Nortel NN43001-504, Telephony Manager Installation Manual

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Nortel Communication Server 1000

WLAN IP Telephony Installation and Commissioning

NN43001-504

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Document status: Standard Document version: 01.02 Document date: 15 June 2007

Sourced in Canada The information in this document is subject to change without notice. The statements, conﬁgurations, technical

data, and recommendations in this document are believed to be accurate and reliable, but are presented without express or implied warranty. Users must take full responsibility for their applications of any products speciﬁed in this document. The information in this document is proprietary to Nortel Networks.

Nortel, the Nortel logo and the Globemark are trademarks of Nortel Networks. All other trademarks are the property of their respective owners.

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Revision history

June 2007

Standard 01.02. This document is up-issued to reﬂect a change in the revision history.

May 2007

Standard 01.01. This document is issued to support Nortel Communication Server 1000 Release 5.0. This document contains information previously contained in the following legacy document, now retired: WLAN IP Telephony Installation and Conﬁguration (553-3001-304).

August 2005

Standard 4.00. This document is up-issued to support Nortel Communication Server 1000 Release 4.5.

September 2004

Standard 3.00. This document is up-issued to support Nortel Networks Communication Server 1000 Release 4.0.

June 2004

Standard 2.00. This document is up-issued to reﬂect changes in technical content.

May 2004

Standard 1.00. This document is issued to support the Nortel Networks WLAN system, including the Nortel Networks WLAN IP Telephony Manager 2245, Nortel Networks WLAN Application Gateway 2246, Nortel Networks WLAN Handset 2210, and Nortel Networks WLAN Handset 2211.

Nortel Communication Server 1000

WLAN IP Telephony Installation and Commissioning

NN43001-504 01.02 Standard

Release 5.0 15 June 2007

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4 Revision history

Nortel Communication Server 1000

WLAN IP Telephony Installation and Commissioning

NN43001-504 01.02 Standard

Release 5.0 15 June 2007

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Contents

New in this release 13

Feature description 13 Other changes 13

Multicast 14 Zones for wireless handsets 14 Open and use the Admin menu on the handset 14 Admin menu options for the WLAN Handset 6120/6140 14 Download the software 14 Feature programming for the WLAN Handset 6120/6140 14 Test the wireless handsets 14 Run Site Survey for the WLAN Handset 6120/6140 14 Diagnostics mode 14 Push-to-talk 14 Wireless handset status messages 15

How to get help 17

Getting help from the Nortel Web site 17 Getting help over the phone from a Nortel Solutions Center 17 Getting help from a specialist by using an Express Routing Code 17 Getting help through a Nortel distributor or reseller 18

Overview 19

Subject 19 Applicable systems 20 Conventions 21 Resources 21 Declaration of conformity 22 Shielded cable 22 Wireless telephone network description 22 Call Server 24 DHCP Server 25

DHCP options 25 TFTP Server 25 Firewall 25 WLAN Handset 2210/2211/2212 and WLAN Handset 6120/6140 25

Nortel Communication Server 1000

WLAN IP Telephony Installation and Commissioning

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Release 5.0 15 June 2007

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6 Contents

Components 26

Language 27

Licenses 27

Wi-Fi Multimedia 27

Wired Equivalent Privacy 28

Wi-Fi Protected Access 28

Wi-Fi Protected Access2 28

Virtual Private Network 28

Push-to-talk feature 28

Text-messaging feature 28

Loud noise environments 29 WLAN IP Telephony Manager 2245 29 WLAN Application Gateway 2246 30 Access Points 30

Handset switchover 31 Handset switchover 31

Loss of signal 31

Planning 33

Challenges of integrating voice applications 33

High overhead of 802.11 34

Rate scaling and variable capacity 34

Power adjustments and variable capacity 35

Quality of Service 35 DHCP server planning 36 TFTP Server planning 38 Syslog Server planning 40 Access point planning 40

Site survey 41

Effective site survey 43

Example of AP placement 44

Solving coverage issues 45

Solving overlap issues 45 Network planning 46 Network recommendation 46

Sample Access Control List 47 Network management 47

Assessment through a WLAN site survey 48

Assessment using NetIQ Vivinet Assessor 49

Monitoring and reporting with Enterprise Network Monitoring System 50

Monitoring and reporting with Communication Server 1000 Telephony

Manager 52

Monitoring and reporting with NetiQ Vivinet Assessor, Vivinet AppManager, and

Vivinet Diagnostics 53

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WLAN IP Telephony Installation and Commissioning

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Communication Server 1000 Telephony Manager 54 Zones 54 Other network design considerations 55

Access Point interference 56

SSID options and limitations 57

Layer 3 implementation 58 WLAN IP Telephony Manager 2245 planning 59

Installation requirements 59

Capacities 59

WLAN IP Telephony Manager 2245 groups 60

Gateway and timing function 64

Roaming and handover 64 Multicast 65 Placement guidelines for the WLAN IP Telephony Manager 2245 65 WLAN Application Gateway 2246 planning 73 WLAN IP Telephony Manager 2245 and WLAN Application Gateway 2246

installation requirements 74

IP address planning 74

IP addressing with DHCP 75 Planning worksheets 75

System information 77

Bandwidth management 77

Zones 77

Zones for wireless handsets 78

Call blocking 79 Codecs 79 Jitter buffer 80 RLR and SLR 80 RTCP 80 Gain adjustment 81 Programmable rings and tones 81

In/Out of Service tones 81 Virtual Ofﬁce 81 Branch Ofﬁce 81

Local mode display 81 Survivable Remote Gateway 82 External Applications Server 83 End-to-end QoS 83 NAT 83

NAT Traversal feature 84

Network conﬁgurations 84

WLAN IP Telephony Manager 2245 in a NAT environment 88

DHCP Server location in a NAT environment 88

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Release 5.0 15 June 2007

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8 Contents

TFTP Server location in a NAT environment 89

WLAN Application Gateway 2246 in a NAT environment 89 CS 1000 features 90 IP Phone 2004 features 91

Installation 93

Required materials 93

Supplied equipment 94 Preinstallation checklist 94 WLAN IP Telephony Manager 2245 installation tasks 94

About the front panel 94

Wall-mount 95

Rack-mount 96

LAN connection 97

Power connection 97 WLAN Application Gateway 2246 installation 97

WLAN IP Telephony Manager 2245 conﬁguration 99

Introduction 99

Functional description 99 Conﬁguration tasks 101 Connect to the WLAN IP Telephony Manager 2245 101

Serial port connection 101

Telnet connection 102 Conﬁgure the network 103

Save the conﬁguration 105

Changing the master IP address 106 Conﬁgure the WLAN IP Telephony Manager 2245 106 Change the password 108

Administration and maintenance 111

Adding a WLAN IP Telephony Manager 2245 to the system 111

Checking in to the Gateway 111 Replacing a WLAN IP Telephony Manager 2245 112

Failed master WLAN IP Telephony Manager 2245 112

Replacing the failed WLAN IP Telephony Manager 2245 112 Removing a WLAN IP Telephony Manager 2245 from the system 113

Wireless handset scenarios 113 Changing the master WLAN IP Telephony Manager 2245 113 View software version 113

For the WLAN IP Telephony Manager 2245 114

For the WLAN Application Gateway 2246 114

For a wireless handset 114 Software updates 114

Update software on the WLAN IP Telephony Manager 2245 115

Nortel Communication Server 1000

WLAN IP Telephony Installation and Commissioning

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Release 5.0 15 June 2007

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Update software on the WLAN Application Gateway 2246 115

Update software on a wireless handset 115

Software update (version 97.070) for the WLAN Handsets 2210/2211/2212 116

Displays 117 Wireless handset download messages 117

Normal download messages 117

Download failure or recovery messages 118

Troubleshooting 119

Troubleshooting the WLAN IP Telephony Manager 2245 119

Error Status screen 119

Network Status screen 120

Software Version Numbers screen 121

Speed or duplex mismatch 122 Troubleshooting the WLAN Application Gateway 2246 122 Troubleshooting the handset 122

Context 122

Access Point problems 123

Conﬁguration problems 123

Duplex mismatch 124

No ring 124

Far-end echo 124 Dropped calls 124

Wireless handset status messages 125

Using Call Server overlay commands 139

TPS CLI commands 141

Determining alias IP addresses 144 Troubleshooting coverage issues 144 Before calling Nortel Technical Support 144

Appendix A WLAN Application Gateway 2246 147

Introduction 147

System overview 148

Front panel 149 Third-party applications 150

Nurse-call systems 151 Installation 151

Conﬁguring the WLAN Application Gateway 2246 IP address 152 Conﬁguration 153

Administration console navigation 154

Task summary list 154

Conﬁguring the OAI Box 155

Conﬁguring network parameters 155

Connecting to the LAN 157

Connecting to the Application Server 158

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WLAN IP Telephony Installation and Commissioning

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Release 5.0 15 June 2007

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Continuing conﬁguration through Telnet 160

Connecting through Telnet 160

Conﬁguring the Telephone Line 161

Deleting a handset 162

Searching for a handset 162

Feature programming 163

Setting or changing a password 164 System status 164

Network status 165

Software versions 166

Telephone line status 167 Certiﬁcation testing 167

WLAN Application Gateway 2246 certiﬁcation 167

Wireless handset certiﬁcation 167 Software 168

Software updates 168

TFTP software updates Systems 170 Planning Worksheet for Handsets 171 Free the serial port for administrative purposes 172

Appendix B Troubleshooting WLAN IP Telephony

installations 173

Site data-gathering tables 173 Product-speciﬁc conﬁguration 176

Terminal proxy server 176

Handsets 177

WLAN IP Telephony Manager 2245 177

Quality of Service 177 WLAN speciﬁc conﬁguration 177

Nortel switches 178

Cisco access points and switches 178 General WLAN conﬁguration 183 DHCP server options 184 DHCP options 184

DHCP support for handsets that emulate the IP Phone 2004 187

Format of the IP Phone 2004 Terminal DHCP Class Identiﬁer ﬁeld 187

Format of the IP Phone 2004 Terminal DHCP Encapsulated Vendor Speciﬁc

option 188

Format of the IP Phone 2004 Terminal DHCP Site Speciﬁc option 189 Quality of Service checklist for voice over WLAN applications 191

RF basics and AP conﬁguration 193 Troubleshooting 196

Diagnosis ﬂows 196 Handset error messages 198

Nortel Communication Server 1000

WLAN IP Telephony Installation and Commissioning

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Release 5.0 15 June 2007

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Timing information 199 Diagnostic Tools 200

Run Site Survey for the WLAN Handset 2210/2211/2212 200

Run Site Survey for the WLAN Handset 6120/6140 201

Diagnostics Mode 204

Syslog Mode 207 Data capture 213

Questions 213

Data checklist 213

Site-data required for the capture analysis 214

Syslog capture conﬁguration 215

Signaling Server log capture 216

General data capture 217 Capture assert error messages with the Conﬁguration Cradle 218 Network speech levels 219 Reference documents 220

Appendix C Compatible Access Points 223 Index 224

Procedures

Procedure 1 Measuring jitter, delay, and packet loss 71 Procedure 2 Wall-mounting the WLAN IP Telephony Manager 2245 96 Procedure 3 Rack-mounting the WLAN IP Telephony Manager 2245 96 Procedure 4 Connecting the power 97 Procedure 5 Connecting to the WLAN IP Telephony Manager 2245 through

a serial port 102

Procedure 6 Connecting to the WLAN IP Telephony Manager 2245 through

Telnet 103 Procedure 7 Saving the conﬁguration 105 Procedure 8 Changing the password 108 Procedure 9 Changing a forgotten password 109 Procedure 10 Replacing a WLAN IP Telephony Manager 2245 112 Procedure 11 Viewing the software version 114 Procedure 12 Updating software (v97.070) for the WLAN Handsets 2210/

2211/ 2212 116 Procedure 13 Installing the WLAN Application Gateway 2246 152 Procedure 14 Connecting to the WLAN Application Gateway 2246 through a

serial port 152 Procedure 15 Conﬁgure the system type from the OAI Box Conﬁguration

option 155 Procedure 16 Conﬁguring the network 156 Procedure 17 Connecting the WLAN Application Gateway 2246 to the

LAN 157 Procedure 18 Connecting to a WLAN Application Gateway 2246 through

Telnet 160 Procedure 19 Conﬁguring a telephone line 161 Procedure 20 Deleting a handset 162

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WLAN IP Telephony Installation and Commissioning

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Release 5.0 15 June 2007

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Procedure 21 Searching for a handset 162 Procedure 22 Programming a feature 163 Procedure 23 Setting or changing a password 164 Procedure 24 Viewing system status 165 Procedure 25 Certifying wireless handsets on an existing system 168 Procedure 26 Transferring the software using FTP 169 Procedure 27 Loading software updates 170 Procedure 28 Using the serial port as the Application Server communication

link 172 Procedure 29 Using the CLI to capture a Signaling Server log 216 Procedure 30 Obtaining the wired and wireless captures 217 Procedure 31 Recording an assert error message 218

Nortel Communication Server 1000

WLAN IP Telephony Installation and Commissioning

NN43001-504 01.02 Standard

Release 5.0 15 June 2007

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New in this release

The following sections detail what is new in WLAN IP Telephony Installation and Commissioning (NN43001-504) for CS 1000, Release 5.0.

Feature description

Support is provided for the WLAN Handset 6120/6140 through the addition of the Nortel WLAN Handset 6100 Series Administration Tool Software. For more information about this tool for the WLAN Handset 6120/6140, including personal computer requirements, how to install the USB driver, and how to install and use the software, see WLAN Handsets Fundamentals

(NN43001-505).

Other changes

This document is renamed and renumbered from WLAN IP Telephony: Installation and Conﬁguration (553-3001-304) to WLAN IP Telephony Installation and Commissioning (NN43001-504). WLAN Handset conﬁguration information is moved to WLAN Handsets Fundamentals (NN43001-505).

For information about changes that are not feature-related,see the following sections:

•

"Multicast" (page 14)

•

"Zones for wireless handsets" (page 14)

•

"Open and use the Admin menu on the handset" (page 14)

•

"Admin menu options for the WLAN Handset 6120/6140" (page 14)

•

"Download the software" (page 14)

•

"Feature programming for the WLAN Handset 6120/6140" (page 14)

•

"Test the wireless handsets" (page 14)

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"Run Site Survey for the WLAN Handset 6120/6140" (page 14)

•

"Diagnostics mode" (page 14)

•

"Push-to-talk" (page 14)

•

"Wireless handset status messages" (page 15)

Nortel Communication Server 1000

WLAN IP Telephony Installation and Commissioning

NN43001-504 01.02 Standard

Release 5.0 15 June 2007

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14 New in this release

Multicast

The WLAN Handset 6140 uses IP multicast addresses.

Zones for wireless handsets

The WLAN Handset 6120/6140 is added to the designated wireless handset types.

Open and use the Admin menu on the handset

The procedures for opening and using the Admin menu on the WLAN Handset 6120/6140 and how to make an alphanumeric string entry are added.

Admin menu options for the WLAN Handset 6120/6140

A full description of all the options available from the Admin menu is given for the WLAN Handset 6120/6140.

Download the software

The procedure for downloading the software for the WLAN Handset 6120/6140 is described.

Feature programming for the WLAN Handset 6120/6140

A full description of the feature programming available for the WLAN Handset 6120/6140 is provided. This section includes soft key assignment, feature assignment, programming memory keys, accessing features, and programming the keys on the WLAN Handset 6120/6140.

Test the wireless handsets

The procedure for testing the WLAN IP 6120 handset is provided.

Run Site Survey for the WLAN Handset 6120/6140

Site Survey is used to evaluate the facility coverage before certifying that an installation is complete.

Diagnostics mode

Diagnostics screen 2 shows the GatewayType for all handsets.

Push-to-talk

With the Push-to-talk (PTT) feature, the WLAN Handset 6120/6140 can operate in a PTT group-broadcast mode like a two-way radio, in addition to the standard telephone operation. This section describes how to initiate and receive a PTT call.

Nortel Communication Server 1000

WLAN IP Telephony Installation and Commissioning

NN43001-504 01.02 Standard

Release 5.0 15 June 2007

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Other changes 15

Wireless handset status messages

The new messages are:

•

Error!

