For stack performance and reliability, the priority of control packets is elevated over that of data packets.
This is done to prevent control packet loss and avoid the timed retries that can lower performance. It is also done to prevent unneeded stack topology changes that can occur if enough stack topology information packets are lost. For these reasons, the SummitStack feature reserves one QoS profile to provide higher priority to control packets. The following sections describe the differences in QoS while using it in stack.