Wednesday, June 29, 2016

Failure in Restricting the Bandwidth After Binding the CAR to the Flows

A flow is created after the relevant Ethernet service is created. After the flow is bound with a CAR, it is found that the CAR does not take effect. (On the instrument, the transmit bandwidth is equal to the receive bandwidth.)

Fault Type

  • QoS
  • Ethernet fault

Symptom

As shown in Figure 1, a unidirectional point-to-point EPL service is configured from PORT1 to PORT2 on the same board.
Figure 1 Unidirectional point-to-point EPL service from PORT1 to PORT2
Create the flow at PORT1. Set the flow type to port+VLAN+priority.
Configure the CAR. Set both the CIR and PIR to 10 Mbit/s. Bind the CAR to the flow. Use the SmartBits to transmit packets at a rate higher than 10 Mbit/s. The receive bandwidth of the instrument, however, is found to be equal to the transmit bandwidth of the instrument.

Cause Analysis

This problem has the following possible causes.
  1. The CAR is not enabled. After the CAR is bound to the flow, the CAR is effective for the flow only if the CAR is enabled.
  2. The flow type does not match the service type. In this fault case, a port flow should be configured for the point-to-point EPL service.
  3. Certain boards do not support the flow of the Port type, because the transmitted service packets probably do not match the specified VLAN+priority. Hence, the CAR does not take effect on the flow.

Procedure

  1. Cause 1: The CAR is not enabled.
    1. Enable the CAR.
      1. On the Main Topology, right-click the NE icon and choose NE Explorer from the shortcut menu.
      2. Select the relevant Ethernet board in the Object Tree. Choose Configuration > QoS Management > Flow Management from the Function Tree.
      3. Click the CAR Configuration tab.
      4. Set Enable/Disable to Enable.
  2. Cause 2: The flow type does not match the service type.
    Re-create a flow of the type (that is, port flow) that matches the service type. Then bind the flow with a CAR.
    1. Re-create a flow.
      1. On the Main Topology, right-click the NE icon and choose NE Explorer from the shortcut menu.
      2. Select the relevant Ethernet board in the Object Tree. Choose Configuration > QoS Management > Flow Management from the Function Tree. Then click .
      3. Click the Flow Configuration tab.
      4. Click New. Set the flow attributes in the New Flow dialog box, according to the completed flow planning and the description of flow parameters.
      5. Click OK. The Operation Result dialog box is displayed, indicating that the flow is successfully created.
    2. Bind the flow with a CAR.
      1. On the Main Topology, right-click the NE icon and choose NE Explorer from the shortcut menu.
      2. Select the relevant Ethernet board in the Object Tree. Choose Configuration > QoS Management > Flow Management from the Function Tree. Then click .
      3. Click the Flow Configuration tab.
      4. Select a flow for which you want to configure the binding. In the Bound ShapingBound CoS and Bound CAR tabs, select the Shaping ID, CoS ID and CAR ID respectively.
      5. Click Apply. The Operation Result dialog box is displayed, indicating that the binding is successful.
  3. Cause 3: The transmitted service packets do not match the specified VLAN+priority.
    1. Select the relevant board from the NE Explorer. Choose Configuration > Ethernet Service > Ethernet LAN Service from the Function Tree.
    2. Check whether each VLAN priority matches the service packets. If not, set the VLAN priority to the other value.

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