ART has been the default routing table backend in OpenBSD for some months now. That means that OpenBSD 6.0 will no longer consult the 4.3 BSD reduced radix tree to perform route lookups.

The principal motivation for adopting a new tree implementation can be explained in three letters: SMP.

I'll describe in a different context why and how ART is a good fit in our revamp of OpenBSD network stack. For the moment, let's have a look at the single-thread performances of this algorithm in OpenBSD -current.