Nexus 6000 Series Switches QoS Configuration Example

Introduction

This document describes how to configure Quality of Service (QoS) on a Cisco Nexus 6000 Series switch.

Prerequisites

Requirements

Cisco recommends that you have knowledge of these topics:

• Cisco Nexus 6000 Series switches
• QoS
• Switching terminology

Tip: Refer to the relevant QoS configuration guide for the related code and additional information.

Components Used

The information in this document is based on the Cisco Nexus 6000 Series switch.

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Related Products

This document can also be used with these hardware and software versions:

• Cisco Nexus 5000 Series switches
• Cisco Nexus 5500 Series switches
• Cisco Nexus 5600 Series switches

Background Information

By default on the Nexus 6000 Series switch, QoS is enabled, classifications are trusted on ingress, and all traffic is placed into a single First In–First Out (FIFO) egress queue. If you desire to modify this behavior, you must configure your own policy.

All of the QoS policies are applied at the hardware level, either on the ingress Unified Port Controller (UPC), the crossbar fabric, or on the egress UPC. The switch supports these QoS policies:

• qos – This policy defines the Modular QoS Command-link (MQC) interface that is used in order to mark and police.
  
  
• network-qos – This policy defines the network-wide characteristics of the QoS properties, such as the Maximum Transition Unit (MTU), and it should be consistent among all of the switches.
  
  
• queuing – This policy defines the MQC interface that is used in order to queue and schedule, and in order to mark on a limited scale.
  
  
• control-plane – This policy defines the MQC interface for Control Plane Policing (CoPP).

Note: The use of the control-plane QoS policy is not covered in this document.

The former three policies are applied in three stages:

• The qos policy is applied on the ingress UPC interface or on the system (crossbar fabric).
  
  
• The network-qos policy is applied on the crossbar fabric.
  
  
• The queuing policy is applied on either the ingress UPC, the egress UPC, or on the crossbar fabric.

For the example that is provided in this document, each policy is applied on the crossbar fabric. Additionally, the interfaces can be configured with the QoS or Queueing policy, as necessary for your design.

Design Overview

These steps are completed in order to modify QoS on the platform:

1. The ingress QoS models are configured, to include:
   
   
   • Trust models
   • Classification and marking models
   • Ingress policing models
   
   
2. The network QoS models are configured.
   
   
3. The egress/Virtual Output Queue (VOQ) queuing models are configured.

Configure

Note: The configuration that is described in this document is intended to be used as an example and should not be considered a best practice for QoS implementation on this or other Nexus Operating System (NX-OS) platforms.

Policy Example

This eight-class model with Fibre Channel over Ethernet (FCoE), which makes use of all QoS groups, is used for the configuration that is described in this document:

Configure the QoS Policy

Use this information in order to configure the QoS policy:

class-map type qos match-any VIDEO
 match dscp 26,28,30,34,36,38
class-map type qos match-any VOICE
 match dscp 46
class-map type qos match-all SIGNALING
 match dscp 24class-map type qos match-any TRANSACTIONAL
 match dscp 18,20,22
class-map type queuing queueVIDEO
 match qos-group 4class-map type queuing queueVOICE
 match qos-group 5
class-map type queuing queueSIGNALING
 match qos-group 3
class-map type queuing queueTRANSACTIONAL
 match qos-group 2
policy-map type qos Global-Classification
 class VOICE
 set qos-group 5 class VIDEO
 set qos-group 4
 class SIGNALING
 set qos-group 3
 class TRANSACTIONAL
 set qos-group 2
 class class-fcoe
 set qos-group 1

Configure the Network QoS Policy

Use this information in order to configure the network QoS policy:

class-map type network-qos nqVIDEO
 match qos-group 4
class-map type network-qos nqVOICE
 match qos-group 5
class-map type network-qos nqSIGNALING
 match qos-group 3
class-map type network-qos nqTRANSACTIONAL
 match qos-group 2
policy-map type network-qos Global-Network-QoS
 class type network-qos nqVOICE
   queue-limit 20480 bytes
 class type network-qos nqVIDEO
   queue-limit 40960 bytes
 class type network-qos nqSIGNALING
   queue-limit 40960 bytes
 class type network-qos nqTRANSACTIONAL
   queue-limit 40960 bytes
 class type network-qos class-fcoe
   pause no-drop
   mtu 2158
 class type network-qos class-default

