ETSI ES 203 178 V1.1.1 (2015-02)

Final draft ETSI ES 203 178 V1.0.5 (2014-12)

ETSI STANDARD
Functional architecture to support European requirements
on emergency caller location determination and transport

2 Final draft ETSI ES 203 178 V1.0.5 (2014-12)

Reference
DES/E2NA-00001-M493-stage2
Keywords
emergency, location, VoIP
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ETSI
3 Final draft ETSI ES 203 178 V1.0.5 (2014-12)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 6
3 Definitions and abbreviations . 7
3.1 Definitions . 7
3.2 Abbreviations . 8
4 Descriptions and assumptions . 9
4.1 Introduction . 9
4.2 Location information descriptions . 10
4.2.1 General . 10
4.2.2 Location value . 10
4.2.3 Location identifier. 10
4.2.4 Location reference . 11
5 Functional architecture to support European requirements on emergency caller location
determination and transport . 11
5.1 Overview . 11
5.2 Architectural requirements . 12
5.2.1 General . 12
5.2.2 ANP - Access Network Provider . 13
5.2.3 VSP - Voice Service Provider. 13
5.2.4 ECSP - Emergency Call Service Provider . 13
5.2.5 PSP - PSAP Service Provider . 14
5.3 Interfaces . 14
5.3.1 Interface definitions . 14
5.3.2 Information flows . 16
5.3.2.1 ia interface . 16
5.3.2.2 ib interface. 17
5.3.2.3 ic interface . 17
5.3.2.4 id interface. 18
5.3.2.5 ie interface . 18
5.3.2.6 if interface . 18
5.3.2.7 ig interface. 19
5.3.2.8 ih interface. 19
5.3.2.9 ii interface . 20
5.3.2.10 ij interface . 21
5.3.2.11 ik interface. 22
5.3.2.12 il interface . 22
5.3.2.13 im interface . 23
5.3.2.14 in interface. 23
5.4 Functional entities . 24
5.4.1 ANP . 24
5.4.1.1 Location Server (LS) . 24
5.4.2 VSP . 25
5.4.2.1 VSP Call Control . 25
5.4.3 ECSP . 26
5.4.3.1 ESRF . 26
5.4.3.2 LS Proxy . 26
5.4.3.3 Other entities . 26
5.4.4 PSAP Service Provider . 27
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4 Final draft ETSI ES 203 178 V1.0.5 (2014-12)
5.4.4.1 Emergency Service Routeing Proxy. 27
5.4.4.2 Route Server . 27
5.4.4.3 Other entities . 27
5.4.5 other functional entities . 28
5.4.5.1 Location Server Discovery Function . 28
5.4.5.2 User Equipment . 28
5.4.5.3 IP-PSAP . 28
5.4.5.4 PSTN-PSAP . 28
5.5 Information flow diagrams . 29
5.5.1 Introduction. 29
5.5.2 ANP provides a location value . 29
5.5.3 ANP provides location reference to the VSP and the ECSP pulls location value . 31
5.5.4 ANP provides to the VSP a location identifier . 32
5.5.5 ANP provides location identifier to the VSP and the PSAP pulls location value . 34
5.6 Extension of the Functional Architecture for Networks with VPN, NAT/PAT and other components
which change Packet Flow Identity . 35
5.7 Extension of the Functional Architecture to support VSP Aggregation Providers . 35
6 Protocol and other requirements . 36
6.1 Generic requirements . 36
6.2 Trust relationships . 36
Annex A (normative): Extension of the Functional Architecture for Networks with VPN,
NAT/PAT and other components which change Packet Flow Identity . 37
A.1 General . 37
A.2 LS chaining solution . 37
A.2.1 Location chaining interface impacts . 39
A.3 HOST_ID solution . 39
Annex B (informative): M/493 Scope . 43
Annex C (normative): Extension of the Functional Architecture to support an aggregating
VSP . 44
C.1 General . 44
C.2 Architectual requirements for VSP Aggregation Provider (VAP) . 44
C.3 Extended Interface definition . 45
C.4 VSP Aggregating Entity . 45
Annex D (informative): Avoiding authentication between the VSP and the ANP. 46
History . 48

ETSI
5 Final draft ETSI ES 203 178 V1.0.5 (2014-12)
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://ipr.etsi.org).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. 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 final draft ETSI Standard (ES) has been produced by ETSI Project End-to-End Network Architectures (E2NA),
and is now submitted for the ETSI standards Membership Approval Procedure.
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "may not", "need", "need not", "will",
"will not", "can" and "cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms
for the expression of provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
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6 Final draft ETSI ES 203 178 V1.0.5 (2014-12)
1 Scope
The present document describes the unified functional architecture to support requirements as outlined in European
Commission (EC) mandate M/493 [i.4] on emergency caller location determination and transport, in particular for the
case where the VoIP service provider and one or several network operators - all serving the customer in the
establishment of an emergency call - are independent enterprises needing to co-operate to determine the location of the
(nomadic) caller. The architecture identifies all necessary interfaces, which are needed to fulfil the requirements
outlined in EC Mandate M/493 [i.4], and provides a basis for the specification of the protocols to be used on those
interfaces.
The present document is applicable to both NGN and pre-NGN IP-based networks. The architecture defined in the
present document is intended to be compatible with IMS-based deployments but does not require compliance to IMS
specifications.
This architecture does not intend to replace existing deployed solutions. It should enable operators and undertakings
providing services to realize transmission of location information to the Public Safety Answering Point.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
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 necessary for the application of the present document.
Not applicable.
2.2 Informative references
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI TS 123 167: "Universal Mobile Telecommunications System (UMTS); LTE; IP Multimedia
Subsystem (IMS) emergency sessions (3GPP TS 23.167)".
[i.2] IETF RFC 6967: "Analysis of Potential Solutions for Revealing a Host Identifier (HOST-ID) in
Shared Address Deployments".
[i.3] Draft-boucadair-intarea-host-identifier-scenarios-03 (March 2013): "Host Identification: Use
Cases".
