Links can be added in either the inbound or outbound QoS sections. Once a link has been added to the QoS Configuration, we can add classes to it. Classes are container objects that are configured with the actual QoS traffic control information. Each class may also have a classifier applied to it, or another class added as a child class. Each class entry has a number of values that may be configured:
- Parent – Specifies the parent class that this entry is a child of. Almost all classes will use this field. Typically, you will want to enter 'root'.
- Class – The name of the class that we are creating. Every class must have this.
- Priority – The priority that this class should have over other classes when allocating bandwidth over the specified Rate %. This field is only valid if the class also contains a classifier. Values for a priority may be 1-7, with 1 being the highest priority and 7 being the lowest. A given priority value may be applied to more than one class, with all classes of that priority given equal priority.
- Rate % – The amount of bandwidth that this class should be guaranteed. This value is given as a percentage of the configured WAN uplink rate configured on the Configure WANs page. The total of the Rate % values for any group of child classes must not exceed the Rate % of the parent class. This setting does does not permanently allocate bandwidth to the class. If a given class is not using its full rate, the remaining bandwidth is available for other classes.
- Max % – The maximum bandwidth that this class is allowed to consume. Once a class is using its Rate %, it will be allowed to consume more bandwidth up to this value, as bandwidth is available depending on the class priority and the utilization by other classes.
- Classifier – If a traffic classifier is to be applied to this class, the name of the classifier should be entered here.
- Default – The class selected as default is where all unclassified traffic will be applied. Only a class with an identifier may be selected as default. This becomes an option once you add a class entry with an identifier; the first such entry will be selected automatically.
- Queue – This option allows different queuing methods to be selected for each class. The differences are not discussed in this document but are explained in the QoS help pages.
Each interface has a root class created by default. This exists on the backend and is implicitly created. The root class has a Rate % and Max % of 100. Classes can be created for each interface inbound and outbound depending on the direction of traffic and desired level of service.