Configuring Congestion Management (Schedule Template Mode)

Pre-configuration Tasks

Before configuring congestion management, map the priority of packets to a PHB.

Context

Both WRR and WDRR use weights. WRR schedules packets in queues based on the number of packets, whereas WDRR schedules packets in queues based on the number of bytes.

There are eight queues on each interface. Different queues can use different scheduling modes, but each queue can use only one scheduling mode. Scheduling modes supported on the device include PQ, WRR, WDRR, PQ+WRR, and PQ+WDRR. When PQ+WRR or PQ+WDRR scheduling mode is used, the device schedules the queues using PQ scheduling first. If multiple queues using PQ scheduling exist, the device schedules the queues in descending order of priority. A larger queue index indicates a higher priority. After PQ scheduling is completed, the device schedules the queues using WRR or WDRR scheduling.

Only the S2720-EI, S5720I-SI, S5720-LI, S5720S-LI, S5720S-SI, S5720-SI, S5730S-EI, S5730-SI, S6720-LI, S6720S-LI, S6720S-SI, and S6720-SI support congestion management using a schedule template.

Procedure

Run system-view
The system view is displayed.
Run qos schedule-profile profile-name
A global schedule template is created and the schedule template view is displayed.
Run qos { pq | wrr | drr }
The scheduling mode of a port queue is set to PQ, WRR, or WDRR.

By default, WRR scheduling is used.
Configure WRR or WDRR weights for port queues.
- If the scheduling mode is WRR, run the qos queue queue-index wrr weight weight command to set the WRR weight for a port queue.
  
  By default, the weight in WRR mode is 1.
  
  Perform this step only when the scheduling mode of a port queue is set to PQ+WRR or WRR.
  
  When WRR scheduling is applied and the weight of a queue is set to 0, the queue applies PQ scheduling and other queues apply WRR scheduling. When configuring the PQ+WRR scheduling mode, ensure that the queues with weight 0 (queue using PQ scheduling) are consecutively configured, without being interrupted by the configuration of the queues using WRR scheduling.
- If the scheduling mode is WDRR, run the qos queue queue-index drr weight weight command to set the WDRR weight for a port queue.
  
  By default, the weight in WDRR mode is 1.
  
  Perform this step only when the scheduling mode of a port queue is set to WDRR or PQ+WDRR.
  
  When WDRR scheduling is applied and the weight of a queue is set to 0, the queue applies PQ scheduling and other queues apply WDRR scheduling. When configuring the PQ+WDRR scheduling mode, ensure that the queues with weight 0 (queue using PQ scheduling) are consecutively configured, without being interrupted by the configuration of the queues using WDRR scheduling.
Run quit
Return to the system view.
Run interface interface-type interface-number
The interface view is displayed.
Run qos schedule-profile profile-name
The scheduling template is applied.

Verifying the Configuration

Run the display qos configuration interface [ interface-type interface-number ] command to check all the QoS configurations on a specified interface.
Run the display qos queue statistics interface interface-type interface-number [ queue queue-index ] command to check the queue-based traffic statistics on the interface.