1. A security device for processing a plurality of network flows, comprising: one or more packet processors configured to receive incoming data packets associated with one or more network flows, at least one of the packet processors being assigned as an owner of one or more network flows, and each packet processor processing data packets associated with flows for which it is the assigned owner; and a packet processing manager configured to assign ownership of network flows to the one or more packet processors, the packet processing manager comprising a global flow table containing global flow table entries mapping network flows to packet processor ownership assignments and a predict flow table containing predict flow entries mapping predicted network flows to packet processor ownership assignments, wherein each predict flow entry comprising a predict key and associated packet processor ownership assignment, the predict key comprising a plurality of data fields identifying a predicted network flow where the value of one or more of the data fields is unknown.