|
|
Table Of Contents
Configuring QoS for IP Telephony
Understanding QoS for IP Telephony
Network Model for Configuring QoS for IP Telephony
Using QPM to Configure QoS for IP Telephony
Configuring QoS Using the IP Telephony Wizard
Selecting Devices for QoS Configuration
Selecting the IP Phone Connections
Selecting the SoftPhone Connections
Selecting the CallManager and Gateways Ready Ports
Selecting the IntraLAN Connections
Selecting the Switch to the WAN Router Connections
Selecting the Router WAN to Switch Connections
Selecting WAN Serial Point-to-Point Connections
Selecting WAN Frame Relay Connections
Viewing the Voice Ready Report
Configuring QoS for IP Telephony
In an AVVID (Architecture for voice, video, and integrated data) 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
•
•
•
•
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.
QPM provides tools that can determine and configure the optimum QoS for a voice network. These include:
•
•
•
Related Topics
•
•
•
•
Network Model for Configuring QoS for IP Telephony
Figure 5-1 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 5-1 IP Telephony Network Model
Table 5-1 lists the network points that require QoS configuration for IP telephony.
Table 5-1 Network Points Requiring QoS Configuration
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
Related Topics
•
•
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 (architecture for voice, video, and integrated data) network.
The solution is an IP Telephony wizard that creates voice policy groups at each network point that requires IP telephony QoS configuration.
Voice policy groups are policy groups that contain the QoS properties and policies for each relevant point in the IP telephony network. A voice policy group 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 policies of certain voice policy groups created by the wizard, to suit specific network configurations, as required.
The IP Telephony wizard creates voice policy groups from voice policy group templates which are provided by QPM in the Policy Group Templates library. These templates follow the IP telephony QoS guidelines, described in the IP Telephony QoS Design Guide at:
www.cisco.com/univercd/cc/td/doc/product/voice/ip_tele/avvidqos
/index.htmIf 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.
Note
Related Topics
•
•
•
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 policy groups, that include the QoS policies 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. All you need to do is select the network elements that require QoS configuration at each network point. The wizard then automatically assigns the interfaces to the appropriate voice policy groups.
Note
The wizard automatically creates voice policy groups in the current deployment group. The deployment group may also contain previously created policy groups containing data policies. If required, you can change the current deployment group when you start working with the wizard. If the required voice policy groups already exist in the deployment group, the wizard uses them and assigns the required interfaces to them. If a required voice policy group does not exist in the deployment group, the wizard creates a new one from the relevant template.
Step-by-step procedures for configuring QoS using the IP Telephony wizard, are described in the following sections.
The steps of the wizard are as follows:
•
•
•
•
•
•
•
•
•
•
•
Before you Begin
To run the wizard, it is assumed that the following preconditions have been met:
•
•
Related Topics
•
•
•
•
Using the IP Telephony Wizard
This topic describes the main features of the IP Telephony wizard pages and how to use them.
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:
•
•
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.
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 deselect 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 policy groups that were created for the current voice role, and summary information about the assignment of network elements in the current configuration step.
The following assignments summary information may be displayed:
•
•
•
•
•
•
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 policy groups 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 policy groups will be saved in the deployment 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.
Related Topics
•
•
•
Introduction
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.
Procedure
Step 1
Step 2
a.
–
–
–
b.
–
–
Step 3
Step 4
Related Topics
•
•
•
Selecting Devices for QoS Configuration
In this step of the wizard, you select the devices that you want to participate in the current IP Telephony wizard session. All the devices in the device group that support IP telephony features (according to model and OS) are displayed in a table. The wizard will configure only the network elements from the selected devices. By default, the wizard selects all the devices.
Devices that do not support IP telephony are not displayed. If required, you can open the Voice Ready report to see all the devices in the current device group and whether or not they support QoS for voice.
Note
Some devices, such as Catalyst 6000 and Catalyst 4000 switches, require global device configuration. If any of the selected devices require global device configuration, the wizard immediately assigns them to the appropriate voice policy groups with a Voice Device voice role. Clicking the link on this page opens an information window describing this feature.
Procedure
Step 1
For more information about the columns in this table, see IP Telephony Wizard: Select IP Telephony Devices Page, page B-96.
Step 2
Step 3
•
For information about the Assignment Summary page, see IP Telephony Wizard: Assignment Summary Page, page B-97.
•
Step 4
The voice policy groups and your network element assignments will be saved, and the next configuration step of the wizard appears ( Selecting the IP Phone Connections).
Related Topics
•
•
•
•
•
Selecting the IP Phone Connections
This step of the wizard describes the QoS requirements for all catalyst ports to which IP phones are connected, and asks you to select the switch ports on which the wizard will configure the QoS settings for the IP phone connections (network points 1 in Figure 5-1).
Procedure
Step 1
For more information about the columns in this table, see IP Telephony Wizard: Select IP Phone Connections Page, page B-99.
Step 2
a.
For more information about this page, see IP Telephony Wizard: Remove Network Elements Page, page B-101.
b.
Step 3
•
The voice policy groups and your IP phones ports assignments will be saved, and the next configuration step of the wizard appears ( Selecting the SoftPhone Connections).