[i.4] M/493: "Standardisation Mandate to the European Standards Organisations (ESO) in support of
the location enhanced emergency call service".
[i.5] IETF RFC 6753: "A Location Dereference Protocol Using HTTP-Enabled Location Delivery
(HELD)".
[i.6] ETSI TS 102 181: "Emergency Communications (EMTEL); Requirements for communication
between authorities/organizations during emergencies".
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7 Final draft ETSI ES 203 178 V1.0.5 (2014-12)
[i.7] ETSI TS 102 650: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); Analysis of Location Information Standards produced by
various SDOs".
[i.8] Directive 2002/22/EC of the European Parliament and of the Council of 7 March 2002 on
universal service and users' rights relating to electronic communications networks and services
(Universal Service Directive).
[i.9] Commission Recommendation 2003/558/EC of 25 July 2003 on the processing of caller location
information in electronic communication networks for the purpose of location-enhanced
emergency call services (notified under document number C(2003)2657).
[i.10] IETF RFC 5222: "LoST: A Location-to-Service Translation Protocol".
[i.11] IETF RFC 4848: "Domain-Based Application Service Location Using URIs and the Dynamic
Delegation Discovery Service (DDDS)".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
access network: portion of the telecommunications network that provides access to the switching function and
terminates the user access signalling
Access Network Provider (ANP): service provider that provides physical and IP connectivity to a user equipment
(UE) via a fixed or mobile access
NOTE: The access network may be provided by a single organization or it may be provided by a number of
different organizations, BUT the interfaces between these organizations are not relevant to the scope of
the present document as it is matter of contractual relations between the parties.
emergency: urgent need for assistance or relief
emergency call: call from a user to an emergency call centre, PSAP or similar agency charged with routeing calls to the
relevant emergency response organization
emergency call facilities: mechanisms provided by public or private communications networks, emergency telephone
stanchions/boxes, fire alarms, etc. the use of which enables emergency calls to be made
Emergency Call Service Provider (ECSP): service provider that acts as a mediator between the voice service
providers and the public safety answering point service providers
emergency caller: individual placing an emergency call to reach the suitable PSAP
emergency response organization: local or national force established to provide assistance to citizens in the event of
their being involved in an emergency situation and requiring specialized help, for example, the police, fire service and
emergency medical services
emergency service: service that provides immediate and rapid assistance in situations where there is a direct risk to life
or limb, individual or public health or safety, to private or public property, or the environment but not necessarily
limited to these situations
emergency situation: abnormal situation of serious nature that develops suddenly and unexpectedly, of which the
evolution is uncertain and which may turn into a crisis or cause damage and casualties
FlowChanger: device in an IP flow, which changes the packet flow identity, for example changing the IP address
and/or port, so the UE can no longer be identified in the original access network
location information: location value, and/or a location identifier and/or a location reference
location value: civic or geodetic position
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8 Final draft ETSI ES 203 178 V1.0.5 (2014-12)
location identifier: public network identifier, which provides a location value
EXAMPLE: A cell ID or line ID (see ETSI TS 123 167 [i.1]).
NOTE: A location value can be obtained from a location identifier by applying a static mapping or the location
identifier may be encoded in such a way that it contains a location value (e.g. a ZIP code).
location reference: identifies a location server and provides sufficient information to allow the location server to
provide the location value for the UE
EXAMPLE: https://ls.example.com:49152/uri/w3g61nf5n66p0, IETF RFC 6753 [i.5].
network-provided location information: any location information pertaining to the calling device that is determined,
provided or verified by the ANP
Next Generation Network (NGN): packet-based network able to provide telecommunication services and able to
make use of multiple broadband, QoS-enabled transport technologies and in which service-related functions are
independent from underlying transport-related technologies
nomadic: having the ability to move across network access points
NOTE: A nomadic user can make calls from different locations. However, unlike a mobile user, the location of a
nomadic user cannot change during a specific call.
originating network: access network in which the emergency call was placed
packet flow identity: all network parameters, which unambiguously identify a IP flow
PSAP address: URI or an E.164 number identifying a PSAP or a group of PSAPs
PSAP Service Provider: service provider that provides connectivity to Public Safety Answering Points (PSAPs) and
directs emergency calls from the ECSP to the PSAP
Public Safety Answering Point (PSAP): physical location where emergency calls are received under the responsibility
of a public authority
NOTE: See Commission Recommendation C(2003)2657 [i.9] and ETSI TS 102 181 [i.6].
regulatory domain: geographical area where a set of regulatory rules applies
telecommunication: any transmission, emission, or reception of signs, signals, writing, images, sounds or intelligence
of any nature, by wire, radio, optical fibre or other electromagnetic system
user access: point of connection to a telecommunication network from which a call can be placed
NOTE: This includes public telephones and "emergency call facilities".
user equipment: device allowing a user access to network services
user-provided location information: any location information originating from user-equipment that is not
independently verified by the ANP
Voice Service Provider (VSP): specific type of application service provider that provides voice related services and
optionally text and video-related services, on IP
VSP Aggregation Provider (VAP): provider that a VSP or group of VSPs can use to support call routing to remote
ECSPs and for the generation of related call data records
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ANP Access Network Provider
AP Access Point
CGN Carrier Grade NAT
DHCP Dynamic Host Configuration Protocol
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9 Final draft ETSI ES 203 178 V1.0.5 (2014-12)
DNS Domain Name Server
EC European Commission
ECSP Emergency Call Service Provider
ESO European Standards Organisation
ESRF Emergency Service Routing Function
ESRP Emergency Service Routeing Proxy
ETSI European Telecommunications Standards Institute
FID Flow Identity
th
FID-N N Flow Identity
FQDN Fully qualified domain name
IETF Internet Engineering Task Force
IMS IP Multimedia Subsystem
IP Internet Protocol
ISDN Integrated Services Digital Network
LS Location Server
th
LS-N N Location Server
NAPTR Naming Authority Pointer
NAT Network Address Translation
NGN Next Generation Network
PAT Port and Address Translation
PBX Private Branch Exchange
PCRF Policy and Charging Rules Function
PSAP Public Safety Answering Point
PSP PSAP Service Provider
PSTN Public Switched Telephone Network
RFC Request For Comment
SIP Session Initiation Protocol
TCP Transmission Control Protocol
UDP User Datagram Protocol
UE User Equipment
URI Uniform Resource Identifier
VAE VSP Aggregating Entity
VAP VSP Aggegation Provider
VoIP Voice over Internet Protocol
VPN Virtual Private Network
VSP Voice Service Provider
4 Descriptions and assumptions
4.1 Introduction
ETSI TS 102 650 [i.7] states that:
"In order to effectively deliver emergency services to the location of a reported incident, it is essential for the
emergency response organization to have timely and accurate information that enables them to correctly identify the
location of the incident.
