Hello!
I want to make an optical link reservation.

I have two Mikrotik CRS317 and network.
Two CRS317, they are connected by an optical channel.
And I have a spare channel - from other switches and Antennas.
This channel enters the device as tagged vlan.

And I have make bonding-interface. The settings are the same on both devices.
But somewhere I make a mistake.

This sfpplus1-uplink - its Fiber Port, Uplink.
sfpplus6 it another port, for reserve.
sfpplus6 have tagged vlan air95 ( reserve "link") The same settings on the second device, ip address 192.168.101.121.

I see Bonding Status Active ports sfpplus1-uplink and inactive ports air95.
I run ping between device. And I see packets between devices in optics ports.
If I disable fiber link - I see how the ping goes through air95 (latency up).

But if fiber ports work - untagged traffic going always goes through sfpplus6...
But in Bridge->Ports Bonding interface have PVID 1.
It does not go through optics, but goes through a backup channel. Where did I go wrong?

ps: I can show you the network diagram if needed.

I may be wrong, but I think that bond link members can only be physical ports, not logical as it's air95 in your case. The reason being link monitoring, which is either done by MII (detecting physical link drops) or ARP (which might work with VLAN-type interfaces). Next: bond really works well between adjacent physical devices, e.g. between two switches directly connected with physical links. If there is other equipment on the link which is not bond-aware, then it's pretty hard to reliably detect link status. And additional (doesn't apply in your case) constraint: all bonded physical links should have same properties (throughput, delay) for load balancer to work properly.

In your case, as you need fail-over, you can treat both links as completely independent, and configure failover on routing level.

Yes, it turned out to be a very strange bonding.
But I have no way to physically stretch the wires from the antennas to the Mikrotik.
Now it works very strange.
I think I'll try to set it up again, a little differently.

Any reason you're not just using LACP? 802.3ad is a much better LAG protocol since it has support for both aggregation and failover. It's a dynamic protocol that will work even with some ports disconnected as a "psuedo-failover" mode.

I don't know him, you may be right. I have already been suggested to use stp..
Does bonding work on top of lacp?
Tomorrow I will try to put everything back, remove the bonding.
It turns out that this is also not an easy task.

My network in attachment.
Right link - link between two CRS 317.
Left - spare channel with other switches.
That's it

I'm not an expert but this topology seems to me a prime candidate for RSTP ... with the microwave link having the high path cost so it'll only be used if any of lower path-cost links fail.

Everything pushes me to use STP.
I'll try