3Com S7902E, Configuration Manual

Page: 1794 / 2621

9
To do… Use the command… Remarks
Enter system view system-view —
Enter ONU port view
interface interface-type
interface-number
—
Enable the ONU downlink
bandwidth allocation
policy and prioritize
high-priority packets
bandwidth downstream policy
enable
Required
By default, the downlink
bandwidth allocation policy is
disabled and high-priority
packets are not prioritized.
Configure the ONU
downlink bandwidth limit
bandwidth downstream
{ max-bandwidth value |
max-burstsize value } *
Optional
By default, the maximum
bandwidth is 999994 kbps, and
the maximum burst buffer is
8388480 bytes.
z
The configuration of high-priority packet buffering (as shown in Sending buffer size of the OLT port )
and that of the downlink bandwidth limit take effect only when the downlink bandwidth allocation
policy is enabled.
z
The configured downlink bandwidth limitation takes effect only on known unicasts, but not on
unknown unicasts, multicasts, or broadcasts.
z
The sum of the minimum uplink bandwidths configured for all the existing ONU ports under an OLT
port cannot exceed 921600 Kbps, namely, 900 Mbps.
Configuring QoS at the ONU Side
Priority mapping on the ONU port
When the ONU receives packets on an ONU port, it assigns local precedence to the packets according
to the 802.1p-to-local precedence mapping table. Table 12-3 shows the default 802.1p-to-local
precedence mapping table.
Table 12-3 Default mapping between CoS precedence values and local precedence values
CoS precedence Local precedence
0 0
1 0
2 1
3 1
4 2
5 2
6 3
7 3