Deploying Voice over Wireless LANs (Hardcover) (無線區域網路語音部署)

Deploying Voice over Wireless LANs

 

The definitive guide to planning, architecting, deploying, supporting, and creating Voice over Wireless LAN solutions

 

 

Recent advances make it possible to deliver high-quality voice and video communications over a wireless LAN (WLAN), replacing costly wired telephone and video surveillance systems and dramatically reducing support costs. However, today’s new voice over WLAN (VoWLAN) technologies require fundamentally different skills and techniques from those used in traditional voice and video systems. Now, there’s a complete guide to every facet of VoWLAN deployment: planning, design, installation, security, maintenance, and troubleshooting.

 

Authored by wireless industry expert and leader Jim Geier, Deploying Voice over Wireless LANs draws on Geier’s extensive experience with real-world VoWLAN deployments. Geier brings together state-of-the-art insights into VoWLAN technologies, standards, products, services, implementation strategies, and much more.

 

Geier begins by introducing key components of today’s VoWLAN systems, including phones, client software, and voice encoders/decoders, as well as VoWLAN signaling essentials such as analog-to-digital (A/D) conversion and compression. Using examples drawn from actual enterprise settings, you’ll learn exactly how VoWLAN products integrate with existing IP infrastructure.

 

Next, he introduces crucial emerging 802.11 standards for effective VoWLAN deployment, including 802.11e quality of service (QoS) standards, 802.11r to minimize packet loss between access points, and 802.11k network discovery. He carefully reviews the security implications of VoWLAN voice, systematically covering both risks and countermeasures. Finally, Geier walks through implementation from start to finish, thoroughly covering analysis, design, installation, configuration, testing, and support.

 

Whatever your role in planning, delivering, managing, or creating wireless voice and video solutions, Deploying Voice over Wireless LANs is your most comprehensive, authoritative resource.

 

Jim Geier founded Wireless-Nets, Ltd., and serves as its principal consultant. His 25 years of experience includes the analysis, design, software development, installation, and support of numerous wireless networking systems. He has been active within the Wi-Fi Alliance and the IEEE 802.11 Working Group and helped develop international standards for WLANs. His books include Wireless Networks First Step (Cisco Press), Wireless LANs (Sams), Wireless Networking Handbook (MTP), and Network Reengineering.

 

• Understand VoWLAN components, applications, and benefits
• See VoWLAN at work in actual enterprise environments
• Master VoWLAN signaling, including voice signal characteristics, A/D conversion, and compression
• Discover the latest 802.11 VoWLAN standards, including 802.11e, 802.11r, and 802.11k
• Secure IP-based VoWLAN systems against intrusion and compromise
• Analyze your organization’s requirements and design an optimal VoWLAN solution
• Plan for capacity, roaming, and integration with cellular systems
• Install, configure, test, verify, and validate your VoWLAN system
• Plan for operational support and implement appropriate administration tools and methods
• Includes a complete VoWLAN glossary

 

This book is part of the Networking Technology Series from Cisco Press®, which offers networking professionals valuable information for constructing efficient networks, understanding new technologies, and building successful careers.

 

 

Table of Contents

Part I Fundamental Elements

Chapter 1 VoWLAN Applications and Benefits

The Role of VoWLAN Solutions

History of VoWLANs

    VoIP

    Wireless LANs

Healthcare

Enterprises

Universities

Retail

Warehouses

Manufacturing

Small Offices and Homes

Security Systems

Determining ROI

    Initial Analysis

    Costs

    Savings

    Payback Period

Chapter Summary

Chapter Review Questions

Chapter 2 VoWLAN System Components

VoWLAN System Overview

Cisco 7920 Wireless IP Phone

Cisco IP Softphone

Cisco CallManager

Cisco CallManager Express

Linksys Wi-Fi Video Cameras

Wireless Network Infrastructures

    Traditional Access Point Networks

    Wireless Switched Networks

    Mesh Networks

Chapter Summary

Chapter Review Questions

Chapter 3 VoWLAN Signaling Fundamentals

Voice Attributes

Video Attributes

VoIP Call Flow

    H.323

    Skinny Client Control Protocol (SCCP)

    Session Initiation Protocol (SIP)

Radio Frequency (RF) Signals

    Modulation

    RF Signal Characteristics

    Gain

    Signal-to-Noise Ratio

    Spread Spectrum

    Orthogonal Frequency Division Multiplexing (OFDM)

