mirror mode vs multi master

Hello,

From Administrator's guide, it is not completely clear what is the

internal difference between mirror mode and n-way multi master. 1) Can 2-way multi master configuration exist? If so, what should be difference in slapd.conf between mirror mode and 2-way multi master? What is the difference in syncrepl behaviour? Or all difference is that external proxy/balancer assumed when mirror mode is meant? 2) Is there quorum based consensus when 3-way multi master is used? If not, how is the conflict resolution performed?