•

Server Unavailable. Restarting...

Nortel Communication Server 1000

WLAN IP Telephony Installation and Commissioning

NN43001-504 01.02 Standard

Release 5.0 15 June 2007

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16 New in this release

Nortel Communication Server 1000

WLAN IP Telephony Installation and Commissioning

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Release 5.0 15 June 2007

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How to get help

This chapter explains how to get help for Nortel products and services.

Getting help from the Nortel Web site

The best way to get technical support for Nortel products is from the Nortel Technical Support Web site:

ww.nortel.com/support

This site provides access to software, documentation, bulletins, and tools to address issues with Nortel products. From this site, you can:

•

download software, documentation, and product bulletins

•

search the Technical Support Web site and the Nortel Knowledge Base for answers to technical issues

•

arrange for automatic notiﬁcation of new software and documentation for Nortel equipment

•

open and manage technical support cases

Getting help over the phone from a Nortel Solutions Center

If you do not ﬁnd the information you require on the Nortel Technical Support Web site, and you have a Nortel support contract, you can also get help over the telephone from a Nortel Solutions Center.

In North America, call 1-800-4NORTEL (1-800-466-7835). Outside North America, go to the following Web site to obtain the telephone

number for your region:

ww.nortel.com/callus

Getting help from a specialist by using an Express Routing Code

To access some Nortel Technical Solutions Centers, you can use an Express Routing Code (ERC) to quickly route your call to a specialist in your Nortel product or service. To locate the current ERC for your product or service, go to:

Nortel Communication Server 1000

WLAN IP Telephony Installation and Commissioning

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Release 5.0 15 June 2007

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18 How to get help

www.nortel.com/erc

Getting help through a Nortel distributor or reseller

If you purchased a service contract for your Nortel product from a distributor or authorized reseller, contact the technical support staff for that distributor or reseller.

Nortel Communication Server 1000

WLAN IP Telephony Installation and Commissioning

NN43001-504 01.02 Standard

Release 5.0 15 June 2007

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Overview

This chapter contains information about the following topics:

•

"Subject" (page 19)

•

"Applicable systems" (page 20)

•

"Conventions" (page 21)

•

"Related information" (page 21)

•

"Declaration of conformity" (page 22)

•

"Shielded cable" (page 22)

•

"Wireless telephone network description" (page 22)

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"Call Server" (page 24)

•

"DHCP Server" (page 25)

•

"TFTP Server" (page 25)

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"Firewall" (page 25)

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"WLAN Handset 2210/2211/2212 and WLAN Handset 6120/6140" (page 25)

•

"WLAN IP Telephony Manager 2245" (page 29)

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"WLAN Application Gateway 2246" (page 30)

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"Access Points" (page 30)

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"Handset switchover" (page 31)

Subject

This document describes the planning, installation, conﬁguration, maintenance, and troubleshooting for the Nortel WLAN system, including the following elements:

•

Nortel WLAN IP Telephony Manager 2245

•

Nortel WLAN Application Gateway 2246 (optional)

•

Nortel WLAN Handset 2210

Nortel Communication Server 1000

WLAN IP Telephony Installation and Commissioning

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Release 5.0 15 June 2007

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20 Overview

•

Nortel WLAN Handset 2211

•

Nortel WLAN Handset 2212

•

Nortel WLAN Handset 6120

•

Nortel WLAN Handset 6140

Note about legacy products and releases

This NTP contains information about systems, components, and features that are compatible with Nortel Communication Server 1000 Release 5.0 software. For more information about legacy products and releases, click the Technical Documentation link under Support & Training on the Nortel home page:

ww.nortel.com

Applicable systems

This document applies to the following systems:

•

Communication Server 1000M Half Group (CS 1000M HG)

•

Communication Server 1000M Single Group (CS 1000M SG)

•

Communication Server 1000M Multi Group (CS 1000M MG)

•

Communication Server 1000E (CS 1000E) Note: When upgrading software, memory upgrades can be required on

the Signaling Server, the Call Server, or both.

System migration

When particular Meridian 1 systems are upgraded to run CS 1000 Release

5.0 software and conﬁgured to include a Signaling Server, they become CS 1000M systems. Table 1 "Meridian 1 systems to CS 1000M systems"

(page 20) lists each Meridian 1 system that supports an upgrade path to

a CS 1000M system.

Table 1 Meridian 1 systems to CS 1000M systems

This Meridian 1 system

Maps to this CS 1000M system

Meridian 1 PBX 51C CS 1000M Half Group Meridian 1 PBX 61C CS 1000M Single Group Meridian 1 PBX 81C CS 1000M Multi Group

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WLAN IP Telephony Installation and Commissioning

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Release 5.0 15 June 2007

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Resources 21

Conventions

In this document, the following systems are referred to generically as system:

• Communication Server 1000M (CS 1000M)

•

Communication Server 1000E (CS 1000E)

The following systems are referred to generically as large systems:

•

Communication Server 1000M Half Group (CS 1000M HG)

•

Communication Server 1000M Single Group (CS 1000M SG)

•

Communication Server 1000M Multi Group (CS 1000M MG)

Resources

This section lists information sources that relate to this document.

NTPs

The following NTPs are referenced in this document:

•

WLAN Handset 2210 User Guide (NN10300-077)

•

WLAN Handset 2211 User Guide (NN10300-078)

•

WLAN Handset 2212 User Guide (NN10300-071)

•

WLAN Handset 6120 User Guide (NN43150-100)

•

Features and Services Fundamentals (NN43001-106)

•

Main Ofﬁce Conﬁguration Guide for Survivable Remote Gateway 50 (NN43001-307)

•

Branch Ofﬁce Installation and Commissioning (NN43001-314)

•

IP Line Fundamentals (NN43001-500)

•

WLAN Handsets Fundamentals (NN43001-505)

Online

To access Nortel documentation online, click the Technical Documentation link under Support & Training on the Nortel home page:

ww.nortel.com

CD-ROM

To obtain Nortel documentation on CD-ROM, contact your Nortel customer representative.

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WLAN IP Telephony Installation and Commissioning

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Release 5.0 15 June 2007

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22 Overview

Declaration of conformity

The WLAN IP Telephony Manager 2245 and WLAN Application Gateway 2246 have been found to comply with the following:

•

FCC Part 15 Class A - Radiate and Conducted Emissions requirements

•

CISPR 22 Class A - Radiate and Conducted Emissions requirements

•

ICES 003 Class A - Radiate and Conducted Emissions requirements

•

EN 55022 Class A - Radiated and Conducted Emissions requirements

•

EN 55024 Immunity Requirements

•

EN 61000-3-2 Harmonic Current Emissions

•

EN 61000-3-3 Flicker Emissions

WARNING

Changes or modiﬁcations to this equipment not approved by Nortel can cause this equipment to not comply with part 15 of the FCC rules and void the user’s authority to operate this equipment.

WARNING

This equipment contains no user-serviceable parts inside. Refer servicing to qualiﬁed service personnel.

Shielded cable

Nortel recommends the use of shielded cable for all external signal connections in order to maintain FCC Part 15 emissions requirements.

Wireless telephone network description

The Nortel WLAN wireless telephone network consists of the following components:

•

Call Server

•

DHCP server

Nortel Communication Server 1000

WLAN IP Telephony Installation and Commissioning

NN43001-504 01.02 Standard

Release 5.0 15 June 2007

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Wireless telephone network description 23

•

Trivial File Transfer Protocol (TFTP) server

•

Firewall

•

Nortel WLAN Handset 2210/2211/2212, and Nortel WLAN Handset 6120/6140

•

Nortel WLAN IP Telephony Manager 2245

•

Nortel WLAN Application Gateway 2246 (optional)

•

Access Point (AP)—one or more as required by the site

Figure 1 "Typical wireless telephone network conﬁguration" (page 24) shows

a typical wireless telephone network conﬁguration. The three different lines indicate the following:

•

Red—signalling

•

Blue dashed—wireless to wireless audio

•

Blue solid—wireless to wired audio

Nortel Communication Server 1000

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Release 5.0 15 June 2007

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24 Overview

Figure 1 Typical wireless telephone network conﬁguration

Call Server

The Call Server can be the Call Server of any Nortel Communication Server (CS) 1000 system running CS 1000 Release 5.0 software.

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WLAN Handset 2210/2211/2212 and WLAN Handset 6120/6140 25

DHCP Server

The existing DHCP Server can be on either side of the ﬁrewall, according to the site administrator’s preference. The DHCP server is optional if the wireless handsets and WLAN IP Telephony Manager 2245 are statically conﬁgured.

DHCP options

If you use a DHCP Server, conﬁgure the following options:

•

DHCP Option 3—the Default Gateway

•

DHCP Option 7—the Syslog Server

•

DHCP Option 42—the Time Server

•

DHCP Option 60—the Class Identiﬁer

•

DHCP Option 66—the IP address of the TFTP Server

•

DHCP Option 151—the IP address of the WLAN IP Telephony Manager 2245

• DHCP Option 152—the IP address for the optional WLAN Application

Gateway 2246

For more information, see "DHCP server options" (page 184).

TFTP Server

A TFTP Server is required in an IP Telephony system to distribute software to the wireless handsets and WLAN IP Telephony Manager 2245. It can reside on a different subnet than the Call Server and APs. The TFTP Server can be located on either side of the ﬁrewall.

Firewall

The ﬁrewall is an optional element that is often used to separate the wireless and wired domains.

WLAN Handset 2210/2211/2212 and WLAN Handset 6120/6140

The WLAN Handset 2210/2211/2212 and WLAN Handset 6120/6140 uses Voice over IP (VoIP) technology on IEEE 802.11-compliant Wireless Local Area Networks (WLANs). Access points (AP) use radio frequencies to transmit signals to and from the wireless handsets.

ATTENTION

In this document, handsets means the WLAN Handset 2210/2211/2212 and WLAN Handset 6120/6140. Where the feature refers only to a speciﬁc handset, the full handset name is used.

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WLAN IP Telephony Installation and Commissioning

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Release 5.0 15 June 2007

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26 Overview

Employees carry wireless handsets to make and receive calls as they move throughout the building. The handsets are used only on the premises; they are not cellular phones. The handsets communicate with the CS 1000 and with the WLAN IP Telephony Manager 2245. Just like wired telephones, the wireless handsets receive calls directly, receive transferred calls, transfer calls to other extensions, and make outside and long-distance calls (subject to corporate restrictions).

The handsets interoperate with other IP Line and IP Trunk features and devices, such as IP Peer, and the IP Phone 20xx and IP Softphone 2050 series of IP Phones, with the exception of some media-related constraints described in "Codecs" (page 79).

The frequencies that are allocated are governed by IEEE guidelines for WLANs and are part of the free spectrum. The WLAN Handset 6120/6140 uses a, b, and g frequencies, and the WLAN Handset 2210/2211/2212 uses the b frequency.

The handsets work only in a Nortel Succession 3.0 (and later) environment coordinated with a Communication Server (CS) 1000 or Business Communications Server (BCM). These handsets communicate with the Nortel call server through the Uniﬁed Network IP Stimulus (UNIStim) protocol. The media path of the voice call goes from the handset directly to the destination device (through the WLAN Telephony Manager 2245). In addition, the handset encapsulates all trafﬁc in the SpectraLink VoicePriority (SVP) protocol. The WLAN Telephony Manager 2245 deencapsulates the VoIP trafﬁc from SVP and passes it onto the network—it does not translate between UNIStim and SVP. Therefore, the Telephony Manager 2245 is in the path of all communication to and from the handset. Likewise, signaling goes from the handset to the Telephony Manager 2245 to the call server.

The WLAN Handset 2211 and the WLAN Handset 6140 are the most durable and they are the only handsets that support Push-to-talk (PTT).

For more information about the handsets, see the following publications:

•

WLAN Handset 2210 User Guide (NN10300-077)

•

WLAN Handset 2211 User Guide (NN10300-078)

•

WLAN Handset 2212 User Guide (NN10300-071)

•

WLAN Handset 6120 User Guide (NN43150-100)

•

WLAN Handsets Fundamentals (NN43001-505)

Components

The WLAN Handset Series 2200 offers the following components for local conﬁguration:

•

Nortel WLAN Handset 2200 Series Conﬁguration Cradle Software—software only

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WLAN IP Telephony Installation and Commissioning

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WLAN Handset 2210/2211/2212 and WLAN Handset 6120/6140 27

•

Nortel WLAN Handset 2200 Series Conﬁguration Cradle—required hardware (serial cable included)

The WLAN Handset 6100 Series offers the following components for local conﬁguration:

•

Nortel WLAN Handset 6100 Series Administration Tool Software—software only

•

Nortel WLAN Handset6100 Series Dual Slot Handset Charger—required hardware (USB cable not included)

•

USB Cable for the Nortel WLAN Handset 6100 Series Dual Slot Handset Charger

ATTENTION

For the purposes of this document

•

Conﬁguration Cradle refers to the Nortel WLAN Handset 2200 Series Conﬁguration Cradle.

•

Handset Administration Tool refers to the Nortel WLAN Handset 6100 Series Administration Tool Software.

•

Dual Slot Handset Charger or Handset Charger refers to the Nortel WLAN Handset 6100 Series Dual Slot Handset Charger.

Language

The handset menus and screens that originate from the Call Server are displayed in the languages supported on the Call Server. The administration and conﬁguration menus, and all other local handset prompts are English-only.

Licenses

The handset appears to the Call Server as a standard IP Phone 2004. Therefore, each wireless handset requires one IP User License and is subject to the same feature packaging requirements as the existing IP Phone 2004.

Wi-Fi Multimedia

The handsets support basic Wi-Fi Multimedia (WMM) to improve Quality of Service (QoS), as deﬁned in the 802.11e speciﬁcation. WMM provides prioritized QoS capability when concurrent applications, each with unique latency requirements, are competing for network resources.

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When WMM is used, all voice trafﬁc originating from the wireless handset is assigned the WMM Voice Access Category, making it the highest priority application. If the wireless network supports WMM, the handsets enable WMM support automatically; otherwise, SpectraLink Voice Prioritization (SVP) is used.

Wired Equivalent Privacy

The handsets support Wired Equivalent Privacy (WEP) as deﬁned by the

802.11a, b, and g speciﬁcation. Nortel offers the product with both 40-bit and 128-bit encryption. WEP increases the security of the wireless LAN to a level similar to a wired Ethernet LAN.

Wi-Fi Protected Access

The handsets support Wi-Fi Protected Access (WPA) using preshared key (PSK), as deﬁned by the 802.11i speciﬁcation. WPA increases the security of the wireless LAN, using key encryption, key rotation, authentication and message integrity checking.

Wi-Fi Protected Access2

The handsets support Wi-Fi Protected Access2 (WPA2) using preshared key (PSK) and Advanced Encryption Standard (AES), as deﬁned by the

802.11i speciﬁcation. WPA2 increases the security of the wireless LAN, using key encryption, key rotation, data encryption, authentication, and message integrity checking.

Virtual Private Network

The WLAN Handset 2212 supports Virtual Private Network (VPN) security. VPN security provides a secure tunnel for the transfer of unencrypted information. A two-phase approach is used to negotiate the tunnel, with Phase 1 protecting Phase 2. Phase 1 uses preshared keys, Difﬁe-Hellman group, hashing, and encryption. Phase 2 uses hashing and encryption. Both phases have limited, conﬁgurable lifetimes.

Push-to-talk feature

With the Push-to-talk (PTT) feature, the WLAN Handset 2211 and the WLAN Handset 6140 can operate in a PTT group-broadcast mode like a two-way radio, in addition to the standard telephone operation.

For more information, see WLAN Handsets Fundamentals (NN43001-505).

Text-messaging feature

All WLAN handsets support text messaging applications through the WLAN Application Gateway 2246. The application server communicates to the WLAN Application Gateway 2246 through a proprietary Open Application

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WLAN IP Telephony Manager 2245 29

Interface (OAI) messaging protocol. The WLAN Application Gateway 2246 forwards the messages to the WLAN IP Telephony Manager, which encapsulates the message for delivery to the handset.

