Communication resilience in a ring network topology

A top optical line terminal (“OLT”) comprising:

• a memory;
• and
• a translation apparatus, including one or more data processors, configured to execute instructions that, upon execution, cause the top OLT to perform operations comprising:
• receiving, in a Ring Network Topology (“RNT”) that includes multiple additional Ethernet nodes, downstream traffic that (i) is traffic that enters into the RNT from a top Ethernet node, (ii) is destined to egress the RNT through a node that is not the top Ethernet node, and (iii) has a virtual local area network (“VLAN”) service address;
• determining which Ethernet Linear Protection Switch (“ELPS”) to forward based on a discovery of upstream traffic learned that is sourced from a different node than the top Ethernet node of the RNT and egresses the top Ethernet node of the RNT;
• determining that the downstream traffic is destined for a device serviced by a given Ethernet node, from among the multiple additional Ethernet nodes, that terminates a given ELPS group;
• monitoring connected ends between two Ethernet nodes on a given path made of two ELPS endpoints via ELPS protocols;
• determining a given VLAN subnetwork that has been mapped to the given ELPS group;
• and
• transmitting the downstream traffic through the RNT using the given VLAN subnetwork and based on a current ELPS protection state of working path or protection path.

A non-transitory computer readable medium storing instructions that, upon execution by one or more data processing apparatus, cause the one or more data processing apparatus to perform operations comprising:

• receiving, in a Ring Network Topology (“RNT”) that includes multiple additional Ethernet nodes, downstream traffic that (i) is traffic that enters into the RNT from a top Ethernet node, (ii) is destined to egress the RNT through a node that is not the top Ethernet node, and (iii) has a virtual local area network (“VLAN”) service address;
• determining which Ethernet Linear Protection Switch (“ELPS”) to forward based on a discovery of upstream traffic learned that is sourced from a different node than the top Ethernet node of the RNT and egresses the top Ethernet node of the RNT;
• determining that the downstream traffic is destined for a device serviced by a given Ethernet node, from among the multiple additional Ethernet nodes, that terminates a given ELPS group;
• monitoring connected ends between two Ethernet nodes on a given path made of two ELPS endpoints via ELPS protocols;
• determining a given VLAN subnetwork that has been mapped to the given ELPS group;
• and
• transmitting the downstream traffic through the RNT using the given VLAN subnetwork and based on a current ELPS protection state of working path or protection path.