Rate Shaping with srTCM Policers

About Single Rate Three Color Marker Policers

A Single Rate Three Color Marker (srTCM) policer meters an IP packet stream and classifies the packets as either green, yellow, or red. An srTCM policer is useful, for example, for ingress policing of a service, where only the length, not the peak rate, of the burst determines service eligibility.

The srTCM color classification is based on specific values that you define:

Committed Information Rate (CIR)

This is the rate, in bytes per second, that you want the BIG-IP® system to commit to the guest. For packets that are part of a flow consuming less than or equal to the CIR value, the system classifies the packets as green.

Committed Burst Size (CBS)

This is a burst size, in bytes, that you want the system to commit to the guest beyond the CIR value. For packets that are part of a burst into the allocated CBS value, the system classifies the packets as yellow.

Excess Burst Size (EBS)

This is a data burst size, in bytes, that exceeds the CIR and CBS values and that you want the system to classify as excessive. For packets that are part of a burst into the specified EBS value, the system classifies the packets as redand might drop them.

In general, when you configure an srTCM policer, the BIG-IP system classifies a packet as green if the packet size does not exceed the CBS, yellow if the packet size exceeds the CBS but not the EBS, and red otherwise.

Note: SrTCM policers that you create run in color-blind mode only. In color-blind mode, the policer ignores any color classifications that might have been previously set on IP packets coming into the BIG-IP system.

Creating a Single Rate Three Color Marker policer

You can create a Single Rate Three Color Marker (srTCM) policer when you want the BIG-IP system to meter an IP packet stream and classify the packets as either green, yellow, or red. An srTCM policer is useful, for example, for ingress policing of a service, where only the length of the burst, and not the peak rate of the burst, determines service eligibility.

1. On the Main tab, click Network > Rate Shaping > Single Rate TCM Policer.

   The screen displays a list of Single Rate Three Color Marker (srTCM) policers.

2. In the Committed Information Rate field, type a rate, in bytes per second, that you want the system to commit to the guest.

   An example of a CIR value is 50000000.

   For packets that are part of a flow consuming less than or equal to the Committed Information Rate value, the system classifies the packets as green.

3. In the Committed Burst Size field, type a burst size, in bytes, that you want the system to commit to the guest beyond the Committed Information Rate value.

   An example of a CBS value is 1000000.

   For packets that are part of a burst into the allocated Committed Burst Size value, the system classifies the packets as yellow.

4. In the Excess Burst Size field, type a data burst size, in bytes, that exceeds the Committed Information Rate and Committed Burst Size values and that you want the system to classify as excessive.

   An example of an EBS value is 2000000.

   For packets that are part of a burst into the specified Excess Burst Size value, the system classifies the packets as Red and might drop them.

5. From the Action list, select the action that you want the system to perform when the system classifies packets as red:

   • Select None when you want the system to take no action, regardless of color classification.
   • Select Dropwhen you want the system to drop packets classifed as red.

6. Click Finished.

After you perform this task, the BIG-IP system includes an srTCM policer, in color-blind mode, that you can apply to network traffic.