Is it possible? brconfig man pages says: The bridge has support for 802.1D Spanning Tree Protocol (STP), which can be used to detect and remove loops in a network topology. Using the stp or -stp commands to brconfig, STP can be enabled or disabled on each port. STP will not work on gif(4) members because they lack a hardware MAC address.
So I assume that it isn't, but in case anybody knows any workable solution over OpenBSD I would like to know. I would prefer this solution instead of having to fight with Cisco gear and L2TP which seems much more complex (and expensive!). I need a bridge over the internet in case the long fiber link between our main and secondary datacenter fails (bandwidth difference is huge, but it would suffice for our critical apps). STP is necessary for obvius reasons. Thanks in advance, Samuel