Cisco Nexus 9000 Series User manual

Cisco Nexus 9000 Series NX-OS Quality of Service Configuration Guide,
Release 7.x
First Published: 2015-01-31
Last Modified: 2020-08-31
Americas Headquarters
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, CA 95134-1706
USA
http://www.cisco.com
Tel: [phone]
800 553-NETS (6387)
Fax: [phone]

THE SPECIFICATIONS AND INFORMATION REGARDING THE PRODUCTS REFERENCED IN THIS DOCUMENTATION ARE SUBJECT TO CHANGE WITHOUT NOTICE.
EXCEPT AS MAY OTHERWISE BE AGREED BY CISCO IN WRITING, ALL STATEMENTS, INFORMATION, AND RECOMMENDATIONS IN THIS DOCUMENTATION ARE
PRESENTED WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED.
The Cisco End User License Agreement and any supplemental license terms govern your use of any Cisco software, including this product documentation, and are located at:
http://www.cisco.com/go/softwareterms.Cisco product warranty information is available at http://www.cisco.com/go/warranty. US Federal Communications Commission Notices are found
here http://www.cisco.com/c/en/us/products/us-fcc-notice.html.
IN NO EVENT SHALL CISCO OR ITS SUPPLIERS BE LIABLE FOR ANY INDIRECT, SPECIAL, CONSEQUENTIAL, OR INCIDENTAL DAMAGES, INCLUDING, WITHOUT
LIMITATION, LOST PROFITS OR LOSS OR DAMAGE TO DATA ARISING OUT OF THE USE OR INABILITY TO USE THIS MANUAL, EVEN IF CISCO OR ITS SUPPLIERS
HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
Any products and features described herein as in development or available at a future date remain in varying stages of development and will be offered on a when-and if-available basis. Any
such product or feature roadmaps are subject to change at the sole discretion of Cisco and Cisco will have no liability for delay in the delivery or failure to deliver any products or feature
roadmap items that may be set forth in this document.
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network
topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional
and coincidental.
The documentation set for this product strives to use bias-free language. For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based
on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. Exceptions may be present in the documentation due to language
that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product.
Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com
go trademarks. Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any
other company. (1721R)
©2016–2020 Cisco Systems, Inc. All rights reserved.

CONTENTS
Preface xi
PREFACE
Audience xi
Document Conventions xi
Related Documentation for Cisco Nexus 9000 Series Switches xii
Documentation Feedback xii
Communications, Services, and Additional Information xii
New and Changed Information 1
CHAPTER 1
New and Changed Information 1
Overview 7
CHAPTER 2
Licensing Requirements 7
About QoS Features 7
Using QoS 8
Classification 8
Marking 8
Policing 9
Queuing and Scheduling 9
Sequencing of QoS Actions 9
Sequencing of Ingress Traffic Actions 9
Sequencing of Egress Traffic Actions 10
High Availability Requirements for QoS Features 10
QoS Feature Configuration with MQC 10
QoS Statistics 10
Default QoS Behavior 11
Virtual Device Contexts 11
Cisco Nexus 9000 Series NX-OS Quality of Service Configuration Guide, Release 7.x
iii

Using Modular QoS CLI 13
CHAPTER 3
About MQC 13
System Classes 14
Default System Classes 14
Using an MQC Object 14
Type qos Policies 15
Type Queuing Policies 15
System-Defined MQC Objects 16
System-Defined MQC Objects for 4q Mode 17
System-Defined MQC Objects for 8q Mode 19
Changing to 8q Mode 22
Changing from 8q Mode to 4q Mode 28
Guidelines and Limitations 28
Configuring an MQC Object 28
Configuring or Modifying a Class Map 28
Configuring or Modifying a Policy Map 30
Applying Descriptions to MQC Objects 31
Verifying an MQC Object 32
Attaching and Detaching a QoS Policy Action 33
Configuring a Service Policy for a Layer 2 Interface 34
Configuring a Service Policy for a Layer 3 Interface 35
Attaching the System Service Policy 36
Attaching a QoS Policy Action to a VLAN 37
Session Manager Support for QoS 38
Configuring QoS TCAM Carving 39
CHAPTER 4
About QoS TCAM Carving 39
About QoS TCAM Lite Regions 42
Guidelines and Limitations 43
Configuring QoS TCAM Carving 44
Enabling Layer 3 QoS (IPv6) 44
Enabling VLAN QoS (IPv4) 47
Notes for Enabling VLAN QoS 49
Cisco Nexus 9000 Series NX-OS Quality of Service Configuration Guide, Release 7.x
iv
Contents

Enabling FEX QoS (IPv4) 49
Enabling Egress QoS (IPv4) 50
Using Templates to Configure TCAM Region Sizes 52
Verifying QoS TCAM Carving 53
Configuring Classification 55
CHAPTER 5
About Classification 55
Prerequisites for Classification 56
Guidelines and Limitations 56
Configuring Traffic Classes 58
Configuring ACL Classification 58
Examples: Configuring ACL Classification 59
Configuring a DSCP Wildcard Mask 60
Configuring DSCP Classification 62
Configuring IP Precedence Classification 63
Configuring Protocol Classification 65
Configuring Layer 3 Packet Length Classification 66
Configuring CoS Classification 67
Configuring CoS Classification for FEX 68
Configuring IP RTP Classification 70
Verifying the Classification Configuration 71
Configuration Examples for Classification 71
Configuring Marking 73
CHAPTER 6
About Marking 73
Trust Boundaries 74
Class of Behavior 74
Prerequisites for Marking 75
Guidelines and Limitations 75
Configuring Marking 76
Configuring DSCP Marking 76
Configuring IP Precedence Marking 78
Configuring CoS Marking 80
Configuring CoS Marking for FEX 81
Cisco Nexus 9000 Series NX-OS Quality of Service Configuration Guide, Release 7.x
v
Contents