Related Topics
•
•
Selecting the SoftPhone Connections
This step of the wizard describes the QoS requirements for a Catalyst 6000 (with PFC) switch that is connected to a PC running a Cisco IP SoftPhone application. You should select the switch ports on which the wizard will configure QoS settings for the SoftPhone connections in your network (network point 2 in Figure 5-1).
Procedure
Step 1
For more information about the columns in this table, see IP Telephony Wizard: Select SoftPhone Connections Page, page B-103.
Step 2
a.
For more information about this page, see IP Telephony Wizard: Remove Network Elements Page, page B-101.
b.
Step 3
•
The voice policy groups and your SoftPhones port assignments will be saved, and the next configuration step of the wizard appears ( Selecting the CallManager and Gateways Ready Ports).
Related Topics
•
•
Selecting the CallManager and Gateways Ready Ports
This step of the wizard describes the QoS requirements for Catalyst ports to which CallManagers or Voice Gateways are connected, and asks you to select the switch ports on which the wizard will configure the QoS settings for these connections in your network (network point 3 in Figure 5-1).
Procedure
Step 1
For information about the columns in this table, see IP Telephony Wizard: Select CallManager Connections Page, page B-105.
Step 2
a.
For more information about this page, see IP Telephony Wizard: Remove Network Elements Page, page B-101.
b.
Step 3
•
The voice policy groups and your CallManager ports assignments will be saved, and the next configuration step of the wizard appears ( Selecting the IntraLAN Connections).
Related Topics
•
•
Selecting the IntraLAN Connections
After QoS configuration of the access interfaces, QoS must be configured throughout the LAN.
In this step, the wizard helps you define the appropriate QoS for the internal LAN ports—the uplinks and downlinks (network points 4, 5 and 6 in Figure 5-1).
Note
The correct QoS configuration for LAN connections is to trust DSCP from Layer 3 devices and trust CoS from Layer 2 devices. The wizard will configure the QoS automatically according to the type of neighboring switch.
If QPM recognizes that the neighboring switch has Layer 3 QoS capabilities, it will trust DSCP from the Layer 3 switch. If there is no neighboring switch (or if the switch is of unknown type), QPM will configure QoS for a Layer 2 device.
Procedure
Step 1
For more information about the columns in this table, see IP Telephony Wizard: Select IntraLAN Connections Page, page B-107.
Step 2
a.
For more information about this page, see IP Telephony Wizard: Remove Network Elements Page, page B-101.
b.
Step 3
•
The voice policy groups and your LAN interfaces assignments will be saved, and the next configuration step of the wizard appears ( Selecting Voice VLAN Devices).
Related Topics
•
•
Selecting Voice VLAN Devices
Since the IP phone ports are configured to use an auxiliary voice VLAN on the switches, and the QoS style on the IP phone ports is set to VLAN-based, it is important to attach the appropriate policies to the voice VLAN. In this step, the wizard configures VLAN-based QoS style for an auxiliary VLAN on the connection of the IP phones to the Catalyst 6000 access switch, and also on the Layer 2 switch to Layer 3 switch connection.
Procedure
Step 1
For more information about the columns in this table, see IP Telephony Wizard: Select Voice VLAN Connections Page, page B-110.
Step 2
a.
For more information about this page, see IP Telephony Wizard: Remove Network Elements Page, page B-101.
b.
Step 3
•
The voice policy groups and your Voice VLAN assignments will be saved, and the next configuration step of the wizard appears ( Selecting the Switch to the WAN Router Connections).
Related Topics
•
•
•
Selecting the Switch to the WAN Router Connections
In this step, the wizard sets QoS for the distribution switch interfaces to the WAN router (network point 7 in Figure 5-1).
Because traffic coming from the WAN side is already classified, the QoS configuration for the distribution switch interface to the router will be to trust the layer 3 DSCP bits.
Procedure
Step 1
For more information about the columns in this table, see IP Telephony Wizard: Select Switch to WAN Router Connections Page, page B-112.
Step 2
a.
For more information about this page, see IP Telephony Wizard: Remove Network Elements Page, page B-101.
b.
Step 3
•
The voice policy groups and your Switch-to-WAN-Router interface assignments will be saved, and the next configuration step of the wizard appears ( Selecting the Router WAN to Switch Connections).
Related Topics
•
•
Selecting the Router WAN to Switch Connections
In this step, the wizard sets QoS for the WAN router connection to the access (layer 2 QoS aware) switch in the branch office (network point 9 in Figure 5-1).
By default, a router trusts the interface to a distribution (layer 3 QoS aware) switch, so no special QoS is required on the router input direction. For example, in Figure 5-1, there is no need to set QoS for the router connection to the Catalyst 6000 distribution switch in the campus. In addition, no special QoS is required on the output direction, since the layer 3 switch knows to trust DSCP from the router and sets the CoS bits accordingly. However, if the switch has only layer 2 QoS capabilities, the router must classify traffic on input and set layer 2 CoS bits on output.
Procedure
Step 1
For more information about the columns in this table, see IP Telephony Wizard: Select Router WAN to Switch Connections Page, page B-114.
