Pipeline chaining

A network forwarding integrated circuit (IC) for processing network packets, the network forwarding IC comprising:

• a plurality of packet processing pipelines for receiving and processing packets, wherein each pipeline is configured to operate as an ingress pipeline and an egress pipeline, wherein each packet processing pipeline comprises:
• a parser configured to parse packets into packet header fields;
• a match-action unit configured to receive sets of the packet header fields from the parser and process the packet header fields through a series of match-action stages;
• and
• a deparser configured to receive modified sets of packet header fields from the match-action unit and reconstruct the packets after the match-action unit processing;
• and
• a traffic management circuit configured to receive packets processed by ingress pipelines and to enqueue the packets for output to egress pipelines based on the ingress pipeline processing,
• wherein a set of packets received by the network forwarding IC are processed by a first pipeline as an ingress pipeline and a second pipeline as an egress pipeline, then subsequently processed by the second pipeline as an ingress pipeline and a third pipeline as an egress pipeline.