A user application may provide a hint which may be used by a compute device to select a tag to be inserted into the packets generated by the user application. Upon some event, the application transmits a hint associated with a network flow generated by the user application to a stack associated with the computing device. One of the layers of the stack—e.g., the operating system in the computing device—may include a hint database that contains rules for selecting tags using a received hint as input. The layer may then insert the tag into one or more packets of the network flow. When processing the packet, network devices in the SDN enabled network recognize the tag and perform an action corresponding to the tag.