traffic on the Internet of today is controlled by a non-linear controller (TCP) at each sender node, which increases packet transmission rate each time an acknowledgment is received in due time, and decreases otherwise. The routers may co-operate with TCP by deliberately dropping packets, so called early drops. The idea is to decrease packet arrival rate before the queue becomes full and hard drops of packets are necessary. State of the art is to compute the probability of an early drop as a static function of the (filtered) queue length. We propose to use an auto-regressive model for the oscillative behavior of the queue length that can be observed in practice. With this model, the queue length can be predicted and a dynamic algorithm for computing the early drop probability can be used. We suggest a very simple modification of existing algorithms, where a short-time prediction is used instead of the current queue value, and demonstrate using ns-2 simulations that the overall throughput increases.

[1]  D.Y. Montuno,et al.  A comparison of active queue management algorithms using the OPNET Modeler , 2002, IEEE Communications Magazine.

[2]  Fernando Paganini,et al.  Internet congestion control , 2002 .

[3]  R. Srikant,et al.  An adaptive virtual queue (AVQ) algorithm for active queue management , 2004, IEEE/ACM Transactions on Networking.

[4]  Wu-chang Fengy,et al.  BLUE: A New Class of Active Queue Management Algorithms , 1999 .

[5]  Fredrik Gustafsson,et al.  Issues on Performance Measurements of TCP , 2002 .

[6]  T. Basar,et al.  Optimal rate control for high speed telecommunication networks , 1995, Proceedings of 1995 34th IEEE Conference on Decision and Control.

[7]  Lennart Ljung,et al.  System Identification: Theory for the User , 1987 .

[8]  Chita R. Das,et al.  Stabilized virtual buffer (SVB) - an active queue management scheme for Internet quality-of-service , 2002, Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE.

[9]  Donald F. Towsley,et al.  On designing improved controllers for AQM routers supporting TCP flows , 2001, Proceedings IEEE INFOCOM 2001. Conference on Computer Communications. Twentieth Annual Joint Conference of the IEEE Computer and Communications Society (Cat. No.01CH37213).

[10]  QUTdN QeO,et al.  Random early detection gateways for congestion avoidance , 1993, TNET.