ETSI TR 102 476 V1.1.1 (2008-07)

Emergency Communications (EMTEL); Emergency calls and VoIP: possible short and long term solutions and standardization activities

DTR/EMTEL-00006

General Information

• Status: Published
• Publication Date: 17-Jul-2008
• Technical Committee: EMTEL - Emergency Communications
• Current Stage: 12 - Completion
• Due Date: 15-Jul-2008
• Completion Date: 18-Jul-2008

Standards Content (Sample)

ETSI TR 102 476 V1.1.1 (2008-07)
Technical Report


Emergency Communications (EMTEL);
Emergency calls and VoIP: possible short and
long term solutions and standardization activities

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2 ETSI TR 102 476 V1.1.1 (2008-07)



Reference
DTR/EMTEL-00006
Keywords
emergency, VoIP
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3 ETSI TR 102 476 V1.1.1 (2008-07)
Contents
Intellectual Property Rights.5
Foreword.5
1 Scope.6
2 References.6
2.1 Normative references.6
2.2 Informative references.7
3 Definitions and abbreviations.8
3.1 Definitions.8
3.2 Abbreviations.8
4 Purpose of the present document.8
4.1 The network evolution.8
4.1.1 Summary.9
4.2 Broadband subscribers .9
4.2.1 Summary.9
5 General on Access to Emergency Services .9
5.1 Service types.10
5.2 The PSAP interface .11
5.3 Network capabilities.11
6 Emergency Calls and VoIP .11
6.1 Description of VoIP scenarios.11
6.1.1 IP-based telephony from fixed terminal.12
6.1.2 Internet telephony from fixed terminal .12
6.1.3 IP-based telephony from nomadic terminal .12
6.1.4 Internet telephony from nomadic terminal.13
6.1.5 IP-based telephony from mobile terminal.13
6.1.6 Internet telephony from mobile terminal .13
6.2 Emergency Calls.14
6.2.1 IP-based telephony from fixed terminal.14
6.2.1.1 Routing.14
6.2.1.2 Identification.14
6.2.1.3 Location.14
6.2.2 Internet telephony from fixed terminal .15
6.2.3 IP-based telephony from nomadic terminal .15
6.2.3.1 Routing.15
6.2.3.2 Identification.16
6.2.3.3 Location.16
6.2.4 Internet telephony from nomadic terminal.17
6.2.5 IP-based telephony from mobile terminal.17
6.2.5.1 Routing.17
6.2.5.2 Identification.18
6.2.5.3 Location.18
6.2.6 Internet telephony from mobile terminal .19
7 Standardization activities .19
7.1 IETF/ECRIT.19
7.1.1 Requirements for Emergency Context Resolution with Internet Technologies.19
7.1.2 A Uniform Resource Name (URN) for Emergency and Other Well-Known Services.19
7.1.3 Security Threats and Requirements for Emergency Call Marking and Mapping .20
7.1.4 LoST: A Location-to-Service Translation Protocol.20
7.1.5 Location-to-URL Mapping Architecture and Framework .20
7.1.6 Best Current Practice for Communications Services in support of Emergency Calling .20
7.1.7 Framework for Emergency Calling using Internet Multimedia .20
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4 ETSI TR 102 476 V1.1.1 (2008-07)
7.1.8 A Dynamic Host Configuration Protocol (DHCP) based Location-to-Service Translation Protocol
(LoST) Discovery Procedure .20
7.2 ETSI.21
7.2.1 Requirements of the NGN network to support Emergency Communication from Citizen to Authority
(TISPAN).21
7.2.2 NGN Architecture to support emergency communication from citizen to authority.21
7.2.3 Emergency Location Protocol.21
7.2.4 Requirements in Emergency Communications in NGN .21
7.2.5 Architecture to support of Emergency Communications.21
7.2.6 Revision of TS 102 164 on the Endorsement of the OMA MLP v 3.2.0.21
7.3 3GPP.22
7.3.1 IP Multimedia Subsystems (IMS) emergency sessions .22
7.3.2 Other organizations working with Emergency Call Standardization.22
Annex A: Bibliography.23
History .24

