Add Class to QoS Policy Window

This window appears when you click Add Class in the Create QoS Policy window. Use it to:

When you complete these tasks, click OK.

Adding a Class to a Policy

  1. In the Classes list, select a class (if one has been defined) or Define Class.
    If you select an existing class , the fields in the Class Definition box are filled in for you, and this task is complete.
    If you select Define Class , continue to the next step.
  2. In the Class Name field, enter a unique name for the class.
  3. Optional: In the Description field, enter text that describes the purpose of the class.
  4. If this class is for a Catalyst 2950 switch, go to Step 8.
  5. In the Match list, select the packet characteristicDSCP values, IP precedence values, or an ACL namethat is special to this class.
    When you choose a characteristic, a corresponding field in the window is enabled, allowing you to be more specific.
  6. If you chose DSCP from the Match list, e nter one or mor e DSCP v alues in the DSCP field. Use spaces to separate multiple values.
  7. If you chose IP Precedence from the Match list, e nter one or mor e IP precedence v alues in the IP Precedence field. Use spaces to separate multiple values.
  8. If you chose ACL from the Match list or if the class is for a Catalyst 2950 switch, s elect the ACL name that the class matches from the ACL list.

Overriding Values in Matching Packets on Catalyst 2950 Switches

To override values in matching packets:

  1. Click the Set tab.
  2. From the Type list, select DSCP if you want to override the DSCP values. Otherwise, select None.
  3. If you chose DSCP, enter the DSCP override value in the DSCP field.

Overriding or Trusting Values in Matching Packets on Catalyst 3550 Switches

To override values in matching packets:

  1. Click the Set/Trust tab.
  2. Click the Set radio button to enable the Set section.
  3. From the Type list, select DSCP or IP Precedence if you want to override the DSCP values, IP precedence values, or ACL name in matching packets with a single DSCP value or IP precedence value. Otherwise, select None.
    Note: You can override DSCP values with an IP precedence value or IP precedence values with a DSCP value.
  4. If you chose DSCP, enter the DSCP override value in the DSCP field.
  5. If you chose IP Precedence, enter the IP precedence override value in the IP Precedence field.

To trust values in matching packets:

  1. Click the Set/Trust tab.
  2. Click the Trust radio button to enable the Trust section.
  3. From the Trust Type list, select Trust CoS, Trust DSCP, or Trust IP Precedence if you want to trust the CoS, DSCP, or IP precedence value of packets that belong to this class. Otherwise, select Not Trusted.

Associating a Policer with the Class

  1. Click the Policer tab.
  2. In the Policers list, select an aggregate policer (if one has been defined), Define Policer, or No Policer.
    If you select an aggregate policer , the fields in the Policer Definition box are filled in for you, and this task is complete.
    If you select Define Policer , continue to the next step.
    If you select No Policer , ignore the remaining steps. N o policing is associated with the class.
  3. In the Policer Name field, enter a name for the policer if you want it to be an aggregate policer. Otherwise, leave this field blank.
    Restriction: This option is not supported on Catalyst 2950 switches. Specifying a nonaggregate policersee the following stepsis supported on these switches if they run the enhanced software image.
  4. In the Rate [kbps] field, enter the maximum transmission rate that you will permit on the interface. The number that you enter is the rate in kilobits per second. You can enter a value between 8 and 2000000, inclusive on the Catalyst 3550 switches. On the Catalyst 2950 switches, you can enter a value from 1000 to 1000000, in multiples of 1000.
  5. In the Max Burst Size [KB] field, enter the maximum burst size that you will permit on the interface. The number that you enter is the size in kilobytes. You can enter a value between 8 and 512000, inclusive on the Catalyst 3550 switches. On the Catalyst 2950 switches, the MAX Burst column has a drop-down menu of choices.
  6. In the Exceed Action list, select an action you want to occur if either maximum is exceeded. Selecting Drop causes the policer to drop a packet in violation. Selecting Police DSCP and Transmit causes the policer to modify the DSCP value and transmit the packet. Selecting None causes the policer to take no action.
  7. If you selected Police DSCP and Transmit, s elect a DSCP value from the Policed DSCP field that the policer will give to a packet in violation.
    Note: This field is available only for Catalyst 2950 switches. For Catalyst 3550 switches, the policer uses the DSCP value it finds in the Policed DSCP Table.