The ability to initiate an emergency communication to summon help when needed is regarded by the European
Commission as a right of all citizens and this ability should ideally be independent of the network and access
technologies deployed or the physical abilities of the citizen.
The rights of individual users to privacy shall be adhered to according to European regulations and it is therefore
essential that all information derived from emergency calls shall only be used for management of the related incident.
Location information for non-emergency calls is out of scope of the present document.
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10 Final draft ETSI ES 203 178 V1.0.5 (2014-12)
In many circumstances, citizens reporting an incident requiring urgent assistance are unable to provide the emergency
service with accurate information about the location of the emergency. This may be due either due to the nature of the
emergency, the callers' lack of local knowledge, their disabilities or lack of linguistic ability, etc. Young children or
cognitively impaired people may not have the language skills to explain their location, speech and/or hearing impaired
users may not be able to use voice terminals, visually impaired or otherwise disabled people may not be able to use text
terminals, elderly or confused people may not be able to use any form of terminal, etc. For these significantly large
categories of users the successful outcome of an emergency call could make the difference between life and death. It is
therefore essential for the emergency responders to be provided with accurate location information via an automated
process based on the communications network being used by the caller.
Implementation of caller location systems is also likely to result a welcome positive impact on the reduction of
malicious calls made by criminal or anti-social persons when they realize that the automatic provision of their location
information to the emergency services could enable their almost instant apprehension."
The M/493 standardization mandate [i.4] is issued on the basis of the European Regulatory Framework for the
electronic communication networks and services. The Universal Service Directive, Article 26, Paragraph 2 states, that
"Member States . shall ensure that undertakings providing end-users with an electronic communications service for
originating national calls to a number or numbers in a national telephone numbering plan provide access to emergency
services". This includes providing emergency caller location.The service addressed by the Universal Service Directive
includes telephony and any publicly available voice service using E.164 numbers, independently from the specific
network technology (i.e. traditional or VoIP network technologies). The architecture in the present document includes
provisions for the universal service directive obligations as described above and emergency calling using emergency
service URNs.
The scope of the M/493 mandate [i.4] is directly reproduced in annex B.
4.2 Location information descriptions
4.2.1 General
Location information is crucial in emergency calling in determining which PSAP needs to receive the call and also
where to dispatch emergency crews to ensure that help is received where it is needed. The definition clause of the
present document defines three types of location information, a location value, a location identifier and a location
reference. Each of the location information types represents a different kind of information about the caller's location
and each can be used by the emergency call service in a different way.
4.2.2 Location value
A location value describes a physical area in which the caller is likely to be present. This may be a civic location, which
describes some kind of street address, or it may be represented as a geodetic location, which uses latitude, longitude and
uncertainty parameters that result in the defining of an area or volume.
However, a location value that is accurate enough to allow routeing of a call to the correct PSAP may not be good
enough to enable dispatch of responders to provide assistance to those in need. Further discussions on accuracy are
beyond the scope of the present document.
The location value describes where the caller is as a consequence of this a location value needs to be considered private
and only made available to authorized entities.
4.2.3 Location identifier
A location identifier is a datum that is public or semi-public and is used to derive a serving area where the UE is present
or the position of a network termination point to which the UE is attached. The area and prescribed identifier may be
associated with the physical access network, such as a mobile Cell-ID, WiFi AP or line identifier. However, the location
identifier does not have to be tied to an access network termination point, provided that the defined area includes the
termination point to which the UE is attached.
A location value derived from a location identifier can be accurate enough to allow routeing to occur to the correct
PSAP but is often not good enough to allow accurate dispatch or emergency responders to provide assistance to those in
need. Further discussions on accuracy are beyond the scope of the present document.
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11 Final draft ETSI ES 203 178 V1.0.5 (2014-12)
Since a location identifier can be translated into a physical area in which a caller is likely to be they should be used with
care to ensure that the physical location of the caller is not inadvertently provided to an unauthorized entity.
4.2.4 Location reference
A location reference is a key, often a URI, which identifies a location server and provides sufficient information to
allow the location server to provide the location value of the UE. The location reference does not explicitly represent a
physical location, the location is returned when the reference is used allowing a location reference to be accessed
multiple times resulting in location updates being provided. This is not possible with a location value or location
identifier.
Unlike a location value or location identifier, a location reference does not in and of itself contain the location of the
caller. This attribute allows a location reference to be used in a range of network environments as long as suitable
authentication and authorization policies are implemented on the location server.
5 Functional architecture to support European
requirements on emergency caller location
determination and transport
5.1 Overview
The functional architecture to support EC requirements on emergency caller location determination and transport
identifies four service provider roles as represented in figure 5.1:
• Access network provider (ANP);
• Voice service provider (VSP);
• Emergency call service provider (ECSP); and
• PSAP service provider (PSP).
The ANP, ECSP and PSP are in the same regulatory domain. The VSP can be inside or outside this domain.
NOTE: On the basis of the European Regulatory Framework the emergency services provision inside a country is
in charge of its administration; so the term "regulatory domain" typically coincides with a single country.
In some cases a specific agreement can be defined between neighbouring countries to correctly manage
the provision of the emergency services, for example in areas close to the common border.
This architecture is neutral regarding deployment and business models. It defines the functional roles of different
network segments. Multiple roles can be played by a single actor or by multiple actors, each actor managing its own
resources to fulfil a role.
Clause 5.2 specifies the functional requirements to be fulfilled by a service provider when playing these roles.
