Voic 802.11e over phần 1 docx

[...]... Filtering 10 0 Security Risks 10 0 WLAN Security Model Interception Fabrication Modification Replay Reaction Interruption Denial of Service Attacks Repudiation Network Architecture 10 0 10 1 10 4 10 6 10 8 10 9 10 9 10 9 11 1 11 1 Mobility and Security Security Policy: A Range of Options 11 3 11 3 802 .11 Security Measures Beyond WEP Wi-Fi Protected Access 802.1x and EAP Advanced Security 11 4 11 4 11 5 Contents 802.1x Network... Considerations 13 8 13 9 Importance of QoS on 802 .11 Networks 14 0 Need for QoS in Wireless Networks Challenges to Wireless QoS Latency in Wireless Networks QoS in 802 .11 14 1 14 1 14 1 14 3 Legacy 802 .11 MAC DCF PCF 14 3 14 4 14 8 Conclusion References 9 11 6 11 7 VPNs Point-to-Point Tunneling Protocol Layer Two Tunneling Protocol 8 xi 15 3 15 3 Engineering Vo802 .11 Networks for Maximum QoS 15 5 QoS on Vo802 .11 Networks 15 5... 15 5 Measuring Voice Quality in Vo802 .11 Detractors to Voice Quality in Vo802 .11 Networks 15 6 15 7 xii Voice over 802 .11 Factors Affecting QoS in Vo802 .11 Networks Improving QoS in IP Routers and Gateways Measures for Delivering Optimal QoS on Vo802 .11 Networks 16 1 Voice Codecs Designed for Vo802 .11 Networks 16 7 Conclusion References 10 16 0 16 0 17 0 17 0 Scalability in Wireless VoIP Networks 17 1 Bandwidth... Repairability 18 6 18 6 18 7 Recoverability 18 7 Achieving the “Five 9s” with a Vo802 .11 Softswitch NEBS 18 7 19 0 Power Availability 19 0 Conclusion References 12 Vo802 .11 Reliability 19 2 19 2 Vo802 .11 Features and Applications 19 3 Features in the Legacy PSTN 19 4 Features and Signaling SCE APIs APIs and Services XML 19 4 19 5 19 6 19 6 19 7 SIP: Architecture for Enhanced Services in Softswitched Vo802 .11 Networks 19 7 Media... Considerations for Wireless VoIP 17 1 Importance of Bandwidth to Scalability 17 2 Which 802 .11 Protocols Are Best for Which Vo802 .11 Applications? 802 .11 b 802 .11 a 802 .11 g 17 3 17 3 17 3 17 3 Why Frequency Bands Are Important Path Loss Illustrated Receiving Antenna Gain Link Margin Diffraction Losses Coax and Connector Losses 17 4 17 4 17 4 17 5 17 5 17 5 Frequency Reuse Planning for Vo802 .11 Networks Frequency Reuse... Frequency Allocation 17 5 17 6 17 6 17 8 FCC Regulations and Power of Vo802 .11 Transmissions 17 9 Point-to-Multipoint Links 17 9 Point-to-Point Links 17 9 Limitations in the AP 18 0 Scalability in VoIP Switching 18 1 Conclusion References 18 2 18 2 Contents 11 xiii 18 3 Understanding Reliability How Availability Is Calculated 18 3 18 4 Reliability in Wireless Access in a Vo802 .11 Network Redundancy in Vo802 .11 Networks Repairability... Servers 19 8 Application Servers 19 8 Architecture Interface Between Call Control and Application Server Application Server Interactions 19 9 19 9 200 Vo802 .11 Networks and E 911 and CALEA Requirements 2 01 E 911 CALEA 2 01 202 Vo802 .11 Applications Made Possible by Softswitch Features 203 xiv Voice over 802 .11 Web Provisioning Voice-Activated Web Interface The Big “So What!?” of Enhanced Features in Vo802 .11 Networks... 19 50s The U.S 10 Voice over 802 .11 Table 2 .1 IEEE 802 .11 Variants 802 .11 Variant Description 802 .11 a Created a standard for WLAN operations in the 5-GHz band, with data rates of up to 54 Mbps Published in 19 99 Products based on this standard were released in 2003 802 .11 b Created a standard (also known as WiFi) for WLAN operations in the 2.4-GHz band, with data rates of up to 11 Mbps Published in 19 99... 802.1x Network Port Authentication EAP 12 0 12 2 12 2 L2TP over IPsec SSL UPN-Related Security Protocols 12 2 12 2 12 3 Kerberos 12 3 Conclusion References 12 5 12 6 Objections Due to Interference and QoS on Vo802 .11 Wireless Networks 12 9 Interference External Sources of Interference Internal Sources of Interference If You Want Interference, Call the Black Ravens 13 0 13 1 13 5 13 8 Line of Sight, Near Line of Sight,... Considerations for Vo802 .11 Networks 207 Current Regulatory Environment for 802 .11 207 Power Limits 208 Interference 209 Laws on Antennas and Towers FCC Preemption of Local Law Height Limitations 214 214 214 Regulatory Issues Concerning VoIP 214 Conclusion References 14 203 Example of a Wireless Killer App: I-Mode 13 203 203 215 216 Economics of Vo802 .11 Networks 217 Vo802 .11 Works: Case Studies Medical . Attacks 10 9 Repudiation 11 1 Network Architecture 11 1 Mobility and Security 11 3 Security Policy: A Range of Options 11 3 802. 11 Security Measures Beyond WEP 11 4 Wi-Fi Protected Access 11 4 802. 1x and. 802. 11 Networks 14 0 Need for QoS in Wireless Networks 14 1 Challenges to Wireless QoS 14 1 Latency in Wireless Networks 14 1 QoS in 802. 11 14 3 Legacy 802. 11 MAC 14 3 DCF 14 4 PCF 14 8 Conclusion 15 3 References. Security 11 5 x Voice over 802. 11 802. 1x Network Port Authentication 11 6 EAP 11 7 VPNs 12 0 Point-to-Point Tunneling Protocol 12 2 Layer Two Tunneling Protocol 12 2 L2TP over IPsec 12 2 SSL 12 2 UPN-Related