3Com S7902E, Руководство по настройке

Страница: 1790 / 2621

5
Figure 12-1 QoS model for uplink traffic in an EPON system
QoS Functions for Downlink Traffic
Processing on an OLT
z
Configuring the OLT to perform priority mapping for packets received from the uplink port
according to the CoS-to-local precedence mapping table and then assign packets to output
queues of the OLT port.
z
Configuring the OLT to perform congestion management for downlink traffic, supporting SP and
WRR queue scheduling algorithms.
z
Configuring the OLT to perform line rate and traffic shaping for downlink traffic.
z
Configuring the maximum downlink bandwidth that the OLT assigns to the ONU.
z
Configuring high-priority packet buffer for downlink traffic that the OLT sends to the specified ONU.
Processing on an ONU
z
Filtering the packets matching certain match criteria according to the configured QoS policy.
z
Configuring the ONU to distribute the received downlink traffic to different output queues based on
the mapping between the CoS precedence and local precedence.
z
Configuring the ONU to perform traffic policing for downlink traffic of a UNI.
Some ONUs support configuring queue scheduling for traffic from a UNI. To perform such
configurations, you should log in to the ONU. For detailed configuration, refer to the ONU user manual.
Figure 12-2 shows the QoS model for downlink traffic in an EPON system.
Figure 12-2 QoS model for downlink traffic in an EPON system