Design of Efficient Packet Marking-Based CMM for Cluster Interconnects

Congestion management in multistage interconnection networks is a serious problem not completely solved. In order to avoid the degradation of network performance when congestion appears, several congestion management mechanisms have been proposed. Most of these mechanisms are based on explicit congestion notification. For this purpose, switches detect congestion and depending on the applied strategy, packets are marked to warn the source hosts. In response, source hosts apply some corrective actions to adjust their packet injection rate. Although these proposals seem quite effective, they either exhibit some drawbacks or are partial solutions. Some of them introduce some penalties over the flows not responsible for congestion, whereas others can cope only with congestion situations that last for a short time. We present different strategies to detect and correct congestion in multistage interconnection networks, and propose new mechanisms targeted to this kind of lossless networks, and based on more refined packet marking strategies combined with a fair set of corrective actions, that makes the mechanisms able to effectively manage congestion regardless of the congestion degree.