Clause 5.3 specifies the interfaces used to support communication between these roles and interfaces with user
equipment and PSAPs.
For each interface the functional description is provided in clause 5.3.1, while clause 5.3.2 provides, without going into
the details of the protocols, the description of the information flows that the functional entities need to exchange to
implement the service.
The communication is specified with reference to the functional entities, defined in clause 5.4, that each role needs to
implement and are explicitly evidenced in figure 5.1.
Clause 5.5 finally provides the information flow diagrams needed to implement the service in different conditions, with
reference to the information elements defined in clause 5.3 and without addressing protocol aspects.
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12 Final draft ETSI ES 203 178 V1.0.5 (2014-12)
The architecture covers two methods for transmission of location values to the PSAPs, the push and the pull method:
• In the push method the location values are transmitted via the ii or ij interface as part of the call setup
signalling information or via the ik or im interface directly to the PSAP as soon as the emergency call request
is sent to the PSAP.
• In the pull method the PSAP receives via the ii or ij interface the information required to acquire a location
value from the LS or the LS Proxy via the ik, il or im interface. The request is triggered manually by the PSAP
operator on a case by case basis or automatically in the PSAP entity with every emergency call request
received.
The method, or combination of methods, for getting a location value from the ECSP to a PSAP is decided via prior
agreement between the ECSP and the PSAP authority.
As a general remark, if an interface is internal to an operator (e.g. the "in" interface as presently depicted in figure 5.1),
its functional description does not mandate the implementation of the corresponding protocols, provided this does not
impact on the functionality of the external interfaces.
Anywhere
Country A
Voice Service
Provider Emergency Call
Service Provider
VSP Call
Control
(ECSP)
ESRF
ie (Emergency
Service Routeing
in
Function)
LS
ib
LS
Proxy
Discovery
ig
if
ia
ic
ih ik
Route
PSAP
Server
Service
id
Provider
ESRP (Emergency
Access Network
LS (Location
Service Routeing
Provider im
Server)
Proxy)
ii
ij
il
UE
IP-PSAP
PSTN-PSAP
Emergency
Caller
Figure 5.1: High level Functional Architecture
5.2 Architectural requirements
5.2.1 General
The following technical requirements describe the set of actions performed by the different roles that can be involved in
the provision of an emergency service. It is the responsibility of national Administrations and Governments to decide on
national implementations for emergency services. Specific attention ought to be paid to the roles that have access to
sensitive end user information like caller identity and caller location.
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13 Final draft ETSI ES 203 178 V1.0.5 (2014-12)
5.2.2 ANP - Access Network Provider
The ANP:
ANP-R1) shall provide IP-based connectivity for the UE to the VSP so that an emergency call can be made;
ANP-R2) shall provide location information to the VSP;
ANP-R3) shall provide routeing information to the VSP when routeing information is requested, so that an
emergency call can be delivered to the ECSP;
ANP-R4) shall provide (push or pull) the UE location information to the ECSP;
ANP-R5) shall provide (push or pull) the current UE location information to the PSAP or LS proxy; and
ANP-R6) shall provide information to location server discovery functions such that the ANP can be
contacted using that information.
NOTE: The management of location information requests to an ANP's LS by VSPs presents challenges to an
ANP as there are many VSPs that may make such requests and the ANP needs to protect itself against any
suspicious requests. A method to manage this without requiring VSP authentication is outlined in
annex D.
5.2.3 VSP - Voice Service Provider
The VSP:
VSP-R1) shall determine that the call is to be classified as an emergency call and, if applicable, its
emergency category;
VSP-R2) shall obtain the identity of the ECSP, in the same regulatory domain as the UE, to handle the call
from the UE;
VSP-R3) shall direct the call to the identified ECSP;
VSP-R4) shall obtain the caller location information provided by the ANP;
VSP-R5) shall convey the caller location information to the ECSP; and
VSP-R6) should convey information provided by the UE to the ECSP.
5.2.4 ECSP - Emergency Call Service Provider
The ECSP:
ECSP-R1) shall be capable of receiving emergency calls from a trusted sender (e.g. a VSP or VAP);
NOTE 1: The VAP is defined in annex C.
ECSP-R2) shall obtain location information from the Access Network Provider if location information is not
included in the emergency call request received from the VSP or VAP or additional location
information is required to select the appropriate destination;
ECSP-R3) shall provide interconnection with IP-based PSPs;
ECSP-R4) shall provide call interworking with existing PSP implementations;
ECSP-R5) shall determine the correct PSAP address to which to direct the emergency call;
NOTE 2: The PSAP address determined by the ECSP may identify a PSAP or a group of PSAPs.
NOTE 3: Determination of the PSAP address is based on location and type of emergency, and not on busy/free
status of the individual PSAP identified by the PSAP address.
ECSP-R6) shall direct the emergency call towards the selected PSAP address;
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14 Final draft ETSI ES 203 178 V1.0.5 (2014-12)
ECSP-R7) shall convey the caller location information to the PSAP Service Provider network; and
ECSP-R7) should convey information provided by the UE via the VSP and VAP to the PSAP Service
Provider network.
NOTE 4: Conveyance of information provided in the user plane may not always be possible (e.g. conveyance of
non-voice band data to a circuit-switched PSP network).
5.2.5 PSP - PSAP Service Provider
The PSP:
PSP-R1) shall accept emergency calls from Emergency Call Service Providers;
PSP-R2) shall acquire all information not provided in the call signalling that is necessary for the selection of
the correct PSAP to which to direct the emergency call;
NOTE 1: In some cases the PSP will have been provided all information necessary in order to direct the call to the
PSAP, for example a destination node E.164 number or a location value in the body of a SIP message. In
other cases the PSP will need to acquire information from external sources before it has sufficient
information to determine the correct PSAP, for example if a location value is required to determine the
correct PSAP and the PSP only has a location URI then the PSP acquires the location value using the
location URI prior to the PSAP selection taking place.
