Look-Up Engine - 2022.2 English

Vitis Networking P4 User Guide (UG1308)

Document ID
UG1308
Version
2022.2 English
Revision

Look-up engines (look-up tables) are used to implement a search over a variety of different kinds of direct addressable and content addressable tables. Vitis Networking P4 includes a library of different Look-up engine types, which can be one of seven types:

  • Binary content addressable memory - Exact match - EM (BCAM)
  • High bandwidth memory (HBM) - EM (BCAM)
  • Semi ternary content addressable memory (STCAM)
  • Ternary content addressable memory - ACL (access control lists) (TCAM)
  • TinyBCAM
  • TinyTCAM
  • Direct table (DCAM)
Each of these tables takes a user defined header input, metadata input and/or internal defined match-action scalars as a search key and its response is used to trigger its associated actions and to store defined action parameters. Note that Vitis Networking P4 only allows one look-up per packet for each table. These tables are described as follows.