H3C Technologies H3C S7500E Series Switches - Manual (Page 45)

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When the OUI and OAM version number list on an EPON service board changes due to addition
or removal of user-defined list entry, all ONUs under the board will re-register.
It is recommended that you configure the maximum ONU-OLT RTT only when necessary. The
relationship between the RTT and the distance (in meters) from the OLT to the ONU can be
roughly expressed by the formula: RTT = (Distance + 157)/1.6393.
The max-rtt command is applicable to unregistered ONUs only.
The encryption reply timeout time must be less than or equal to the key update time.
Configuring Dynamic Bandwidth Allocation and Related Parameters
Dynamic bandwidth allocation (DBA) is used by an OLT to adjust the uplink bandwidth of individual
ONUs in real time according to the traffic status of the ONUs.
BA is implemented through a request-response mechanism:
An OLT obtains the traffic information of ONUs from the bandwidth requests (REPORT messages)
received from ONUs, uses a suitable bandwidth allocation algorithm to calculate the bandwidth to be
allocated for this cycle within the specified uplink ONU bandwidth range, and notifies the results to the
ONUs through bandwidth authorization (GATE messages). This ensures that uplink data sent by
ONUs will not conflict with each other.
Compared with static (fixed) bandwidth allocation, DBA is more suitable for bursty IP/Ethernet services.
DBA reduces bandwidth wastes and allows for more efficient uplink bandwidth utilization. With DBA
adopted, the order and the time for ONUs to send uplink frames are controlled by the OLT.
There are two types of DBA algorithms: internal DBA algorithm and external DBA algorithm.
The internal DBA algorithm is implemented internally by a chip.
The external DBA algorithm is implemented through loading an external DBA algorithm file.
Follow these steps to configure dynamic bandwidth allocation and related parameters
To do... Use the command... Remarks
Enter system view system-view —
Enter OLT port view interface olt interface-number —
Load the specified
external DBA
algorithm file
dba-algorithm update file-url
Use an
external DBA
algorithm
Use the specified
external DBA
algorithm
dba-algorithm enable extdba
Use the internal DBA algorithm dba-algorithm enable intdba
Use either internal DBA
algorithm or external DBA
algorithm.
By default, the internal DBA
algorithm is used.