Passive Optical Networks

2. The OLT transmits a Discovery GATE message with StartTime. GATE is a

message to the ONU which notifies the time range in which upstream data

can be transmitted. The GATE used for ranging is called the Discovery

GATE.

3. An ONU which has no LLID assigned first set its local time to the value of

Timestamp of the Discovery GATE received. After waiting for a random

length of time Twait from the StartTime specified in the Discovery GATE, it

transmits a Register Request message. The maximum value of random wait is

also specified in the Discovery GATE. The ONU local time (¼ StartTime þ

random delay) is written in the Timestamp of Register Request.

4. For a Register Request which was received normally at the OLT, the OLT

calculates the RTD ¼ OLT local time ...