An adaptive random early detection (ARED) algorithm that adapts its dropping probability to the marking probability of edge routers is presented in this paper. A new marking probability metering algorithm is also proposed.

The paper describes the problems that arise when using existing RED variants for differentiated services (Diffserv), and proposes ARED as a response to these deficiencies. It describes the proposed ARED algorithm with a quantitative description, followed by a description of the algorithm. The paper also describes the algorithm with a three-color marker, and describes a metering algorithm for marking probability. Thus, an implementer can use the marking algorithm in the edge routers, and the ARED algorithm in core routers.

Because of the nature of the algorithm, the adaptive parameters are carried in the Internet protocol (IP) packets, and transferred to other routers in the Diffserv domain. The authors use the options field in the IP packet to do so. Generally, because of the variably sized length of the option field, the hardware may not look into the option field, and may participate only in fast route forwarding and pass option processing to software. This is an important issue, which should be kept in mind while implementing the algorithm for performance impact. More complex real life analysis and simulation needs to be done to validate the algorithm. An investigation of how the scheme interacts with both Diffserv and multi-protocol label switching (MPLS) traffic engineering also needs to be conducted, to provide a high-level view of the process.