Configuring DSCP Port Marking 82
Verifying the Marking Configuration 84
Configuration Examples for Marking 84
Configuring Policing 85
CHAPTER 7
About Policing 85
Shared Policers 85
Prerequisites for Policing 86
Guidelines and Limitations 86
Configuring Policing 88
Configuring Ingress Policing 88
Configuring Egress Policing 88
Configuring 1-Rate and 2-Rate, 2-Color and 3-Color Policing 90
Configuring Markdown Policing 95
Configuring Shared Policers 97
Verifying the Policing Configuration 99
Configuration Examples for Policing 99
Configuring Queuing and Scheduling 101
CHAPTER 8
About Queuing and Scheduling 101
Modifying Class Maps 101
Congestion Avoidance 102
Congestion Management 102
Explicit Congestion Notification 102
Approximate Fair Drop 103
Traffic Shaping 105
Prerequisites for Queuing and Scheduling 106
Guidelines and Limitations 106
Configuring Queuing and Scheduling 109
Configuring Type Queuing Policies 110
Configuring Congestion Avoidance 111
Configuring Tail Drop on Egress Queues 111
Configuring WRED on Egress Queues 114
Configuring AFD on Egress Queues 116
Cisco Nexus 9000 Series NX-OS Quality of Service Configuration Guide, Release 7.x
vi
Contents

Configuring Congestion Management 118
Configuring Bandwidth and Bandwidth Remaining 118
Configuring Bandwidth and Bandwidth Remaining for FEX 120
Configuring Priority 122
Configuring Priority for FEX 124
Configuring Traffic Shaping 126
Applying a Queuing Policy on a System 128
Verifying the Queuing and Scheduling Configuration 129
Controlling the QoS Shared Buffer 129
Managing Dynamic Buffer Sharing 130
Monitoring the QoS Packet Buffer 130
Configuration Examples for Queuing and Scheduling 132
Example: Configuring WRED on Egress Queues 132
Example: Configuring Traffic Shaping 132
Configuring Network QoS 133
CHAPTER 9
About Network QoS 133
Prerequisites for Network QoS 133
Guidelines and Limitations 133
Dynamic Packet Prioritization 134
Configuring Network QoS Policies 135
Copying a Predefined Network QoS Policy 135
Configuring a User-Defined Network QoS Policy 135
Applying a Network QoS Policy on a System 136
Verifying the Network QoS 137
Configuring Link Level Flow Control 139
CHAPTER 10
Link Level Flow Control 139
Guidelines and Restrictions for Link Level Flow Control 139
Information About Link Level Flow Control 140
Link Level Flow Control on Interfaces 140
Link Level Flow Control on Ports 141
Mismatched Link Level Flow Control Configurations 141
How to Configure Link Level Flow Control 141
Cisco Nexus 9000 Series NX-OS Quality of Service Configuration Guide, Release 7.x
vii
Contents

Configuring Link Level Flow Control Receive 141
Configuring Link Level Flow Control Transmit 142
Configuring a Link Level Flow Control Watchdog Interval 143
Configuration Examples for Link Level Flow Control 146
Example: Configuring a No-Drop Policy 146
Example: Configuring Link Level Flow Control Receive and Send 147
Configuring Priority Flow Control 149
CHAPTER 11
About Priority Flow Control 149
Prerequisites for Priority Flow Control 150
Guidelines and Limitations for Priority Flow Control 150
Default Settings for Priority Flow Control 153
Configuring Priority Flow Control 153
Enabling Priority Flow Control on a Traffic Class 155
Configuring a Priority Flow Control Watchdog Interval 158
Configuring Pause Buffer Thresholds and Queue Limit Using Ingress Queuing Policy 161
Configuring QoS Pause Buffer and Dynamic Queue Limits 163
Verifying the Priority Flow Control Configuration 164
Configuration Examples for Priority Flow Control 164
Monitoring QoS Statistics 167
CHAPTER 12
About QoS Statistics 167
Prerequisites for Monitoring QoS Statistics 167
Guidelines and Limitations 167
Enabling Statistics 169
Monitoring the Statistics 170
Clearing Statistics 171
Configuration Examples For Monitoring QoS Statistics 171
Micro-Burst Monitoring 173
CHAPTER 13
Micro-Burst Monitoring 173
Guidelines and Limitations for Micro-Burst Monitoring 173
Configuring Micro-Burst Detection Per-Queue 175
Clearing Micro-Burst Detection 177
Cisco Nexus 9000 Series NX-OS Quality of Service Configuration Guide, Release 7.x
viii
Contents

Verifying Micro-Burst Detection 178
Example of Micro-Burst Detection Output 178
FEX QoS Configuration 179
APPENDIX A
FEX QoS Configuration Information 179
TCAM Carving for FEX QoS 181
FEX QoS Configuration Example 182
Verifying the FEX QoS Configuration 198
Additional References 199
APPENDIX B
RFCs 199
Cisco Nexus 9000 Series NX-OS Quality of Service Configuration Guide, Release 7.x
ix
Contents

Cisco Nexus 9000 Series NX-OS Quality of Service Configuration Guide, Release 7.x
x
Contents