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Network Testing and Emulation Solutions

Multiple Layer-2 Switches

Goal: Emulate the behavior of five Layer-2 Switches connected together for traffic fail-over testing.

In this test scenario, the function of several layer-2 switches will be emulated using multiple LANforge Bridge devices with Spanning Tree Protocol (STP) so that each bridge can be connected to at least two others and fail-over tests can be demonstrated.
 
  1. Setup seven Netsmith Connections.
    1. Right-click inside the Netsmith window and select New Connection screenshot
    2. Accept defaults Auto Create everything then click OK.
    3. Repeat and create a total of seven (7) connections screenshot
    4. Click the Apply button to commit the changes in Netsmith to the LANforge-Server screenshot
      1. NOTE: Modifications in Netsmith are only sent to the LANforge-Server after Applying them

    For more information see LANforge-GUI User Guide: Virtual Interfaces

  2. Setup five Bridge devices.
    1. Right-click inside the Netsmith window and select New Bridge screenshot
    2. Select the Bridge button, enter a name and quantity 5 screenshot
      1. NOTE: The 5 bridges here are sw-0, sw-1, sw-2, sw-3, and sw-4
    3. In Netsmith, position the bridge devices into separate areas so they can be grouped with WanLink entry points screenshot

    For more information see LANforge-GUI User Guide: Ports (Interfaces)

  3. Move the WanLinks into their desired positions.
    1. Position the WanLink entry points in groups near the bridges as follows: screenshot
      1. 2 entry points near sw-0, sw-1, and sw-2 (one to sw-3 and one to sw-4)
      2. 3 entry points near sw-3 and sw-4 (one to sw-0, sw-1, and sw-2)
      3. Bridges sw-3 and sw-4 should also have a WanLink between them
    2. Click Netsmith Apply to commit the changes screenshot
  4. Modify each Bridge to enable Spanning Tree Protocol (STP) and add Bridge Members.
    1. Right-click bridge sw-0 and select Modify Port screenshot
    2. Select the 'Set Bridge Info' and 'Spanning Tree' checkboxes, then add bridge members rddVR1 and rddVR3 screenshot
      1. NOTE: Selecting the 'Spanning Tree' checkbox enables Spanning Tree Protocol (STP) for that port
      2. Click the Apply or OK button to commit the changes in bridge configuration to the LANforge-Server
    3. Right-click bridge sw-1 and select Modify Port screenshot
      1. Enable STP and add members rddVR5 and rddVR7
    4. Right-click bridge sw-2 and select Modify Port screenshot
      1. Enable STP and add members rddVR11 and rddVR13
    5. Right-click bridge sw-3 and select Modify Port screenshot
      1. Enable STP and add members rddVR0, rddVR4, rddVR8 and rddVR10
    6. Right-click bridge sw-4 and select Modify Port screenshot
      1. Enable STP and add members rddVR2, rddVR6, rddVR9 and rddVR12
  5. Create virtual interfaces for traffic generation and fail-over tests.
    1. Right-click sw-0 and select Create Ports and choose Redirect screenshot
      1. This step will create two Redirect Devices, rddA and rddB
    2. Add rddA to bridge sw-0 screenshot
      1. Click the Apply or OK button to commit the changes in bridge configuration to the LANforge-Server
    3. Right-click rddB and select Create Ports, then select the MAC-VLAN button screenshot
      1. Enter a starting MAC address, quantity 5, and starting IP address
    4. Repeat for bridge sw-1 screenshot
      1. NOTE: The Netsmith display has been 'zoomed-out' by clicking the '-' magnifying glass icon located at the top left of the Netsmith display
    5. Repeat for bridge sw-2 screenshot
  6. Create Layer-3 connections.
    1. On the Layer-3 tab, create a Layer-3 UDP connection between
      rddB#0 and rddD#0 screenshot
    2. Create 4 more connections between the remaining rddB and rddD ports screenshot
    3. Create 5 connections between the rddD and rddF ports screenshot
      1. Repeat this step for the rddF and rddB ports for a total of 15 connections
  7. Test Fail-Over condition. screenshot
    1. On the Layer-3 tab, select all 15 connections and click Start
  8. In Netsmith, verify traffic is flowing through sw-3 or sw-4 via 3 separate WanLinks screenshot
    1. In this case, VRWL1.1.001, VRWL-1.1.003 and VRWL-1.1.006 all show traffic flowing
  9. Right-click WanLink VRWL-1.1.001 and select Toggle WanLink screenshot
  10. After approximately 1 minute, the traffic will find an alternate path screenshot
  11. Right-click WanLink VRWL-1.1.001 and select Toggle WanLink screenshot
  12. After approximately 1 minute, traffic resumes on its original path screenshot
  13. Traffic flow after simulating multiple path failures screenshot
    1. A sample LANforge HTML report of this fail-over test can be found here:
    2. Fail-Over Test Sample HTML Report

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