If I may ask here. One thing that would be nice for the records is to get a little bit more details on your setup doing that if you have no problem providing it obviously. Specially the PF configuration tie to this bgp router as well may well be very educating to many.
I don't know how up-to-date is, but it's a good reference: http://www.bsws.de/en/technic/network.shtml
I always wonder what simple difference from stock install might be there in the hardware or sysctl to get there, what network card are use now, but more important is the PF configuration use in some router as well. I really do not recall have seen one email on the subject. That would be great to have. Not something to preach by, but something useful and base line if you want to start with.
If you search in misc@ archive you'll find a lot of interesting PF/NICs/BGPD/HARDWARE/NETWORK-related threads. The needed info is out here, sure.
In https://calomel.org/ you have a lot of very useful and clear documents too.
As usual, we also have the main source: the code. -- Thanks, Jordi Espasa Clofent