PSP-R3) shall, if the call destination provided by the ECSP does not uniquely identify a PSAP, determine
the correct PSAP identifier to which to direct the emergency call;
PSP-R4) shall determine a network access where the identified PSAP is connected;
NOTE 2: In the most simple case the PSP is provided the identity of the desired PSAP by the ECSP. However,
PSAP selection inside the PSP may employ more complex policies for destination selection. Such
policies may be used to avoid congestion or to ensure that the provisions of the emergency caller are
better accommodated. These provisions may include the need for language translation services or indicate
some kind of disability such as hearing or speech.
PSP-R5) shall route the emergency call to the selected network access (determined according
...

ETSI STANDARD
Functional architecture to support European requirements
on emergency caller location determination and transport

2 ETSI ES 203 178 V1.1.1 (2015-02)

Reference
DES/E2NA-00001-M493-stage2
Keywords
emergency, location, VoIP
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3 ETSI ES 203 178 V1.1.1 (2015-02)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 6
3 Definitions and abbreviations . 7
3.1 Definitions . 7
3.2 Abbreviations . 9
4 Descriptions and assumptions . 9
4.1 Introduction . 9
4.2 Location information descriptions . 10
4.2.1 General . 10
4.2.2 Location value . 10
4.2.3 Location identifier. 10
4.2.4 Location reference . 11
5 Functional architecture to support European requirements on emergency caller location
determination and transport . 11
5.1 Overview . 11
5.2 Architectural requirements . 12
5.2.1 General . 12
5.2.2 ANP - Access Network Provider . 13
5.2.3 VSP - Voice Service Provider. 13
5.2.4 ECSP - Emergency Call Service Provider . 13
5.2.5 PSP - PSAP Service Provider . 14
5.3 Interfaces . 14
5.3.1 Interface definitions . 14
5.3.2 Information flows . 16
5.3.2.1 ia interface . 16
5.3.2.2 ib interface. 17
5.3.2.3 ic interface . 17
5.3.2.4 id interface. 18
5.3.2.5 ie interface . 18
5.3.2.6 if interface . 18
5.3.2.7 ig interface. 19
5.3.2.8 ih interface. 19
5.3.2.9 ii interface . 20
5.3.2.10 ij interface . 21
5.3.2.11 ik interface. 22
5.3.2.12 il interface . 22
5.3.2.13 im interface . 23
5.3.2.14 in interface. 23
5.4 Functional entities . 24
5.4.1 ANP . 24
5.4.1.1 Location Server (LS) . 24
5.4.2 VSP . 25
5.4.2.1 VSP Call Control . 25
5.4.3 ECSP . 26
5.4.3.1 ESRF . 26
5.4.3.2 LS Proxy . 26
5.4.3.3 Other entities . 26
5.4.4 PSAP Service Provider . 27
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4 ETSI ES 203 178 V1.1.1 (2015-02)
5.4.4.1 Emergency Service Routeing Proxy. 27
5.4.4.2 Route Server . 27
5.4.4.3 Other entities . 27
5.4.5 other functional entities . 28
5.4.5.1 Location Server Discovery Function . 28
5.4.5.2 User Equipment . 28
5.4.5.3 IP-PSAP . 28
5.4.5.4 PSTN-PSAP . 28
5.5 Information flow diagrams . 29
5.5.1 Introduction. 29
5.5.2 ANP provides a location value . 29
5.5.3 ANP provides location reference to the VSP and the ECSP pulls location value . 31
5.5.4 ANP provides to the VSP a location identifier . 32
5.5.5 ANP provides location identifier to the VSP and the PSAP pulls location value . 34
5.6 Extension of the Functional Architecture for Networks with VPN, NAT/PAT and other components
which change Packet Flow Identity . 35
5.7 Extension of the Functional Architecture to support VSP Aggregation Providers . 35
6 Protocol and other requirements . 36
6.1 Generic requirements . 36
6.2 Trust relationships . 36
Annex A (normative): Extension of the Functional Architecture for Networks with VPN,
NAT/PAT and other components which change Packet Flow Identity . 37
A.1 General . 37
A.2 LS chaining solution . 37
A.2.1 Location chaining interface impacts . 39
A.3 HOST_ID solution . 39
Annex B (informative): M/493 Scope . 43
Annex C (normative): Extension of the Functional Architecture to support an aggregating
VSP . 44
C.1 General . 44
C.2 Architectual requirements for VSP Aggregation Provider (VAP) . 44
C.3 Extended Interface definition . 45
C.4 VSP Aggregating Entity . 45
Annex D (informative): Avoiding authentication between the VSP and the ANP. 46
History . 48

ETSI
5 ETSI ES 203 178 V1.1.1 (2015-02)
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://ipr.etsi.org).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. 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 ETSI Standard (ES) has been produced by ETSI Project End-to-End Network Architectures (E2NA).
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI
6 ETSI ES 203 178 V1.1.1 (2015-02)
1 Scope
The present document describes the unified functional architecture to support requirements as outlined in European
Commission (EC) mandate M/493 [i.4] on emergency caller location determination and transport, in particular for the
case where the VoIP service provider and one or several network operators - all serving the customer in the
establishment of an emergency call - are independent enterprises needing to co-operate to determine the location of the
(nomadic) caller. The architecture identifies all necessary interfaces, which are needed to fulfil the requirements
outlined in EC Mandate M/493 [i.4], and provides a basis for the specification of the protocols to be used on those
interfaces.
The present document is applicable to both NGN and pre-NGN IP-based networks. The architecture defined in the
present document is intended to be compatible with IMS-based deployments but does not require compliance to IMS
specifications.
This architecture does not intend to replace existing deployed solutions. It should enable operators and undertakings
providing services to realize transmission of location information to the Public Safety Answering Point.
2 References
2.1 Normative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are necessary for the application of the present document.
Not applicable.
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI TS 123 167: "Universal Mobile Telecommunications System (UMTS); LTE; IP Multimedia
Subsystem (IMS) emergency sessions (3GPP TS 23.167)".
[i.2] IETF RFC 6967: "Analysis of Potential Solutions for Revealing a Host Identifier (HOST-ID) in
Shared Address Deployments".
