Cisco Nexus 5000 NX-OS User manual

Cisco Nexus 5000 NX-OS Quality of Service Configuration Guide,
Release 5.1(3)N2(1)
First Published: March 13, 2012
Last Modified: February 12, 2013
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Text Part Number: OL-26657-01

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CONTENTS
Preface Preface vii
Audience vii
Document Conventions vii
Documentation Feedback viii
Obtaining Documentation and Submitting a Service Request ix
CHAPTER 1 New and Changed Information 1
New and Changed Information for this Release 1
CHAPTER 2 Overview 3
Information About Quality of Service 3
Modular QoS CLI 3
QoS for Traffic Directed to the CPU 5
CHAPTER 3 Configuring Classification 7
Information About Classification 7
Ingress Classification Policies 8
Licensing Requirements for Classification 8
Configuring Classification 8
Configuring Class Maps 8
Configuring CoS Classification 9
Configuring Precedence Classification 10
Configuring DSCP Classification 12
Configuring Protocol Classification 13
Configuring IP RTP Classification 14
Configuring ACL Classification 15
Verifying the Classification Configuration 16
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CHAPTER 4 Configuring Policy Maps 17
Information About Policy Types 17
Configuring Policy Maps 19
Creating Policy Maps 19
Configuring Type QoS Policies 21
Configuring Type Network QoS Policies 22
Configuring Type Queuing Policies 23
Verifying the Policy Map Configuration 24
CHAPTER 5 Configuring Marking 27
Information About Marking 27
Configuring Marking 27
Configuring DSCP Marking 27
Configuring IP Precedence Marking 29
Configuring CoS Marking 30
Required CoS Marking Configuration in a Layer 3 Topology 31
Verifying the Marking Configuration 32
CHAPTER 6 Configuring QoS on the System 35
Information About System Classes 35
System Classes 35
Default System Classes 35
MTU 36
Configuring System QoS 37
Attaching the System Service Policy 37
Restoring the Default System Service Policies 38
Configuring the Queue Limit for a Specified Fabric Extender 39
Enabling the Jumbo MTU 40
Verifying the Jumbo MTU 41
Verifying the System QoS Configuration 41
CHAPTER 7 Configuring QoS on Interfaces 43
Information About Interface QoS 43
Trust Boundaries 43
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Policy for Fibre Channel Interfaces 44
QoS for Multicast Traffic 44
Configuring Interface QoS 45
Configuring Untagged CoS 45
Configuring an Interface Service Policy 45
Configuring a Service Policy for a Layer 3 Interface 46
Verifying the Interface QoS Configuration 47
CHAPTER 8 Configuring QoS on VLANs 49
Information About VLAN QoS 49
Precedence of QoS Policies 49
Example of Interface, System, and VLAN Policy Precedence 50
Example of Interface and System QoS Policy Precedence 50
Example of System and VLAN Policy Precedence 50
Example of VLAN QoS and VACL Policy Precedence 51
Limiting TCAM Entries for VLAN QoS 52
Guidelines and Limitations for VLAN QoS 52
Configuring VLAN QoS 53
Configuring or Changing the Interface QoS TCAM Limit 53
Removing the Interface QoS Limit from the TCAM 54
Configuring a Service Policy on a VLAN 54
Removing a Service Policy from a VLAN 55
Verifying the VLAN QoS Configuration 56
Feature History for VLAN QoS 56
CHAPTER 9 Configuring Queuing and Flow Control 57
Information About Queues 57
Ingress Queuing Policies 57
Egress Queuing Policies 57
Buffering and Queue Limits on the Cisco Nexus 5000 Platform 58
Buffering and Queue Limits on the Cisco Nexus Device 59
Information About Flow Control 60
Link-Level Flow Control 60
Priority Flow Control 60
Configuring Queuing 61
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Configuring the Queue Limit for a Specified Fabric Extender 61
Configuring No-Drop Buffer Thresholds 62
Configuring the Buffer Threshold for the Cisco Nexus 2148T Fabric Extender 63
Enabling Virtual Output Queuing Limits for Unicast Traffic on the Cisco Nexus Device 64
Configuring Flow Control 65
Link-Level Flow Control 65
Configuring Priority Flow Control 65
Configuring Link-Level Flow Control 66
Disabling Slow Port Pruning on Multicast Traffic on the Cisco Nexus 5500 Series
Device 66
Verifying the Queue and Flow Control Configurations 67
CHAPTER 10 QoS Configuration Examples 69
QoS Example 1 69
QoS Example 2 70
QoS Example 3 72
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Preface
The Preface contains the following sections:
•Audience, page vii
•Document Conventions, page vii
•Documentation Feedback, page viii
•Obtaining Documentation and Submitting a Service Request, page ix
Audience
This publication is for network administrators who configure and maintain Cisco Nexus devices and Cisco
Nexus 2000 Series Fabric Extenders.
Document Conventions
Command descriptions use the following conventions:
DescriptionConvention
Bold text indicates the commands and keywords that you enter literally
as shown.
bold
Italic text indicates arguments for which the user supplies the values.
Italic
Square brackets enclose an optional element (keyword or argument).[x]
Square brackets enclosing keywords or arguments separated by a vertical
bar indicate an optional choice.
[x | y]
Braces enclosing keywords or arguments separated by a vertical bar
indicate a required choice.
{x | y}
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DescriptionConvention
Nested set of square brackets or braces indicate optional or required
choices within optional or required elements. Braces and a vertical bar
within square brackets indicate a required choice within an optional
element.
[x {y | z}]
Indicates a variable for which you supply values, in context where italics
cannot be used.
variable
A nonquoted set of characters. Do not use quotation marks around the
string or the string will include the quotation marks.
string
Examples use the following conventions:
DescriptionConvention
Terminal sessions and information the switch displays are in screen font.screen font
Information you must enter is in boldface screen font.boldface screen font
Arguments for which you supply values are in italic screen font.
italic screen font
Nonprinting characters, such as passwords, are in angle brackets.< >
Default responses to system prompts are in square brackets.[ ]
An exclamation point (!) or a pound sign (#) at the beginning of a line
of code indicates a comment line.
!, #
This document uses the following conventions:
Means reader take note. Notes contain helpful suggestions or references to material not covered in the
manual.
Note
Means reader be careful. In this situation, you might do something that could result in equipment damage
or loss of data.
Caution
Documentation Feedback
To provide technical feedback on this document, or to report an error or omission, please send your comments
to: [email protected].
We appreciate your feedback.
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Preface
Documentation Feedback

Obtaining Documentation and Submitting a Service Request
For information on obtaining documentation, using the Cisco Bug Search Tool (BST), submitting a service
request, and gathering additional information, see What's New in Cisco Product Documentation, at: http://
www.cisco.com/c/en/us/td/docs/general/whatsnew/whatsnew.html.
Subscribe to What's New in Cisco Product Documentation, which lists all new and revised Cisco technical
documentation as an RSS feed and delivers content directly to your desktop using a reader application. The
RSS feeds are a free service.
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Preface
Obtaining Documentation and Submitting a Service Request

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Obtaining Documentation and Submitting a Service Request