I've a backbone and ap, and cpes

with this structure

PPPOE Server (Router OS Level 5) -- PointToPoint bRIDGE -- StationPseudoBridge -- switch -- ap bridge -- cpe in station wds

the pppoe connection of the cpe after few minutes freeze, and the respective pppoe interface on pppoe server crash, but the client does not disconnect pppoe connection.

i suppose a comunication problem between StationPseudoBridge switch and ap

all routerOS version is 3.6 before 3.5 and 3.4 but the problem persists.

pppoe server is a xeon dual core hp dl 320 G5

ps the authentication is with an radius server but i have the same problem with the pppoe built in secrets.
if i test a pppoe connection only with p2p works fine.