Tagging is not in 3.3 release or 3.3 stable. It has been added to --current and what will become 3.4 release. If you want to try it out grab the latest snapshot. That is why you are getting errors with brconfig.
http://www.openbsd.org/34.html <snip> A large number of bug fixes, changes, and optimizations to our packet filter pf(4) including: * packet tagging (e.g. filter on tags added by bridge based on MAC address) * stateful TCP normalization (prevent uptime calculation and NAT detection) * passive OS detection (filter or redirect connections based on source OS) * SYN proxy (protect servers against SYN flood attacks) * adaptive state timeouts (prevent state table overflows under attack) </snip> Jason Houx
