Cisco Systems 416 User Manual

CHAPTER

Provisioning: Configuring QoS for IP Telephony

In an Architecture for Voice, Video, and Integrated Data (AVVID) network, you must configure QoS for IP telephony to ensure voice quality.

The following topics provide information about the need for configuring QoS in an IP telephony environment and the tools that enable you to do this.

• Understanding QoS for IP Telephony, page 7-1

• Using QPM to Configure QoS for IP Telephony, page 7-3

• Configuring QoS Using the IP Telephony Wizard, page 7-4

• Modifying Voice Policies, page 7-17

• Viewing the Voice Ready Report, page 7-18

• Advanced IP Telephony Network Configuration, page 7-19

Understanding QoS for IP Telephony

Real-time based applications in a network, such as voice applications, have different characteristics and requirements than those of data applications. Voice applications tolerate minimal variation in the amount of delay affecting delivery of their voice packets.

Voice traffic is also intolerant of packet loss and jitter, both of which degrade the quality of the voice transmission delivered to the recipient end user. To effectively transport voice traffic over IP, mechanisms are required that ensure reliable delivery of packets with low latency.

In an enterprise environment, network congestion can occur at any time in any portion of the network campus, branch office, or WAN. For successful deployment of IP telephony, you must ensure end-to-end network quality for voice traffic.

To ensure voice quality, you must use QoS in all areas of the enterprise network. To make a proper QoS configuration, you must first identify the points where QoS is a concern, then choose the appropriate QoS tools to use, and deploy to the devices in the network.

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Understanding QoS for IP Telephony

QPM provides tools that can determine and configure the optimum QoS for a voice network. These include:

• Provisioning tools—Lets you define the correct policies for interfaces on the voice paths.

QPM provides voice policies that contain the QoS configurations and traffic rules required at each relevant point in the network that needs QoS for IP telephony.

• Deployment tools—Lets you deploy these policies on the network and monitor the deployment

process.

• Reporting tools—Graphs and charts help you identify and troubleshoot QoS related issues.

Related Topics

• Network Model for Configuring QoS for IP Telephony, page 7-2

• Using QPM to Configure QoS for IP Telephony, page 7-3

• Viewing the Voice Ready Report, page 7-18

• Chapter 9, “Provisioning: Deploying QoS Policies”

Chapter 7 Provisioning: Configuring QoS for IP Telephony

Network Model for Configuring QoS for IP Telephony

Figure 7-1 shows a typical network model for configuring QoS for IP telephony in an enterprise

environment. QPM supports the QoS methods required to configure IP telephony QoS for high-speed campus domains, branch offices, and WAN implementations.

Figure 7-1 IP Telephony Network Model

Campus

CallManagerSoftPhone

Catalyst 6000 Access Switch with PFC

Catalyst 6000 Distribution switch

with PFC

WAN

Catalyst 3500 Access Switch

Remote Branch

Catalyst 2900 Access Switch

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Chapter 7 Provisioning: Configuring QoS for IP Telephony

Table 7-1 explains the network points that require QoS configuration for IP telephony.

Table 7-1 Network Points Requiring QoS Configuration

Network Point in Figure 7-1 Description

1 Access switch—IP phone ports

2 Layer 3 QoS-aware access switch (with PFC)—SoftPhone port

3 Layer 3 QoS-aware access switch (with PFC)—CallManager

port

4 Layer 3 QoS-aware access switch (with PFC) uplink port to

distribution switch (with PFC)

5 Distribution switch (downlink) port to Layer 3 QoS-aware

access switch (with PFC)

6 Distribution switch (downlink) port to Layer 2 QoS-aware

access switch

7 Layer 3 distribution switch port to WAN router

8 WAN interface

9 Branch office router interface to Layer 2 QoS-aware switch

Using QPM to Configure QoS for IP Telephony

Related Topics

• Understanding QoS for IP Telephony, page 7-1

• Using QPM to Configure QoS for IP Telephony, page 7-3

Using QPM to Configure QoS for IP Telephony

The QPM IP Telephony application provides a solution for configuring QoS for voice traffic in an AVVID network.

The solution is an IP Telephony wizard that creates voice policies at each network point that requires IP telephony QoS configuration.

