If the service board of the device is a GPON service board, the device has two multicast forwarding mechanisms and you can configure the forwarding mechanism based on MVLAN.

Single-copy duplication

This is the most common duplication mode of GPON multicast (it also refers to the mode mentioned in this document unless otherwise stated). This mode makes the best of the GPON downstream WDM transmission principle and sends multicast data to all ONTs using the non-encrypted GEM port bearer channel. Each ONT receives the multicast data according to the multicast filtering table. For the corresponding hardware forwarding entry, see "Multicast Forwarding Table."

Multi-copy duplication

The primary difference between single-copy duplication and multi-copy duplication is that, in multi-copy duplication, multicast data is duplicated to corresponding service ports according to user requirements, encapsulated in the encrypted unicast GEM port channel, and then sent to the ONT. The following table shows the multicast forwarding table at the GPON board level.