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Configuring Quality of Service

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Quality of Service

Table Of Contents

Quality of Service

Create QoS Policy

QoS Wizard

Interface Selection  

QoS Policy Generation

QoS Configuration Summary

Edit QoS Policy

Associate or Disassociate QoS Policy

Add or Edit a QoS Class

Edit Match DSCP Values

Edit Match Protocol Values

Add Custom Protocol  

Edit Match ACL

Edit Match DSCP Values


Quality of Service


The Quality of Service (QoS) Wizard allows a network administrator to enable Quality of Service (QoS) on the router's WAN interfaces. QoS can also be enabled on IPSec VPN interfaces and tunnels. The QoS edit windows enables the administrator to edit policies created using the wizard.

Create QoS Policy

The QoS Wizard allows a network administrator to enable Quality of Service (QoS) on the router's WAN interfaces. QoS can also be enabled on IPSec VPN interfaces and tunnels.

The policy is applied to outgoing traffic on the interface.

Create QoS Policy Tab

Click to add a new QoS policy.

Edit QoS Policy Tab

Click to edit an existing QoS policy.

Launch QoS Wizard Button

Click to launch the QoS wizard. The QoS wizard allows you to configure QoS policies on your WAN interfaces.

QoS Wizard

This window summarizes the information that you will be providing as you complete the QoS Policy wizard.

Click the Next button to begin configuring a QoS policy.

Interface Selection  

Choose the interface on which you want to configure the QoS policy in this window. This window lists WAN interfaces, and interfaces which do not have a configured outbound QoS policy. VPN interfaces are included in the list, but interfaces used for Easy VPN clients, and interfaces with an existing QoS policy are not included. QoS is not supported for Easy VPN clients.

Details Button

Click to view configuration details about the interface. The window displays the interface's IP address and subnet mask, names of access rules and policies applied to the interface, and connections the interface is used for.

DSCP marking (trusted)

Click to use Differentiated Services Code Point (DSCP) markings to classify traffic. Cisco network devices such as IP phones and switches add DSCP markings to packets. Configuring DSCP on the router allows these markings to be used to classify traffic. If the Cisco IOS image on the router does not support DSCP marking, this option will not appear.

NBAR protocol discovery (untrusted)

Click to use Networked Based Application Recognition (NBAR) protocol discovery to classify traffic. When an application is recognized and classified by NBAR, a network can invoke services for that specific application. NBAR ensures that network bandwidth is used efficiently by classifying packets and then applying Quality of Service (QoS) to the classified traffic. If the Cisco IOS image on the router does not support NBAR protocol discovery, this option will not appear.

QoS Policy Generation

Use this window to allocate the bandwidth to the different types of traffic carried on the selected interface. The percentage value that you enter represents 1000 Kbps. For example, if you enter 5%, a bandwidth of 5000 Kbps is allocated. The total percentage value for all types of traffic excluding Best Effort cannot exceed 75%.

Voice—Voice traffic. The default value is 33 percent of the bandwidth.

Call Signalling—Signalling needed to control voice traffic. The default value is 5 percent of the bandwidth.

Routing—Traffic generated by this and other routers to manage the routing of packets. The default value is 5 percent of the bandwidth.

Management—Telnet, SSH and other traffic generated to manage the router. The default value is 5 percent of the bandwidth.

Transactional—Examples would be traffic generated for retail applications, or database updates. The default value is 5 percent of the bandwidth.

Best Effort—Remaining bandwidth for other traffic, such as e-mail traffic. The default value is 47 percent of the bandwidth. The value of Best Effort is dynamically updated based on the total percentage for the other types of traffic.

QoS Configuration Summary

The QoS Wizard Summary window displays a summary of the QoS policy created based on your choices in the wizard. This policy map will be attached to the selected interface. Each class that the SDM QoS wizard configures is summarized in this screen. A partial display follows. showing the interface that the policy is bound to, the classification type (NBAR or DSCP), the policy name, and several of the QoS classes created.

