I'm working on a Transparent LAN Service between to ONTs. I've got enough provisioned where we have connectivity across the network but the customer does plan on having a closed ring and the current configuration is introducing a loop. The problem is that they switch that plugs into the ONT is sending BPDU packets but not receiving anything back. I am assuming that the ONT is blocking BPDU traffic from being sent upstream to the Internet service provider's network. Is there any documentation that can confirm this and provide the configuration to permit BPDU traffic?