Voice policies are policies that contain the QoS properties and traffic rules for each relevant point in the IP telephony network. A voice policy contains a voice role attribute, which specifies the role of an interface, according to its type, function and location on the network, such as, IP phone, Switch to WAN Router. QPM allows you to modify properties and traffic rules of certain voice policies created by the wizard, to suit specific network configurations, as required.

The IP Telephony wizard creates voice policies from voice policy templates which are provided by QPM in the Policy Templates library. These templates follow the IP telephony QoS guidelines, described in the IP Telephony QoS Design Guide:

www.cisco.com/warp/customer/771/srnd/qos_srnd.pdf

If the required templates do not exist during IP telephony QoS configuration, they can also be generated by the wizard and stored in the library.

Some templates that are provided by QPM, such as ATM links, might not be used by the IP Telephony wizard.

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Configuring QoS Using the IP Telephony Wizard

You can also create voice policies without the wizard, using the voice policy templates supplied by QPM. You assign the voice policies in the same way as you would data policies.

After you have completed the IP Telephony wizard, you can modify properties and policies of the voice policies created by the voice wizard, to suit a specific network configuration.

Related Topics

• Configuring QoS Using the IP Telephony Wizard, page 7-4

• Modifying Voice Policies, page 7-17

• Working with Policy Templates, page 6-4

Configuring QoS Using the IP Telephony Wizard

The IP Telephony wizard allows you to configure QoS for voice traffic on the network. The wizard handles VoIP configuration in common IP telephony network topologies. It guides you through the steps required to define your IP telephony network topology.

At each step, the wizard automatically creates the voice policies, that include the QoS properties and traffic rules required at each network point (interface) where QoS is a concern. The wizard presents only the interfaces on which the relevant QoS can be configured.

You need to select the network elements that require QoS configuration at each network point. The wizard then automatically assigns the interfaces to the appropriate voice policies.

QPM allows you to import files which contain device role information about devices (see Removing

Devices, page 4-15). Device role information is used by the IP Telephony wizard during the selection of

interfaces to voice roles.

For example, for the wizard to select an Ethernet 10/100 port on the switch to an IP phone voice role, the switch must be an access type switch (i.e., have an “access” device role). If the switch has a “distribution” device role, QPM will not select it. If the device role information imported from a file is not up-to-date, you can manually override it in the Device Properties page (see Viewing and Editing

Device Properties, page 4-10).

The wizard automatically creates voice policies in the current policy group. The policy group may also contain previously created policies containing data traffic rules.

If required, you can change the current policy group when you start working with the wizard.

• If the required voice policies already exist in the policy group, the wizard uses them and assigns the

required interfaces to them.

• If a required voice policy does not exist in the policy group, the wizard creates a new one from the

relevant template.

Related Topics

• Using QPM to Configure QoS for IP Telephony, page 7-3

• Using the IP Telephony Wizard, page 7-5

• Adding Devices to the Device Inventory, page 4-3

• Working with Policy Templates, page 6-4

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Using the IP Telephony Wizard

This topic describes the following main features of the IP Telephony wizard pages, and how to use those features:

• Description, page 7-5

• Advanced, page 7-5

• Selection Table, page 7-5

• Assignment Summary, page 7-5

• Saving Your Assignments, page 7-6

Description

Each configuration step page of the wizard includes a description of the QoS policies that will be configured on the interfaces for the selected voice role. You can view or hide this description by clicking the arrow button next to Description. By default, the description is hidden.

Advanced

The Advanced section of a configuration step page provides two buttons:

• Remove—This button opens a page in which you can remove network elements that were assigned

for a voice role.

This option allows you to change your selection of network elements after they have been assigned to voice policies. The wizard removes the assignment of selected elements from the voice policy.

Configuring QoS Using the IP Telephony Wizard

• Recommend—If QPM recommended rules are available for a specific voice role, clicking this

button activates the wizard to accept the recommended selection of network elements for the current voice role.

The network elements are selected but not assigned to voice policies. A list of the rules for the current voice role is displayed.

You can view or hide the Advanced section by clicking the arrow button next to Advanced. By default, this section is hidden.

Selection Table

In each configuration step, you select the network elements that require QoS configuration. The available network elements are presented in a table. You can hide this table by clicking the arrow button next to Selection Table. By default, the selection table is open. For information about using a selection table, see Using QPM Tables, page 3-16.

