D-Link DGS-1520 Emulator - Page 936

wrr wdrr DGS-1520 Series Gigabit Ethernet Smart Managed Switch CLI Reference Guide Specifies the queues in the frame count Weighted Round-Robin (WRR) scheduling. If the weight of a queue be configured to zero, the queue is in the SP scheduling mode. Specifies the queues of all ports in the frame length (quantum) Weighted Deficit Round-Robin (WDRR) scheduling. If the weight of a queue be configured to zero, the queue is in the SP scheduling mode. Default The default queue scheduling algorithm is WRR. Command Mode Interface Configuration Mode. Command Default Level Level: 12. Usage Guideline Specify schedule algorithms to WRR, SP, RR or WDRR for the output queue. By default, the output queue scheduling algorithm is WRR. WDRR operates by serving an accumulated set of backlogged credits in the transmit queue in a round robin order. Initially, each queue sets its credit counter to a configurable quantum value. Every time a packet from a CoS queue is sent, the size of the packet is subtracted from the corresponding credit counter and the service right is turned over to the next lower CoS queue. When the credit counter drops below 0, the queue is no longer serviced until its credits are replenished. When the credit counters of all CoS queues reaches 0, the credit counters will be replenished at that time. All packets are serviced until their credit counter is zero or negative and the last packet is transmitted completely. When this condition happens, the credits are replenished. When the credits are replenished, a quantum of credits are added to each CoS queue credit counter. The quantum for each CoS queue may be different based on the user configuration. To set a CoS queue in the strict priority mode, any higher priority CoS queue must also be in the strict priority mode. WRR operates by transmitting permitted packets into the transmit queue in a round robin order. Initially, each queue sets its weight to a configurable weighting. Every time a packet from a higher priority CoS queue is sent, the corresponding weight is subtracted by 1, and the packet in the next lower CoS queue will be serviced. When the weight of a CoS queue reaches zero, the queue will not be serviced until its weight is replenished. When weights of all CoS queues reach 0, the weights get replenished at a time. Example This example shows how to configure the queue scheduling algorithm to the strict priority mode. Switch#configure terminal Switch(config)#interface eth1/0/1 Switch(config-if)#mls qos scheduler sp Switch(config-if)# 83-12 mls qos trust This command is used to configure the trust state of a port to trust either the CoS field or the DSCP field of the arriving packet for subsequent QoS operation. Use the no form of this command to revert to the default setting. mls qos trust {cos | dscp} no mls qos trust 932