Design and analysis of multi-level active queue management mechanisms for emergency traffic

Multiple average-multiple threshold (MAMT) active queue management (AQM) is proposed as a solution for providing available and dependable service to traffic from emergency users after disasters. MAMT is a simple but effective approach that can be applied at strategic network locations, where heavy congestion is anticipated. It can provide low loss to emergency packets while dropping non-emergency packets only as much as necessary. Fluid flow analysis and simulation is conducted to provide guidelines for proper MAMT design, especially regarding the queue size and averaging parameters that are most important. This work considers non-responsive traffic exclusively, since non-responsive traffic types are currently getting the most attention from emergency management organizations. Plus, very little work has been performed regarding AQM and non-responsive traffic. It demonstrates queue oscillation problems that previously may have been attributed to the interactions between TCP and AQM, but which are actually inherent to AQM and can be greatly reduced with proper parameter settings. MAMT is shown to perform well over a range of loads and can effectively protect emergency traffic from surges in non-emergency traffic. (C) 2004 Elsevier B.V. All rights reserved.