Contents

Introduction· 1

Prerequisites· 1

Example: Rate limiting ICMP packets· 1

Network configuration· 1

Analysis· 1

Applicable hardware and software versions· 2

Restrictions and guidelines· 2

Procedures· 2

Verify the configuration· 3

Configuration files· 3

Introduction

This chapter provides examples for configuring control plane-based QoS policies.

Prerequisites

The configuration examples in this document were created and verified in a lab environment, and all the devices were started with the factory default configuration. When you are working on a live network, make sure you understand the potential impact of every command on your network.

This document assumes that you have basic knowledge of QoS policies.

Example: Rate limiting ICMP packets

Network configuration

As shown in Figure 1, the device receives a large number of ICMP packets from the Internet. As a result, CPU usage is high, and device performance degrades.

Configure a control plane-based QoS policy to meet the following requirements:

·     Rate limit ICMP packets sent to the control plane to 320 kbps.

·     Drop excess ICMP packets.

Figure 1 Network diagram

Analysis

To meet the network requirements, you must perform the following tasks:

·     Use the if-match command to classify ICMP packets into a class.

·     Use the car command to configure the rate limit value for ICMP packets and drop excess packets.

Applicable hardware and software versions

The following matrix shows the hardware and software versions to which this configuration example is applicable:

Restrictions and guidelines

When you configure a control plane-based QoS policy to rate limit ICMP packets, follow these restrictions and guidelines:

·     By default, the predefined QoS policy is applied to the control plane. The predefined QoS policy identifies packet types by system index and uses a default rate limit value for each packet type. To display the predefined QoS policy, use the display qos policy control-plane pre-defined command.

·     You can use the if-match control-plane protocol or if-match control-plane protocol-group command to classify protocol packets.

·     You can only configure the car command or a combination of the car and accounting packet commands in the behavior associated with the class. Only the CIR value in pps in the car command takes effect.

Procedures

# Create a class named ICMP, and use the ICMP protocol as the match criterion.

<Device> system-view

[Device] traffic classifier ICMP

[Device-classifier-ICMP] if-match control-plane protocol icmp

[Device-classifier-ICMP] quit

# Create a behavior named ICMP, and configure a CAR action for ICMP packets.

[Device] traffic behavior ICMP

[Device-behavior-ICMP] car cir 320

[Device-behavior-ICMP] quit

# Create a QoS policy named ICMP, and associate the class ICMP with the behavior ICMP in the QoS policy.

[Device] qos policy ICMP

[Device-qospolicy-ICMP] classifier ICMP behavior ICMP

[Device-qospolicy-ICMP] quit

# Apply the QoS policy ICMP to the inbound direction of the control plane.

[Device] control-plane slot 1

[Device-cp-slot1] qos apply policy ICMP inbound

[Device-cp-slot1] quit

Verify the configuration

# Verify that the QoS policy is correctly applied to the control plane.

[Device] display qos policy control-plane slot 1

Control plane slot 1

  Direction: Inbound

  Policy: ICMP

   Classifier: ICMP

     Operator: AND

     Rule(s) :

      If-match control-plane protocol icmp

     Behavior: ICMP

      Committed Access Rate:

        CIR 320 (kbps), CBS 20480 (Bytes), EBS 0 (Bytes)

        Green action  : pass

        Yellow action : pass

        Red action    : discard

        Green packets : 0 (Packets)

        Red packets   : 0 (Packets)

Configuration files

#

traffic classifier ICMP operator and

 if-match control-plane protocol icmp

#

traffic behavior ICMP

 car cir 320 cbs 20480 ebs 0 green pass red discard yellow pass

#

qos policy ICMP

 classifier ICMP behavior ICMP

#

control-plane slot 1

 qos apply policy ICMP inbound