Let me introduce a few failure scenarios here, supposing I have an Omada Mesh network properly set up as fallback, but not yet actually being used as a backhaul because the wired uplinks are working up until this incident time T where one of the described failure modes occur. Which events follow this incident?

1. The EAPs are PoE-powered by a single cable acting as the sole uplink and the switch goes down partially: a mistyped ACL is put in place impeding cross L2 traffic (usually named L3 ) however there are other APs not affected by this ACL in the same L2 domain and/or or in a different L3 domain.

   1. Chatter continues on wired L2 if some EAP has some other form of uplink.

   2. EAPs switch to wireless mesh and the ACL is effectively circumvented.

   3. Mesh continues through wired fabric (I'm not sure if this is a supported operation mode) if the unaffected EAPs are in the same L2 domain.

   4. This situation was not predicted and connectivity isn’t attainable anymore.

2. The EAPs are PoE-powered by the PoE injector but the uplink switch goes down completely:

   1. EAPs switch to wireless mesh as long as one of the participants has a form of uplink.

   2. This situation was not predicted and connectivity isn’t attainable anymore.

3. The EAPs are PoE-powered by the supplied PoE injector where the connected mains are not protected by any kind of UPS solution, bringing PoE supply down with it when a blackout happens. All EAPs, though, are connected to a capable and ready to run uplink with 802.3af/at ports, so they stop for a brief while but come back up again in a few seconds. The OC200 may or may not be connected and powered to and by this same switch.

   1. The wireless mesh is reestablished in a few moments even without help from the OC200.

   2. The wireless mesh is reestablished if, and only if, the OC200 is reachable through some EAP the whole time.

   3. Mesh connectivity must wait for the OC200 to come back up.

   4. This situation was not predicted and connectivity isn’t attainable anymore.

Of course, "none of the above and here's why your understanding is so stupendously wrong that I don’t even know where to start explaining basic netmasks to a baboon" is always a valid answer.

Cheers!