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Network Testing and Emulation Solutions

Multiple Stations with a Hunt Script

Goal: Do packet sized testing with a hunt script using multiple stations.

We will manipulate the parameters of 10 Layer 3 connections using a single hunt script. The WiFi stations will change packet size as a group by being part of a Test Group. In this scenario, we will create traffic to different upstream destinations using MAC VLANs, and have our AP wired up to eth1 of our LANforge machine. Requires a CT-520 for only stations, or a CT-521 if you also want a WiFi monitor station.

  1. Create 10 virtual stations: in the ports tab, highlight radio wiphy0 and click the Create button. In this scenario, we are using WPA2 SSID jedtest. screenshot

    1. Check DHCP-IPv4

    2. Quantity: 10

    3. Station ID: 100

    4. SSID: jedtest

    5. Password: jedtest1

    6. Select WPA2

    7. Click Apply and then close the window.

    8. You should see stations sta100 - sta109.

    For more information see creating virtual stations

  2. (Simple Method) Create ten MAC VLANs on the eth1. In this scenario, our upstream network is In the Ports tab, highlight eth1 and click Create screenshot

    1. Quantity: 10

    2. IP:

    3. IP Mask:

    4. Click Apply and close the window.

    5. You should see 10 MAC VLANs, eth1#0 - eth1#9

  3. (Optional Advanced Method) Create many MAC VLANs behind eth1 using a redirect device. screenshot

    1. Create a bridge (br0) and add eth0 to it.

    2. Using Status->Resource 1->Netsmith, create a virtual router.

    3. Add br0 to the virtual router.

    4. Right click on br0, select Modify.

    5. Select DHCP, create a pool from

    6. Create a redirect device (r0a/r0b) and add r0a to the bridge.

    7. Select r0b in the Ports Tab, click Create, and create 10 MAC VLANs.

      1. Select MAC VLAN

      2. Quantity: 10

      3. Select DHCPv4

      4. Click Apply and close the window

      5. You will see ports r0b#0 - r0b#9

  4. Create ten Layer-3 cross connects. We will start at 10Mbps transmit on them as a reasonable start. In general hunt scripts start low and try to work their way higher. When using more stations, set a lower starting transmit rate. screenshot

    1. Name: sta-mac-100

    2. Endpoint-A: eth#0

    3. Endpoint-B: sta100

    4. Type: LANforge-TCP

    5. Size: Auto

    6. Minimum TxRate: 10Mbps

    7. Maximum TxRate: Same

    8. Click Apply Leave the window open.

  5. If you want to force packet sizes, expand the Create/Modify Cross Connect window to Box #5: screenshot

    1. Set TCP MSS to force maximum segment size. The mouse-over tip reminds us that the Ethernet frame size becomes 54+TCP MSS size.

    2. Select TCP_NODELAY to disable the NAGLE algorithm. This disables the OS frame re-sizing behavior.

  6. Create nine more stations. Click Batch-Create screenshot

    1. Quantity: 9

    2. Click Apply and close window

    3. Close the Create/Modify Cross Connect window.

  7. You will see ten Layer-3 connections ita- the Layer-3 tab. screenshot

  8. Create a Test Group. In the Test Group tab, click Create screenshot

    1. Name: sta-mac

    2. Highlight all the sta-max-1xx connections and click ← Add Cx

    3. Click Apply

    4. Click Script

    5. Configure the Test Group Script. screenshot

      1. Group Name: sta-mac

      2. Script Type: ScriptHunt

      3. Script Name: start-10Mbps

      4. Starting Rate: 10M

      5. Max Jitter: high 100ms

      6. Max RT Latency: 500ms

      7. Click OK

  9. Start the test, highlight the test group and click Start. screenshot

  10. You will see the script report window. screenshot

  11. When the test is finished, click Graphical Report to see graphs. screenshot

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