A few improvements suggested to the PPPoE WAN configuration.

1. Neither an MTU nor an MRU value should be required, instead one must accept blank to mean the PPPoE software defaults, not some value supplied by omada developers or users.
2. Document /tell if the devices support PPPoE "Baby Jumbo Frames" (RFC4638) / ppp-max-payload tag. in which case maximum MTU value is not 1492 but 1500. most current server software and linux clients do support it, in which case underlying ethernet device gets an MTU of 1508. There are a lot of fiber ISP using PPPoe which support this option
3. If something fails , it is very dificult to diagnose failure because some message is printed in the controller log and nothing else. provide a debug option.