1. A computer-implemented method, comprising: receiving application information that defines two or more traffic flows associated with two or more message types generated by a particular application program, including information identifying one or more points at which the application generates the traffic flows; receiving, for a particular network device in a network that comprises a plurality of other heterogeneous network devices, device information that defines one or more quality of service treatments that the particular network device is capable of applying to data processed by the particular network device; based on the device information and the application information, determining one or more processing policies that associate the traffic flows with the quality of service treatments; creating and storing one or more mappings of the application information to the quality of service treatments that may be used with the processing policies to generate a quality of service value when the application program generates traffic flows of one of the message types; causing generation of the quality of service value, wherein the generation of the quality of service value is based on said one or more mappings and is performed before transmitting said traffic flows of one of the message types to said network; enforcing one of the processing policies at the particular network device in response to receiving traffic from the application program that matches one of the traffic flows of the one of the message types.