I also have problems, with pause frames bringing down the network even with flow control on the switch disabled. One customer has an old broken D-Link router which hangs after about 10-15 minuts uptime and then starts spewing pause frames like mad (flow control can't be disabled on that router). This causes other customers connected to the same switch to lose connection (link still up but no PPPoE traffic can flow), the switch blinks all LEDs and its IP becomes unreachable too. Even ACL configured to pass only PPPoE frames (8863/8864 unicast in both directions, and 8863 broadcast from customers) doesn't help, pause frames seem to bypass it. The RB250GS (latest firmware - 1.13) doesn't crash, everything returns to normal as soon as that broken router is turned off. I had the same issue with a cheap non-managed TP-Link 5-port switch, and hoped to solve it with the RB250GS. Or do I need a RB750 for this kind of bridge filtering (block pause frames)? Don't need gigabit, it's all behind a LocoM5 anyway (which fortunately doesn't pass these evil pause frames further upstram, as that could bring down the rest of much larger network).