Good morning! I’m new here, so if this is an inappropriate place for this, please feel free to kick me and laugh.
It would be very handy if dual-port radios like the ePMP 4600c that we use had an option for arp-mon bond. It’s very simple to do in Linux. Here’s an example situation:
I have a 20km 60GHz link. Unfortunately it’s not operating in Siberia, so I need a rain-fade. Currently we build mini PC’s with at least 3 network interfaces, built a bridge with a bond and put the 60GHz as the primary and the rain fade link as the backup. Works great, but it also means adding a PC at the tower site, and that means putting a whole cable run up to both the primary and backup radios, then also to whatever switching hardware I happen to have on the tower. I’m sure everyone knows how annoying that could be at FM sites!
Instead, let’s say a bond is inside the ePMP with the primary port being the SFP+ and the backup being the WLAN interface. Set the ethernet port as a bridge onto the bond and connect that port to whatever is on the tower. Tada! Automatic failovers that work in a matter of a few milliseconds.
Yes, I know that MikroTik switching hardware has an arp monitor bond, but they face multiple major disadvantages.
Of course, the primary radio on the tower may be multi-gigabit, so having the gigabit port on the radio act as a bridge might not be ideal. I’ll be honest, I’ve been pitching this idea to Ubiquiti, since it’s such a mind-numbingly simple piece of code, but I’m not sure they still have any developers left.
And also, could someone who managed the site please fix the “Point-to-oint” on the PTP graphic on Fixed Wireless Access - Cambium Networks ? 
Bugs me every time I see it.
Thank you for pointing this out. I’ve let the relevant people know (and also mentioned the “netowrk” typo).