Symptom

After CAR is enabled on an interface, the traffic rate data collected by the U2000 is still the data generated before CAR enabling.

 

The network shown in the preceding figure is used as an example. In this example, a customer detects on interface 5 that the download rate of a subscriber is 2 Mbit/s; however, only 1 Mbit/s bandwidth is sold to the subscriber. Therefore, the customer enables QoS CAR on interface 4 to restrict the bandwidth of the subscriber to 1 Mbit/s.

After the bandwidth is restricted, the maximum bandwidth detected on interfaces 2 and 3 becomes 1 Mbit/s, indicating that the restriction has taken effect. However, when the customer creates a performance monitoring instance on the U2000 and tests the traffic rate on interface 4, the bandwidth of that subscriber is still displayed as 2 Mbit/s.

The configurations of interface 4 are as follows:

#

interface GigabitEthernet1/0/2.1213

qos car cir 10000 pir 20000 cbs 1870000 pbs 3740000 green pass yellow pass red discard outbound

statistic enable

#

Cause Analysis

A device generates traffic rate data based on the data generated before CAR is enabled.

To correctly collect the traffic rate data generated after CAR is enabled, use the Interface CAR Statistics function of XQoS. The MIB table required for the collection is hwXQoSIfCarStatisticsEntry (1.3.6.1.4.1.2011.5.25.32.4.1.4.3.9.1).

Solution

Perform the following steps:

                               Step 1      Choose Performance > Performance Monitoring Management from the U2000.

 

                               Step 2      Choose QoS > XQoS > Interface CAR Statistics from the navigation tree in the Performance Monitoring Management window.

 

                               Step 3      Click Create to create a performance monitoring task. In the dialog box that is displayed, select a CAR-enabled interface.

The following example lists the detailed configurations of such an interface:

#

interface GigabitEthernet1/0/2.1213

qos car cir 10000 pir 20000 cbs 1870000 pbs 3740000 green pass yellow pass red discard outbound

statistic enable

#

 

                               Step 4      Click Next. In the dialog box that is displayed, click Create Data Monitor Template. In the Create Data Monitoring Template dialog box, select outbound indicators and click OK.

 

                               Step 5      Select the new data monitoring template and click Next to create a performance monitoring task.

                               Step 6      View the interface traffic rate. (Traffic data is available only when the created performance monitoring task has been executed for two collection periods.)

The Outbound LoadOUT Rate indicator indicates the traffic rate after CAR is enabled.

 

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