Interface:  FastEthernet0/0

Classification:  DSCP

Policy Name: SDM-QoS-Policy-1

Policy Details

----------------------------------------------------------------------
Class Name: SDM-Voice-1
----------------------------------------------------------------------
Enabled: Yes
Match DSCP: ef
Queuing: LLQ
Bandwidth Percentage: 33

----------------------------------------------------------------------
Class Name: SDM-Signalling-1
----------------------------------------------------------------------
Enabled: Yes
Match DSCP: cs3,af31
Queuing: CBWFQ
Bandwidth Percentage: 5

----------------------------------------------------------------------
Class Name: SDM-Routing-1
----------------------------------------------------------------------
Enabled: Yes
Match DSCP: cs6
Queuing: CBWFQ
Bandwidth Percentage: 5

----------------------------------------------------------------------
Class Name: class-default
----------------------------------------------------------------------
Enabled: Yes
Match Protocols:
Queuing: Fair Queue
Random Detect: Yes

----------------------------------------------------------------------
Class Name: SDM-Streaming-Video-1
----------------------------------------------------------------------
Enabled: No
Match DSCP: cs4

Edit QoS Policy

The Edit QoS Policy window allows you to view and change configured QoS policies, and associate policies with router interfaces.

Policy Name List

Choose a QoS policy name in this list to display the details of that policy.

Interface

If the displayed policy is associated with an interface, the name of that interface is displayed, for example FastEthernet 0/0.

Association

Click to change the association of a QoS policy with an interface. If the policy is currently associated with an interface, you can disassociate the policy, or change the traffic direction the policy is applied to. The Association button is disabled when a frame-relay serial interface is displayed in the Interface field.

QoS Class Buttons

The buttons above the Class List area allow you edit and reorder class information for the policy

Add Button—Click to add a QoS class to the policy.

Edit Button—Select a class and click this button to edit it in the displayed dialog. The Edit button is disabled when a read-only Qos class is selected.

Delete Button—Select a class and click this button to remove a QoS class from this policy. The Delete button is disabled when a read-only Qos class is selected.

Cut Button—Select a class and click this button to remove it from its current position in the list. Use the Paste button to place the class in the position that you want. The Cut button is disabled when a read-only Qos class is selected.

Copy Button—Select a class and click this button to copy the class information. The Copy button is disabled when a read-only Qos class is selected.

Paste Button—Click to edit copied class information and provide a new name for the class. If you choose Add this class to the policy, the class will be placed with the enabled polices in the class. The Paste button is disabled when a read-only Qos class is selected.

Move Up Button—Choose a class and click this button to move a class up the class list. This button can only be used to move enabled classes. The Move Up button is disabled when a read-only Qos class is selected.

Move Down Button—Choose a class and click this button to move a class down the class list. This button can only be used to move enabled classes. The Move Down button is disabled when a read-only Qos class is selected.

Class List Display

The Edit QoS Policy window displays the details of the QoS Classes that make up the selected policy.

Icon Column

The first column may contain an icon indicating the status of a QoS policy.

If this icon appears next to the QoS class, it is read-only, and it cannot be edited, deleted, or moved to another position in the class list.


Class Name

The name of the QoS class. Cisco SDM predefines names for QoS classes.

Enabled

A green checkmark indicates this class is enabled. A red icon with a white X indicates the class is not enabled for this policy. To enable a class, click Edit and enable the class in the Edit QoS Class window.

Match

Whether the QoS class looks for matches to Any or to All of the selected DSCP values. If you choose Any, traffic must meet only one of the match criteria. If you choose All, traffic must meet all of the match criteria. The DSCP values chosen are displayed in the DSCP column.

Classification

This portion of the display contains the following columns:

DSCP—The DSCP values that are chosen for possible match.

Protocols—The protocols included in this QoS class. A video traffic QoS class might have protocols such as cuseeme, netshow, and vdolive. A routing traffic QoS class might have protocols such as BGP, EIGRP, and OSPF.

ACL—The name or number of an ACL that specifies the traffic that this QoS class applies to.

Action

This portion of the display contains the following columns:

Queuing—This column lists the queuing type, Class Based Weighted Fair Queuing (CBWFQ), Low Latency Queuing (LLQ), or Fair Queuing, and displays the bandwidth allocated to the class.

Set DSCP—The DSCP value that is given to this type of traffic by the QoS class.

Drop—The column displays Yes if this type of traffic is to be dropped, or No if it is not to be dropped.

Apply Changes and Discard Changes Buttons

Changes that you make in this window are not immediately delivered to the router. To deliver changes that you make, click Apply Changes. If you do not want the changes that you have made in this window to be sent to the router, click Discard Changes.

Associate or Disassociate QoS Policy

Use this window to change the associations that a QoS policy has to router interfaces.

Interface Column

This column lists the router interfaces.


