Advanced QoS policies
Overview
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.
Port scheduler above offered allowance control
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.
Parameter |
Default Value |
---|---|
delta-consumed-agg-rate percent |
20 |
delta-consumed-higher-tier-rate percent |
5 |
unconsumed-agg-rate percent |
100 |
unconsumed-higher-tier-rate percent |
100 |
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.
Basic configurations
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.
Creating an advanced QoS policy
Configuring and applying advanced policies is optional. If no advanced policy is explicitly applied to a SAP or IP interface, then no default advanced policy is applied.
To create a new advanced policy, define the following:
a slope policy ID value. The system does not dynamically assign a value.
a description. The description provides a brief overview of policy features.
the child control parameters, which 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
The following displays an example of an advanced policy configuration:
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#
Applying advanced policies
Apply advanced policies to the following entities.
Queue group
Use the following CLI syntax to apply advanced policies to ingress queue groups.
config>qos queue-group-templates ingress queue-group group1 policer 1 adv-config-policy child1
Use the following CLI syntax to apply advanced policies to egress queue groups.
config>qos queue-group-templates egress queue-group group1 policer 1 adv-config-policy child1
SAP ingress
Use the following CLI syntax to apply advanced policies to an ingress SAP.
qos sap-ingress 11 policer 1 adv-config-policy child1 queue 1 adv-config-policy child1
SAP egress
Use the following CLI syntax to apply advanced policies to an egress SAP.
qos sap-egress 11 policer 1 adv-config-policy child1 queue 1 adv-config-policy child1
Default advanced policy values
The default policies cannot be edited or deleted. Advanced policy parameter defaults lists default advanced policy parameters.
Field | Default | |
---|---|---|
offered-measurement |
||
high-rate-hold-time |
0 |
|
time-average-factor |
0 |
|
sample-interval |
1 |
Service management tasks
This section discusses advanced QoS policy service management tasks.
Deleting QoS policies
Delete advanced policies from the following entities.
Queue group
Use the following CLI syntax to delete advanced policies from ingress queue groups.
config>qos queue-group-templates ingress queue-group group1 policer 1 no adv-config-policy
Use the following CLI syntax to delete advanced policies from egress queue groups.
config>qos queue-group-templates egress queue-group group1 policer 1 no adv-config-policy
SAP ingress
Use the following CLI syntax to delete advanced policies from an ingress SAP.
qos sap-ingress 11 policer 1 adv-config-policy child1 queue 1 no adv-config-policy
SAP egress
Use the following CLI syntax to delete advanced policies from an egress SAP.
qos sap-egress 11 policer 1 adv-config-policy child1 queue 1 no adv-config-policy
Copying and overwriting advanced policies
An existing advanced policy can be copied, renamed with a new policy ID value, or used to overwrite an existing policy ID. The overwrite option must be specified or an error occurs if the destination policy ID exists.
config>qos>copy {adv-config-policy} source-policy-id dest-policy-id [overwrite]
Editing advanced policies
Existing advanced policies and entries in the CLI or NMS can be edited. The changes are applied immediately to all services where this policy is applied. To prevent configuration errors, copy the policy to a work area, make the edits, then write over the original policy.