US Patent 9998955 Multi-tier stateful network flow management architecture

A packet transformation node of a multi-tier flow management system receives a packet of a particular network flow. The packet transformation node produces a modified version of the packet with changes to one or more header elements based on a rewrite entry generated at a rewriting decisions tier of the system, and transmits the modified version to a destination. A rewriting decisions node of the system generates rewrite entries corresponding to various packet processing requirements, based at least partly on state information regarding various flows for which rewriting entries have already been generated.