Multi-level active queue management with dynamic thresholds

Abstract

In this paper, we propose a new active queue management scheme for a network device (e.g. router, switch, etc.) with a shared buffer where the buffer is logically organized into multiple queues. Conventional schemes allocate buffer space to each queue through the use of static buffer thresholds. Although very simple, these static thresholds are often determined using simple heuristics and cannot adapt to changing traffic conditions. These schemes could also result in unnecessary packet drops which lead to poor network performance since congested or heavily loaded queues cannot gain access to buffers not utilized by the lightly loaded queues. The proposed active queue management scheme, which uses dynamic buffer thresholds, adapts to changing load conditions and dynamically allocates buffer space to all queues using a simple recursive algorithm. The implementation of the scheme is also simple and requires low processing overhead to compute the dynamic buffer thresholds and packet drop probabilities.