In addition to the right click menu on the node itself, the user can start or stop either the Source or Destiniation nodes from within any scripting window with the QIE channel functions.
qie.isSourceNodeRunning();
qie.stopSourceNode();
qie.startSourceNode();
qie.isDestinationNodeRunning('endpointId');
qie.stopDestinationNode('endpointId');
qie.startDestinationNode('endpointId');