Hello NANOG, We are currently in the process of rolling out a Motorola GPON solution and running into some hiccups and wanted to see if we were doing something unique or if anyone else has run into the issue and we just haven't found the right solution. Our configuration has the OLTs using single tagged VLANs down to each customer ONT, rather than using Q in Q connections. This VLAN is shared among all customers that terminate at a single site, which may have 1-2 OLTs sharing that same VLAN. This VLAN is then carried back via switching to our core equipment which handles routing. We have noticed that malfunctioning customer equipment have generated loops on the network which has caused unusual forwarding problems in the OLT, and many of the ONTs we are in the process of deploying, 1400GTI, don't include the ability to detect these loops. If anyone wants more information feel free to follow up with me off list. We are hoping we aren't the only ones attempting this and can find a sane solution to the issue. Josh Hoppes Cedar Falls Utilities