ETSI

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5 ETSI TR 102 476 V1.1.1 (2008-07)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://webapp.etsi.org/IPR/home.asp).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Report (TR) has been produced by ETSI Special Committee Emergency Communications(EMTEL).
The present document is one of several deliverables covering the communication needs of individuals and authorities in
emergency situations, as identified below:
TR 102 180: "Basis of requirements for communication of individuals with authorities/organizations in case of
distress (Emergency call handling)";
TS 102 181: "Requirements for communication between authorities/organizations during emergencies";
TS 102 182: "Requirements for communications from authorities/organizations to individuals, groups or the
general public during emergencies";
TR 102 410: "Basis of requirements for communications between individuals and between individuals and
authorities whilst emergencies are in progress".
ETSI

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6 ETSI TR 102 476 V1.1.1 (2008-07)
1 Scope
The present document gives an overview of standardisation activities and summarises different methods for VoIP
providers to deliver emergency communication services. VoIP is growing quickly, especially in countries with a high
broadband penetration. Therefore the use of this technology for the provision of emergency communication services
will be considered. For this, specific features can be introduced such as location and routing facilities.
The present document is applicable to ETSI technical bodies for the defining of services and specifying technical
solutions.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• Non-specific reference may be made only to a complete document or a part thereof and only in the following
cases:
- if it is accepted that it will be possible to use all future changes of the referenced document for the
purposes of the referring document;
- for informative references.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
For online referenced documents, information sufficient to identify and locate the source shall be provided. Preferably,
the primary source of the referenced document should be cited, in order to ensure traceability. Furthermore, the
reference should, as far as possible, remain valid for the expected life of the document. The reference shall include the
method of access to the referenced document and the full network address, with the same punctuation and use of upper
case and lower case letters.
NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are indispensable for the application of the present document. For dated
references, only the edition cited applies. For non-specific references, the latest edition of the referenced document
(including any amendments) applies.
Not applicable.
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7 ETSI TR 102 476 V1.1.1 (2008-07)
2.2 Informative references
The following referenced documents are not essential to the use of the present document but they assist the user with
regard to a particular subject area. For non-specific references, the latest version of the referenced document (including
any amendments) applies.
[i.1] ETSI TR 102 180: "Basis of Requirements for communication of Individuals with
authorities/organizations in case of distress (emergency call handling)".
[i.2] ETSI TS 102 424 (V1.1.1): "Telecommunications and Internet converged Services and Protocols
for Advanced Networking (TISPAN); Requirements on the NGN network to support Emergency
Communication from Citizen to Authority".
[i.3] ETSI TS 123 167: "Universal Mobile Telecommunications System (UMTS); IP Multimedia
Subsystem (IMS) emergency sessions (Release 7)".
[i.4] IETF RFC 5012: "Requirements for Emergency Context Resolution with Internet Technologies".
[i.5] IETF RFC 5031: "A Uniform Resource Name (URN) for Emergency and Other Well-Known
Services".
[i.6] IETF RFC 5069: "Security Threats and Requirements for Emergency Call Marking and Mapping".
[i.7] Draft-ietf-ecrit-mapping-arch-03: "Location-to-URL Mapping Architecture and Framework" by H.
Schulzrinne.
NOTE: This reference can is available at http://www.ietf.org/internet-drafts/draft-ietf-ecrit-mapping-arch-03.txt.
[i.8] Draft-ietf-ecrit-lost-10: "LoST: A Location-to-Service Translation Protocol", by T. Hardie, A.
Newton, H. Schulzrinne and H. Tschofenig.
NOTE: This reference can is available at http://www.ietf.org/internet-drafts/draft-ietf-ecrit-lost-10.txt.
[i.9] Draft-ietf-ecrit-phonebcp: "Best Current Practice for Communications Services in support of
Emergency Calling", by B. Rosen and J. Polk.
NOTE: This reference can is available at http://www.ietf.org/internet-drafts/draft-ietf-ecrit-phonebcp-04.txt.
[i.10] Draft-ietf-ecrit-framework-05: "Framework for Emergency Calling using Internet Multimedia", by
B. Rosen, H. Schulzrinne, A. Newton and J. Polk.
NOTE: This reference can is available at http://www.ietf.org/internet-drafts/draft-ietf-ecrit-framework-05.txt.
[i.11] Draft-ietf-ecrit-dhc-lost-discovery: "A Dynamic Host Configuration Protocol (DHCP) based
Location-to-Service Translation Protocol (LoST) Discovery Procedure", by H. Schulzrinne,
H. Tschofenig and J. Polk.
NOTE: This reference can is available at http://www.ietf.org/internet-drafts/draft-ietf-ecrit-dhc-lost-discovery-
03.txt.
[i.12] ETSI TS 182 009: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); NGN Architecture to support emergency communication from
citizen to authority; [Endorsed document 3GPP TS 23.167, Release 7]".
[i.13] ETSI TS 102 164 (V2.1.1): "Telecommunications and Internet converged Services and Protocols
for Advanced Networking (TISPAN); Emergency Location Protocols; [OMA-TS-MLP-V3_2-
20051124-C]".
[i.14] ETSI EG 202 339: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); Definition of requirements on the functional architecture for
supporting Emergency and Priority user services".
[i.15] ITU Recommendation E.164: "List of ITU Recommendation E.164 assigned country codes".
ETSI

