Epon System Parameter Configuration - 3Com S7906E Configuration Manual

EPON System Parameter Configuration

Configuring the maximum ONU-OLT RTT
During ONU registration, an OLT obtains the Round Trip Time (RTT) value of an ONU through the
exchange of discovery GATE messages and REGISTER_REQ messages between the OLT and the
ONU. By configuring a maximum RTT at the OLT side, you can set the coverage range of the EPON
system. An ONU whose RTT is greater than the RTT configured on the OLT cannot be registered.
Setting a short RTT prevents ONUs too far away from the OLT from being registered with the EPON
system (a far-away ONU suffers high optical power attenuation). Setting a long RTT can expand the
coverage range of the EPON system, allowing as many ONUs as possible to be registered successfully.
The process of RTT measurement is as follows:
1) The OLT sends an ONU a discovery GATE message containing the OLT local time T
time stamp in the discovery GATE message is T
2) Upon receiving the discovery GATE message, the ONU modifies its local time to be the time stamp
T in the message and sends a REGISTER_REQ message to the OLT at T
0
stamp of the REGISTER_REQ message is T
3) The OLT receives the REGISTER_REQ message at T
4) The OLT calculates the ONU RTT by using the formula: RTT=(T
5) If the OLT becomes idle at T
is { T3-RTT, ∆T }. That is, the ONU will start sending data at T3-RTT and send data for a period of
∆T.
Follow these steps to configure EPON system parameters:
To do...
Enter system view
Enter OLT port view
Configure the Maximum
ONU-OLT RTT
Exit to system view
Enter FTTH view
Configure OUI and extended
OAM version number list
Configure the key update time
and encryption reply timeout
time of the encryption
0.
).
1
and remains idle for a period of ∆T, the timeslot assigned to the ONU
3
Use the command...
system-view
interface olt interface-number
max-rtt value
quit
ftth
epon-parameter ouilist { oui
oui-value oam-version
version-value } &<1-9> slot
slot-number
encryption timer { update
update-time |
no-reply-timeout timeout }*
slot slot-number
2-2
after a delay (the time
1
.
2
-T )-(T -T )=T
2 0 1 0
Remarks
—
—
Optional
13524 TQ by default
—
—
Required
By default, the OUI and
extended OAM version number
must be configured as 111111
and 1 respectively.
Optional
By default, the key update time
is 10 seconds and the
encryption reply timeout time is
3000 milliseconds.
, namely, the
0
-T .
2 1