ap-bridge <> station-bridge is still what you need to ptp.
But what is the established practice to connect two ap-bridge radios?
as far as rstp, I guess I don't see where the loop is coming in. If you could provide some more details as to where you are having a layer2 segment loop... Anyway, rstp wont hurt, its just some overhead so you can leave it on if you are concerned.
Give three APs "A", "B" and "C", where A has bridged ptp links to both B and C; B has bridged ptp links to both A and C; and C has bridged ptp links to both B and C; then there is a cycle in which a broadcast packet (for example) could be forwarded from A, to B, to C, to A, etc. (RSTP detects the cycle and choose of the three two-way links above to disable.)
If you are putting in multiple links for redundancy, you might want to look at something more than rstp
Redundancy is the idea. In fact what we want is a 5GHz backhaul mesh, except I'm concerned that using a mesh rather than a bridge would result in problems where we use non-MT switches, which do not support the HWMP+ protocol. For example, suppose two APs are linked by both radio backhaul, and by Ethernet through a non-MT switch. Would HWMP+ detect the loop?
like doing OSPF to load balance two links...
I would love
to set up OSPF, since our backbone will soon be too large to be a single broadcast domain. A working configuration is going to take some trial and error though, as my networking experience is limited (background in software development).