API Guide

Configuring QoS is a three-step process:
1. Create class-maps to classify the traffic flows. The following are the different types of class-maps:
● qos (default)—Classifies ingress data traffic.
● queuing —Classifies egress queues.
● control-plane—Classifies control-plane traffic.
● network-qos—Classifies traffic-class IDs for ingress buffer configurations.
● application —Classifies application-type traffic. The reserved policy-map policy-iscsi defines the actions for class-iscsi
traffic.
2. Create policy-maps to define the policies for the classified traffic flows. The following are the different types of policy-maps:
● qos (default)—Defines the following actions on the traffic classified based on qos class-map:
○ Policing
○ Marking with a traffic class ID
○ Modifying packet fields such as CoS and DSCP
● queuing —Defines the following actions on the egress queues classified based on queuing class-map:
○ Shaping
○ Assigning bandwidth for queues
○ Assigning strict priority for queues
○ Buffering configuration for queues
○ Weighted random early detection (WRED)/Explicit congestion notification (ECN) configuration on queues
● control-plane—Defines the policing of control queues for rate-limiting the control-plane traffic on CPU queues.
● network-qos—Defines the Ingress buffer configuration for selected traffic-classes matched based on network-qos
class-map.
● application —Defines the following actions for the application classified traffic:
○ Modifying packet fields such as CoS and DSCP.
○ Marking traffic class IDs.
3. Apply the policy-maps to the port interface, system for all interfaces, or control-plane traffic as follows:
● Apply control-plane polices in Control-Plane mode.
● Apply QoS and network-QoS policies in the input direction on physical interfaces or in System-QoS mode.
● Apply queuing policies in the output direction on physical interfaces or in System-QoS mode.
● Apply an application type policy-map in System-QoS mode.
When you apply a policy at the system level (System-QoS mode), the policy is effective on all the ports in the system.
However, the interface-level policy takes precedence over the system-level policy.
Quality of service
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