QoS Configuration on Cisco Device | DSCP, Traffic Policing | Lab with GNS3 and Ostinato | CCNA, CCNP

3 min read 10 months ago
Published on Sep 07, 2024 This response is partially generated with the help of AI. It may contain inaccuracies.

Introduction

This tutorial will guide you through configuring Quality of Service (QoS) on a Cisco device, focusing on modifying Differentiated Services Code Point (DSCP) values and implementing traffic policing on outbound traffic. These techniques are essential for managing bandwidth and ensuring that critical applications receive the necessary resources. This lab will utilize GNS3 and Ostinato, providing hands-on experience relevant for CCNA and CCNP certifications.

Step 1: Setting Up the Lab Environment

  1. Install GNS3: Download and install GNS3 from the official website.
  2. Set Up Cisco IOS: Ensure you have the necessary Cisco IOS images for your virtual devices.
  3. Install Ostinato: Download and install Ostinato, which will be used for traffic generation and analysis.
  4. Create a New Project: Open GNS3 and create a new project for your QoS configuration lab.
  5. Add Devices
    • Drag and drop a Cisco router into the workspace.
    • Add a few virtual machines to simulate end-user devices.
  6. Connect Devices: Use the appropriate connections to link your Cisco router to the virtual machines.

Step 2: Configuring DSCP on Cisco Router

  1. Access the Router
    • Launch the console for the router in GNS3.
  2. Enter Global Configuration Mode:
    enable
    configure terminal
    
  3. Define a Class Map
    • Create a class map to match the traffic you want to prioritize.
    class-map match-all VOICE
    match dscp ef
    

  4. Define a Policy Map
    • Create a policy map to specify actions for the matched traffic.
    policy-map QOS_POLICY
    class VOICE
    priority 1000
    

  5. Apply the Policy Map to an Interface
    • Choose the appropriate interface and apply the policy.
    interface GigabitEthernet0/1
    service-policy output QOS_POLICY
    

Step 3: Configuring Traffic Policing

  1. Define a Traffic Policing Policy
    • Create a policy map for traffic policing.
    policy-map POLICE_POLICY
    class VOICE
    police 8000 1000 exceed-action drop
    

  2. Apply the Policing Policy
    • Apply the traffic policing policy to the desired interface.
    interface GigabitEthernet0/1
    service-policy input POLICE_POLICY
    

Step 4: Testing the Configuration with Ostinato

  1. Launch Ostinato: Open Ostinato and create a new project.
  2. Add Streams
    • Create traffic streams that match the DSCP settings configured on the router.
  3. Start Traffic Generation: Begin sending traffic from Ostinato to simulate real-world conditions.
  4. Monitor Traffic: Use Ostinato's monitoring tools to observe how the traffic is prioritized and policed.

Conclusion

In this tutorial, you have learned how to set up a QoS configuration on a Cisco device, including modifying DSCP values and implementing traffic policing. By practicing these skills in a lab environment with GNS3 and Ostinato, you will gain a solid understanding of QoS principles, which are crucial for effective network management. For further study, consider exploring additional QoS concepts or applying these configurations in real-world scenarios to enhance your networking skills.