[i.3] Draft-boucadair-intarea-host-identifier-scenarios-03 (March 2013): "Host Identification: Use
Cases".
[i.4] M/493: "Standardisation Mandate to the European Standards Organisations (ESO) in support of
the location enhanced emergency call service".
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7 ETSI ES 203 178 V1.1.1 (2015-02)
[i.5] IETF RFC 6753: "A Location Dereference Protocol Using HTTP-Enabled Location Delivery
(HELD)".
[i.6] ETSI TS 102 181: "Emergency Communications (EMTEL); Requirements for communication
between authorities/organizations during emergencies".
[i.7] ETSI TS 102 650: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); Analysis of Location Information Standards produced by
various SDOs".
[i.8] Directive 2002/22/EC of the European Parliament and of the Council of 7 March 2002 on
universal service and users' rights relating to electronic communications networks and services
(Universal Service Directive).
[i.9] Commission Recommendation 2003/558/EC of 25 July 2003 on the processing of caller location
information in electronic communication networks for the purpose of location-enhanced
emergency call services (notified under document number C(2003)2657).
[i.10] IETF RFC 5222: "LoST: A Location-to-Service Translation Protocol".
[i.11] IETF RFC 4848: "Domain-Based Application Service Location Using URIs and the Dynamic
Delegation Discovery Service (DDDS)".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
access network: portion of the telecommunications network that provides access to the switching function and
terminates the user access signalling
Access Network Provider (ANP): service provider that provides physical and IP connectivity to a user equipment
(UE) via a fixed or mobile access
NOTE: The access network may be provided by a single organization or it may be provided by a number of
different organizations, BUT the interfaces between these organizations are not relevant to the scope of
the present document as it is matter of contractual relations between the parties.
emergency: urgent need for assistance or relief
emergency call: call from a user to an emergency call centre, PSAP or similar agency charged with routeing calls to the
relevant emergency response organization
emergency call facilities: mechanisms provided by public or private communications networks, emergency telephone
stanchions/boxes, fire alarms, etc. the use of which enables emergency calls to be made
Emergency Call Service Provider (ECSP): service provider that acts as a mediator between the voice service
providers and the public safety answering point service providers
emergency caller: individual placing an emergency call to reach the suitable PSAP
emergency response organization: local or national force established to provide assistance to citizens in the event of
their being involved in an emergency situation and requiring specialized help, for example, the police, fire service and
emergency medical services
emergency service: service that provides immediate and rapid assistance in situations where there is a direct risk to life
or limb, individual or public health or safety, to private or public property, or the environment but not necessarily
limited to these situations
emergency situation: abnormal situation of serious nature that develops suddenly and unexpectedly, of which the
evolution is uncertain and which may turn into a crisis or cause damage and casualties
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8 ETSI ES 203 178 V1.1.1 (2015-02)
FlowChanger: device in an IP flow, which changes the packet flow identity, for example changing the IP address
and/or port, so the UE can no longer be identified in the original access network
location identifier: public network identifier, which provides a location value
EXAMPLE: A cell ID or line ID (see ETSI TS 123 167 [i.1]).
NOTE: A location value can be obtained from a location identifier by applying a static mapping or the location
identifier may be encoded in such a way that it contains a location value (e.g. a ZIP code).
location information: location value, and/or a location identifier and/or a location reference
location reference: identifies a location server and provides sufficient information to allow the location server to
provide the location value for the UE
EXAMPLE: https://ls.example.com:49152/uri/w3g61nf5n66p0, IETF RFC 6753 [i.5].
location value: civic or geodetic position
network-provided location information: any location information pertaining to the calling device that is determined,
provided or verified by the ANP
Next Generation Network (NGN): packet-based network able to provide telecommunication services and able to
make use of multiple broadband, QoS-enabled transport technologies and in which service-related functions are
independent from underlying transport-related technologies
nomadic: having the ability to move across network access points
NOTE: A nomadic user can make calls from different locations. However, unlike a mobile user, the location of a
nomadic user cannot change during a specific call.
originating network: access network in which the emergency call was placed
packet flow identity: all network parameters, which unambiguously identify a IP flow
PSAP address: URI or an E.164 number identifying a PSAP or a group of PSAPs
PSAP Service Provider: service provider that provides connectivity to Public Safety Answering Points (PSAPs) and
directs emergency calls from the ECSP to the PSAP
Public Safety Answering Point (PSAP): physical location where emergency calls are received under the responsibility
of a public authority
NOTE: See Commission Recommendation C(2003)2657 [i.9] and ETSI TS 102 181 [i.6].
regulatory domain: geographical area where a set of regulatory rules applies
telecommunication: any transmission, emission, or reception of signs, signals, writing, images, sounds or intelligence
of any nature, by wire, radio, optical fibre or other electromagnetic system
user access: point of connection to a telecommunication network from which a call can be placed
NOTE: This includes public telephones and "emergency call facilities".
user equipment: device allowing a user access to network services
user-provided location information: any location information originating from user-equipment that is not
independently verified by the ANP
Voice Service Provider (VSP): specific type of application service provider that provides voice related services and
optionally text and video-related services, on IP
VSP Aggregation Provider (VAP): provider that a VSP or group of VSPs can use to support call routing to remote
ECSPs and for the generation of related call data records
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9 ETSI ES 203 178 V1.1.1 (2015-02)
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ANP Access Network Provider
AP Access Point
CGN Carrier Grade NAT
DHCP Dynamic Host Configuration Protocol
DNS Domain Name Server
EC European Commission
ECSP Emergency Call Service Provider
ESO European Standards Organization
ESRF Emergency Service Routing Function
ESRP Emergency Service Routeing Proxy
ETSI European Telecommunications Standards Institute
FID Flow Identity
th
FID-N N Flow Identity
FQDN Fully Qualified Domain Name
IETF Internet Engineering Task Force
IMS IP Multimedia Subsystem
IP Internet Protocol
ISDN Integrated Services Digital Network
LS Location Server
th
LS-N N Location Server
NAPTR Naming Authority Pointer
NAT Network Address Translation
NGN Next Generation Network
PAT Port and Address Translation
PBX Private Branch Exchange
PCRF Policy and Charging Rules Function
PSAP Public Safety Answering Point
PSP PSAP Service Provider
PSTN Public Switched Telephone Network
RFC Request For Comment
SIP Session Initiation Protocol
TCP Transmission Control Protocol
UDP User Datagram Protocol
UE User Equipment
URI Uniform Resource Identifier
VAE VSP Aggregating Entity
VAP VSP Aggegation Provider
VoIP Voice over Internet Protocol
VPN Virtual Private Network
VSP Voice Service Provider
4 Descriptions and assumptions
4.1 Introduction
ETSI TS 102 650 [i.7] states that:
"In order to effectively deliver emergency services to the location of a reported incident, it is essential for the
emergency response organization to have timely and accurate information that enables them to correctly identify the
location of the incident.
