The Remote Desktop Connection Broker role service supports session load balancing between RD Session Host servers in a farm, and reconnection to an existing session in a load-balanced RD Session Host server farm.
<ClassType ID="Microsoft.Windows.Server.2012.RemoteDesktopServicesRole.Service.RDConnectionBroker" Accessibility="Public" Abstract="false" Base="Microsoft.Windows.Server.2012.RemoteDesktopServicesRole.Service" Hosted="true" Singleton="false"/>