Examples include sampling a transmit rate of an egress port queue on a destination node, determining a utilization percentage of the egress port queue based on the transmit rate and a total rate capacity of the egress port, and determining a backlog percentage of the egress port queue. Examples also include determining an output rate for a virtual output queue on a source node based on the utilization percentage and the backlog percentage. The virtual output queue is for the egress port queue.