The ability to initiate an emergency communication to summon help when needed is regarded by the European
Commission as a right of all citizens and this ability should ideally be independent of the network and access
technologies deployed or the physical abilities of the citizen.
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10 ETSI ES 203 178 V1.1.1 (2015-02)
The rights of individual users to privacy shall be adhered to according to European regulations and it is therefore
essential that all information derived from emergency calls shall only be used for management of the related incident.
Location information for non-emergency calls is out of scope of the present document.
In many circumstances, citizens reporting an incident requiring urgent assistance are unable to provide the emergency
service with accurate information about the location of the emergency. This may be due either due to the nature of the
emergency, the callers' lack of local knowledge, their disabilities or lack of linguistic ability, etc. Young children or
cognitively impaired people may not have the language skills to explain their location, speech and/or hearing impaired
users may not be able to use voice terminals, visually impaired or otherwise disabled people may not be able to use text
terminals, elderly or confused people may not be able to use any form of terminal, etc. For these significantly large
categories of users the successful outcome of an emergency call could make the difference between life and death. It is
therefore essential for the emergency responders to be provided with accurate location information via an automated
process based on the communications network being used by the caller.
Implementation of caller location systems is also likely to result a welcome positive impact on the reduction of
malicious calls made by criminal or anti-social persons when they realize that the automatic provision of their location
information to the emergency services could enable their almost instant apprehension."
The M/493 standardization mandate [i.4] is issued on the basis of the European Regulatory Framework for the
electronic communication networks and services. The Universal Service Directive, Article 26, Paragraph 2 states, that
"Member States . shall ensure that undertakings providing end-users with an electronic communications service for
originating national calls to a number or numbers in a national telephone numbering plan provide access to emergency
services". This includes providing emergency caller location.The service addressed by the Universal Service Directive
includes telephony and any publicly available voice service using E.164 numbers, independently from the specific
network technology (i.e. traditional or VoIP network technologies). The architecture in the present document includes
provisions for the universal service directive obligations as described above and emergency calling using emergency
service URNs.
The scope of the M/493 mandate [i.4] is directly reproduced in annex B.
4.2 Location information descriptions
4.2.1 General
Location information is crucial in emergency calling in determining which PSAP needs to receive the call and also
where to dispatch emergency crews to ensure that help is received where it is needed. The definition clause of the
present document defines three types of location information, a location value, a location identifier and a location
reference. Each of the location information types represents a different kind of information about the caller's location
and each can be used by the emergency call service in a different way.
4.2.2 Location value
A location value describes a physical area in which the caller is likely to be present. This may be a civic location, which
describes some kind of street address, or it may be represented as a geodetic location, which uses latitude, longitude and
uncertainty parameters that result in the defining of an area or volume.
However, a location value that is accurate enough to allow routeing of a call to the correct PSAP may not be good
enough to enable dispatch of responders to provide assistance to those in need. Further discussions on accuracy are
beyond the scope of the present document.
The location value describes where the caller is as a consequence of this a location value needs to be considered private
and only made available to authorized entities.
4.2.3 Location identifier
A location identifier is a datum that is public or semi-public and is used to derive a serving area where the UE is present
or the position of a network termination point to which the UE is attached. The area and prescribed identifier may be
associated with the physical access network, such as a mobile Cell-ID, WiFi AP or line identifier. However, the location
identifier does not have to be tied to an access network termination point, provided that the defined area includes the
termination point to which the UE is attached.
ETSI
11 ETSI ES 203 178 V1.1.1 (2015-02)
A location value derived from a location identifier can be accurate enough to allow routeing to occur to the correct
PSAP but is often not good enough to allow accurate dispatch or emergency responders to provide assistance to those in
need. Further discussions on accuracy are beyond the scope of the present document.
Since a location identifier can be translated into a physical area in which a caller is likely to be they should be used with
care to ensure that the physical location of the caller is not inadvertently provided to an unauthorized entity.
4.2.4 Location reference
A location reference is a key, often a URI, which identifies a location server and provides sufficient information to
allow the location server to provide the location value of the UE. The location reference does not explicitly represent a
physical location, the location is returned when the reference is used allowing a location reference to be accessed
multiple times resulting in location updates being provided. This is not possible with a location value or location
identifier.
Unlike a location value or location identifier, a location reference does not in and of itself contain the location of the
caller. This attribute allows a location reference to be used in a range of network environments as long as suitable
authentication and authorization policies are implemented on the location server.
5 Functional architecture to support European
requirements on emergency caller location
determination and transport
5.1 Overview
The functional architecture to support EC requirements on emergency caller location determination and transport
identifies four service provider roles as represented in figure 5.1:
• Access network provider (ANP);
• Voice service provider (VSP);
• Emergency call service provider (ECSP); and
• PSAP service provider (PSP).
The ANP, ECSP and PSP are in the same regulatory domain. The VSP can be inside or outside this domain.
NOTE: On the basis of the European Regulatory Framework the emergency services provision inside a country is
in charge of its administration; so the term "regulatory domain" typically coincides with a single country.
In some cases a specific agreement can be defined between neighbouring countries to correctly manage
the provision of the emergency services, for example in areas close to the common border.
This architecture is neutral regarding deployment and business models. It defines the functional roles of different
network segments. Multiple roles can be played by a single actor or by multiple actors, each actor managing its own
resources to fulfil a role.