If text-messaging functions are programmed, the handset can receive text messages. While you access text messages, the handset is in messaging mode. Incoming calls ring with the second call-ringing sound.

Loud noise environments

The handsets are designed to provide optimal voice quality. However, when used in extremely loud noise environments, (for example, close to working heavy machinery), degradation in call quality can be experienced due to echo. Avoid using the handsets in loud noise environments.

WLAN IP Telephony Manager 2245

The WLAN IP Telephony Manager 2245 is a device that manages IP telephony network trafﬁc on the WLAN system. It is required to utilize the 11Mbs maximum transmission speed available in the handsets. The WLAN IP Telephony Manager 2245 acts as a proxy for the wireless handsets. It provides a number of services including a QoS mechanism, AP bandwidth management, and efﬁcient RF link utilization.

The WLAN IP Telephony Manager 2245 works with the APs to provide Quality of Service (QoS) on the WLAN. All voice packets are encapsulated by the wireless handsets. The encapsulated voice packets to and from the wireless handsets are handled by the WLAN IP Telephony Manager 2245 and routed to and from a Call Server.

SpectraLink Voice Priority (SVP) is the QoS mechanism implemented on the wireless handsets and APs to enhance voice quality over the wireless network. SVP gives preference to voice packets over data packets on the wireless medium, increasing the probability that all voice packets are transmitted and with minimum delay. SVP is fully compliant with the IEEE

802.11 and 802.11a, b, and g standards. Each subnet, where the wireless handsets operate, requires at least one

WLAN IP Telephony Manager 2245. One standalone unit can process up to 80 simultaneous calls depending on the model, as listed in Table 2 "WLAN

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Telephony Manager 2245 model numbers and capacities" (page 30).If

greater capacity is required, multiple units can be used in a master-slave arrangement.

Table 2 WLAN Telephony Manager 2245 model numbers and capacities

Model number Maximum

number users

NTTQ60BA 10 simultaneous users NTTQ60CA 20 simultaneous users NTTQ60AA 80 simultaneous users (standard)

WLAN Application Gateway 2246

The WLAN Application Gateway 2246 is an optional device that enables third-party applications to communicate directly with up to 10 000 wireless handsets. The WLAN Application Gateway 2246 is connected to the LAN Ethernet switch through an RJ-45CAT5 cable.

For more information about the WLAN Application Gateway 2246, see

Appendix "WLAN Application Gateway 2246" (page 147).

A WLAN Application Gateway 2246 supports 64 to 10 000 wireless handsets, depending on the model of Gateway, as listed in Table 3 "WLAN

Application Gateway 2246 models and capacities" (page 30).

Table 3 WLAN Application Gateway 2246 models and capacities

Model number

Maximum number of users

NTTQ65AA

NTTQ65BA

128

NTTQ65CA

256

NTTQ65DA

512

NTTQ65EA

1024

NTTQ65FA

10 000

Access Points

802.11a, b, and g APs provide the connection between the wired Ethernet LAN and the wireless (802.11) LAN. APs must be positioned in all areas where the wireless handsets are used. The number and placement of APs

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Handset switchover 31

affect the coverage area and capacity of the wireless system. Typically, the requirements for use of handsets are similar to that of other wireless data devices.

The APs must be either SVP-compliant or WMM-compliant to support QoS. For a list of supported APs, see Appendix "Compatible Access Points"

(page 223).

Handset switchover

When a user on an active call is moving about, the call switches from AP to AP in the subnet. This changeover is transparent to the user.

Loss of signal

If a wireless handset is out of range of all APs, it waits 20 seconds for a signal to return. If a signal is not reacquired within 20 seconds, the wireless handset loses connection to the Call Server and any calls are dropped. When the wireless handset comes back into range of an AP, it reestablishes a connection to the Call Server and goes through the system registration process.

Note: If a wireless handset is out of contact with the system for four seconds (worst case scenario) when the UNIStim messaging is occurring, a UNIStim failure could result, causing the wireless handset to lose the UNIStim association with the Line Telephony Proxy Server (LTPS).

Handset switchover

If a user on an active call is moving about, the call switches from AP to AP in the subnet. This changeover is transparent to the user.

Loss of signal

ATTENTION

If a wireless handset is out of contact with the system for four seconds (worst case scenario) during UNIStim messaging, a UNIStim failure could occur and cause the wireless handset to lose the UNIStim association with the Line Telephony Proxy Server (LTPS).

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Planning

This chapter contains information about the following topics:

•

"Challenges of integrating voice applications" (page 33)

•

"DHCP server planning" (page 36)

•

"TFTP Server planning" (page 38)

•

"Syslog Server planning" (page 40)

•

"Access point planning" (page 40)

•

"Network planning" (page 46)

•

"Network recommendation" (page 46)

•

"Network management" (page 47)

•

"Zones" (page 54)

•

"Other network design considerations" (page 55)

• "WLAN IP Telephony Manager 2245 planning" (page 59)

•

"Multicast" (page 65)

•

"Placement guidelines for the WLAN IP Telephony Manager 2245" (page 65)

•

"WLAN Application Gateway 2246 planning" (page 73)

•

"WLAN IP Telephony Manager 2245 and WLAN Application Gateway 2246 installation requirements" (page 74)

•

"IP address planning" (page 74)

•

"Planning worksheets" (page 75)

Challenges of integrating voice applications

The integration of voice applications on any data network causes some challenges. WLANs create a number of problems for voice, above and beyond those inherent to most data networks, such as:

•

high overhead of 802.11

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•

rate scaling and variable capacity

•

power adjustments and variable capacity

•

Quality of Service (QoS)

High overhead of 802.11

Unlike many other 802.n standards, 802.11 has a very high amount of overhead associated with transmitting a packet. To compare an 802.3 network with an 802.11 network, the difference in overhead for transmitting line-rate minimum frame sizes compared to the line-rate maximum frame sizes on an 802.3 network can be signiﬁcant, yet not nearly as signiﬁcant as on an 802.11 network.

For 802.11, the difference in effective throughput varies dramatically with packet size because of the amount of overhead involved in transmitting a frame. Therefore, the effective throughput of the medium is potentially higher for data clients that use very large packet sizes than it is for voice clients that use smaller packets. As an example, using very conservative assumptions for average frame size, no rate scaling, and no contention or collisions, transmission overhead consumes as much as 67% of the total

802.11 medium capacity. By contrast, in an 802.3 network using the same assumptions, the overhead is about 8%.

Rate scaling and variable capacity

802.11b supports four transmission rates or data rates. Usually, as a handset gets farther from an Access Point (AP), both devices scale down to lower transmission rates to compensate for a weaker signal. As a result, a transmission at the 5.5 megabits per second (Mb/s) data rate takes approximately twice as long as the same size packet transmitted at the 11 Mb/s data rate. Longer transmission times mean less transmission time for other handsets. Therefore, rate scaling compromises the overall throughput of the medium.

Rate scaling is necessary to extend the coverage of the AP beyond a very tight region around the AP, but the effects must be taken into account when determining medium capacity. For example, if the maximum call capacity for an AP is 12 when all handsets are using the 11 Mb/s physical (PHY) layer, two handsets scaling down to 5.5 Mb/s as they move away from the AP reduces the total call capacity of that AP to roughly 10. This factor makes engineering the number of APs for the network difﬁcult, because handsets are roaming around and rate scaling up and down as necessary. Handsets are moving, and as they do, the engineering target of call capacity becomes a moving target.

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Power adjustments and variable capacity

A WLAN has dynamic mechanisms in place for adjusting channels, adjusting power, and ﬁlling coverage holes, all in response to changes in the Radio Frequency (RF) environment. All of these mechanisms present challenges to the engineering of voice networks.

Dynamic adjustments work well for guaranteeing minimum coverage and connectivity of devices, particularly data devices. Voice requires more planned engineering.

Usually, the number of calls per area (square foot) and calls per AP determines the number of APs required to support the voice applications and devices. Power adjustments affect these parameters. Ifan AP increases power, it provides coverage for a larger area, meaning a greater call demand for the AP. Doubling the power of an AP can quadruple its coverage area, which means up to four times as much call demand as originally engineered. That increased coverage area also has substantial portions of lower data rate coverage. In addition, the added cochannel interference to other cells using the same channel degrades their call capacity. The net effect is that a network previously tuned for voice is now less capable of meeting the demands of voice than it was before the dynamic power adjustment.

Automatic RF changes do not always have a negative impact on voice-engineered networks. Admission control techniques help with the oversubscription problems related to increasing cell sizes dynamically. Hole ﬁlling, after an AP failure occurs, also provides substantial value to a voice solution.

When VoWLAN drives the engineering of the network both in scale and capacity, sometimes automatic RF features create more challenges than they resolve.

Quality of Service

802.11 is a shared media technology, but only one device can use the media at a time. The AP abides by this rule as well.

Because the transmitting device cannot detect collisions, 802.11 uses a statistical mechanism to reduce the possibility of collisions when two devices are ready to transmit at the same time. After the medium becomes available, the mechanism requires the devices to wait a random amount of time before starting transmission. Because of this simple mechanism, a nonvoice device is as equally as likely to be allowed to transmit as a voice device is.

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For example, if a data device does seize the medium, it can send a 1500-byte frame at the lowest data rate (if it is far away from the AP), and further delay voice frames. In addition, several data devices contending for the medium can each, in turn, send large frames before the voice device gained access to the medium.

Without a way to give preferential transmission opportunities to voice devices, supporting voice applications is a tremendous challenge on 802.11 WLANs. SpectraLink Voice Priority (SVP) has evolved into a de facto standard for Quality of Service (QoS) and serves as a model to illustrate the functions that a successful QoS mechanism can implement.

The 802.11e standard ultimately resolves QoS issues, but the delays in the standard create a number of additional implementation-speciﬁc challenges. Wi-Fi Multimedia (WMM) is a step toward full 802.11e compliance for voice and multimedia, but it is not a solution. Because it is a step, QoS feature evolution must progress towards better and more solid standards-based QoS capabilities.

WMM reﬁnes 802.11 to give statistical preference to certain classes over other classes. It is fully backward-compatible to legacy non-WMM devices, which function just like WMM best-effort class devices.

DHCP server planning

The handset IP-related parameters can be conﬁgured manually or through a DHCP server (RFC 1541 and RFC 1533). Any DHCP server can be used, but it must support the following capabilities.

• Provide Client IP address

•

DHCP Option 1—Subnet Mask

•

DHCP Option 3—Default Gateway

•

DHCP Option 60—Class Identiﬁer. The wireless handsets use the Class Identiﬁer of Nortel-221x-A or Nortel-61xx-A. The DHCP server can use the string in the Class Identiﬁer to uniquely identify a wireless handset.

•

DHCP Option 66. This can be used to specify the address of the TFTP Server. If this option is not conﬁgured, the wireless handset looks at the Next server Boot server (siaddr) Option for the address of the TFTP Server* Vendor Speciﬁc Option 43, 128, 144, 157, 191, or 251. Only one of these options is required. The DHCP server encodes the Server 1 information using the same format as the IP Phone 2004. If the Server 2 information is also present in the option, it is ignored.

•

DHCP Option 151. This option contains the IP address of the WLAN IP Telephony Manager 2245. If Option 151 is not conﬁgured, the wireless

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handset performs a DNS lookup of the name SLNKSVP2, if Options 6 (DNS Server) and 15 (Domain Name) are conﬁgured.

•

DHCP Option 152. If an optional WLAN Application Gateway 2246 is used in the system, its IP address can be speciﬁed with this option.

Each wireless handset effectively uses two IP addresses in the wireless subnet: one for the physical wireless handset and a second alias IP address that is used on the WLAN IP Telephony Manager 2245. When allocating addresses in a subnet scope on the DHCP server, a contiguous block of IP addresses as large as the number of wireless handsets supported must be marked as unavailable for distribution for other uses by the DHCP server.

When multiple WLANs are connected to a single Nortel Wireless Security Switch (WSS), the DHCP server can require speciﬁc conﬁguration modiﬁcations. For a speciﬁc WSS that is used for special DHCP conﬁguration requirements, see the WSS documentation.

The WLAN handsets support numerous DHCP extensions for assigning various conﬁguration options. The WLAN handsets supply a vendor class identiﬁer string, which in this case is Nortel-221x-A and Nortel-61xx-A. The WLAN handsets do not accept these options from the DHCP server encapsulated in a 43 Vendor Type option (which is the normal way vendor classes work). Consequently, you do not deﬁne these options as part of a vendor class on the DHCP server. Instead, you deﬁne them as new options that are assigned using the native code numbers that you give them.

The WLAN handsets speciﬁcally request a list of options in the DISCOVER message. The list of options (aside from the IP address and subnet mask) needed by a WLAN handset is:

• Class Identiﬁer (60)

•

TFTP Server (66)

•

Signaling Server Address and other parameters (43, 128, 144, 157, 191, or 251)

•

WLAN IP Telephony Manager 2245 Address (151)

•

WLAN Application Gateway 2246 Address (152)

For an example, see Figure 2 "Sample DHCP reservation showing assigned

parameters" (page 38).

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Figure 2 Sample DHCP reservation showing assigned parameters

Another use for the DHCP server is to make code upgrades to the handset easier. To prevent handsets from checking for code upgrades, assign the value of 255.255.255.255 for the TFTP server address.

A problem can arise for handset users who travel. For example, the company employing the handset solution is a retailer with many stores. Each store has a local call server for the local employees who use various VoIP devices, so all the attributes are deﬁned at the scope level. What happens if supervisors, who travel from store to store, want to use their handsets at each location? The supervisors can be assigned to a signaling server that does not recognize their phones. The best way to support these users is to create unique reservations in each remote scope for each user’s WLAN handset and specify the proper signaling server. This solution can be cumbersome if there are a large number of users who travel.

TFTP Server planning

A TFTP Server (RFC1350) holds the software images for updating the handsets and the WLAN IP Telephony Manager 2245. After the IP address of the TFTP server is conﬁgured on a wireless handset, each time the wireless handset is powered on, the wireless handset checks its version of ﬁrmware against the ﬁrmware on the TFTP Server, and if the version is different, the wireless handset downloads the new ﬁrmware from the TFTP Server. Similarly, when a WLAN IP Telephony Manager 2245 reboots, or is manually reset by the operator, it checks its version of software against the version on the TFTP Server. If the versions are different, the WLAN IP Telephony Manager 2245 downloads the new software.

The WLAN Handsets 2210/2211/2212 and WLAN Handsets 6120/6140 share the same conﬁguration ﬁle that provides ﬁrmware version information for the TFTP process. The actual software ﬁles are speciﬁc to either the WLAN Handset 2200 series or the WLAN Handset 6100 series. At an installation, which uses both the WLAN Handsets 2210/2211/2212 and the WLAN Handsets 6120/6140, the software ﬁles for both handset series must be installed and available on the TFTP server for the site.

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Only one TFTP server is needed in the network, and it need not be colocated with the handsets or the WLAN IP Telephony Manager 2245.

There is a client-dependent aspect to how the handsets function with the TFTP server. How well a server works with the handsets can vary between code versions on the handset.

You can conﬁgure handsets to not contact the TFTP server upon boot up, by conﬁguring 255.255.255.255 as the IP address for the TFTP server (either directly in the handset or through the DHCP option). You can conﬁgure the WLAN IP Telephony Manager 2245 to not contact the TFTP server by changing the TFTP server address to none in the conﬁguration.

The following information must be considered when planning for a TFTP Server:

•

The process for the wireless handset to check its version of ﬁrmware against what is available on the TFTP Server takes less than two seconds on a quiet network.

•

If the TFTP Server is ofﬂine or unreachable, the wireless handset tries for about 10 seconds before giving up and using its existing version of ﬁrmware.

•

The wireless handset ﬁrmware downloading process takes about 30 seconds.

•

The TFTP Server must be capable of supporting multiple TFTP sessions.

•

When a wireless handset makes a TFTP request, it uses ﬁle names without a full path name. Therefore, software updates for the WLAN IP Telephony Manager 2245 and handsets must be installed into the root directory of the TFTP Server.

When the software ﬁles are uploaded to the TFTP server. they must be unzipped. Allow time for the TFTP server to refresh and be aware of the ﬁles before attempting to download software to the wireless handsets and WLAN IP Telephony Manager 2245. Monitor the TFTP Server for any errors.

