RADIUS uses a vendor-specific attribute (VSA) 1 command to modify the active QoS policy on a session. This VSA has the following format:
av-pair = "policy-type=command 9 parameter1 ,...,parametern"
Use the following Cisco VSA 1 format to add and remove classes and QoS actions to and from the QoS policy that is currently active on a session:
Before the ISG can construct a policy using the policing parameters specified in the RADIUS message, a QoS policy must be active on the session. If a QoS policy is not active in the specified direction, the ISG does not create the policy.
When implementing the changes specified in the Cisco VSA, the ISG does not make the changes to the originally configured QoS policy on the ISG device. Instead, the ISG copies the active QoS policy for the session and then makes the required changes to the policy copy, which is referred to as a transient policy
. The originally configured QoS policy on the ISG device is not changed.
The following sections describe the Cisco VSA 1 commands used to automatically modify policing parameters of active policies:
To remove traffic classes and QoS actions defined in the active QoS policy on a session, use the remove-class primitive. This attribute has the following format:
target field—Indicates the QoS policy to be modified. The only valid value for this field is sub, which indicates the active QoS policy attached to the subscriber session. The Access-Accept or CoA message that includes this attribute must be targeting a subscriber session.
class-list field—A list of class names enclosed in parentheses that identifies the class or classes to be removed. The class names you specify must be either user-configured class maps or the system-generated class-default class. The order in which you specify the class names indicates the hierarchical level of the class within the QoS policy.
For example, the following VSA1 attribute removes the Bronze class and all associated QoS policy actions from the nested child policy that is applied to the parent class-default class:
When you remove a traffic class from a QoS policy, all of the attributes for the class are also removed. To re-add the class with the same attributes, you must reissue the add-class RADIUS attribute and provide the required parameters and values.