Match-Action Engine - 2022.2 English

Vitis Networking P4 User Guide (UG1308)

Document ID
2022.2 English

Match-Action engines are a combination of Look-up engines and Action engines. Multiple actions are mapped, or activated, by the response of a Look-up engine. The Look-up engine response is used to enable only one action engine and store parameters required by the action.

Match-Action engines perform the following sequence of operations:

  • Constructing look-up keys from user defined metadata
  • Table look-up using the constructed key and returning a response
  • Choosing an action and executing it based on the above response
  • Performing programmed computations and returning an output
  • Interfacing to/from user externs

An example of a simple Match-Action engine is provided in Sample P416 Program.