The TFTP Server can be located anywhere on the network if the wireless handsets have the subnet mask and default IP gateway conﬁgured correctly. However, the wireless handset expects a response within two seconds to any TFTP request. Therefore, the TFTP Server must not be located, for example, at the other end of a slow WAN link.

If too many wireless handsets are attempting to download new software simultaneously, the downloads can slow down or return error messages. To reduce the number of retries and error messages, manage the download process by staggering the times the wireless handsets download the software.

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Nortel has tested the following TFTP servers. They are listed in order of preference.

•

Nortel TFTP server (ONMS application)

•

3COM TFTP

•

PumpkinTFTP

Syslog Server planning

A Syslog Server listens for incoming syslog messages on UDP port 514 and then processes the messages according to local administrative procedures. Usually the syslog messages are logged for subsequent review by the system operator. A number of devices used within a handset wireless conﬁguration are capable of sending messages to a Syslog Server.

The Syslog Server can be any RFC 3164-compliant log server. You can conﬁgure the WLAN IP Telephony Manager 2245, WLAN Application Gateway 2246, WLAN APs 2220/2221/2230/2231, and the WLAN Handsets 2210/2211/2212/6120/6140 to generate syslog messages. For information about conﬁguring syslog messages, see the documentation for the Wireless Security Switches and WLAN APs. For information about conﬁguring syslog messages on the WLAN IP Telephony Manager 2245, see "Conﬁgure the

network" (page 103).

There are numerous third-party Syslog Servers available. You can use any RFC 3164-compliant Syslog Server.

Access point planning

APs utilize radio frequencies to transmit signals to and from the wireless handsets.

It is essential to know where to install the APs to provide effective coverage for wireless handset use. It is necessary to verify that coverage is available where it is needed. The ﬁrst step is to deﬁne exactly where the coverage is needed, which requires a site survey.

Recommendation

A site survey must be performed before installing a wireless LAN. A site survey is also recommended when an existing network structure is modified or when physical changes are made to a site.

Nortel recommends the use of the Nortel Site Survey Tool to perform the site survey.

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A site survey is critical to designing and implementing a wireless LAN. The site survey is used to determine the number of APs needed to support the wireless handset users and to determine the best placement of the APs. Different AP vendors provide different tools to do this.

Site survey

To conduct a site survey, set up an AP at a particular location. Use a computer equipped with a wireless LAN device and site survey software or a handset operating in Site Survey mode to measure the strength of the signal from the AP. Move the wireless device around and repeat the measurements to determine the optimum number and best locations for the APs. This method helps identify dead zones and areas where building materials or other factors affect the performance of the network.

Site Survey mode

The handset Site Survey mode displays negative dBm levels. These levels represent the strength of the received signal (Received Signal Strength Indication or RSSI) from an AP. The RSSI information aids in determining if WLAN coverage is adequate.

For information about using the Site Survey mode, see WLAN Handsets Fundamentals (NN43001-505).

Note: The handsets do not require connectivity to a 2245 IP Telephony Manager or the Call Server to enable the Site Survey mode to be used. The minimum conﬁguration required is the Extended Service Set Identiﬁer (ESSID) of the WLAN or test AP and the WEP keys, if applicable.

Access point requirement considerations for b radio

Each site is unique in its AP requirements. Consider the following points when determining how many APs are needed and where to place them:

•

Minimum Radio Signal Strength—All APs in the coverage area must receive a signal strength better than -70dBm. Measurement is made in negative dBm, which measure the amount of signal loss due to distance. Therefore, stronger signals are those with smaller values. For example,

-50 and -60 indicate stronger signals than -70; -80 is a weaker, poorer signal than -70.

•

Adjacent APs and channel interference—In order to avoid undesirable interference from adjacent APs, ensure that adjacent APs do not use channels that overlap on the same frequencies.

For more information, see Figure 3 "Frequencies used by b radio" (page

42). In the ﬁgure, channels on the same horizontal line do not overlap.

In the coverage area of any given AP, signals from other APs using overlapping channels must be at least -15 to -20dBm weaker. Because

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the Site Survey mode displays signals only from APs on the same Extended Service Set ID (ESSID), check for signals from APs using all ESSIDs to avoid channel overlap.

Figure 3 Frequencies used by b radio

•

Wireless handset range—Wireless LAN coverage must be available wherever wireless handsets are used. Although the typical range for a wireless handset is comparable to that of a laptop computer utilizing a wireless LAN PC Card, the range can not be exactly the same. Therefore, it is preferable to use a handset to carry out the site survey, if possible. Remember that wireless handsets might be used in areas where data devices are not typically used, such as stairwells, washrooms, hallways, and outdoor areas.

• Number of wireless handsets per AP—Estimate the number of wireless

handsets and the anticipated call volume per AP area to ensure that the maximum number of calls per AP is not exceeded. For the maximum number of calls per AP for each supported manufacturer, see Appendix

"Compatible Access Points" (page 223).

•

The data rates at which the wireless handsets operate—Higher data rates (such as 11Mbs) can only be sustained while well within the range of the AP. If the wireless handsets are operating near the limits of the radio frequency (RF) coverage from the AP, they automatically drop to 1 Mbs operation.

handsets require approximately: — 7% of available bandwidth per call at 11 Mbs operation — 10% of the available bandwidth per call for 2 Mbs operation

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— 15% of the available bandwidth per call for 1 Mbs operation.

Note: These requirements mean that areas with a high-use density must receive RF coverage at the highest data rate of operation.

•

LAN bandwidth—Estimate anticipated peak call volume to ensure that enough bandwidth is available to handle the network trafﬁc generated by all the wireless handsets. Handsets require approximately 150 kbps of bandwidth per call. Network trafﬁc can be monitored and analyzed using a network sniffer or an SNMP workstation.

•

Number of other wireless devices per AP—The wireless handsets can share bandwidth with other wireless devices. To ensure adequate RF bandwidth availability, consider the number of wireless data devices in use per AP.

Note: In a very large or complex site, it can be advisable to contract a professional site survey.

Effective site survey

Consider the following points for an effective site survey.

Network usage

Examine the network usage:

•

How many people use a wireless handset?

•

What areas of the site require wireless handset access?

•

How many hours each day are wireless handsets typically in use?

•

Which locations are likely to generate the largest amount of trafﬁc?

•

Where is future network expansion most likely?

Mobility requirements

Assess the mobility requirements:

•

How many wireless handset users are in motion continually, such as in a warehouse or hospital?

•

How many users work from different ﬁxed locations throughout the site?

Physical site study

Perform a study of the physical site:

•

Study blueprints of the proposed site. A site blueprint provides a map of the site, including the location of objects such as walls, partitions, and anything else that could affect the performance of a wireless handset. This helps identify areas where wireless handsets are less likely to perform well. Many obstructions are not readily visible and, in some

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cases, a room originally built for a speciﬁc purpose, such as a radiology lab, can be converted into something completely different, such as a conference room. The blueprint can also show areas proposed for future building expansion.

•

Mark possible wireless handset usage locations on the blueprint and refer to the marked blueprint during the physical walk-through and inventory.

Walk-through and survey

Conduct a physical walk-through and survey:

•

Document any items or materials near a proposed AP location that might interfere with reception or transmission and affect wireless handset performance, such as metal shelving.

•

Document stock and inventory levels, current environmental conditions, and any materials that can interfere with wireless handset transmissions.

•

Walk around the site with a site survey tool before installing APs. Use two portable computers with wireless hardware operating on a point-to-point basis. Using diagnostic software provided by the AP vendor, a coverage area for a potential AP can be determined by keeping one portable computer in one place and moving around with the other computer. Check with the vendor as to what tools are provided and what approach is recommended for deploying their APs.

RF transmission testing

After the APs are installed and conﬁgured, measure the strength of the Radio Frequency (RF) transmissions. Signal strength testing ensures that all usage areas have adequate coverage. This can be performed in two ways.

1. Use the handsets to determine AP signal strength using the Site Survey

mode.

2. Use two portable computers with wireless hardware operating on a

point-to-point basis. Using diagnostic software provided by the AP vendor, a coverage area for a potential AP can be determined by keeping one portable computer in one place and moving around with the other computer. Check with the vendor as to which tools are provided and which approach is recommended for deploying their APs.

Adjust the APs as needed.

Example of AP placement

Figure 4 "Sample AP placement diagram for b radio" (page 45) is an

example of an AP placement diagram based on the results of a site survey.

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Figure 4 Sample AP placement diagram for b radio

Solving coverage issues

To resolve coverage issues, add and relocate APs.

Solving overlap issues

To resolve overlap issues, reassign channels to the APs or relocate the APs. Like channels require 15–20dBm separation. See Figure 5 "b radio

assignment" (page 46).

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Figure 5 b radio assignment

For more information about overlap, see the AP vendor documentation.

Network planning

You must ensure that all connections and interfaces for the IP Telephony network are conﬁgured as full-duplex. Duplex mismatches anywhere on the WLAN can cause the wireless IP Telephony system not to function normally.

Network recommendation

To maximize security and to minimize accessibility for unnecessary trafﬁc to reach the WLAN Handsets, Nortel recommends that you adopt the following measures:

•

Create a separate VLAN for voice trafﬁc and map the handsets to this VLAN to mask the handsets from other devices on the network.

•

Implement Access Control Lists (ACLs) on the WLAN infrastructure to contain the handsets but deny other trafﬁc.

— The WLAN IP Telephony 2245 uses IP protocol 119 and

encapsulates both signalling and media (RTP) into a common packet format allowing the access points to prioritize legitimate handset trafﬁc.

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— Necessary trafﬁc for instance DHCP must be allowed, while all other

trafﬁc is denied.

Sample Access Control List

The following is a sample ACL for a voice VLAN named VLAN120.

set security acl ip SpectraLink permit udp 0.0.0.0

255.255.255.255 eq 68 0.0.0.0 255.255.255.255 eq 67 set security acl ip SpectraLink permit udp 0.0.0.0

255.255.255.255 eq 67 0.0.0.0 255.255.255.255 eq 68 set security acl ip SpectraLink permit cos 6 udp 0.0.0.0

255.255.255.255 0.0.0.0 255.255.255.255 eq 69 set security acl ip SpectraLink permit cos 7 119 0.0.0.0

255.255.255.255 0.0.0.0 255.255.255.255 set security acl ip SpectraLink deny 0.0.0.0 255.255.255.255 commit security acl SpectraLink set security acl map SpectraLink vlan VLAN120 in set security acl map SpectraLink vlan VLAN120 out

Network management

Network management is as much strategy and process as it is applications. Managing a converged network consists of four key phases:

Assessment—Network Health Checks and WLAN Site Surveys (post-deployment) are critical assessment items. The main goal is to verify the ability of the network to provide voice at the required Quality of Experience (QoE).

Predeployment—Before you deploy VoIP handsets, make the network ready by rolling-out QoS across the network. This phase assumes the WLAN itself is already deployed.

Ongoing monitoring—Regularly monitor the performance of the converged network to ensure that voice quality continues to meet expectations as the network grows and evolves over time.

Reporting and planning—Keep track of exceptions and problems and form plans to resolve issues. The resolution of problems takes you back through the assessment, predeployment (QoS configuration), and monitoring phases again.

Nortel ties this business cycle together seamlessly with a set of products that provide a comprehensive solution. This solution is comprised of integrated and innovative standards-based technologies, such as Real Time Control Protocol Extended Reports (RTCP-XR) for detailed real-time management of calls in progress. The overall solution is referred to as Proactive Voice Quality Management (PVQM).

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Assessment through a WLAN site survey

Technical support for VoWLAN is contingent on customers performing a site survey of the WLAN. Currently, Nortel recommends the use of the Ekahau Site Survey tool to verify the network deployment, although other site survey tools are acceptable. The Ekahau product runs on a PC and uses a WLAN network interface card (NIC) to collect data for analysis. The output of the tool is a number of robust visualizations of the network. The software veriﬁes the basic coverage of the network and provides a number of visualizations that are useful for VoWLAN deployments.

Perform capacity planning using the data rate analysis view, which shows a color-coded view of the maximum data rate across all APs in the network. With this view, you can see where your handsets can use the 11 Mb/s data rate as opposed to scaling down to lower rates. Planning based on data rate can have a big impact on voice-call-capacity planning.

Predict AP selection and roaming using the strongest AP view. This view shows the AP with the strongest signal for each location in the building and uses color codes for each AP. With the AP view, you can predict the APs that are likely to be the primary choice of voice devices to use given their location. You can also predict where the handoff to another AP (and which AP) can occur for a moving user.

Perform resiliency planning through the AP reachability view. This view presents a color-coded visualization of the number of reachable APs from each point in the network. Locations where the tool detects one AP, locations where the tool detects two APs, locations where the tool detects three APs, and so on, are marked in distinct colors. With this visualization, you can see where the network is vulnerable to a single point of failure. It is preferable to have at least two APs that are capable of offering coverage to every point in the building.

You can also use the AP reachability view to perform location service planning. A minimum of three APs must be reachable for triangulation to be effective. Therefore, use the AP reachability feature to verify a consistent 3+ AP coverage across the building.

Location capabilities have a number of client dependencies, so verifying triangulation coverage is more complex than it appears. There are two main location-solution types:

•

those that use the client to collect information about the APs in the network (client-based location)

•

those that use the APs to collect information about the client (network-based location)

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Both location-solution types use a form of triangulation to compute the location of the device. Depending on the power level of the AP, it can sometimes hear devices that it cannot transmit to. These factors combined create the following two scenarios:

•

It is difﬁcult to calibrate network-based solutions by using a laptop running the site survey, because APs can sometimes hear clients that cannot hear the AP. If AP transmission power levels are not at a maximum, they can hear clients over a greater distance than their own transmissions can travel. This scenario can cause the site survey application to underestimate the number of APs that can participate in triangulation.

•

Client-based solutions cannot triangulate APs that are not detectable because their power is lower. But the site survey application can accurately reﬂect the number of APs that can be used for triangulation.

Assessment using NetIQ Vivinet Assessor

The Network Health Check is probably the most critical step toward ensuring a smooth rollout for any VoIP deployment. This statement applies even more so to VoWLAN, because a WLAN is a more challenging QoS environment than modern wired networks.

The NetIQ Vivinet Assessor 3.0 or later is the tool of choice for network health checking. (Previously NetIQ Chariot, now an Ixia product, was recommended for network health checking.) This product uses a laptop (for WLAN testing for WLAN mobility) as a voice-trafﬁc generation and analysis tool. You can conﬁgure several nodes in various parts of the network, to simulate calls to and from those areas. Each node simulates call volumes through trafﬁc generation so that you can stress-test access links, backbones, and WAN links as necessary. You can also conﬁgure codecs, packetization rates, and other factors to closely mimic the future VoIP environment.

Vivinet Assessor performs a comprehensive analysis of the simulated trafﬁc, including reports on delay, jitter, and packet loss. The R values or Mean Opinion Score (MOS) are reported for these simulated trafﬁc loads to provide a baseline for performance expectations. These analyses are also used for capacity planning because they show the capacity at which the Quality of Experience (QoE) ratings start to fall. More importantly, the process of analyzing the network reveals many latent network problems that can otherwise remain undetected until deployment.

For example, duplex mismatches can exist in various locations of the network, and data applications, being very tolerant to packet loss, typically do not reveal the problem unless it is severe. The issue is immediately

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noticeable when a voice call traverses such a link. Vivinet Assessor is extremely useful for identifying the symptoms of issues and ﬁxing such problem areas in the network long before the customer places the ﬁrst call.

Monitoring and reporting with Enterprise Network Monitoring System

Enterprise Network Monitoring System (ENMS) 10.5 is a cross-portfolio management platform for fault management, network visualization, and troubleshooting. It can receive traps and statistics from the CS 1000, as well as virtually all other Nortel products. It can:

•

discover the call server equipment that it supports

•

display the information for the slot or port to which the call server components are attached

•

discover the TLAN and ELAN connections on a CS 1000 Signaling Server

ENMS differs from the Communication Server 1000 Telephony Manager in that ENMS is a comprehensive monitoring platform for virtually all Nortel products, while Communication Server 1000 Telephony Manager supports only VoIP products and features. ENMS is the product that ties all the other management packages together.