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8 ETSI TR 102 476 V1.1.1 (2008-07)
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
IP network: packet transport network deploying the IP protocol
Voice over Internet Protocol (VoIP): is the generic name, which defines the transportation of voice traffic by means
of transmission in packets using Internet Protocol (IP)
NOTE: VoIP traffic can be routed on a controlled private network or the internet, which is a public network, or a
combination of the two. Internet telephony and managed IP-based telephony are sub elements of VoIP.
IP-based telephony (or managed IP-based telephony): specific VoIP service, where the voice traffic is carried by
data packets fully or partially on managed IP network, in which case the management of network means management of
quality, reliability and security of calls
internet telephony (or Voice over Internet (VoIT)): a specific VoIP service using transmission in packets on the
Internet public network which is by definition open and noncontrollable
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
3GPP Third Generation Partnership Project
DNS Domain Name System
EGEA Expert Group on Emergency Access
ETSI European Telecommunications Standards Institute
IETF Internet Engineering Task Force
NTP Network Termination Point
PATS Publicly Available Telephony Services
PIDF-LO Presence Information Data Format – Location Object
PSAP Public Safety Answering Point
PSTN Public Switched Telephone Network
RPC Remote Procedure Call
SIM Subscriber Identification Module for GSM
VoIP Voice over Internet Protocol
URI Uniform Resource Identifier
USIM Subscriber Identification Module for UMTS
4 Purpose of the present document
4.1 The network evolution
New communications networks are IP-based. The number of broadband telephones is increasing quickly and more and
more calls no longer reach a circuit switched network.
Emergency calls traditionally reach the PSAP through the PSTN. Actors offering VoIP services without a PSTN
network, e.g. municipality networks, need to transfer emergency calls through a circuit switched network, typically the
old PSTN. Since IP allows for transfer of more information related to the call and the caller, it could be beneficial to
allow for direct IP-interconnect to PSAPs. It is also foreseeable that the days of the circuit switched networks are
coming to an end. That means that the requirements for IP-interconnections of PSAPs are developed. It can also be
argued why new IP-based public communications operators would not have the possibility to connect directly to PSAPs
over IP.
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9 ETSI TR 102 476 V1.1.1 (2008-07)
Apart from the above mentioned reasons for EMTEL to work on IP-interconnection of PSAPs, it is likely to be an
advantage to try and define a PSAP IP interface. It could lead to easier reaching common functionality meeting
requirements on Emergency Services which in turn could lead to a possibility to utilize common platforms and easier
exchange of experiences. This is done with the knowledge that other standardization bodies are working on different
aspects of the problem.
4.1.1 Summary
- The circuit switched network era will end.
- The routing from IP networks to PSTN for reaching PSAPS is not necessary when PSAPs are connected
directly to IP networks.
- A pure IP-interface for PSAPs should be defined.
- More information can be transferred through IP into the PSAPs compared to today's circuit switched signalling
interfaces (trunk or access signalling).
- Common requirements are beneficial for meeting requirements on Emergency Services, cost for systems and
exchange of experiences.
4.2 Broadband subscribers
The increasing penetration of broadband has opened the market for VoIP over broadband. From being a complement to
the PSTN it is becoming a replacement. Driving factors are the possibility to reduce subscription and call costs and also
other services, e.g. the possibility to log into the network and thus receive calls to your actual location.
When becoming a replacement subscribers would expect that the behaviour of the telephony service concerning
Emergency Calls is the same as in the PSTN. Due to technical reasons this is not possible to guarantee when a call is set
up from the Internet.
This problem is addressed in many international working groups in e.g. IETF, 3GPP, and ETSI. There is a need to
coordinate the VoIP Emergency Call standardization activities and also to define the requirements on the PSAP IP
interface.
For this reason EMTEL in this TR defines short and long term requirements for Emergency Calls from broadband
connections with the aim to facilitate a harmonized European approach. The individual subscriber should not be forced
to know technical details of the network he is connected to for making Emergency Calls.
4.2.1 Summary
- VoIP is going from being a complement to PSTN into becoming a replacement.
- The subscriber expects Emergency Calls to work "as usual".
- It is desirable to have a harmonized approach in Europe since the VoIP service is borderless.
- There are a lot of standardization activities going on in different groups.
5 General on Access to Emergency Services
The efficient operation of Emergency Services requires fulfilment of the following basic functions.
1) Routing to the appropriate PSAP (as defined by the relevant authority).
2) Identification of the caller (network identity through e.g. NTP and/or U/SIM).
3) Location of the caller.
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10 ETSI TR 102 476 V1.1.1 (2008-07)
These three basic functional requirements are valid independent of what service type the Emergency Call is set up
from the Communications Network and to the PSAP and which interface is used. See figure 1.
AcAccceessss to to PSAPPSAP
112112
IP
InternetInternet
intinteerfrfaceace
InternetInternet
PSAPSAPP
ElectronElectronicic
ElectronElectronicic
CCoommunimmunicaticationon
CCoommunimmunicaticationon
TTeelephonylephony
netwnetwoorkrk
netwnetwoorkrk
oror I IPP
intinteerrffaacece

