Cisco ASR 9000 Series

Configuring Hierarchical Modular QoS on Cisco ASR 9000 Series Routers
How to Configure Hierarchical QoS
QC-131
Cisco ASR 9000 Series Aggregation Services Router Modular Quality of Service Configuration Guide
OL-23108-02
• Policers
– Color-blind policers are supported in both top and bottom policies
– Policers are not required in bottom-level classes
– Police rates can be configured as absolute rates or as percentages
– For bottom-level policers, the top-level policer rate is used as the reference bandwidth
• Statistics for all levels in the hierarchy
Enhanced Hierarchical Ingress Policing
In hierarchical policing, traffic is policed first at the child policer level and then at the parent policer
level. It is possible for traffic that conforms to the committed rate specified by the child policer to be
dropped by the parent policer.
In Enhanced Hierarchical Ingress Policing, the child-conform-aware command prevents the parent
policer from dropping any ingress traffic that conforms to the committed rate specified in the child
policer.
How to Configure Hierarchical QoS
When configuring hierarchical QoS, consider the following guidelines:
• When defining polices, start at the bottom level of the hierarchy. For example, for a two-level
hierarchical policy, define the bottom-level policy and then the top-level policy. For a three-level
hierarchical policy, define the bottom-level policy, the middle-level policy, and then the top-level
policy.
• Do not specify the input or output keyword in the service-policy command when configuring a
bottom-level policy within a top-level policy.
• Configure bottom-level policies only in middle-level and top-level policies.
This section describes the following tasks:
• Configuring the Three-Parameter Scheduler, page 132
• Policing Traffic at Two Levels of Hierarchy, page 137
• Attaching Hierarchical Policies to Physical and Virtual Links, page 139
• Configuring Enhanced Hierarchical Ingress Policing, page 141