Packet networks require queues (buffers) to absorb short term arrival rate fluctuations. Yet network implementors have always observed that queues at bottlenecks tend to fill and stay filled, which contributes extra delay and removes the ability to absorb bursts. In [1] Floyd and Jacobson proposed the RED (Random Early Detection) active queue management algorithm. RED is simple, robust and quite effective at reducing persistent queues. However, while it has been used widely and successfully on Internet routers, [1] offers little guidance on how to set configuration parameters and RED has gained the reputation of being very difficult to tune. This paper develops RED in different way, treating it as a servo control loop and deriving all the loop parameters from measurable properties of a router. The result is a `self-tuning' RED whose parameters are completely determined by the queue output bandwidth (average departure rate). This new RED performs substantially better than the original version and works for a much wider variety of traffic and link bandwidths. It also admits a substantially simpler and more efficient implementation, one particularly well suited for ASIC forwarding engines. Please note: This is an early draft of an in-progress paper. Several important sections are still missing and the simulation data needs to be reorganized so that the story it tells is clearer. 1.0

This paper proposes a new method of bandwidth allocation during congestion, called the proportional allocation of bandwidth. Traditionally, max-min fairness has been proposed to allocate bandwidth under congestion. Our allocation scheme considers the situation where flows might have different subscribed information rates, based on their origin. In proportional allocation of bandwidth, during congestion all flows get a share of available bandwidth, which is in proportion to their subscribed information rate. We suggest a method for implementing this with minimum signaling and without storing per-flow state. Our method is based on the principles of differentiated services - diffserv. We show by simulation that it is possible to obtain proportional bandwidth allocation without per-flow state storing and minimum signaling.

The field of control provides the principles and methods used to design physical and information systems that maintain desirable performance by sensing and automatically adapting to changes in the environment. Over the last forty years the field has seen huge advances, leveraging technology improvements in sensing and computation with breakthroughs in the underlying principles and mathematics. Automatic control systems now play critical roles in many fields, including manufacturing, electronics, communications, transportation, computers and networks, and many military systems.

This paper proposes a new method of bandwidth allocation during congestion, called the proportional allocation of bandwidth. Traditionally, max-min fairness has been proposed to allocate bandwidth under congestion. Our allocation scheme considers the situation where flows might have different subscribed information rates, based on their origin. In proportional allocation of bandwidth, during congestion all flows get a share of available bandwidth, which is in proportion to their subscribed information rate. We suggest a method for implementing this with minimum signaling and without storing per-flow state. Our method is based on the principles of differentiated services -- diffserv. We show by simulation that it is possible to obtain proportional bandwidth allocation without per-flow state storing and minimum signaling.