Quality of Service (QoS) Policy Profile Modification on SFE/SGE Managed Switches

Objective

Network traffic is normally random and irregular. Quality of Service (QoS) is used to improve the performance of the network and to prioritize the network traffic according to the specified criteria. A policer allows the switch to control the maximum traffic rate sent or received on an interface and it also allows the partition of a network into multiple priority levels.

This article explains how to configure a Quality of Service policy profile on the SFE/SGE Managed Switches.

Applicable Devices

• SFE/SGE Managed Switches

Software Version

• v3.0.0.18

Policy Binding Configuration

Add Policy Profile

Step 1. Use the web configuration utility to choose Quality of Service > Advanced Mode > Policy Table. The Policy Table page opens:

 

Step 2. Click Add. The Add QoS Policy Profile window appears:

Step 3. Enter the name of the policy you wish to create in the New Policy Name field.

Step 4. Check the Class Map check box, then choose a particular class map from the drop-down list next to it.  A class map defines a a particular network traffic that is of interest.

Step 5. Check the Action check box and then choose either Trust CoS-DSCP or Set option.

• Trust CoS-DSCP — Click this if you want the device to automatically determine the queue based on the Class of Service (CoS) tag or Differentiated Services Code Point (DSCP) tag. CoS tag values are used with layer 2 switches while DSCP tag values are used with layer 3 switches.

• Set — Click this if you want to configure CoS manually. Then choose the option you want to define from the drop-down list next to it and enter the value for the option in the New Value field. The possible options are:

– DSCP — This allows you to configure Differentiated Services Code Point values. The range of DSCP values is 0 - 63. DSCP is a field in the IP header used for packet classification.

– Queue — This allows you to determine the queue to be used. The range of queue is 0 - 4 .

– CoS — This allows you to configure Class of Service values. The range of CoS values is 0 to 7. CoS is a 3-bit field in the Ethernet frame used to assign priorities which can be used by QoS to differentiate network traffic.

Step 6. Check the Police check box to enable policer functionality. It allows you to control incoming and outgoing traffic on an interface.

Step 7. From the Type drop-down list choose either Aggregate or Single.

• Aggregate — Multiple classes share the policer. Policing can be done on the traffic belonging to different ports and can have different class maps.

• Single — This allows you to configure information rate and exceed actions manually.

Step 8. In the Ingress Committed Information Rate (CIR) field enter the required value. CIR guarantees that frames which are within CIR level will be delivered but it is not guaranteed when frames exceed this limit. This field is enabled only when the policy is single.

Step 9. In the Ingress Committed Burst Size (CBS) field enter the required value. The Committed Burst Size is the amount of data that a network will accept in a given committed rate measurement interval (Tc). Tc is defined as the ratio of CbS to CIR. This field is enabled only when the policy is single.

Step 10. Choose the desired value from the Exceed Action drop-down list. This decides what to do to the incoming traffic when they exceed the CIR limit. Choose Drop if you want to drop the packets when CIR limit is exceeded or choose  Out of Profile DSCP if you want to put a remark in the DSCP value which indicates that CIR value is exceeded or else choose  None this will simply forwards the packets even though the CIR limit is exceeded.

Step 11. Click Apply. The required Quality of Service policy is added. Click Close to return to the Policy Table page.

Caution: This only saves your configuration to the running configuration file. This means any changes made will be lost if the device is rebooted. If you wish to save these changes even after a system reboot, you need to copy the running configuration file to the startup configuration file. See Copy Configuration File on SFE/SGE Series Managed Switches for more information on how to do this.

Edit Policy Profile

Step 1. Use the Switch Configuration Utility to choose Quality of Service > Advanced Mode > Policy Table. The Policy Table page opens:

Step 2. Check the check box next to the policy name you wish to edit and then click Edit. The Edit QoS Policy Profile window appears:

Step 3. From the Policy Name drop-down list choose the policy you want to edit.

Step 4. Check the Class Map check box, then choose a particular class map from the drop-down list next to it.  A class map defines a a particular network traffic that is of interest.

Step 5. Check the Action check box and then choose either Trust CoS-DSCP radio button or Set radio button.

•  Choose the Trust CoS-DSCP radio button if you want the device to automatically determine the queue based on the Class of Service (CoS) tag or Differentiated Services Code Point (DSCP) tag. CoS tag values are used with layer 2 switches while DSCP tag values are used with layer 3 switches.

