Compared with PSTN network, what are the advantages of NGN network? (Multiple choice)

Which of the following descriptions about GP ON Type C single-homing protection is correct?

The number of users under the OLT can also determine whether the VLA adopts single-layer or double-layer VLAN mode. Single-layer VLAN can be used when the number of users is small, and double-layer VLAN must be used when the need to differentiated services and the number of users is second to ().

Traffic suppression on the uplink port of MA5680T suppresses multicast only for unknown multicast traffic.

The maximum upstream and downstream concurrent bandwidth required by the ONU is 200 Mbps upstream and 500 Mbps downstream. When using GPON access, what is the maximum splitting ratio that should be planned?