Figure 1: Network overview 2
5.1 Service types
All Emergency Communication have to originate over a Service Type. Below a list of possible Service Types is given:
Voice Services:
1) POTS (Plain Old Telephone Service);
2) Mobile telephony (circuit switched);
3) Satellite telephony;
4) Voice over IP:
Fixed (The subscriber cannot move the service to another Network Access Point);
Nomadic (The subscriber can move the service to another Network Access Point);
Mobile Communication Services on Packet Access;
Internet telephony.
Other Services:
1) Video calls (E.g. from 3G-telephone);
2) Data calls (E.g. alarm from a device);
3) E-mail;
4) SMS (Short Message Service);
5) MMS (Multimedia Messaging Service);
6) Real-time Instant-Messaging and Chat.
The present document deals with the Service Type for Voice over IP category 4.
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11 ETSI TR 102 476 V1.1.1 (2008-07)
5.2 The PSAP interface
The interface between the Communications Network (telecom or Internet) and the PSAP can be of two main types.
1) Circuit switched (PSTN-based).
The content of the communication - voice - and the signaling information for call handling and transport of
emergency related information will be done using the same interface.
2) IP-based.
Only the content of the communication - voice - will be delivered from access network.
a) IP-based telephony.
The signalling information for call handling and the emergency related information will be
delivered from VoIP session provider.
b) Internet telephony.
The signalling information for call handling and the emergency related information will be
delivered from user equipment.
Other data can be communicated between the network and PSAP related to the emergency communication, including
location. The interfaces used are not described in the present document.
5.3 Network capabilities
Independent of what interfaces are implemented, the functional requirements are the same. Therefore, information
conveyed over any interface should facilitate identification and location of the caller. Furthermore the VoIP provider
should be able to route the Emergency Call to the pre-defined PSAP.
The present document does not specify the actual protocols used for the interfaces between the Internet or
Communications Network and the PSAP.
6 Emergency Calls and VoIP
In order to address problems associated with the implementation of VoIP emergency calls, various scenarios and the
corresponding options for handling emergency calls are discussed.
6.1 Description of VoIP scenarios
Voice over IP can be subdivided in a number of scenarios depending on how the telephony service is offered
technically, but no one is generally accepted yet.
From the point of view of emergency telecommunications one of these scenarios (worked out and used by the
telecommunications regulation authorities in several European countries) categorizes the provided services on whether
the PSTN network is available by the user through the VoIP network or not:
Type 1 non PATS peer-to-peer services to make and receive voice calls over the Internet only, usually
within the same application community. The terminal equipments do not have PSTN telephone
numbers (according to the ITU Recommendation E.164 [i.15]), the service providers do not
provide the normal "112" or "E112" services. The PSAP can receive emergency calls from these
terminals only if it has Internet type VoIP interface and the users have retrieved the PSAP's IP ID
number(s).
Type 2 VoIP Out services to make voice calls over the Internet to the PSTN (Public Switched Telephony
Network, the standard public network), but not to receive calls from the PSTN. Though the
terminal equipments do not have ITU Recommendation E.164 [i.15] type telephone numbers, the
service providers can provide the normal "112" or "E112" services. At present roughly half of
European countries do not require the service providers of
...