    FCC Rules

Wireless Impairments

    Poor Signal Coverage

    Latency

    RF Interference

    Limited Capacity

    Multipath

Chapter Summary

Chapter Review Questions

Part II Critical Technologies

Chapter 4 Wireless LAN Technologies

Infrastructure Mode

    Scanning

    Data Transfer

    Roaming

Ad Hoc Mode

Wireless Medium Access

    DCF

    PCF

802.11 Physical Layer Standards

    802.11a

    802.11b

    802.11g

    802.11n

    Comparison of 802.11 Standards

Wireless Configuration Parameters

    SSID

    RF Channels

    Transmit Power

    Data Rates

    Power-Save Mode

    RTS/CTS

    Fragmentation

    RTS/CTS and Fragmentation Summary

Chapter Summary

Chapter Review Questions

Chapter 5 VoWLAN Security Solutions

Security Implications

    Passive Monitoring

    Unauthorized Access

    Denial of Service

Encryption

    WEP

    TKIP

    AES

    WPA

    802.11i

    Virtual Private Networks

Authentication

    Open System Authentication

    Shared Key Authentication

    IEEE 802.1X

    Cisco LEAP

Tips for Enhancing Security

    SSID Broadcasting

    Systems Management

    Access Point Installation

    Rogue Access Points

    Signal Propagation

Chapter Summary

Chapter Review Questions

Part III Implementation Steps

Chapter 6 Analyzing VoWLAN Requirements

Overall Requirements Analysis Steps

Identifying Potential Requirements

    Applications

    Users

    Utilization

    Coverage Areas

    Roaming

    Environment

    Security

    Client Devices

    Existing Systems

    Policies and Preferences

    Budget

    Schedules

Verifying and Validating Requirements

Documenting Requirements

Chapter Summary

Chapter Review Questions

Chapter 7 Designing a VoWLAN Solution

Overall Design Steps

Deployment Models

    Single-Site Architecture

    Multisite WAN with Centralized Call Processing

    Multisite WAN with Distributed Call Processing

Roaming

Security

Network Infrastructure

    Virtual LANs

    Multicasting

    Switch Recommendations

    Quality of Service

Placement of Access Points

    Wireless Capacity Analysis

    RF Site Survey

Document Findings

Chapter Summary

Chapter Review Questions

Chapter 8 Installing, Configuring, and Testing a VoWLAN System

Installing Access Points

    Getting Started

    Mounting Practices

    Antenna Alignment

    Electrical Power Distribution

Configuring Access Points

    Configuration Setting Access

    Firmware

    VLANs

    SSID

    Transmit Power

    RF Channel

    Data Rates

    Filtering

    Protection Mechanisms

Installing and Configuring Cisco CallManager Software

    Cisco CallManager Software Installation

    System Parameters

    Subscriber Setup

    Device Mobility Issues

Configuring Wireless IP Phones

    Firmware

    Network Settings

    RF Settings

    Phone Settings

Verifying System Operation

    Association Tests

    Authentication Tests

    Registration Tests

    Phone Call Tests

    Load Tests

    Follow-up Tests

    Battery Life Issues

Chapter Summary

Chapter Review Questions

Chapter 9 Supporting a VoWLAN System

Configuration Management

    RF Channel Changes

    Transmit Power Changes

    New Applications

    Signal Coverage

    Firmware Version

    Security Improvement

Network Monitoring

    Performance Monitoring

    Coverage Monitoring

    Configuration Monitoring

    Security Policy Management

Security Assessment Steps

    Review Existing Security Policies

    Review the System Architecture

    Review Operational Support Tools and Procedures

    Interview Users

    Verify Configurations of Wireless Devices

    Investigate Physical Installations of Access Points

    Identify Rogue Access Points

    Perform Penetration Tests

    Analyze Security Gaps

    Recommend Improvements

Maintenance Functions

    Inoperative Access Points

    Poor Performance

    Poor Signal Coverage

    Broken Hardware

    Keep Firmware Up to Date

    Monitor Performance

    Verify Coverage

    Inspect Access Points

Engineering Functions

    Advanced Problem Resolution

    Coverage Expansion

    Capacity Increases

    Firmware Review

    Technology Upgrade

    Design Review

Help Desk Planning

    Connection Problems

    Poor Signal Coverage

    Poor Performance

    System Status

    Additional Considerations

CiscoWorks Wireless LAN Solution Engine

    Automatic Access Point Configuration

    Assisted Site Surveys

    Centralized Firmware Updates

    Dynamic Grouping

    VLAN Configuration

    Multiple SSID Support

    Customizable Thresholds

    Fault Status

    Intrusion Detection System

    Security Policy Monitoring

    Secure User Interface

    Air/RF Scanning and Monitoring

    Self-healing Functions

    Reporting, Trending, Planning, and Troubleshooting

Chapter Summary

Chapter Review Questions

Appendix A Answers to Chapter Review Questions

Glossary