Configuring Relative Strict-Priority Scheduling for Aggregate Shaping Rates

To configure relative strict priority scheduling for aggregate shaping rates:

1. Create a scheduler profile for the strict-priority queue.
   host1(config)# scheduler-profile relativeStrict host1(config-scheduler-profile)# shaping-rate 500000 host1(config-scheduler-profile)# weight 0 host1(config-scheduler-profile)# exit

   Configuring the weight of 0 reduces latency and jitter.

2. Create a scheduler profile for the nonstrict best-effort queue.
   host1(config)# scheduler-profile be host1(config-scheduler-profile)# shaping-rate 1000000 burst 1 host1(config-scheduler-profile)# weight 8 host1(config-scheduler-profile)# exit

   Tip: If you need to impose a shaping rate on the nonstrict queues to meet a functional requirement, you can specify a rate less than the aggregate rate. The key is that the burst size must be one, or small. The burst size determines the maximum-sized packet that can squeeze in front of a relative strict-priority packet in the round robin.

3. Create a scheduler profile for the aggregate bandwidth.
   host1(config)#scheduler-profile vcAggregate host1(config-scheduler-profile)#shaping-rate 1000000 host1(config-scheduler-profile)#exit
4. Create a QoS profile, configure node shaping for each queue, and add each of the queues to the QoS profile.
   host1(config)# qos-profile relative-strict-aggregate host1(config-qos-profile)# atm-vc node scheduler-profile vcAggregate host1(config-qos-profile)# atm-vc queue traffic-class best-effort
   scheduler-profile be host1(config-qos-profile)# atm-vc queue traffic-class voice scheduler-profile relativeStrict host1(config-qos-profile)# exit host1(config)#

This configuration creates the hierarchy shown in Figure 1.

Figure 1: Sample Relative Strict-Priority Scheduler Hierarchy