What gives priority on an egress interface, for database traffic that connected on an ingress interface, without changing the CoS value?

A QoS group is a locally significant identifier used for internal classification within a device, not directly for prioritizing traffic on an egress interface without a policy map applying an action to it.

A policy map is a QoS configuration component that defines classes of traffic and applies specific QoS actions such as setting bandwidth, queueing, or policing to them on an interface. This mechanism allows traffic to be prioritized based on its classification without modifying its existing CoS value.

A CoS map typically maps CoS values to internal QoS groups or output queues, but it does not independently define how priority is given to traffic without an overarching policy map.

A class map is used to classify traffic based on various criteria, but it only identifies the traffic; it does not apply an action or prioritize it by itself and must be associated with a policy map.