ENMS 10.5 makes convergence management quick and easy with the Converged View in the new IP Service Management (IPSM) display. The IPSM display provides a business-oriented overview of the Convergence Service. With IPSM, an operator can see the status of overall service level that is being provided, and easily zoom in with detailed troubleshooting tools if a problem is indicated. If a phone is unreachable, or if there is a degradation of quality in a call, it is indicated in the IPSM tabular view. The call quality alert shows the near-end and far-end IP address and Terminal Number (TN).

Figure 6 "ENMS 10.5 IPSM overview" (page 51) shows the IPSM overview

with a list of the phones that are registered to a particular CS 1000 system. Many details, including type of phone, ﬁrmware revision, IP address, set TN, registered TN, source, and destination IP port are displayed. Phones or components of the CS 1000 system change color to indicate status. The pie chart in the lower left corner of the display updates to show overall status and quality of the phones and CS 1000 systems in the display.

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Figure 6 ENMS 10.5 IPSM overview

After you click on a speciﬁc IP Phone, the panel in the lower right portion of the screen displays details automatically, such as the CS 1000 system, with which the IP Phone is registered. You can then right-click on the phone to show a data network path trace graphically, as shown in Figure 7 "ENMS

10.5 IPSM convergence view" (page 52).

For troubleshooting purposes, you can view a path trace to the signaling server or any other IP address.

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Figure 7 ENMS 10.5 IPSM convergence view

ENMS can provide down to physical slot port connectivity for the wired network. This topology data is extremely useful when shown in the Converged View of a Path Trace. You can set the display to refresh periodically to display the latest information about IP address changes.

With RTCP-XR, you can right-click on the set in the IPSM Convergence or tabular view and retrieve detailed real-time set statistics, such as local and remote latency and jitter.

Monitoring and reporting with Communication Server 1000 Telephony Manager

Communication Server 1000 Telephony Manager is an element manager for the CS 1000, as well as a platform for receiving traps and collecting call statistics and other performance-related data. Call and performance statistics are collected from the CS 1000 and stored on the Communication Server 1000 Telephony Manager server. You can display this data in a number of graphical reporting views, many of which are predeﬁned for ease of use. With these features, the Communication Server 1000 Telephony Manager server can act in a basic performance-management role for voice (this is not the same thing as Proactive Voice Quality Monitoring) within the management framework.

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Call tracking is another feature that is not speciﬁcally related to QoS monitoring or fault monitoring, but that is important to solution manageability. With this feature, you can:

•

track calls that ﬁt deﬁned proﬁles and collect data for later trend analysis

•

monitor individual extensions in real time

•

have alarm notiﬁcations sent to pagers or workstations for calls that ﬁt speciﬁed proﬁles

Communication Server 1000 Telephony Manager can perform some alarm-management functions and is a trap receiver for the voice products it supports. It polls call servers, through SNMP, for additional alarms that are not sent as traps. Alarms can be received from the CS 1000. Communication Server 1000 Telephony Manager can display fault information locally and also send the traps on to ENMS, Vivinet Manager, or other management platforms.

Monitoring and reporting with NetiQ Vivinet Assessor, Vivinet AppManager, and Vivinet Diagnostics

Vivinet Assessor is a Network Health Check and diagnostics tool. The software also has a number of features for the ongoing monitoring and reporting of issues. You can install Performance Endpoint agents on laptops that have WLAN interfaces, to monitor the performance and quality of the WLAN. Send this data to the Vivinet Manager for reporting and analysis. You can conﬁgure the agents with a schedule for generating VoIP trafﬁc to run spot checks on the ability of the network to support VoIP at required quality levels.

Vivinet AppManager is a product that can be purchased separately and used in conjunction with Vivinet Diagnostics to provide detailed service-level monitoring, reporting, and troubleshooting in a diverse network environment.

For the CS 1000, Vivnet AppManager provides information about the percentage of devices available versus unavailable, health of interfaces, Voice Call Quality and QoS for Signaling Server, and Voice Gateway Media Cards. AppManager also provides summary analysis for data loss, jitter, latency, and R-Value.

Vivinet Diagnostics is a product that can be purchased separately and used in conjunction with Vivinet AppManager. After Vivinet AppManager receives a call-quality alert from a Nortel voice system such as a CS 1000 or BCM for a call in progress, AppManager generates an alert.

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The alert from Vivinet AppManager activates Vivinet Diagnostics, which traces the path of the call, collects diagnostic information, and can perform root cause analysis. You can save the results for further analysis and action. For an example, see Figure 8 "NetiQ Vivinet Diagnostics example" (page

54).

Figure 8 NetiQ Vivinet Diagnostics example

Communication Server 1000 Telephony Manager

You can conﬁgure voice devices, from stations to communication servers (including CS 1000), from the Communication Server 1000 Telephony Manager server. You can also perform station administration through the Communication Server 1000 Telephony Manager.

Although it has bulk conﬁguration capabilities, the Communication Server 1000 Telephony Manager best serves small- to medium-size environments. For larger VoIP installations, Enterprise Subscriber Manager is a more scalable set-management platform.

Perform the actual conﬁguration of the WLAN handsets manually or use the DHCP server. Conﬁgure the call server aspects of the handset (such as TN and DN) on the CS 1000, preferably through the Communication Server 1000 Telephony Manager.

Zones

Nortel recommends that the handsets be assigned to dedicated zones. The zones can be used to manage the bandwidth of the WLAN IP Telephony Manager 2245 groups. As well, zone designations can be used to list the wireless handsets that are currently registered or are registered using LD 117 commands.

For more information, see "Bandwidth management" (page 77).

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Other network design considerations

WLAN Handsets 2210/2211/2212 are 802.11b-only devices and the WLAN Handsets 6120/6140 are 802.11b, 802.11g and 802.11a devices, which creates challenging choices for network deployments. The following list describes some of the points to consider when determining network deployment:

•

Separation of devices by multiple SSIDs on the same radio does not create multiple shared mediums—the devices still transmit and receive using common radio resources on a common channel.

•

Current QoS mechanisms in the industry are most effective at protecting and prioritizing trafﬁc on the downstream, that is, from AP to Mobile Unit (MU). Wi-Fi Multimedia (WMM) improves upstream prioritization by giving a statistical edge to different classes of devices so they are more likely to transmit ahead of lower class devices. Still, other devices sometimes cheat on the contention window to gain a statistical advantage, though there are drawbacks to this method. There is no real arbitration or coordination between multiple devices that need to transmit packets upstream.

•

The 802.11g devices in a mixed 802.11b/g network are statistically favored by a 2:1 ratio over 802.11b devices. For example, this means that if there is one 802.11g device and one 802.11b device and both are trying to saturate the medium with a data transfer, the 802.11g device transmits, on average, two frames for every one frame from the 802.11b device. If there are two 802.11g devices for every one 802.11b device, on average, four 802.11g transmissions occur before one 802.11b transmission occurs.

•

Although 802.11g devices transmit more often, because of higher data rates, they spend less time transmitting packets. This means that

802.11g devices are not necessarily favored in the network. Having too many 802.11g devices relative to 802.11b devices upsets this balance.

There is no easy way to determine whether to maintain an 802.11g-only network or an 802.11b-only network. If there is a signiﬁcant amount of upstream trafﬁc from data devices, the best course of action is to keep data devices off the 802.11b/g network entirely. Large numbers of

802.11g devices can also cause problems with 802.11b handsets on the medium. However, if you force the 802.11g devices to use 802.11b for communication, the situation can become worse.

Disabling 802.11g support and maintaining a dual-mode 802.11a/b network can make 802.11a more attractive for dual-mode data clients and reduce the amount of data devices using the 2.4 GHz spectrum. Enabling 802.11g support can increase the number of data devices sharing the 2.4 GHz

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channels, which is detrimental to voice devices. As a general policy, for large amounts of data, use 802.11a for data and 802.11b for voice, but leave 802.11g disabled.

Alternately, if there are few 802.11b/g data devices and the WLAN is to be used primarily for voice, consider enabling 802.11g support. The goal is to carefully control the number of data devices that share radio resources with voice devices.

For example, if a large number of laptops exist in a campus and if 802.11g mode is enabled, it is probable that a large proportion of those laptops use

802.11g (2.4 GHz) for connectivity, which makes it much more difﬁcult to provide good quality voice for handsets. If 802.11g is disabled, it is probable that a large proportion of those laptops use 802.11a (5 GHz) because it offers much higher throughput compared with 802.11b, and voice quality beneﬁts.

Access Point interference

When more than three APs are deployed, the APs themselves are a signiﬁcant source of interference. This is known as cochannel interference. Therefore, it is important to consider how channel reuse impacts network capacity.

To maximize the distance between APs operating on the same channel, tile the channels. To scale capacity, add more APs in the same geographic region and at the same time, reduce the transmit power of each AP.

However, the overall throughput increase does not increase proportionally with the number of APs that are added because each individual AP loses throughput, even though the number of APs per square foot is increasing. Note that the biggest loss of per-AP throughput occurs when going from nonchannel-reuse to reusing channels. For more information about this subject, see the whitepaper available from w

ww.nortel.com.

The goal is to achieve the required call density for the number of calls per square foot. Getting the most calls per AP is not a useful objective of capacity planning. The parameters that must be tuned to engineer a voice network for capacity are:

•

channel reuse factor (that is, the number of channels in the channel plan)

•

transmit power of each AP

•

the radius of the cell (that is, based on the physical distance between APs)

Because of the complexity of this topic and the simulation data that is required, it is not possible to discuss tuning all three variables or even two variables at a time. An example of a light to medium ofﬁce environment (mostly cube space but some walls) is provided instead.

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Example

The channel reuse factor for 802.11b networks is ﬁxed at three (three nonoverlapping channels in the 2.4 GHz range), corresponding to channels 1, 6, and 11. The transmit power is ﬁxed at 50 mW, which establishes the radius of the cell.

Now the effects of cell size, based on the other ﬁxed parameters, can be compared.

If the deployed cells have a radius of anywhere from 33 ft to 75 ft, the call capacity per square foot is essentially the same. This means that packing cells in tighter than a 75 ft radius per AP is a waste of money. This example shows that in a typical ofﬁce environment with APs at half power, you can deploy APs anywhere from 100 ft to 150 ft from each other. More walls mean there must be less distance between APs, and lowering the power of the AP lessens the required distance between APs, both of which also serve to increase the net call density.

SSID options and limitations

The traditional WLAN deployment requirement was to implement separate SSIDs for voice and for data. This requirement no longer exists, though it is still a useful deployment option in some circumstances.

If all devices implement common security encryption mechanisms (for example, Wi-Fi Protected Access), a single SSID can be offered to support both voice and data. The beneﬁt of this conﬁguration is that users cannot control to which network they connect. This is a security mechanism that prevents curious or malicious users from putting their laptops in the telephony VLAN. At the same time, it prevents inadvertent conﬁguration mistakes. Either way, the simpliﬁed user interface to the network beneﬁts both network administrators and end users.

If data devices do not use the same encryption mechanism as WLAN handsets, it is best to implement multiple SSIDs—one for the handsets and the other for the data devices.

If necessary, one way to ensure that multiple handset SSIDs on the same AP still work without oversubscribing the medium is to cut in half the number of calls per AP conﬁgured on the WLAN IP Telephony Manager 2245.

Nortel does not recommend a closed system for VoWLAN installations that use more than one SSID, including converged data and voice WLANs. The reason is that the SSID serves a valuable purpose in roaming. When it is hidden by not being included in the beacon, roaming devices must attempt to try all closed system APs. This result can dramatically impact call handoff times.

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Layer 3 implementation

Where possible, simplify the number of subnets that are used for client devices. Even in a Distributed Campus architecture, you can have a few central subnets for clients. As a general rule, Nortel recommends that wired or wireless IP phones be placed in a separate VLAN (subnet) from data devices. This placement can be accomplished by providing one VLAN (subnet) for all WLAN telephony devices, as shown in Figure 9 "Single

telephony VLAN implementation" (page 58). The data client VLAN design is

an abstraction (the best practice is to simplify). The WLAN data network can have many client subnets, or one— that is unimportant in this context because the focus is support of VoWLAN.

Figure 9 Single telephony VLAN implementation

Consolidating VoWLAN handsets into one VLAN (subnet) has a few advantages. First, it allows the WLAN IP Telephony Manager 2245 design to be greatly simpliﬁed. Instead of purchasing and deploying at least one WLAN IP Telephony Manager 2245 per voice subnet, you can now install one WLAN IP Telephony Manager 2245 for the single voice subnet. For larger VoWLAN deployments, more WLAN IP Telephony Manager 2245s may be required in that single subnet to support the number of calls; however, fewer WLAN IP Telephony Manager 2245s are needed than in an equivalent multisubnet deployment.

A second advantage is that external security measures are easier and less costly to implement. It is common practice to put a telephony WLAN behind a ﬁrewall for security reasons. This is because security features on handsets, particularly authentication capabilities, tend to lag behind the

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industry. So to mitigate risks, you can use a ﬁrewall to block all but the ports needed for IP Telephony. This practice becomes complex and costly when multiplied by a number of subnets. A more cost-effective alternative to implementing a ﬁrewall is to assign private addresses to the handsets and let the WLAN IP Telephony Manager 2245 network address translation (NAT) capabilities serve as a form of secure ﬁrewall to the telephony LAN (T-LAN). Of course this is not as secure as using a traditional ﬁrewall to secure the T-LAN.

The downside of putting all telephony devices into the same subnet is that broadcasts are increased. Also, while security is simpliﬁed, the importance of implementing adequate security measures increases because more devices will be impacted in the event of a security breach.

WLAN IP Telephony Manager 2245 planning

Both the WLAN IP Telephony Manager 2245 and the WLAN Application Telephony Gateway 2246 are connected to the Ethernet switch.

Installation requirements

The WLAN IP Telephony Manager 2245 requires a CAT5 cable connection between its network port and the Ethernet switch. The WLAN IP Telephony Manager 2245 can auto-negotiate to the type of port on the Ethernet switch. It supports 10BaseT, 100BaseT, full-duplex and half-duplex port types.

Nortel recommends 100BaseT full-duplex.

Note: When multiple WLAN IP Telephony Managers 2245 are used, all the WLAN IP Telephony Managers 2245 must use a uniform media type. Do not use full-duplex on some and half-duplex on others, or 10BaseT on some and 100BaseT on others.

Capacities

The WLAN IP Telephony Manager 2245 is available in three models:

•

WLAN IP Telephony Manager 2245-80: Serves 500 powered-on handsets (80 simultaneous calls).

•

WLAN IP Telephony Manager 2245-20: Serves 20 powered-on handsets.

•

WLAN IP Telephony Manager 2245-10: Serves 10 powered-on handsets.

Capacity is measured by active calls for the WLAN IP Telephony Manager 2245-80 and by powered on handsets for the WLAN IP Telephony Manager 2245-10 and the WLAN IP Telephony Manager 2245-20. The capacity of a system that is not based on 100Base-T, full-duplex is lower. Nortel recommends that you not use older technology equipment.

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In any subnet where wireless handsets are used, each subnet must have one or more WLAN IP Telephony Managers 2245. A WLAN IP Telephony Manager 2245 group on a subnet consists of one or more WLAN IP Telephony Managers 2245 and their associated wireless handsets. Only one master WLAN IP Telephony Manager 2245 can be on a subnet.

WLAN IP Telephony Manager 2245 groups

WLAN IP Telephony Manager 2245 groups are those that have more than one WLAN IP Telephony Manager 2245 in order to accommodate larger systems and a higher volume of wireless telephony trafﬁc.

Master WLAN IP Telephony Manager 2245

In a group comprised of multiple WLAN IP Telephony Managers 2245, a master WLAN IP Telephony Manager 2245 must be identiﬁed and must be conﬁgured with a static IP address. The wireless handsets and the other WLAN IP Telephony Managers 2245 locate the master by using the static IP address of the master. The loss of a nonmaster WLAN IP Telephony Manager 2245 does not signiﬁcantly affect the operation of the remaining WLAN IP Telephony Managers 2245. However, the loss of the master WLAN IP Telephony Manager 2245 results in a loss of all communication between all the WLAN IP Telephony Managers 2245. This causes the loss of all active calls, and wireless handsets cannot check in until communication with the master is reestablished.

