QoS

Introduction

In data communications, Quality of Service (QoS) provides differentiated service guarantees for diversified traffic in terms of bandwidth, delay, jitter, and drop rate, all of which can affect QoS.

QoS manages network resources and prioritizes traffic to balance system resources.

QoS policy

A QoS policy has two components: traffic class and traffic behavior. By associating a traffic class with a traffic behavior in a QoS policy, you can perform QoS actions on matching packets.

A QoS policy can only be applied to an interface to perform bandwidth control. Only one QoS policy can be applied to one direction of an interface. In the current software version, a QoS policy can be applied to the inbound or outbound direction of an interface.

Traffic class

A traffic class is as set of criteria used to match packets. The device supports only IPv4 ACLs and IPv6 ACLs as criteria.

Traffic behavior

A traffic behavior is used control the amount of bandwidth consumed by matching packets.

Enahcned mode

If you enable this mode on an interface, the device performs hardware-based bandwidth control based on the QoS policy. If you do not enable this mode on an interface, the device performs software-based bandwidth control.

Global CAR

Global committed access rate (CAR) is an approach to policing traffic flows globally. It adds flexibility to common CAR where traffic policing is performed only on a per-traffic class or per-interface basis. In this approach, CAR actions are created in system view and each can be used to police multiple traffic flows as a whole.

Global CAR provides the following CAR actions: aggregate CAR and hierarchical CAR. Only aggregate CAR is supported in the current software version. A QoS policy can use global CAR to control bandwidth.

An aggregate CAR action is created globally. It can be directly applied to interfaces or used in the traffic behaviors associated with different traffic classes to police multiple traffic flows as a whole. The total rate of the traffic flows must conform to the traffic policing specifications set in the aggregate CAR action.

vSystem support information

Support of non-default vSystems for this feature depends on the device model. This feature is available on the Web interface only if it is supported.

Restrictions and guidelines

If you do not enable the enhanced mode for an interface, you must select Traffic policing before configuring traffic behavior parameters.

If you configure the EBS for global CAR, you must configure the CBS or PIR. If you configure the PIR, the PIR must be greater than or equal to the CIR.

Configure QoS

Prerequisites

Complete the following tasks before you configure this feature:

• Assign IP addresses to interfaces on the Network > Interface Configuration > Interfaces page.

• Configure routes on the Network > Routing page. Make sure the routes are available.

• Create security zones on the Network > Security Zones page.

• Add interfaces to security zones. You can add interfaces to a security zone on the Security Zones page or select a security zone for an interface on the Interfaces page.

• Configure security policies to permit the target traffic on the Policies > Security Policies page.

Configure global CAR

1. Click the Policies tab.

2. In the navigation pane, select QoS Policies > Global CAR.

3. Click Create.

4. Create a global CAR action.

   Figure-1 Creating a global CAR action

   

   Table-1 Global CAR configuration items

   Item	Description
   Name	Enter a name for the global CAR action.
   CIR	Specifies the committed information rate (CIR) in kbps,
   CBS	Specifies the committed burst size (CBS) in bytes.
   EBS	Specifies the excess burst size (EBS) in bytes.
   PIR	Specifies the peak information rate (PIR) in kbps.
   Green action	Specifies the action to take on packets that conform to the CIR. pass: Permits the packet to pass through. remark-dot1p-pass: Sets the 802.1p priority of the packet to a new value and permits the packet to pass through. The value range is 0 to 7. remark-dscp-pass: Sets the DSCP priority of the packet to a new value and permits the packet to pass through. The value range is 0 to 63. remark-mpls-exp-pass: Sets the EXP priority of the MPLS packet to a new value and permits the packet to pass through. The value range is 0 to 7. remark-prec-pass: Sets the IP precedence of the MPLS packet to a new value and permits the packet to pass through. The value range is 0 to 7. discard: Drops the packet.
   Yellow action	Specifies the action to take on packets that conform to the PIR but not to the CIR. Available actions are the same as those for the green action.
   Red action	Specifies the action to take on packets that conform to neither CIR nor PIR. Available actions are the same as those for the green action.

5. Click OK.

Configure a QoS policy

1. Click the Policies tab.

2. In the navigation pane, select QoS Policies > QoS Policies.

3. Click Create. The page for creating a QoS policy opens. select an interface apply a QoS policy.

   Figure-2 Creating a QoS policy

   

   Table-2 Global CAR configuration items

   Item	Description
   Name	Select an interface apply a QoS policy.
   Enable enhanced mode	Enable enhanced mode for the interface.
   Direction	Select the direction to apply the QoS policy.

4. Click the value in the Direction column for the new QoS policy. On the page that opens, click Create.

   Figure-3 Traffic behavior and class list

   

   Figure-4 Configuring a traffic behavior and a traffic class (enhanced mode enabled)

   

   Figure-5 Configuring a traffic behavior and a traffic class (enhanced mode not enabled)

   

   Table-3 Traffic behavior and traffic class configuration items

   Item	Description
   Global CAR name	Specify a global CAR name as the traffic behavior. You can select a global CAR action or create a global CAR action. For more information, see "Configure global CAR." This parameter is available only if the enhanced mode is enabled.
   Traffic policing	Configure traffic policing.
   Match IPv4 ACL	Specify an IPv4 ACL by its number as the match criterion. The value range for the ACL number is 2000 to 3999.
   Match IPv6 ACL	Specify an IPv6 ACL by its number as the match criterion. The value range for the ACL number is 2000 to 3999.
   Match logic	Specify a match logic. AND: To match a traffic class, a packet must match all IPv4 or IPv6 ACLs of the traffic class. OR: To match a traffic class, a packet needs to match only one IPv4 or IPv6 ACL of the traffic class.
   Global CAR name	Specify a global CAR name as the traffic behavior.
   CIR	Specify the CIR.
   CBS	Specify the CBS.
   EBS	Specify the EBS.
   PIR	Specify the PIR.
   Green action	Specifies the action to take on packets that conform to the CIR. pass: Permits the packet to pass through. remark-dot1p-pass: Sets the 802.1p priority of the packet to a new value and permits the packet to pass through. The value range is 0 to 7. remark-dscp-pass: Sets the DSCP priority of the packet to a new value and permits the packet to pass through. The value range is 0 to 63. remark-mpls-exp-pass: Sets the EXP priority of the MPLS packet to a new value and permits the packet to pass through. The value range is 0 to 7. remark-prec-pass: Sets the IP precedence of the MPLS packet to a new value and permits the packet to pass through. The value range is 0 to 7. discard: Drops the packet.
   Yellow action	Specifies the action to take on packets that conform to the PIR but not to the CIR. Available actions are the same as those for the green action.
   Red action	Specifies the action to take on packets that conform to neither CIR nor PIR. Available actions are the same as those for the green action.

5. Click OK.