Step 2
a.
For more information about this page, see IP Telephony Wizard: Remove Network Elements Page, page B-101.
b.
Step 3
•
The voice policy groups and your Router-to-Switch interface assignments will be saved, and the next configuration step of the wizard appears ( Selecting WAN Serial Point-to-Point Connections).
Related Topics
•
•
Selecting WAN Serial Point-to-Point Connections
This step of the wizard allows you to select the interfaces on which to configure QoS for the Serial Point-to-Point links in the WAN segment of your network. You should select all MLP and HDLC interfaces (from both the central and the remote sites) that carry voice traffic. For Point-to-Point links with speeds equal to or less than 768 kbs, you should select Multilink interfaces—selecting a serial interface may cause a deployment failure.
The wizard will automatically configure QoS separately for groups of interfaces with link speeds greater than 768kbs, and those with link speeds equal to or less than 768kbs.
Procedure
Step 1
For more information about the columns in this table, see IP Telephony Wizard: Select WAN Point to Point Connections Page, page B-116.
Step 2
a.
For more information about this page, see IP Telephony Wizard: Remove Network Elements Page, page B-101.
b.
Step 3
•
The voice policy groups and your WAN-Serial-Point-to-Point interface assignments will be saved, and the next configuration step of the wizard appears ( Selecting WAN Frame Relay Connections).
Related Topics
•
•
•
Selecting WAN Frame Relay Connections
If the interface connections in the WAN segment of your network support Frame Relay configuration, this step of the wizard allows you to select the Frame Relay DLCI's WAN links. When you assign a role to a DLCI, the role will also be assigned to the interface to which the DLCI belongs. QPM will configure both the DLCIs and the interfaces.
Note
The wizard describes the tools that will be used to configure the QoS settings for these interfaces.
You must select all the Frame Relay interfaces (from both the central and the remote sites) that carry voice traffic. The wizard will automatically configure QoS separately for groups of interfaces, according to their link speed.
Procedure
Step 1
For more information about the columns in this table, see IP Telephony Wizard: Select WAN Frame Relay Connections Page, page B-118.
Step 2
a.
For more information about this page, see IP Telephony Wizard: Remove Network Elements Page, page B-101.
b.
Step 3
•
The voice policy groups and your WAN-Frame-Relay interface assignments will be saved, and the last step of the wizard appears ( End).
Related Topics
•
•
•
End
The final step of the IP Telephony wizard informs you that all the QoS settings have been completed and that the wizard has added and saved the policies in the current deployment group.
From this page, you can select to go to the Deployment wizard to deploy the deployment group directly, or to the Policy Groups page to view a detailed summary of all the voice policy groups that were created by the wizard. From the Policy Groups page, you can modify the properties and policies configured in the voice policy groups, if required.
Procedure
Step 1
Step 2
The Policy Groups page or the Deployment wizard appears.
Related Topics
•
•
•
Modifying Voice Policy Groups
After you have completed the IP Telephony wizard, you can modify properties and policies of the voice policy groups created by the voice wizard, to suit a specific network configuration. You can also add nonvoice policies to the default voice policy groups.
Note
After you have completed the IP Telephony wizard and you selected not to deploy your QoS policies directly (see End), the Policy Groups page automatically appears. The Policy Groups page displays all voice policy groups together with non voice policy groups in the current deployment group. For each voice policy group, its associated voice role is displayed.
You can modify any of the properties and policies of a voice policy group, except for its device constraints. Changing the device constraints will cause the voice policy group to lose its voice role. In this case, the IP Telephony wizard will be unable to assign network elements to the voice policy group. You edit a voice policy group just like any policy group. The difference is that when saving, QPM checks the device constraints of the voice policy group. If any changes were made, you must save the voice policy group as a regular policy group without a voice role.
A full description of modifying policy groups is provided in Modifying a Policy Group, page 6-19.
Related Topics
•
Viewing the Voice Ready Report
The Voice Ready report provides you with an overview of the system's readiness for voice, displaying a list of all the configurable and nonconfigurable devices in the current device group.
The report displays the voice ready status of each device, and the reason for nonvoice readiness, where relevant. For a device to be "voice ready", it must have all the required software and hardware to support QoS for voice and be supported by QPM. Nonconfigurable devices do not have the required software or hardware to support QoS for voice, and/or are not supported by QPM. From this report, you can also view the properties of the devices in the list.
Note
It is recommended that you view the Voice Ready report after adding or importing the devices in your IP telephony network to QPM's device inventory, so that you can check whether your devices support voice QoS.
In the second step of the IP Telephony wizard, only the devices that support IP telephony features are displayed in a table. Devices that do not support IP telephony are not displayed. By opening the Voice Ready report, you can see all the devices in the current device group, including those that do not support QoS for voice.
Procedure
Step 1
Note
For more information about the columns in this table, see Voice Ready Report Page.
Step 2
Related Topics
Posted: Tue Apr 20 10:08:12 PDT 2004
All contents are Copyright © 1992--2004 Cisco Systems, Inc. All rights reserved.
Important Notices and Privacy Statement.