Configure the Queuing Policy

Use this information in order to configure the queuing policy:

class-map type queuing queueVIDEO
  match qos-group 4
class-map type queuing queueVOICE
  match qos-group 5
class-map type queuing queueSIGNALING
  match qos-group 3
class-map type queuing queueTRANSACTIONAL
  match qos-group 2
policy-map type queuing Global-Queuing
  class type queuing queueVOICE
    priority
  class type queuing queueVIDEO
    bandwidth percent 10
  class type queuing queueSIGNALING
    bandwidth percent 20
  class type queuing queueTRANSACTIONAL
    bandwidth percent 25
  class type queuing class-fcoe
    bandwidth percent 20
  class type queuing class-default
    bandwidth percent 25

Crossbar Application

Here is an example of the crossbar fabric application:

system qos
  service-policy type qos input Global-Classification
  service-policy type network-qos Global-Network-QoS
  service-policy type queuing output Global-Queuing
  service-policy type queuing input Global-Queuing

Verify

In order to verify that your configuration works properly, enter the show queueing interface <x/y> command into the CLI:

Ethernet1/1 queuing information:
 TX Queuing
   qos-group sched-type oper-bandwidth
     0 WRR 25
     1 WRR 20
     2 WRR 25
     3 WRR 20
     4 WRR 10
     5 priority 0

 RX Queuing
   qos-group 0
   q-size: 100160, HW MTU: 1500 (1500 configured)
   drop-type: drop, xon: 0, xoff: 0
   Statistics:
     Pkts received over the port : 13896
     Ucast pkts sent to the cross-bar : 0
     Mcast pkts sent to the cross-bar : 13896
     Ucast pkts received from the cross-bar : 0
     Pkts sent to the port : 0
     Pkts discarded on ingress : 0
     Per-priority-pause status : Rx (Inactive), Tx (Inactive)

   qos-group 1
   q-size: 165120, HW MTU: 2158 (2158 configured)
   drop-type: no-drop, xon: 62720, xoff: 88320
   Statistics:
     Pkts received over the port : 0
     Ucast pkts sent to the cross-bar : 0
     Mcast pkts sent to the cross-bar : 0
     Ucast pkts received from the cross-bar : 0
     Pkts sent to the port : 0
     Pkts discarded on ingress : 0
     Per-priority-pause status : Rx (Inactive), Tx (Inactive)

   qos-group 2
   q-size: 75520, HW MTU: 1500 (1500 configured)
   drop-type: drop, xon: 0, xoff: 0
   Statistics:
     Pkts received over the port : 0
     Ucast pkts sent to the cross-bar : 0
     Mcast pkts sent to the cross-bar : 0
     Ucast pkts received from the cross-bar : 0
     Pkts sent to the port : 0
     Pkts discarded on ingress : 0
     Per-priority-pause status : Rx (Inactive), Tx (Inactive)

   qos-group 3
   q-size: 75520, HW MTU: 1500 (1500 configured)
   drop-type: drop, xon: 0, xoff: 0
   Statistics:
     Pkts received over the port : 0
     Ucast pkts sent to the cross-bar : 0
     Mcast pkts sent to the cross-bar : 0
     Ucast pkts received from the cross-bar : 0
     Pkts sent to the port : 0
     Pkts discarded on ingress : 0
     Per-priority-pause status : Rx (Inactive), Tx (Inactive)

   qos-group 4
   q-size: 75520, HW MTU: 1500 (1500 configured)
   drop-type: drop, xon: 0, xoff: 0
   Statistics:
     Pkts received over the port : 0
     Ucast pkts sent to the cross-bar : 0
     Mcast pkts sent to the cross-bar : 0
     Ucast pkts received from the cross-bar : 0
     Pkts sent to the port : 0
     Pkts discarded on ingress : 0
     Per-priority-pause status : Rx (Inactive), Tx (Inactive)

   qos-group 5
   q-size: 55040, HW MTU: 1500 (1500 configured)
   drop-type: drop, xon: 0, xoff: 0
   Statistics:
     Pkts received over the port : 0
     Ucast pkts sent to the cross-bar : 0
     Mcast pkts sent to the cross-bar : 0
     Ucast pkts received from the cross-bar : 0
     Pkts sent to the port : 0
     Pkts discarded on ingress : 0
     Per-priority-pause status : Rx (Inactive), Tx (Inactive)

Troubleshoot

There is currently no specific troubleshooting information available for this configuration.