A comparison of RED's byte and packet modes

Abstract

Routers making use of Random Early Detection (RED) queueing take action to notify sources of growing congestion levels in the network before their resources are exhausted. The RED system hinges on two calculations: tracking the average queue size and the probability that an incoming packet is marked for congestion. These two calculations can be done in terms of the number of packets arriving at the router or in terms of the size of those packets (in bytes). Intuitively, these calculation methods off er different costs and benefits to traffic. This paper quantitatively assesses the impact of using the different queueing and marking methods on the performance of traffic traversing a RED gateway. We show that in some cases the calculation method makes a difference in the performance of the system, while in other cases the choice has little impact. We also provide a framework for rating the RED variants in particular situations in an attempt to aid in the choice of variant to use in a specific situations.