Configure QOS (Filter, Marking and Classifying) on Nexus 9000

Introduction

This document describes how to configure and verify Quality of Service (Filter, Marking and Classifying) on Nexus 9000 switches.

Background Information

Marking and classifying traffic in Quality of Service (QoS) is crucial for network performance and ensuring that critical applications receive the necessary level of service.

Summary of its uses:

1. Traffic Differentiation: Networks carry various types of traffic, including voice, video, data, and real-time applications. Marking and classifying traffic allow network administrators to differentiate between these types based on their importance, sensitivity to delay, and bandwidth requirements.

2. Resource Allocation: By classifying traffic, network devices can allocate resources such as bandwidth, buffer space, and processing power more effectively. Critical applications can be prioritized over less time-sensitive traffic, ensuring that they receive the necessary resources to function optimally.

3. QoS Guarantees: Marking and classifying traffic enable the implementation of QoS policies that enforce service level agreements (SLAs) and guarantee certain performance metrics for specific applications or user groups. This ensures a consistent quality of experience for end-users, minimizing the impact of congestion or network issues.

4. Congestion Management: In times of network congestion, QoS mechanisms prioritize traffic based on its classification, ensuring that critical applications continue to function smoothly while non-essential traffic possibly experiences delays or is dropped. This helps maintain network stability and prevents degradation of service for important applications.

5. Optimized Network Utilization: By intelligently managing traffic through QoS mechanisms, network resources are utilized more efficiently. Unused bandwidth can be dynamically allocated to high-priority applications, maximizing the overall performance of the network.

6. Enhanced User Experience: Marking and classifying traffic based on its importance to users or the business allows organizations to deliver a better user experience. Critical applications such as VoIP or video conferencing receive priority treatment, resulting in clearer calls, smoother video streams, and improved productivity.

7. Security and Compliance: QoS can also be used to enforce security policies by prioritizing traffic from trusted sources or applying traffic shaping to limit bandwidth for certain types of traffic, such as peer-to-peer file sharing or streaming services. Additionally, QoS mechanisms can help organizations meet compliance requirements by ensuring the prioritization and protection of sensitive data flows.

Overall, marking and classifying traffic in QoS are essential components of network management, enabling organizations to optimize performance, ensure reliable service delivery, and meet the diverse requirements of modern applications and users.

Prerequisites

Requirements

Cisco recommends that you have knowledge of these topics:

• NXOS Platform
• QoS
• Elam understanding
• Access lists (ACL)

Components Used

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, ensure that you understand the potential impact of any command.

Topology

Note: For this example N9K2 is the device configured for Filter, Marking and Classifying. N9K1 and N9K3 emulate hosts source and destination.

module-1(TAH-elam-insel6)# report 
SUGARBOWL ELAM REPORT SUMMARY
slot - 1, asic - 0, slice - 1
============================

Incoming Interface: Eth1/47

<Snipped>

Packet Type: IPv4

Dst MAC address: 84:3D:C6:3A:6A:BF
Src MAC address: 74:A2:E6:C6:28:FF

Sup hit: 1, Sup Idx: 2750

Dst IPv4 address: 192.168.20.2
Src IPv4 address: 192.168.1.1

Ver = 4, DSCP = 5, Don't Fragment = 0
Proto = 1, TTL = 254, More Fragments = 0
Hdr len = 20, Pkt len = 84, Checksum = 0x9b89

L4 Protocol : 1
ICMP type : 8
ICMP code : 0

N9K2(config-if)# show queuing interface e1/47

slot 1
=======
Egress Queuing for Ethernet1/47 [System]
------------------------------------------------------------------------------
<Snipped>
+-------------------------------------------------------------+
| QOS GROUP 7 |
+-------------------------------------------------------------+
| | Unicast |Multicast |
+-------------------------------------------------------------+
| Tx Pkts | 5| 0|
| Tx Byts | 510| 0|
| WRED/AFD & Tail Drop Pkts | 0| 0|
| WRED/AFD & Tail Drop Byts | 0| 0|
| Q Depth Byts | 0| 0|
| WD & Tail Drop Pkts | 0| 0|
+-------------------------------------------------------------+