Have you tested the Huawei unit? Have you tried using iPERF3 to run your tests across your bridge? i'd be curious to see if that 225Mbps figure increased somewhat. For what it's worth, i'd consider possibly adding a second set of p300's over a bridge you already know has packet loss. using STP to either balance out your load, or failover if one bridge should falter might be better. one question i would ask, what is your link utilization also, are you needing 600Mbps?