As the number of components in cluster-based systems increase, cost and power consumption increase as well. One way to reduce both problems is re- ducing the amount of components in the interconnection networks. Critical to the usability of networks with less components are management systems that eliminate HOL blocking during situations of congestion. This paper starts by exploring research concerning the dynamics of congestion trees and introduces three previously developed mechanisms that solve the nega- tive side-effects caused by them.