By selecting the Display Configuration Info. check box in the first configuration step, you can choose to view assignment summary information after each configuration step. The check box will remain selected in all the other steps. Similarly, you can uncheck this check box in the first configuration step if you don’t want to view the summary information. You can override the default selection at each step, if required.

Assignment Summary

As you work through the wizard, you can choose to view an assignment summary page that displays the voice policies that were created for the current voice role, and summary information about the assignment of network elements in the current configuration step.

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Configuring QoS Using the IP Telephony Wizard

The following assignments summary information may be displayed:

• The total number of network elements you selected in this configuration step.

• The number of network elements that were selected, but found to be previously assigned to voice

policies with this voice role.

• The number of network elements that were newly assigned to a voice policy with this voice role.

(This may include elements that were previously assigned to voice policy groups with different voice roles.)

• The number of network elements that were selected in this configuration step, but were not assigned

to the voice role because they have no policies for this voice role. These elements appear in the selection list because they have the same interface type as other elements that can be selected.

For example, although GigabitEthernet interfaces have the same interface type as FastEthernet interfaces, they cannot be connected to an IP phone. During IP phone configuration, these interfaces will not be assigned to voice policy groups for the IP Phones voice role.

• The number of related assignment elements. These are network elements that were not selected (or

were not in the selection table), but were assigned to voice policy groups to complete the configuration correctly. For example, when you configure traffic shaping on a DLCI, you must also enable it on a main frame-relay interface.

• The number of reassigned network elements. If network elements were found to be already assigned

to voice policy groups with different voice roles, the wizard overrides the previous assignment and assigns them to voice policies with the new voice role.

Chapter 7 Provisioning: Configuring QoS for IP Telephony

From this assignment summary page, you can also view detailed information about a voice policy group, and a list of the newly assigned network elements.

Saving Your Assignments

You work through each step of the wizard by clicking the Next button in each page, or you can use the Navigation TOC that is displayed on the left side of each page to move directly to the step you want to do.

Clicking Next to move to the next configuration step, or selecting another step forward in the Navigation TOC, saves the voice policies and the assignments that were made for that voice role, to the deployment group.

Clicking Cancel, Back, or selecting another step backward in the Navigation TOC, undoes any configuration changes you made in that step.

If the Display Configuration Info check box is selected, clicking Next opens the assignments summary page for that configuration step.

The voice policies will be saved in the policy group, but the assignment of interfaces to them will not be saved.

After reviewing your assignments summary, clicking Next in this page saves both the voice policy groups and the interface assignments, and opens the next step of the wizard.

Step-by-step procedures for configuring QoS using the IP Telephony wizard, are described in the following sections.

• Introduction

• Selecting IP Telephony Devices

• Selecting IP Phone Connections

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• Selecting SoftPhone Connections

• Selecting CallManager Connections

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• Selecting IntraLAN Connections

• Selecting Voice VLAN Connections

• Selecting Switch to WAN Router Connections

• Selecting Router WAN to Switch Connections

• Selecting WAN Point to Point Connections

• Selecting WAN Frame Relay Connections

• End

Before you Begin

To run the wizard, it is assumed that the following preconditions have been met:

• Voice VLANs have been configured on all the relevant ports of the devices to enable the wizard to

attach QoS properties to these VLANs.

• All the relevant devices in your network were added or imported to QPM’s device inventory.

Related Topics

• Configuring QoS Using the IP Telephony Wizard, page 7-4

Configuring QoS Using the IP Telephony Wizard

Introduction

Step 1 Choose Provisioning > Policy View.

Step 2 Click Voice Policy.

• IP Telephony Wizard: Assignment Summary Page, page B-129

• Viewing Policy Information, page 8-14

The first page is an introduction to the wizard. It includes an overview of why QoS configuration is necessary for VoIP networks, and how the wizard will guide you to configure QoS for IP telephony.

Before you run the wizard, ensure that all the required devices in your IP telephony network have been added to the device inventory. If not, you must exit the wizard and add or import them. After adding your devices, you can check that your devices support voice QoS, by running the Voice Ready report. The Voice Ready report shows all the devices in the current device group, and whether or not they support voice QoS.

This page also displays the name of the current deployment group that will be used by the wizard for defining the IP telephony policies. You can change the current deployment group, if required.

To open the Introduction page of the wizard:

The Policy View page opens.

The IP Telephony Wizard - Introduction page appears.

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