•   Choose the Set radio button if you want to configure manually. Then choose the field you want to define from the drop-down list next to it.  The possible options are:

– DSCP — This allows you to configure Differentiated Services Code Point values. The range of DSCP values is 0 - 63. DSCP is a field in the IP header used for packet classification.

– Queue — This allows you to determine the queue to be used. The range of queue is 0 - 4 .

– CoS — This allows you to configure Class of Service values. The range of CoS values is 0 to 7. CoS is a 3-bit field in the Ethernet frame used to assign priorities which can be used by QoS to differentiate network traffic.

Step 6. Check the Police check box to enable policer functionality. It allows you to control incoming and outgoing traffic on an interface.

Step 7. From the Type drop-down list choose either Aggregate or Single.

• Aggregate — Multiple classes share the policer. Policing can be done on the traffic belonging to different ports and can have different class maps.

• Single — This allows you to configure information rate and exceed actions manually.

Step 8. In the Ingress Committed Information Rate (CIR) field enter the required value. CIR guarantees that frames which are within CIR level will be delivered but it is not guaranteed when frames exceed this limit. This field is enabled only when the policy is single.

Step 9. In the Ingress Committed Burst Size (CBS) field enter the required value. The Committed Burst Size is the amount of data that a network will accept in a given committed rate measurement interval (Tc). Tc is defined as the ratio of CbS to CIR. This field is enabled only when the policy is single.

Step 10. Choose the desired value from the Exceed Action drop-down list. This decides what to do to the incoming traffic when they exceed the CIR limit. Choose Drop if you want to drop the packets when CIR limit is exceeded or choose  Out of Profile DSCP if you want to put a remark in the DSCP value which indicates that CIR value is exceeded or else choose  None this will simply forwards the packets even though the CIR limit is exceeded.

Step 11. Click Apply. The required Quality of Service policy is modified. Click Close to return to the Policy Table page.

Caution: This only saves your configuration to the running configuration file. This means any changes made will be lost if the device is rebooted. If you wish to save these changes even after a system reboot, you need to copy the running configuration file to the startup configuration file. See Copy Configuration File on SFE/SGE Series Managed Switches for more information on how to do this.

Add QoS Policy Binding

Note: A policy should be created in prior to binding a policy. Log in to the switch configuration utility and choose Quality of Service > Advanced mode> Policy table in order to create a policy.

Step 1. Log in to the switch configuration utility and choose Quality of Service > Advanced Mode > Policy Binding. The Policy Binding page opens:

The following fields are displayed:

• Interface— Interfaces for which a policy is defined.

• Policy Name — Policy name assigned to the interface.

Step 2. Click the Add button. The Add QoS Policy Binding window appears:

Step 3. Click the Port or LAG radio button. If you want to apply bandwidth settings on a particular port then click Port and if you want to apply bandwidth settings on a bundle of a few or all individual ports then click LAG. Choose the desired value from the drop-down list next to it.

Step 4. Choose a policy from the Policy Name drop-down list. A policy contains a series of actions that you want to apply on a set of classified inbound traffic.

Step 5. Click Apply to save the changes.

Caution: This only saves your configuration to the running configuration file. This means any changes made will be lost if the device is rebooted. If you wish to save these changes even after a system reboot, you need to copy the running configuration file to the startup configuration file. See Copy Configuration File on SFE/SGE Series Managed Switches for more information on how to do this.

Step 6. Click Close to return to the Policy Binding page.

Modify QoS Policy Binding

Step 1. Log in to the switch configuration utility and choose Quality of Service > Advanced Mode > Policy Binding. The Policy Binding page opens:

Step 2. Click the Edit button of the interface you want to edit. The Edit Qos Policy Binding window appears:

Note: The Edit QoS Policy Binding in this example is done on interface g1.

Step 3. Choose the desired policy from the Policy Name drop-down list.

Step 4. Click Apply to save the changes.

Caution: This only saves your configuration to the running configuration file. This means any changes made will be lost if the device is rebooted. If you wish to save these changes even after a system reboot, you need to copy the running configuration file to the startup configuration file. See Copy Configuration File on SFE/SGE Series Managed Switches for more information on how to do this.