Group capacities

The number of calls that an individual WLAN IP Telephony Manager 2245 can support is dependent on the number of WLAN IP Telephony Manager 2245s in the subnet. Assuming that a 100 Mb/s full-duplex connection to the network exists, a single stand-alone WLAN IP Telephony Manager 2245 can manage up to 80 active calls. If two WLAN IP Telephony Manager 2245s are installed in a master/slave conﬁguration, each can support up to 64 active calls for a total of 128 calls.

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Table 4 "Multiple WLAN IP Telephony Manager 2245-80 capacities" (page

61) lists the call capacities for WLAN IP Telephony Manager 2245-80

groups. Table 5 "Multiple WLAN IP Telephony Manager 2245-10 and

2245-20 capacities" (page 62) lists the handset capacities for WLAN IP

Telephony Manager 2245-10 and 2245-20 groups.

Table 4 Multiple WLAN IP Telephony Manager 2245-80 capacities

Number of

WLAN IP

Telephony

Managers

2245

Calls per WLAN IP

Telephony

Manager

2245

Total

calls Erlangs

Number of

wireless

handsets

10% use

Number of

wireless

handsets

15% use

Number of

wireless

handsets

20% use

1 80 80 65 500 433 325 2 64 128 111 1000 740 555 3 60 180 160 1500 1067 800 4 58 232 211 2000 1407 1055 557

285 262 2500 1747 1310 6 56 336 312 3000 2080 1560 7

56 392 367 3500 2447 1835 8 55 440 415 4000 2767 2075 9 55 495 469 4500 3127 2345

550 524 5000 3493 2620 11 55 605 578 5500 3853 2890 12 54 648 621 6000 4140 3105 13 54 702 674 6500 4493 3370 14 54 756 728 7000 4853 3640 15 54 810 782 7500 5213 3910 16 54 874 836 8000 5573 4180

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Table 5 Multiple WLAN IP Telephony Manager 2245-10 and 2245-20 capacities

Number of WLAN IP Telephony Managers 2245

Number of handsets WLAN IP Telephony Manager 2245-10

Number of handsets WLAN IP Telephony Manager 2245-20

110 20 220 40 330

not applicable

440

not applicable

For example, if there are two subnets for handsets in a campus and some handsets are directed to one subnet and some to the other, there are two Call Admission Control domains operating independently. Speciﬁcally, if both speciﬁed a limit of seven calls for each AP, it is possible to have seven calls admitted by each WLAN IP Telephony Manager 2245 on the same AP—therefore, the AP is oversubscribed by 2:1.

If multiple subnets are required, the best way to support them is to leverage the Layer 3 WLAN IP Telephony Manager 2245 design. With this design, the WLAN IP Telephony Manager 2245s are all in one subnet but SVP is routed from the second client subnet. Although this is a supported conﬁguration, all the engineering guidelines for latency, jitter, and packet loss must still be maintained. The Layer 3 design guidelines for having clients and WLAN IP Telephony Manager 2245 in different subnets does not mean that the WLAN IP Telephony Manager 2245 master and slaves can also be separated by routers—they must still be collocated in the same VLAN (subnet).

WLAN handsets The WLAN Handsets 2210/2211/2212/6120/6140 support both G.711 and G.729 codecs, but only using a 30 ms packetization rate.

The WLAN IP Telephony Manager 2245 translates between packetization rates, meaning that from the WLAN IP Telephony Manager 2245 to the handset, the call uses the packetization rate speciﬁed by the CS 1000 (for example, 20 ms). Nortel recommends that the CS1000 paketization rate match the 2245 at 30ms. For BCM, the packetization rate must be 30ms.

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The handsets encapsulate their voice payloads in SVP for QoS. The handsets further synchronize communications, so that the handsets are able to avoid collisions with each other more effectively than the usual

802.11 collision avoidance mechanisms. Each handset maintains a list of up to four APs as potential candidates for roaming. The handsets are aggressive in roaming to other APs, which tends to prevent them from using a suboptimal data rate when another AP can provide better service. The handsets also communicate with the WLAN IP Telephony Manager 2245 and discover which APs are at full call capacity, so that the handsets can direct their calls through an AP that has call capacity available.

Under optimal conditions, meaning no interference and all devices in proximity of the AP, up to 10 voice calls from a handset are supported on a single AP 2330. When conﬁguring the maximum call parameter of a WLAN IP Telephony Manager 2245, never conﬁgure it above 10. A more realistic rule of thumb that allows for devices to move about and rate scale accordingly is anywhere from six to eight calls per AP. A noisy RF environment can impact the numbers further.

To provide data devices some amount of guaranteed bandwidth, lower the maximum voice calls per AP to prevent voice calls from consuming all available throughput. For example, limiting the maximum calls per AP to seven allows data trafﬁc to reserve up to 30 per cent of media capacity. If the network supports other handset calls on the 802.11b network, you must leave adequate capacity for those calls too. Note that the call admission control function of the WLAN IP Telephony Manager 2245 cannot serve to limit those other voice calls on a per-AP basis.

There is an alternative control on the WLAN IP Telephony Manager 2245 that affects call capacity across APs. This control allows the WLAN IP Telephony Manager 2245 to ﬁx the data rates that handsets use. The options are Automatic and 1 Mb/2 Mb only. When you choose the latter, maximum call capacity drops by slightly more than half if G.711 is in use, or by slightly more than two-thirds if G.729 is in use. Most of the variability of call capacity is removed as rate scaling effects are eliminated. Therefore, you can get more predictable call capacity at the expense of maximum number of calls under optimum conditions. Note that with this option enabled, throughput for 802.11b data devices is severely impacted by even one or two voice calls.

If the automatic option to have higher potential capacity is selected, there is a risk of occasionally being oversubscribed under the worst conditions. For example, if eight calls is the conﬁgured limit on the WLAN IP Telephony Manager 2245, and if all eight calls are from handsets on the edge of coverage, the cell is oversubscribed. If ﬁve calls is the conﬁgured limit and handsets are restricted to 1 Mb/2 Mb, capacity is wasted when most handsets are close that could otherwise be used by other data devices.

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To gain this type of predictability, engineer the maximum calls per AP based on 1 Mb/2 Mb rate selections in the handsets, conﬁgure that number as the call limit on the WLAN IP Telephony Manager 2245, and then conﬁgure the actual rate of the handsets (on the WLAN IP Telephony Manager 2245) to Automatic. That way, the WLAN is engineered for the worst case, but in optimal conditions, more throughput is left over for other devices to use, because the handsets use higher data rates.

To summarize, do not use the 1 Mb/2 Mb option, even if the network is engineered to that type of coverage.

Gateway and timing function

WLAN IP Telephony Managers 2245 provide both the connection or gateway to the Call Server for the wireless handsets, and the timing function for active calls. This gateway function is distributed across the WLAN IP Telephony Manager 2245 group.

The number of active WLAN IP Telephony Managers 2245 is determined dynamically. Whenever a WLAN IP Telephony Manager 2245 is added to or removed from the system, the distribution of timing function for active calls, as well as the gateway function, is affected.

Roaming and handover

Roaming is the ability of the wireless handset to go anywhere in the WLAN Extended Service Set RF signal coverage area, and to make and receive calls. Handover is the ability of the wireless handset to maintain an active call without interruption while moving within a WLAN Extended Service Set (ESS) RF signal coverage area of a WLAN. This means that the wireless handset hands over the WLAN RF signal from AP to AP without interrupting the data stream.

Access points on the same subnet

The handset can perform handover and roaming across SVP-compliant APs that reside on the same subnet as the wireless handset and WLAN IP Telephony Manager 2245 group.

Mobility across different subnets when using DHCP

If a WSS is not in use and the wireless handset IP address is acquired through DHCP, the wireless handset must be powered down and powered up when entering a new subnet. This enables functionality of the wireless handset when entering the WLAN RF signal coverage area of a different WLAN IP Telephony Manager 2245 group on a different subnet. After the wireless handset establishes communication within the Extended Service Set Identiﬁer (ESSID) of the new WLAN, obtains another IP address from the DHCP server, and checks in with the group master, normal functionality

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returns. If the wireless handset is conﬁgured to use ESSID of the new WLAN, it automatically discovers the ESSID of the APs operating in broadcast mode.

Table 6 "Roaming and handover capabilities summary" (page 65)

summarizes the capabilities.

Table 6 Roaming and handover capabilities summary

IP address

WSS in use

Roaming capability Handover capability

Static No No No Static Yes Yes Yes DHCP No Yes, if the

wireless handset is power-cycled between subnets.

DHCP Yes Yes Yes

Multicast

IP multicast addresses are used by the WLAN Handset 2211 and the WLAN IP 6120 Handset Push-to-talk (PTT) feature. The use of IP multicast addresses requires that multicasting be enabled on the Layer 2 switch used by the deﬁned group (WLAN IP Telephony Manager 2245 master and slaves and wireless handsets).

Routers are typically conﬁgured with ﬁlters to prevent multicast trafﬁc from ﬂowing outside of speciﬁc domains. The wireless LAN can be placed on a separate VLAN or subnet to reduce the effects of broadcast and multicast trafﬁc from devices in other network segments.

Placement guidelines for the WLAN IP Telephony Manager 2245

To reduce the impact that jitter, delay and packet loss has on voice quality, proper placement of the WLAN IP Telephony Manager 2245 is critical. See

Figure 10 "Maximum delay, jitter and packet loss" (page 66). The WLAN IP

Telephony Manager 2245 provides three critical functions to help achieve exceptional voice quality over WLAN:

•

Timing

•

Quality of Service (QoS)

•

Connection Admission Control

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Before adding the WLAN IP Telephony Manager 2245 to the network:

•

Ensure that the APs used in the network are Voice Interoperability for Enterprise Wireless (VIEW) certiﬁed. For more information, go to

ww.spectralink.com/consumer/partners/view_certiﬁcation.jsp.

•

Ensure that the handsets are running Nortel Phase II software (97.070 or greater).

Figure 10 Maximum delay, jitter and packet loss

Strict timing requirements dictate that the WLAN IP Telephony Manager 2245 must be placed as close as possible to the handsets, ideally in the same subnet.

End-to-end jitter, delay and packet loss budget is a general VoIP best practice:

•

End-to-end delay is the time it takes for voice to go from the microphone of the sending telephone to the earpiece of the receiving telephone.

•

End-to-end jitter must not exceed 30 ms north of the SVP server (PBX to the WLAN IP Telephony Manager 2245) and must not exceed 1 ms south of the SVP server (the WLAN IP Telephony Manager 2245 to the AP).

•

End-to-end packet loss is the number of packets that are lost in the network.

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To achieve excellent voice quality, Nortel recommends using G711 CODEC with the following conﬁguration:

•

End-to-end delay < = 150 ms (one way)

•

Packet loss < = 0.5%

•

The maximum jitter buffer for the handsets set as low as possible.

For more information, see Converging the Data Network with VoIP Fundamentals (NN43001-260).

The jitter budget for the link south of the WLAN IP Telephony Manager 2245 ensures that packets arrive at the handset within the 30 ms arrival window. The evenly spaced packet ﬂow on the outbound side of the WLAN IP Telephony Manager 2245 allows the handset to conserve battery life by not using extra battery power to wait for late arriving packets. It also allows efﬁcient roaming while the handset moves from one AP coverage area to another. See Figure 11 "Jitter removal for packets going to the AP" (page

67).

Figure 11 Jitter removal for packets going to the AP

The following ﬁgures describe end-to-end delay for differing topologies:

•

For an example of an end-to-end delay for a LAN, see Figure 12

"Example 1: End-to-end delay and packet loss for a LAN" (page 68).

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•

For an example of an end-to-end delay for a WAN, see Figure 13

"Example 2: End-to-end delay and packet loss for a WAN" (page 69).

•

For an example of an end-to-end delay for a LAN to a Public Switched Telephone Network (PSTN), see Figure 14 "Example 3: End-to-end

delay and packet loss for a LAN to a PSTN" (page 70).

Figure 12 Example 1: End-to-end delay and packet loss for a LAN

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Figure 13 Example 2: End-to-end delay and packet loss for a WAN

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Figure 14 Example 3: End-to-end delay and packet loss for a LAN to a PSTN

Use the following tools to measure jitter, delay and packet loss:

•

Ping (to estimate delay and packet loss)

•

Netmeeting (to generate RTP trafﬁc)

•

Ethernet (to capture and analyze the RTP trafﬁc)

For more information, see Figure 15 "Measuring jitter, delay and packet

loss" (page 71) and Procedure 1 "Measuring jitter, delay and packet loss" (page 71).

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Figure 15 Measuring jitter, delay and packet loss

Procedure 1 Measuring jitter, delay, and packet loss

Step Action 1

Connect PC 2 to LAN segment C.

Obtain the IP address of PC 2.

Start Netmeeting.

Connect PC 1 to the LAN on segment B.

Ping PC 2 and note the length of the round-trip delay.

Start Ethernet and capture packets on the correct interface.

Conﬁgure a ﬁlter for RTP packets.

Start a Netmeeting session on PC 2.

End the Netmeeting session and stop the packet capture.

10 Save the ﬁle and analyze the trace to make sure that the jitter, delay,

and packet loss are within speciﬁcations.

Move PC 2 to segment A and repeat Step 1 to Step 10.

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—End—

For an example of packet stream analysis for jitter and packet loss, see

Figure 16 "Part 1: Example of analysis of a packet stream captured between segment A and B" (page 72) and Figure 17 "Part 2: Example of analysis of a packet stream captured between segment A and B" (page 73).

Figure 16 Part 1: Example of analysis of a packet stream captured between segment A and B

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Figure 17 Part 2: Example of analysis of a packet stream captured between segment A and B

Usually the WLAN IP Telephony Manager 2245 is placed in the same subnet as WLAN handsets. This was previously a rule, but it is now just a recommendation. The WLAN IP Telephony Manager 2245 sometimes must be placed in a different subnet from the handsets. However, the rules for delay, jitter, and packet loss still apply.

Ethernet connectivity between the WLAN IP Telephony Manager 2245 and the call server, or other voice endpoint, must never exceed 100 milliseconds (ms) of one-way delay, 30 ms of jitter, and 2% packet loss end to end regardless of the physical properties of the link. Whether the WLAN IP Telephony Manager 2245 is in the same subnet with handsets, the link between the WLAN IP Telephony Manager 2245 and the handset must be under 100 ms of one-way delay, 1 ms of jitter and under 2% packet loss.

WLAN Application Gateway 2246 planning

The optional WLAN Application Gateway 2246 requires a 10 Mbs half-duplex switched Ethernet connection.

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WLAN IP Telephony Manager 2245 and WLAN Application Gateway 2246 installation requirements

Locate the WLAN IP Telephony Manager 2245 and optional WLAN Application Gateway 2246 in a space with:

•

sufﬁcient backboard mounting space and proximity to the LAN access device (switched Ethernet switch), Call Server, and power source

•

rack-mount unit (if using)

•

easy access to the front panel, which is used for cabling

•

for the WLAN Application Telephony Gateway 2246, a maximum distance of 325 feet (100 meters) from the Ethernet switch

•

for the WLAN IP Telephony Manager 2245, a maximum distance of 325 feet (100 meters) from the Ethernet switch

IP address planning

The WLAN IP Telephony Manager 2245, the optional WLAN Application Gateway 2246, and each of the wireless handsets and APs associated with them, requires an IP address.

ATTENTION

IMPORTANT!

The master WLAN IP Telephony Manager 2245 must have an IP address statically conﬁgured.

If using DHCP for the rest of the network, the DHCP Server must have the static IP address of the master WLAN IP Telephony Manager 2245 conﬁgured on it. If using DNS, the DNS Server must have the static IP address of the master WLAN IP Telephony Manager 2245 conﬁgured on it.

The wireless handsets can be conﬁgured to use DHCP or can be assigned a static IP address. If there is no DHCP Server, the system administrator must determine what IP addresses are to be used for static addressing. As well, whether static IP addressing or DHCP is used, a pool of alias IP addresses must be conﬁgured on the WLAN IP Telephony Manager for the use of the wireless handsets. Ensure that the pool of alias IP addresses is reserved exclusively for the use of the wireless handsets.

