VoIP Emergency Calling

Dr. Karl Heinz Wolf, NIC.AT, AustriaKarl Heinz Wolf studied Electrical Engineering and Computer Science at the Technical University of Vienna. Since his thesis work, he has focused on VoIP-related technologies, and now works for NIC.AT, which he joined in June 2007. In addition, Karl has contributed to a number of projects related to VoIP-based emergency calls. Furthermore, he has developed several prototypes of emergency calling technologies and is active in emergency-relevant working groups in the IETF.Richard Barnes, BBN Technologies, USARichard Barnes is a leader in standards related to security and real-time applications on the Internet. He currently chairs the IETF GEOPRIV working group, and serves on the program committee for the Emergency Services Workshop. In addition, as a scientist at BBN Technologies, he leads efforts to prototype geolocation and emergency services technologies.

• Foreword ixUseful Links xiList of Abbreviations xiii1 Introduction 11.1 Calling over the Internet 21.2 VoIP Emergency Calling Problem Statement 21.3 Emergency Communication 51.4 Overview of this Book 6References 72 Emergency Calling 92.1 Overview 92.2 Infrastructure Requirements 102.3 The Role of Location Information 12References 163 The ECRIT Emergency Calling Architecture 193.1 Overview 203.2 Location Information 223.2.1 PIDF-LO 233.2.2 Location by Value and Location by Reference 303.2.3 Location Conveyance 333.3 Service URNs 393.4 Determining the Appropriate PSAP – the LoST Protocol 403.4.1 The Mapping Process – findService 413.4.2 Retrieving the Service List – listServicesByLocation 443.4.3 Address Validation 463.4.4 Areas of Responsibility – serviceBoundary 473.4.5 LoST Server Discovery 493.4.6 LoST Architecture 503.4.7 Private and Public LoST Trees 533.4.8 LoST Synchronization 543.5 The Emergency Call Itself 573.5.1 Initiating Emergency Calls 583.5.2 Routing Emergency Calls 603.5.3 Assembling the SIP INVITE Message 613.6 Home Dial String Configuration via LoST 623.7 Deployment Models 663.8 Considerations for Proxies 693.9 Standardization 713.10 Summary 73References 744 Including Location Information 774.1 Location Configuration 784.1.1 HTTP Enabled Location Delivery (HELD) 784.1.2 DHCP Options for Location Configuration 844.1.3 LLDP-MED 864.1.4 Protocol Comparison 884.1.5 Conversion between Location Formats 884.2 Positioning Using GPS 904.3 Network-Based Positioning 914.4 Location Hiding 924.5 Default Location 94References 945 Implementation and Regulatory Considerations 975.1 Distribution of Implementation Tasks 985.1.1 Emergency Call Centers (PSAPs) 985.1.2 VoIP Software and Hardware Manufacturers 995.1.3 Network Operators and ISPs 1005.1.4 VoIP Operators 1015.1.5 PSTN Operators 1025.1.6 Unassigned Responsibilities 1025.1.7 Summary 1035.2 Austria 1035.2.1 The Telecommunications Act 1045.2.2 KEM-V 1045.2.3 RTR Guidelines for VoIP Operators 1055.2.4 AK-TK Recommendations 1065.2.5 Emergency Calling in Austria 1075.3 The United States 1125.3.1 9-1-1 Regulation 1135.3.2 9-1-1 History 1165.3.3 Automatic Location Information 1205.4 The European Union 1225.5 Japan 1235.5.1 Regulatory Framework 1235.5.2 Call Handling 1265.5.3 Location Information and Privacy 1275.6 Summary 129References 1306 VoIP Emergency Calling in Practice 1336.1 Software 1336.1.1 HELD Clients and Servers 1346.1.2 DHCP Location Encoders and Decoders 1376.1.3 Wireshark for DHCP Location 1396.1.4 OpenLLDP 1396.1.5 HELD Support in Firefox 1406.1.6 LoST Implementations 1416.1.7 Zap! with Emergency Calling Extensions 1426.1.8 Ecritdroid 1456.1.9 EcritXUL 1476.1.10 Multi-Part Body Extension to Asterisk 1496.1.11 IMS Core Emergency Services 1506.2 Practice Exercises 1516.2.1 Location Configuration: DHCPv4 with Civic Addresses 1526.2.2 Location Configuration: Simulating a HELD Server 1556.2.3 Location Configuration: Location-Enabling a Network with HELD 1566.2.4 Mapping: Querying the LoST Server 1606.2.5 SIP Calling: Call Setup with Location Configuration 1626.2.6 ECRIT Calling: A Complete System 166References 1707 Security 1717.1 ECRIT Security 1727.1.1 Determining the Caller’s Location 1727.1.2 Determining the Proper PSAP 1757.1.3 Delivering the Call 1757.1.4 Considerations for Proxies 1767.2 Location Security 1777.2.1 Location Privacy 1787.2.2 Location Assurance 1827.2.3 Location Protection 1847.3 PSAP and VoIP Network Security 1867.3.1 Basic PSAP Protection Measures 1877.3.2 PSAP Fraud Mitigation 1887.3.3 VoIP Provider Call Validation 192References 1958 Ongoing Emergency Calling Work 1978.1 Prototyping, Implementation, and Interoperability 1988.2 Ongoing Standardization Issues 2008.2.1 Default PSAPs 2008.2.2 Unauthenticated Emergency Calls 2008.2.3 VPN Problems 2018.2.4 Home Emergency Dial String Issues 2018.2.5 Updating the List of Available Emergency Services – the LoST Service List Boundary 2028.2.6 Order of Location Configuration 2048.2.7 Notifying Users of Emergency Calls 2058.2.8 Connecting Emergency Dial Strings and Emergency Authorities 2058.2.9 Disconnection during an Emergency Call 2068.2.10 LLDP-MED ELIN will not be Supported 2068.2.11 Civic Boundaries 2068.2.12 LoST Service Boundary References and Location Types 2078.2.13 Emergency Calls to Counseling Services 2088.3 Ongoing Implementation Issues 2098.3.1 Service URNs as Request URIs 2098.3.2 Converting from the DHCP Location Format to PIDF-LO 2098.3.3 LLDP-MED Difficulties 2108.3.4 Multi-Part SIP Bodies and Message Size 210References 2119 Summary and the Outlook for the Future 213Index 217