Packet classification provides a means by which packets internal to a specific network node can be classified, and consequently prioritized, within and by both user- and kernel-mode network components. Such classification and prioritization uses include activities such as CPU processing attention, or transmission onto the network. The Generic Packet Classifier (GPC) is utilized through an interface called the Generic Packet Classifier Interface, or GPC Interface, which facilitates an "information store" that can be used, or associated, with specified (defined) subsets of packets.
The GPC's importance hinges on its ability to provide lookup tables and classification services within the network stack, and is thus the first step in an overall and ubiquitous prioritization scheme for network traffic.