Techniques are described for centralized management of quality of service (QoS) characteristics of network data flows. A service management system maintains a database that associates access information, such as a username and password, with QoS information. A router of other network device associates a data flow with access information, and queries the service management system with the access information to obtain the QoS information. The router forwards data of the data flow in accordance with the QoS information obtained from the service management system. As the access information may be a username and password, an existing system, such as a Remote Authentication Dial-In User Service (RADIUS) system, may easily be adapted for use as the service management system. As a result, QoS information may easily be centrally managed for numerous routers or other network devices.