For information about conﬁguring a static IP address on a WLAN IP Telephony Manager 2245, see "WLAN IP Telephony Manager 2245

conﬁguration" (page 99). For information about conﬁguring a static IP

address for a WLAN Application Gateway 2246, see "Conﬁguring the WLAN

Application Gateway 2246 IP address" (page 152). For information about

conﬁguring a static IP address on the handsets, see WLAN Handsets Fundamentals (NN43001-505). For information about assigning IP addresses to the APs, see the vendor-speciﬁc documentation.

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Record the static IP address assignments and store them in a safe place.

IP addressing with DHCP

A pool of alias IP addresses must be conﬁgured on the WLAN IP Telephony Manager 2245 for the use of the wireless handsets. The use of a 22-bit subnet mask provides IP addresses for approximately 500 wireless handsets (1024 nodes). Allocate a pool of an equal number of IP addresses on the DHCP server for the wireless handsets.

For example:

142.223.204.1 to 142.223.205.254 are allocated on the DHCP Server for the use of the wireless handsets.

142.223.206.1 to 142.223.207.254 are conﬁgured on the WLAN IP Telephony Manager for IP aliases for the wireless handsets.

Ensure that all these IP addresses are reserved on the DHCP Server for the use of the wireless handsets and not assigned to any other device.

Planning worksheets

Complete this worksheet and the worksheet in Table 8 "Wireless handset

planning worksheet" (page 76) before beginning the installation.

Copy and complete this worksheet in Table 7 "WLAN IP Telephony Manager

2245 planning worksheet" (page 75) for each WLAN IP Telephony Manager

2245. Obtain the necessary information from the network administrator.

Table 7 WLAN IP Telephony Manager 2245 planning worksheet

Unit number IP address Hostname Subnet Mask Default Gateway Master WLAN IP Telephony

Manager 2245 TFTP Download Master IP

address Primary DNS Server IP address Secondary DNS Server IP

address DNS Domain

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WINS Server IP address Workgroup name Syslog Server IP address First alias IP address Last alias IP address

Copy and complete the worksheet from Table 8 "Wireless handset planning

worksheet" (page 76) to maintain a conﬁguration record for the handsets.

Table 8 Wireless handset planning worksheet

Line * MAC Address * User Name

Dialin g Ext.

IP Address (if statically configured)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 *—required only if using the optional WLAN Application Gateway 2246.

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System information

This chapter contains information about the following topics:

•

"Bandwidth management" (page 77)

•

"Codecs" (page 79)

•

"Jitter buffer" (page 80)

•

"RLR and SLR" (page 80)

•

"RTCP" (page 80)

•

"Gain adjustment" (page 81)

•

"Programmable rings and tones" (page 81)

•

"Virtual Ofﬁce" (page 81)

•

"Branch Ofﬁce" (page 81)

•

"Survivable Remote Gateway" (page 82)

• "External Applications Server" (page 83)

•

"End-to-end QoS" (page 83)

•

"NAT" (page 83)

• "CS 1000 and Meridian 1 features" (page 90)

•

"IP Phone 2004 features" (page 91)

Bandwidth management

The existing CS 1000 Release 5.0 software bandwidth management mechanism using bandwidth zones applies to the handsets.

Zones

A WLAN IP Telephony Manager 2245 group consists of a master WLAN IP Telephony Manager 2245, zero to 15 WLAN IP Telephony Manager 2245 slaves, and their associated wireless handsets.

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It is good practice to create a Bandwidth Management Zone for each WLAN IP Telephony Manager 2245 group (one group per subnet) in LD 117. Use the CHG ZDES command to name the zone with the IP address of the master WLAN IP Telephony Manager 2245.

=> NEW ZONE <zone number>

=> CHG ZDES <zone number> <Wnnn.nnn.nnn.nnn>

where

W indicates WLAN IP Telephony Manager 2245 and nnn.nnn.nnn.nnn is the IP address of the master WLAN IP Telephony

Manager 2245.

=> PRT ZDES ALL

This allows the system administrator or support personnel to print a list of the IP addresses of all the master WLAN IP Telephony Managers 2245 in the system simply by printing the Zone designators in LD 117. They are printed as Wnnn.nnn.nnn.nnn. This enables support personnel to easily obtain the IP address of a WLAN IP Telephony Manager 2245 so they can telnet to the WLAN IP Telephony Manager 2245 in order to diagnose and correct problems.

Zones for wireless handsets

Assign the virtual line TNs for the wireless handsets (conﬁgured in LD 11) to the zone number assigned to its home WLAN IP Telephony Manager 2245 group. Using LD 117, this enables support personnel to list the current registration status of all wireless handsets that belong to the zone of a speciﬁc WLAN IP Telephony Manager 2245 group.

=> STIP ZONE <zone number>

All wireless handsets currently registered (checked in) with their home WLAN IP Telephony Manager 2245 group is listed. The format of the list is TERMIP = <alias IP address>, which is located in the same subnet as the IP address of the master WLAN IP Telephony Manager 2245 of the group. Any wireless handsets that are currently checked in with another WLAN IP Telephony Manager 2245 group are listed with a TERMIP in a different subnet from that of their home WLAN IP Telephony Manager 2245 group ZDES.

Current registration status of wireless handsets

To list the current registration status of all wireless handsets that are registered in a speciﬁc subnet, regardless of their home zone, use either of the following LD 117 commands.

STIP TERMIP <subnet of the WLAN IP Telephony Manager 2245 group>

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Codecs 79

PRT IPDN <subnet of the WLAN IP Telephony Manager 2245 group>

Alias IP address

Using the DN of a wireless handset, support personnel can obtain the current or most recent alias IP address used by a wireless handset when it checked in with the master of a WLAN IP Telephony Manager 2245 group, and subsequently registered with the LTPS and Call Server.

=> PRT DNIP <DN of wireless handset>

Wireless telephone type designation

Unless there is another preferred use for the DES (Designator) prompt in LD 11, Nortel recommends using the DES prompt to indicate the type of WLAN Handset—either type 2210, 2211, 2212, or 6120—for the i2004 type of virtual line TN. This allows support personnel to enter 2210, 2211, 2212 or 6120 at the LD 20 DES prompt and receive a list of handsets that are conﬁgured on the Call Server.

Call blocking

The WLAN IP Telephony Manager 2245 controls the media stream and blocks calls due to bandwidth constraints on any AP without notifying the Call Server.

•

The WLAN IP Telephony Manager 2245 can be conﬁgured with the maximum number of simultaneous calls allowed on a single AP.

•

On an incoming call for a wireless handset associated with a full AP, the caller hears ringback and the Call Forward No Answer (CFNA) treatment is applied, such as forwarding the call to voice mail. The called party is not notiﬁed of the incoming call.

•

If the call originates from a wireless handset that is on a bandwidth-restricted AP, the caller hears a warning tone and the call is blocked.

•

If a wireless handset moves into an area serviced by an AP that is already at capacity, the wireless handset does not associate with the new AP. Instead, the wireless handset attempts to remain associated with an AP that has sufﬁcient bandwidth. This could result in packet loss, degraded signal and voice quality, and a call could be dropped.

•

UNIStim signaling, such as watchdog updates or lamp audit, are not affected by the bandwidth constraint.

Codecs

G.711, G.729A, and G.729B codecs are supported. The RTP packets that transit between the wireless handsets and the WLAN IP Telephony Manager 2245 always contain 30 ms of voice. The WLAN IP Telephony Manager

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2245 repackages the voice data to the correct packet size. The jitter buffer is always conﬁgured to 70 ms, and any UNIStim messages that conﬁgure the jitter buffer are ignored.

ATTENTION

IMPORTANT!

If the wireless handset is registered to the same LTPSas the IP Phones, conﬁgure only the subset of codecs supported by both the wireless handsets and the IP Phones.

If it is necessary for the IP Phone to use a codec that is not supported on the wireless handsets, such as G.723.1, the wireless handsets must be conﬁgured on their own separate node.

If a remote endpoint is conﬁgured for G.723.1 as the Best Bandwidth (BB) Codec and G.711 as the Best Quality (BQ) Codec, (G.729 is not conﬁgured), the media path negotiates to G.711. The result can be unexpected consequences on a narrow-band link.

Jitter buffer

The handsets do not support a conﬁgurable jitter buffer. If they receive the Jitter Buffer Conﬁguration UNIStim message, the command is ignored. The jitter buffer is ﬁxed at 70 ms.

There are two implications of a ﬁxed jitter buffer setting:

•

If the system jitter buffer setting is less than 70 ms (default is 50 ms), there is a slightly longer delay in the IP Phone receive direction.

•

If the system jitter buffer setting is longer than 70 ms to accommodate severe network jitter, there could be slightly higher packet loss in the IP Phone receive direction.

The longer than normal jitter buffer setting is reasonable since extra jitter is introduced by the RF portion of the link.

RLR and SLR

The handsets do not support UNIStim messages used to adjust the Receive Loudness Rating (RLR) and Send Loudness Rating (SLR) of the wireless handset.

RTCP

Handsets do not support Real-time Transport Control Protocol (RTCP). Incoming RTCP packets sent to the wireless handsets are actually sent to the WLAN IP Telephony Manager 2245 and are discarded. If the wireless handset is queried for RTCP parameters, the wireless handset returns dummy values of 0 jitter, 0 latency, and 0 packet loss.

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Gain adjustment

The handsets ignore any UNIStim messages that adjust the loss plan of the wireless handset.

Programmable rings and tones

The wireless handsets support alerting cadences but only a single alerting frequency.

The wireless handsets have the same call progress tone capability as the existing IP Phones 2004.

In/Out of Service tones

When the handset completes registration with the Call Server, it plays the In Service tone. When the handset loses connection with the Call Server and resets, it plays the Out of Service tone.

Virtual Ofﬁce

The handsets support Virtual Ofﬁce. For more information, see Features and Services Fundamentals (NN43001-106) and IP Line Fundamentals (NN43001-500).

Branch Ofﬁce

The handsets are supported in a branch ofﬁce location using the Branch Ofﬁce feature. Branch Ofﬁce refers to the Media Gateway 1000B and the Survivable Remote Gateway (SRG). A WLAN IP Telephony Manager 2245 and supported APs must be installed at the branch ofﬁce location. Branch ofﬁce wireless handsets do not require wireless handset infrastructure in the main ofﬁce.

The wireless handsets in a branch ofﬁce conﬁguration behave like an IP Phone 2004 in the Branch Ofﬁce feature. The wireless handsets are administered in the same manner as the IP Phone 2004. The display on the wireless handsets is almost the same as the display on the IP Phone 2004, with one exception—the Local mode display.

Local mode display

The default state of the wireless handset is Standby. To determine whether the wireless handset is in Local mode, press the off-hook (Green) or the MENU keys on the WLAN Handset 2210/2211/2212 or the soft keys and the Nav keys on the WLAN Handset 6120/6140. Pressing these keys changes the state of the handset to Active Idle or Active Off-Hook, therefore putting the handset in communication with the primary Signaling Server.

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For the MG 1000B, if a wireless handset is registered to the Small System Controller (SSC) in Local mode, the local-mode license information appears on the wireless handset on the second line of the display. Since the maximum number of display characters on the wireless handset is 19 characters, the local-mode license information about the wireless handset display is truncated. See Table 9 "IP Phone 2004 and handset Local mode

license display (MG 1000B only)" (page 82).

Table 9 IP Phone 2004 and handset Local mode license display (MG 1000B only)

IP Phone 2004 Handset

Licensed days left x Licensed days lft x Licensed days left xx Licensed ds lft xx Beyond licensed period Beyond licensd prd

For more information about Branch Ofﬁce, see Branch Ofﬁce Installation and Commissioning (NN43001-314).

Survivable Remote Gateway

The handset can be deployed in a Survivable Remote Gateway (SRG) conﬁguration for both SRG 1.0 and SRG50.

The handset supports Virtual Ofﬁce in SRG for Normal mode. It is not supported in Local mode.

Test Local mode is not accessible because the Services key is not supported in Local mode.

The navigation keys are supported in Normal mode and not in Local mode. Since the default state of the wireless handset is Standby, it is only possible

to determine if the wireless handset is in Local mode by pressing the off-hook (Green) or MENU keys. Pressing these keys changes the state of the handset to Active Idle or Active Off-Hook, therefore putting it in communication with the primary Signaling Server in the main ofﬁce.

Note 1: In order to allow SRG 1.0 systems based on BCM 3.6, to correctly operate with the handsets, they must have a software patch installed. The patch can be downloaded from the Nortel Electronic Software Delivery Web site. The BCMSRG 3.6 WLAN IP Telephony Feature patch is called BCM_360[1].039__WLAN_IP_Telephony_Patch.exe, which includes 51 ﬁles required for automated patch installation.

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Note 2: No patch is required for SRG 1.0 based on BCM 3.7 or SRG50 systems

For more information about SRG, see Main Ofﬁce Conﬁguration Guide for Survivable Remote Gateway 50 (NN43001-307).

External Applications Server

The External Applications Server (XAS) applications are not available on the handsets.

End-to-end QoS

End-to-end QoS, such as DiffServ, and Layer 2 QoS, such as 802.1 Qp, are not supported on the wireless telephone system. Any UNIStim commands sent to the wireless handsets attempting to adjust Layer 2 or Layer 3 QoS parameters are ignored.

However, the WLAN IP Telephony Manager 2245 can tag packets with a Differentiated Services Code Point (DSCP) tag. For more information, see

"Quality of Service" (page 177). You can also provide QoS mechanisms

through the conﬁguration of network equipment. The Layer 2 switch port to which the WLAN IP Telephony Manager 2245 is

connected can be conﬁgured to add 802.1 Qp tagging. The Layer 3 port that acts as the gateway for the WLAN IP Telephony Manager 2245 can be conﬁgured to add the appropriate DiffServ tagging. Since all of the signaling and media trafﬁc passes through the WLAN IP Telephony Manager 2245, all packets are tagged with the appropriate priority. If more than one WLAN IP Telephony Manager 2245 is used, each Layer 2 port to which a WLAN IP Telephony Manager 2245 is connected must be conﬁgured to add the

802.1 Qp tagging.

NAT

Handsets can be deployed in an Network Address Translation (NAT) environment.

This section describes important considerations that must be taken into account when using the handsets in a NAT environment. Failure to comply with or heed these considerations can result in wireless handset malfunction.

For detailed information about NAT and the NAT Traversal feature, see IP Line Fundamentals (NN43001-500).

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NAT Traversal feature

The NAT Traversal feature is used where the IP Phone (this includes the handsets) is located on the private side of the NAT router, while the rest of the Server resides on the public side.

To ensure correct deployment of the wireless handsets in this type of network conﬁguration, most, if not all, of the WLAN equipment must reside on the private side of the NAT router.

Network conﬁgurations

The WLAN Handset 2212 has a VPN feature that enables an IPsec tunnel to a Nortel VPN Router, which is the only IPsec platform supported today. This feature alters some of the usual design recommendations for the telephony components, such as the WLAN IP Telephony Manager 2245. Usually, the WLAN IP Telephony Manager 2245 is placed in the same subnet with the handsets.

With the VPN feature enabled, the WLAN IP Telephony Manager 2245 now resides behind the VPN Router in a different subnet from the handsets; however, even though the same-subnet restriction has been lifted, it is still very important to locate the WLAN IP Telephony Manager 2245 as close to the handsets as possible. In this case, it is located immediately behind the VPN Router (and in the same subnet as the VPN Router). The VPN Router must also be located as close to the handsets as possible.

You can deploy the handsets behind a NAT router with no Security Switch, as shown in Figure 18 "VPN design over a Layer 2 network" (page 85). This conﬁguration includes a Layer 2 switch, which can be any Layer 2 switch (for example, Nortel Ethernet Switch 450). No Layer 3 device, such as a router, can be located between the wireless handsets and the WLAN IP Telephony Manager 2245.

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Figure 18 VPN design over a Layer 2 network

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Figure 19 VPN design over a Layer 3 network

ATTENTION

If the WLAN IP Telephony Manager 2245 is not in the same subnet as the handsets, the handsets do not work.

