Implementations of some subset matching schemes.
The most straight-forward solution, which provides subset matching at line-rate, is to map all of the possible queries to a set of multicast groups.
A solution to subset matching is to simply use a single multicast group to send a copy of each packet to all interfaces and then, drop the redundant copies for interfaces that are not in the multicast group at the egress pipeline.
With bitstring compression, we map sets of inputs to conservative covering multicast groups, and then rely on egress pruning to remove unnecessary replicas.
Each implementation is a self-contained p4app. For example, you can run:
p4app egress_prune_v14.p4app