Donald Eastlake Donald Eastlake Hickory Hill Consulting Brocade ZTE Corporation Draft [TRILL-Active-PS] lists basic problems which any active-active solutions should address, these problems include frame duplications, loop, MAC address flip-flop and unsynchronized information among member RBridges. For each problem, there may be multiple ways to deal with it. Some solutions solve all or most of the problems listed, and at the same time introduces extra issues. This draft tries to analyze and compare the different solutions for each of the issues, gives a brief summary on the pros and cons, and/or the applicable scenarios.