| Abstract: | Interaction between transmission control protocol (TCP) and random
early detection (RED) gateway in the Internet congestion control
system has been modelled as a discrete-time dynamic system which
exhibits complex bifurcating and chaotic behaviours. In this paper, a
hybrid control strategy using both state feedback and parameter
perturbation is employed to control the bifurcation and stabilize the
chaotic orbits embedded in this discrete-time dynamic system of
TCP/RED. Theoretical analysis and numerical simulations show that the
bifurcation is delayed and the chaotic orbits are stabilized to a
fixed point, which reliably achieves a stable average queue size in
an extended range of parameters and even completely eliminates the
chaotic behaviour in a particular range of parameters. Therefore it
is possible to decrease the sensitivity of RED to parameters. By
using the hybrid strategy, we may improve the stability and
performance of TCP/RED congestion control system significantly. |
