Advanced QoS policies

The adv-config-policy contains queue and policer configuration parameters that are not expected to be useful to most users. The policy only contains queue and policer child control parameters within a child-control node.

The parameters within the child-control node are intended to allow more precise control of the method that hierarchical virtual scheduling employs to emulate the effect of a scheduling context upon a member child queue or policer.

When a policy is created, it may be applied to a queue or policer defined within a sap-egress or sap-ingress QoS policy. It may also be applied to a queue or policer defined within an ingress or egress queue-group template. When a policy is currently associated with a QoS policy or template, the policy may be modified but not deleted (even if the QoS policy or template is not in use).

While the system maintains default values for the advanced configuration parameters, no default adv-config-policy exists.

For information about the tasks and commands necessary to access the CLI and to configure and maintain the router, see the Entering CLI Commands chapter in the 7450 ESS, 7750 SR, 7950 XRS, and VSR Classic CLI Command Reference Guide.

When the H-QoS algorithm within a port scheduler policy is configured to above-offered-allowance-control, it is possible to tune the distribution of unconsumed bandwidth for parented queues. This is achieved by applying an advanced configuration policy to the queue and configuring the following:

configure
  qos
    adv-config-policy
      child-control
        bandwidth-distribution
          above-offered-allowance
            unconsumed-agg-rate percent <percent-of-unconsumed-agg-rate>
            delta-consumed-agg-rate percent <percent-of-delta-consumed-agg-rate>
            unconsumed-higher-tier-rate percent <percent-of-unconsumed-higher-tier-rate>
            delta-consumed-higher-tier-rate percent <percent-of-delta-consumed-high-tier-rate>

When above-offered-allowance-control is enabled, both queues and schedulers use the default values. Default values of the percentages lists the default values for the percentages.

The percentage values can be tuned for parented queues by applying an advanced configuration policy to the queue with modified percent values.

See H-QoS algorithm selection, for information about the use of the parameters with the above-offered-allowance-control H-QoS algorithm.

An advanced QoS policy must conform to the following:

• Each advanced policy must have a unique policy ID.

• Default values can be modified but parameters cannot be deleted.

ALA-7>config>qos# info
#------------------------------------------
echo "QoS Policies Configuration"
#------------------------------------------
...
        adv-config-policy "childPolicy1" create
            description "Test"
            child-control
                offered-measurement
                    add percent 30
                    granularity percent 30
                exit
                bandwidth-distribution
                    above-offered-cap percent 5
                    granularity percent 5
                exit
            exit
        exit
...
#------------------------------------------
ALA-7>config>qos# 

This section discusses advanced QoS policy service management tasks.