ATTENTION

In Figure 18 "VPN design over a Layer 2 network" (page 85), Figure 19 "VPN

design over a Layer 3 network" (page 86), Figure 20 "Not recommended VoWLAN design" (page 87), and Figure 21 "Network conﬁguration 3 with Full DHCP Server" (page 89), the clouds can represent a corporate intranet or the public Internet.

Make the VPN Router public interface the default gateway for the handsets, and if not the direct gateway for clients, at least ensure that trafﬁc comes from the WLAN into the public interface, not the private interface.

Connect the private interface of the VPN Router to the trusted side of the network. Make sure that client DHCP trafﬁc ﬂows through the VPN Router. If a network path around the VPN Router exists for the handsets to get

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DHCP assignments, the routing requirements on the VPN Router become much more complicated. To support such a scenario, you must conﬁgure static routes on the public interface as well as inject those routes into the routing protocol on the private interface. Therefore, Nortel recommends that you do not use the network design shown in Figure 20 "Not recommended

VoWLAN design" (page 87) as a design for the VPN feature.

Figure 20 Not recommended VoWLAN design

If you deploy the VPN feature of the WLAN Handset 2212 in a mixed network where WLAN Handsets 2211/2210s are also in use, the design recommendation becomes a little more complex. If you place a WLAN IP Telephony Manager in the subnet with the WLAN Handsets 2210/2211, and place a WLAN IP Telephony Manager in the subnet with the VPN Router to support the WLAN Handset 2212, admission control problems for the telephony WLAN can occur. Each WLAN IP Telephony Manager counts the number of their own devices placing calls over APs, but does not count the number of calls controlled by the other WLAN IP Telephony Manager. This creates a blind spot for each device, and it is possible to oversubscribe an AP by up to 2:1. The best solution to this problem is to have the WLAN

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Handsets 2210/2211 handsets use the same WLAN IP Telephony Manager as the WLAN Handset 2212 (VPN). This WLAN IP Telephony Manager is on the other (remote) side of the VPN Router from the handsets, that is, over a routed hop.

WLAN IP Telephony Manager 2245 in a NAT environment

The IP Telephony Manager 2245 must be in constant communication with the handsets to ensure handset functionality. Since the IP Telephony Manager 2245 must be on the same subnet as the handsets, the IP Telephony Manager 2245 must be located on the private side of the NAT router. The wireless VoIP network does not function if the IP Telephony Manager 2245 is located on the public side of the NAT router.

Port 10000 is used for bidirectional UDP trafﬁc between the handset alias IP addresses of the IP Telephony Manager 2245 and the Echo Server on the TPS used for NAT detection. Any network security devices that monitor network trafﬁc between the IP Telephony Manager 2245 and the Signaling Server(s) must be conﬁgured to allow trafﬁc using port 10000 to pass freely between these devices.

DHCP Server location in a NAT environment

The WLAN Handsets only support Full DHCP. The device acting as a DHCP Server to the WLAN Handsets must be conﬁgurable to send the vendor-speciﬁc DHCP ﬁelds.

In some cases, the NAT router acts as the DHCP Server. In this case, conﬁgure the NAT router with the required DHCP parameters and necessary information.

If a separate DHCP Server is used, it must be located on the private side of the network. See Figure 21 "Network conﬁguration 3 (with Full DHCP

Server)" (page 89) for more information.

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Figure 21 Network conﬁguration 3 with Full DHCP Server

TFTP Server location in a NAT environment

The TFTP Server can be located on the public side of the network. In this case, the NAT router (and Wireless Security Switch if deployed) can have to be conﬁgured to allow WLAN Handsets access to the TFTP Server (allow trafﬁc through on the required ports). This scenario is represented in Figure

21 "Network conﬁguration 3 (with Full DHCP Server)" (page 89).

Another option is to place the TFTP Server on the private side of the network.

WLAN Application Gateway 2246 in a NAT environment

If a WLAN Application Gateway 2246 is to be deployed, the requirements are similar to that of the TFTP server.

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The WLAN Application Gateway 2246 can be located on the public side of the network as long as trafﬁc is allowed on the correct ports. This scenario is represented in Figure 21 "Network conﬁguration 3 (with Full DHCP

Server)" (page 89).

Alternatively, the WLAN Application Gateway 2246 can be placed on the private side of the network.

CS 1000 features

Nearly all CS 1000 features are supported on the wireless telephone system and WLAN Handsets 22x1. Partially supported features are listed in Table

10 "Partially supported CS 1000 features" (page 90). The features that are

not supported are listed in Table 11 "CS 1000 not supported" (page 90).

Table 10 Partially supported CS 1000 features

Feature Feature full name Description

DIG Dial Intercom Group Handsfree call option is not supported. HOT I Intercom Hotline Voice Intercom Hotline (default) is

not supported. The Ringing option is supported.

RGA Ring Again Since the handsets cannot buzz, there is

no Ring Again tone. The only way to use the Ring Again feature is to determine if the Ring Again indicator is flashing, which is possible only when the wireless handset is in the active state.

Table 11 CS 1000 not supported

Feature Feature full name Description

AAB Automatic Answerback Cannot automatically enable Handsfree. VCC Voice Call Cannot automatically enable Handsfree.

Active Call Failover Not supported.

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IP Phone 2004 features

Table 12 "IP Phone 2004 features" (page 91) provides information about the

IP Phone 2004 features for the handsets.

Table 12 IP Phone 2004 features

Feature

Supported on the WLAN handsets Description

Keypad Yes Navigation keys Yes Up—Volume Up button

Down—Volume Down button

Left button—

Right button—

6 feature keys Yes 4 soft-labelled keys Yes Display Partially IP phone 2004: 5x24 display

Handsets: 4x19 display

Message Waiting Indicator

Yes Small envelope icon in the top right of the

handset LCD display

Branch Office Yes Survivable Remote

Gateway

Yes

Virtual Office Partially No Services key.

Use FCN+7 for the Services key to support

Virtual Office. XAS No No Expand key. Personal Directory

Callers List Redial List

Yes

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Feature

Supported on the WLAN handsets Description

Password Admin No The handsets can be password-protected,

but this is different from the IP Phone 2004

password protection mechanism.

The IP Phone 2004 password protection

is supported, in addition to the handset

password protection. KEM No

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Installation

This chapter contains information about the following topics:

•

"Required materials" (page 93)

•

"Preinstallation checklist" (page 94)

•

"WLAN IP Telephony Manager 2245 installation tasks" (page 94)

•

"WLAN Application Gateway 2246 installation" (page 97)

Required materials

The following equipment must be provided by the customer:

•

power outlet(s)—must accept the provided AC adapter, one for the WLAN IP Telephony Manager 2245 and one for the WLAN Application Gateway 2246 (if used).

•

plywood backboard space—the WLAN IP Telephony Manager 2245 is designed to be wall-mounted to

/2 in. plywood securely screwed to

the wall.

optional WLAN IP Telephony Manager 2245 rack-mount kit (must be ordered separately), containing mounting plates and screws

•

screws—used to mount the WLAN IP Telephony Manager 2245 to the wall. Four #8 -

/2 in. pan-head wood screws (or similar devices) are

required.

•

10BaseT CAT5 cable with an RJ-45 connector for the optional WLAN Application Gateway 2246—provides a connection to the Ethernet switch.

•

CAT5 cable with an RJ-45 connector for the WLAN IP Telephony Manager 2245—provides a connection to the Ethernet switch.

•

DB-9 female null-modem cable—required for initial conﬁguration of the WLAN IP Telephony Manager 2245 and WLAN Application Gateway

2246.

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Supplied equipment

Each WLAN IP Telephony Manager 2245 and WLAN Application Gateway 2246 is shipped with one Class II AC adapter with 24V DC, 1A output.

Preinstallation checklist

Ensure that the following requirements are met prior to installation:

•

The location chosen for the WLAN IP Telephony Manager 2245 and WLAN Application Gateway 2246 is adequate and power is available.

• APs are SVP-compatible and coverage is adequate.

•

A dedicated line is available for remote modem access, if needed.

•

The telephone system administrator is on-site to program the existing telephone system.

WLAN IP Telephony Manager 2245 installation tasks

The following are the tasks that must be completed to install the WLAN IP Telephony Manager 2245:

1. "Wall-mount" (page 95). or

"Rack-mount" (page 96).

2. "LAN connection" (page 97).

3. "Power connection" (page 97).

About the front panel

The front panel of the WLAN IP Telephony Manager 2245 contains ports to connect to the following:

•

power

•

LAN

•

administrative computer through an RS-232 port Status LEDs supply information about status and activity of the WLAN IP

Telephony Manager 2245. See Figure 22 "WLAN IP Telephony Manager

2245 front panel" (page 95).

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Figure 22 WLAN IP Telephony Manager 2245 front panel

•

RS-232 port—the male DB-9 connector (DTE). Provides an RS-232

connection to a terminal, terminal emulator, or modem for system administration.

•

Link LEDs — LNKOK—lit when there is a network connection — ACT—lit when there is system activity — COL—lit if there are network collisions

•

NETWORK—connects the WLAN IP Telephony Manager 2245 to the

wired Ethernet LAN

•

ERROR LED—lit when the system has detected an error

•

Status LEDs—indicate system error messages and status

— 1—heartbeat — 2—active calls — 3, 4, 5—currently unused

•

PWR—connects to the AC adapter supplying power to the system

WARNING

Use only the provided Class II AC adapter with 24V DC, 1A output.

Wall-mount

The WLAN IP Telephony Manager 2245 can be mounted either vertically or horizontally.

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Procedure 2 Wall-mounting the WLAN IP Telephony Manager 2245

Step Action 1

Use a 18-inch drill bit to drill four pilot holes, on 1.84 by 12.1 inch centers (approximately equivalent to 1-1316 inch by 12-18 inch).

Insert the #8 x 34-inch screws in the pilot holes and tighten, leaving a 18 to 14-inch gap from the wall.

Slide the WLAN IP Telephony Manager 2245 over the screws until the WLAN IP Telephony Manager 2245 drops into place in the keyhole openings of the ﬂange.

Tighten screws fully.

—End—

Rack-mount

The rack-mount kit is designed for mounting the WLAN IP Telephony Manager 2245 in a standard 19-inch rack and contains the following equipment:

•

Mounting plates—two for each WLAN IP Telephony Manager 2245 to be mounted.

•

Screws—four rack-mount screws for each WLAN IP Telephony Manager 2245 to be mounted.

Follow the steps in Procedure 3 "Rack-mounting the WLAN IP Telephony

Manager 2245" (page 96) to rack-mount the WLAN IP Telephony Manager

2245.

Procedure 3 Rack-mounting the WLAN IP Telephony Manager 2245

Step Action 1

Remove the corner screws from the WLAN IP Telephony Manager

2245.

Screw the U-shaped end (round screw holes) of the two mounting plates to the WLAN IP Telephony Manager 2245.

Screw the other end of the two mounting plates (oblong screw holes) to the rack.

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Repeat steps 1-3 for each additional WLAN IP Telephony Manager

2245. The mounting plate is designed to provide the correct minimum spacing between units. When mounting multiple units, stack the units in the rack as closely as possible.

—End—

LAN connection

Use an RJ-45 cable to connect the NETWORK port on the WLAN IP Telephony Manager 2245 to the connecting port on the Ethernet switch.

Power connection

Follow the steps in Procedure 4 "Connecting the power" (page 97) to connect the power to the WLAN IP Telephony Manager 2245.

Procedure 4 Connecting the power

Step Action 1

Connect the power plug from the AC adapter to the jack labeled PWR on the WLAN IP Telephony Manager 2245.

WARNING

Use only the provided Class II AC adapter with output 24V DC, 1A.

Plug the AC adapter into a 110V AC outlet to supply power to the WLAN IP Telephony Manager 2245.

The system cycles through diagnostic testing and the LEDs blink for approximately one minute.

When the system is ready for use, verify the following: a. ERROR LED is off. b. Status 1 is blinking.

—End—

WLAN Application Gateway 2246 installation

For information about installing the optional WLAN Application Gateway 2246, see Appendix "WLAN Application Gateway 2246" (page 147).

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WLAN IP Telephony Manager 2245 conﬁguration

This chapter contains information about the following topics:

•

"Introduction" (page 99)

•

"Conﬁguration tasks" (page 101)

• "Connect to the WLAN IP Telephony Manager 2245" (page 101)

•

"Conﬁgure the network" (page 103)

•

"Conﬁgure the WLAN IP Telephony Manager 2245" (page 106)

• "Change the password" (page 108)

Introduction

The WLAN IP Telephony Manager 2245 acts as a proxy for the wireless handsets and provides several services for them. It is connected to the same subnet as the wireless handsets. The wireless handsets always communicate voice and signaling directly with the WLAN IP Telephony Manager 2245, using the proprietary SpectraLink Voice Protocol (SVP).

SVP is required for quality of service (QoS) because the current IEEE 802.11a/b/g wireless LAN standard provides no mechanism for differentiating audio packets from data packets. This standard is undergoing revision to version 802.11e to provide functionality in an industry standard similar to SVP, therefore ensuring high-quality voice in a mixed-client environment.

Functional description

The WLAN IP Telephony Manager 2245 provides the following services to the handsets:

• It acts as a proxy for every wireless handset; that is, all UNIStim signaling and RTP media to and from the wireless handset pass through the WLAN IP Telephony Manager 2245. Except for the initial DHCP and TFTP sessions, the wireless handsets only communicate with the WLAN IP Telephony Manager 2245.

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Each WLAN IP Telephony Manager 2245 is conﬁgured with an IP address with which all of the wireless handsets communicate. In addition, each WLAN IP Telephony Manager 2245 is conﬁgured with a pool of IP addresses. When a wireless handset registers with a WLAN IP Telephony Manager 2245, the wireless handset is assigned one of the IP addresses from the pool. All communication between this WLAN IP Telephony Manager 2245 and other devices (TPS, IP Phones, gateways, and other wireless handsets) is always done through its pool IP address. In this sense, the WLAN IP Telephony Manager 2245 acts as a NAT (Network Address Translation)

Note: The WLAN IP Telephony Manager 2245 has a single physical Ethernet interface and MAC address; therefore, all of the IP addresses are mapped to a single MAC address.

•

The WLAN IP Telephony Manager 2245 server tags and untags packets with the SVP header. SVP packets have the protocol byte of the IP header conﬁgured to 0x77. SVP-compliant APs use this proprietary tagging to give priority to tagged packets. For UDP (UNIStim and RTP) packets going from the wireless handset to the network, the WLAN IP Telephony Manager 2245 replaces the SVP protocol number, 0x77, with the UDP number, 0x11. For packets going from the network to the wireless handset, the protocol number is changed from 0x11 to 0x77.

Because the packets that traverse the network between the wireless handset and the WLAN IP Telephony Manager 2245 are not standard IP packets (the packets use a nonstandard protocol number), there can be no Layer 3 routing in the path. Therefore, the wireless handsets and WLAN IP Telephony Managers 2245 must be in the same logical subnet.

• RTP packets between the wireless telephone and the WLAN IP Telephony Manager 2245 always contain 30 ms worth of voice, no matter what is conﬁgured on the Call Server. The WLAN IP Telephony Manager 2245 repackages the RTP packets to conform to the size that is conﬁgured in the Call Server. This provides more efﬁcient use of the available Radio Frequency (RF) bandwidth at the expense of slightly increased jitter and latency.

•

The WLAN IP Telephony Manager 2245 is conﬁgured with a maximum allowable number of simultaneous media streams on a single AP. The WLAN IP Telephony Manager 2245 keeps track of the number of media streams on each AP and blocks calls to and from a wireless handset that would exceed the conﬁgured capacity. For more information about call blocking, see "Call blocking" (page 79).

•

The WLAN IP Telephony Manager 2245 has limitations for high availability. There are some types of failure that can result in complete outages. Every group of WLAN IP Telephony Manager 2245s in a single subnet has a master node. If this node fails or if connectivity to it is lost,

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Nortel NN43001-504, Telephony Manager Installation Manual

Specifications and Main Features

Frequently Asked Questions

User Manual