8. Multiple Layer-2 Switches

Goal: Emulate the behavior of five Layer-2 Switches connected together for traffic fail-over testing. Return to LANforge-ICE Cookbook

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.

   A: Right-click inside the Netsmith window and select New Connection
   B: Accept defaults, Auto Create everything then click OK
   C: Repeat and create a total of seven (7) connections
   D: Click the Apply button to commit the changes in Netsmith to the LANforge-Server • NOTE:   Modifications in Netsmith are only sent to the LANforge-Server after Applying them

   • For more information, see the LANforge-GUI User Guide: Virtual Interfaces
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2. Setup five Bridge devices.

   A: Right-click inside the Netsmith window and select New Bridge
   B: Select the Bridge button, enter a name, click Apply then repeat to create four more bridges. • NOTE:   The 5 bridges here are sw-0, sw-1, sw-2, sw-3, and sw-4
   C: In Netsmith, position the bridge devices into separate areas so they can be grouped with WanLink entry points

   • For more information, see the LANforge-GUI User Guide: Ports (Interfaces)
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3. Move the WanLinks into their desired positions.

   A: Position the WanLink entry points in groups near the bridges as follows: • 2 entry points near sw-0, sw-1, and sw-2 (one to sw-3 and one to sw-4) • 3 entry points near sw-3 and sw-4 (one to sw-0, sw-1, and sw-2) • Bridges sw-3 and sw-4 should also have a WanLink between them
   B: Click Netsmith Apply to commit the changes

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4. Modify each Bridge to enable Spanning Tree Protocol (STP) and add Bridge Members.

   A: Right-click bridge sw-0 and select Modify Port
   B: Select the 'Set Bridge Info' and 'Spanning Tree' checkboxes, then add bridge members rddVR1 and rddVR3 • NOTE:   Selecting the 'Spanning Tree' checkbox enables Spanning Tree Protocol (STP) for that port • Click the Apply or OK button to commit the changes in bridge configuration to the LANforge-Server
   C: Right-click bridge sw-1 and select Modify Port • Enable STP and add members rddVR5 and rddVR7
   D: Right-click bridge sw-2 and select Modify Port • Enable STP and add members rddVR11 and rddVR13
   E: Right-click bridge sw-3 and select Modify Port • Enable STP and add members rddVR0, rddVR4, rddVR8 and rddVR10
   F: Right-click bridge sw-4 and select Modify Port • Enable STP and add members rddVR2, rddVR6, rddVR9 and rddVR12
   G: Right-click all WanLinks and select Toggle WanLink so that they are running • NOTE:   Set each WanLink to at least 4Mbps to work with the traffic speeds used below

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5. Create virtual interfaces for traffic generation and fail-over tests.

   A: Right-click sw-0 and select Create Ports and choose Redirect • This step will create two Redirect Devices, rddA and rddB
   B: Add rddA to bridge sw-0 • Click the Apply or OK button to commit the changes in bridge configuration to the LANforge-Server
   C: Right-click rddB and select Create Ports, then select the MAC-VLAN button • Enter a starting MAC address, quantity 5, and starting IP address
   D: Repeat for bridge sw-1 • NOTE: The Netsmith display has been 'zoomed-out' by clicking the '-' magnifying glass icon located at the top left of the Netsmith display
   E: Repeat for bridge sw-2

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6. Create Layer-3 connections.

   A: On the Layer-3 tab, create a Layer-3 UDP connection between rddB#0 and rddD#0
   B: Create 4 more connections between the remaining rddB and rddD ports
   C: Create 5 connections between the rddD and rddF ports • Repeat this step for the rddF and rddB ports for a total of 15 connections

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7. Test Fail-Over condition.

   A: On the Layer-3 tab, select all 15 connections and click Start
   B: In Netsmith, verify traffic is flowing through sw-3 or sw-4 via 3 separate WanLinks • In this case, VRWL1.1.001, VRWL-1.1.003 and VRWL-1.1.006 all show traffic flowing
   C: Right-click WanLink VRWL-1.1.001 and select Toggle WanLink
   D: After approximately 1 minute, the traffic will find an alternate path
   E: Right-click WanLink VRWL-1.1.001 and select Toggle WanLink
   F: After approximately 1 minute, traffic resumes on its original path
   G: Traffic flow after simulating multiple path failures • A sample LANforge HTML report of this fail-over test can be found here: Fail-Over Test Sample HTML Report

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  Email Candela Technologies at: support@candelatech.com if you have any questions or suggestions.