Regarding the T-CONT of ONT, the following statement is wrong:

ICMP is a link layer protocol, ICMP message is triggered by the physical layer, and then respond by IP layer or a higher layer protocol.

In GPON network, which of the following description is correct?

The value of PPP protocol's PROTOCOL field is 8021, what is the representative of protocol?

(single) Is the following description correct? ONT call emulation refers to the use of the ONT test module instead of the user's phone for call testing. When the ONT POTS user cannot provide voice services, the ONT call emulation test is performed remotely through the OLT command line to help the user diagnose whether the POTS user call of the ONT is normal. ONT can be offline when performing ONT call sim-ulation