消息包中的内容如下:
1 Gate:DA=MAC Control,SA= OLT MAC address,content=Grant+sync time
2 Register_req:DA= MAC Control,SA=ONU MAC address,conten=Panding grants
3 Register:DA=ONU MAC address,SA=OLT MAC address,content=LLID+
Sync time+pending grants
4 Gate:DA=MAC Control,SA=OLT MAC address,content=Grant
5 Register_ACK:DA=MAC Control,SA=ONU MAC address,content=echo of LLID
+echo of sync time.