Hello, friend!
From the perspective of network architecture, PON does not need to be connected to a ring network.
You can perform transparent transmission in two directions on the network.
The VLAN that the MA5680T transparently transmits to the upstream port must be changed to another upstream port of the MA5680T.
For more information about networking protection, See Product Documentation > Feature Description > Networking Protection Feature > RRPP.
Thanks!