Note If you select the interface SDM uses to communicate with the router, you cause the connection between SDM and the router to be dropped.


Inbound Column

Check the box in this column if you want to associate the QoS policy to inbound traffic on the chosen interface.

Outbound Column

Check the box in this column if you want to associate the QoS policy to inbound traffic on the chosen interface.

Add or Edit a QoS Class

You can create and edit QoS traffic classes, and specify whether the class is to be added to the QoS policy.

Add this class to the policy

Check this option to include this QoS class in QoS policy. If this option is not checked, then the selected QoS class is marked as Disabled in the Edit QoS Policy window.

Class Name

The QoS class name is displayed in this field if you are editing an existing class. You must enter a classname if you are adding a new class to a policy, or pasting information from a QoS class that you have copied.

Class Default

This option appears when there is no class-default in the QoS policy. Click Class Default if you want to add class-default—the default class—instead of creating a new class. There are several configuration parameters that you cannot set for class-default:

Classification box—You cannot specify classification criteria.

Action box—You cannot specify that traffic be dropped. Additionally, you can only specify that Fair Queuing be used.

Classification

Choose the types of items and values that you want the router to examine traffic for. If you click All, traffic must match all criteria. If you click Any, traffic need only match a single criterion. You must specify a value type in the list and click Edit to specify the values. To specify that the class is to match http, edonkey, and smtp, for example, choose Protocol, and click Edit. Then choose those protocols in the Edit Match Protocol Values dialog and click OK. The protocols that you chose appear in the Value column of the Classification list.

If you want the class to match traffic defined in an ACL, click Access Rule, and then click Edit. In the dialog that appears, you can choose an existing ACL, create a new one, or clear existing associations if you are editing a QoS class.

Action

Choose the action that the router is to take when it finds traffic that matches the specified DSCP values.

Drop—Drop the traffic. If you select Drop, other options in the Action area are disabled.

Set DSCP— Choose the DSCP value that you want the traffic to be reset to.

Queuing— LLQ is available if the traffic uses the RTP protocol or has a DSCP value of EF. If the traffic does not have these attributes, the LLQ option is not available. If you are adding or editing the default class—class-default—only Fair Queuing is available.

Bandwidth Percentage—The percentage value that you enter is used as an absolute percentage of the total bandwidth on the interface.

Bandwidth Remaining Percentage—The percentage value that you enter is used as a relative percentage of the total bandwidth on the interface. For instance, you can specify that 30 percent of the available bandwidth be allocated to one class, and 60 percent of the bandwidth be allocated to another QoS class. To use this option, all other classes must use this option. The Bandwidth Remaining Percentage option is disabled if LLQ is selected.

Random Detect—Enables Weighted Random Early Detection (WRED) and Distributed WRED (DWRED) on the router. This option is disabled if LLQ is selected. Random Early Detection drops packets during periods of high congestion, thus telling the source host to decrease the transmission rate.

Edit Match DSCP Values

To add a DSCP value to to the match list, choose a value from the Available DSCP Values column on the left, and click the top double-arrowhead button to add it to the Selected DSCP Values column. To remove a value from the Selected DSCP Values column, choose the value and click the bottom double-arrowhead button.

Edit Match Protocol Values

To add a protocol to a class, choose a protocol from the Available Protocols column on the left, and click the top double-arrowhead button to add it to the Selected Protocols column. To remove a protocol from the Selected Protocols column, choose the protocol and click the bottom double-arrowhead button.

Add Custom Protocol  

This window allows you to add custom protocols that are not available in the Edit Protocols window. Do the following to define a custom protocol:


Step 1 Select the name of the custom protocol from the Name list.

Step 2 Select whether it will be used as a TCP or a UDP protocol.

Step 3 Define the port numbers that this protocol will use. Enter a port number in the New Port Number field, and click Add to add it to the Port Numbers list. To remove a port number from the list, choose the number and click Remove.


Edit Match ACL

Choose either Select an existing rule (ACL), or Create a new rule (ACL) and select. Additional dialogs are displayed to enable you to create or select an existing rule. If you want to clear existing rule associations, you can choose None (clear associations).

Edit Match DSCP Values

To add a DSCP value to to the match list, choose a value from the Available DSCP Values column on the left, and click the top double-arrowhead button to add it to the Selected DSCP Values column. To remove a value from the Selected DSCP Values column, choose the value and click the bottom double-arrowhead button.