I set all the routers with fixed ip, etc...
as you can see in the graphic ( https://dl.dropboxusercontent.com/u/11910758/monitoring2.png ) the connection between the main router (01) and the bridge router (wumc710) sometimes have an issue. as consequence the router 02 also. but the main problem is that after the bridge has problem (even a few seconds - that should not ) the router 02 must be restart to start working again....
last week when I set the fix ip on the router 02 I made a full restart (factory defaults)...
no idea on what can be done...