Packet scheduling in a network processor

A circuit operates to manage transmittal of packets in a network packet processor. The circuit includes a packet descriptor manager (PDM), a packet scheduling engine (PSE), and a packet engines and buffering module (PEB). The PDM generates a metapacket and a descriptor from a command signal, where the command signal identifies a packet to be transmitted by the circuit. The PSE models the packet through a model of the network topology, determining an order in which to transmit the packet among a number of packets based on the modeling. Once the packet is scheduled for transmission, the PEB performs processing operations on the packet to produce a processed packet based on instructions indicated in the descriptor. The PEB then causes the processed packet to be transmitted toward the destination.