Clause 5.2 specifies the functional requirements to be fulfilled by a service provider when playing these roles.
Clause 5.3 specifies the interfaces used to support communication between these roles and interfaces with user
equipment and PSAPs.
For each interface the functional description is provided in clause 5.3.1, while clause 5.3.2 provides, without going into
the details of the protocols, the description of the information flows that the functional entities need to exchange to
implement the service.
The communication is specified with reference to the functional entities, defined in clause 5.4, that each role needs to
implement and are explicitly evidenced in figure 5.1.
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12 ETSI ES 203 178 V1.1.1 (2015-02)
Clause 5.5 finally provides the information flow diagrams needed to implement the service in different conditions, with
reference to the information elements defined in clause 5.3 and without addressing protocol aspects.
The architecture covers two methods for transmission of location values to the PSAPs, the push and the pull method:
• In the push method the location values are transmitted via the ii or ij interface as part of the call setup
signalling information or via the ik or im interface directly to the PSAP as soon as the emergency call request
is sent to the PSAP.
• In the pull method the PSAP receives via the ii or ij interface the information required to acquire a location
value from the LS or the LS Proxy via the ik, il or im interface. The request is triggered manually by the PSAP
operator on a case by case basis or automatically in the PSAP entity with every emergency call request
received.
The method, or combination of methods, for getting a location value from the ECSP to a PSAP is decided via prior
agreement between the ECSP and the PSAP authority.
As a general remark, if an interface is internal to an operator (e.g. the "in" interface as presently depicted in figure 5.1),
its functional description does not mandate the implementation of the corresponding protocols, provided this does not
impact on the functionality of the external interfaces.
Anywhere
Country A
Voice Service
Provider
Emergency Call
Service Provider
VSP Call
Control
(ECSP)
ESRF
ie (Emergency
Service Routeing
in
Function)
LS
ib
LS
Proxy
Discovery
ig
if
ia
ic
ih ik
Route
PSAP
Server
Service
id
Provider
ESRP (Emergency
Access Network
LS (Location
Service Routeing
Provider im
Server)
Proxy)
ii
ij
il
UE
IP-PSAP
PSTN-PSAP
Emergency
Caller
Figure 5.1: High level Functional Architecture
5.2 Architectural requirements
5.2.1 General
The following technical requirements describe the set of actions performed by the different roles that can be involved in
the provision of an emergency service. It is the responsibility of national Administrations and Governments to decide on
national implementations for emergency services. Specific attention ought to be paid to the roles that have access to
sensitive end user information like caller identity and caller location.
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13 ETSI ES 203 178 V1.1.1 (2015-02)
5.2.2 ANP - Access Network Provider
The ANP:
ANP-R1) shall provide IP-based connectivity for the UE to the VSP so that an emergency call can be made;
ANP-R2) shall provide location information to the VSP;
ANP-R3) shall provide routeing information to the VSP when routeing information is requested, so that an
emergency call can be delivered to the ECSP;
ANP-R4) shall provide (push or pull) the UE location information to the ECSP;
ANP-R5) shall provide (push or pull) the current UE location information to the PSAP or LS proxy; and
ANP-R6) shall provide information to location server discovery functions such that the ANP can be
contacted using that information.
NOTE: The management of location information requests to an ANP's LS by VSPs presents challenges to an
ANP as there are many VSPs that may make such requests and the ANP needs to protect itself against any
suspicious requests. A method to manage this without requiring VSP authentication is outlined in
annex D.
5.2.3 VSP - Voice Service Provider
The VSP:
VSP-R1) shall determine that the call is to be classified as an emergency call and, if applicable, its
emergency category;
VSP-R2) shall obtain the identity of the ECSP, in the same regulatory domain as the UE, to handle the call
from the UE;
VSP-R3) shall direct the call to the identified ECSP;
VSP-R4) shall obtain the caller location information provided by the ANP;
VSP-R5) shall convey the caller location information to the ECSP; and
VSP-R6) should convey information provided by the UE to the ECSP.
5.2.4 ECSP - Emergency Call Service Provider
The ECSP:
ECSP-R1) shall be capable of receiving emergency calls from a trusted sender (e.g. a VSP or VAP);
NOTE 1: The VAP is defined in annex C.
ECSP-R2) shall obtain location information from the Access Network Provider if location information is not
included in the emergency call request received from the VSP or VAP or additional location
information is required to select the appropriate destination;
ECSP-R3) shall provide interconnection with IP-based PSPs;
ECSP-R4) shall provide call interworking with existing PSP implementations;
ECSP-R5) shall determine the correct PSAP address to which to direct the emergency call;
NOTE 2: The PSAP address determined by the ECSP may identify a PSAP or a group of PSAPs.
NOTE 3: Determination of the PSAP address is based on location and type of emergency, and not on busy/free
status of the individual PSAP identified by the PSAP address.
ECSP-R6) shall direct the emergency call towards the selected PSAP address;
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14 ETSI ES 203 178 V1.1.1 (2015-02)
ECSP-R7) shall convey the caller location information to the PSAP Service Provider network; and
ECSP-R8) should convey information provided by the UE via the VSP and VAP to the PSAP Service
Provider network.
NOTE 4: Conveyance of information provided in the user plane may not always be possible (e.g. conveyance of
non-voice band data to a circuit-switched PSP network).
5.2.5 PSP - PSAP Service Provider
The PSP:
PSP-R1) shall accept emergency calls from Emergency Call Service Providers;
PSP-R2) shall acquire all information not provided in the call signalling that is necessary for the selection of
the correct PSAP to which to direct the emergency call;
NOTE 1: In some cases the PSP will have been provided all information necessary in order to direct the call to the
PSAP, for example a destination node E.164 number or a location value in the body of a SIP message. In
other cases the PSP will need to acquire information from external sources before it has sufficient
information to determine the correct PSAP, for example if a location value is required to determine the
correct PSAP and the PSP only has a location URI then the PSP acquires the location value using the
location URI prior to the PSAP selection taking place.
PSP-R3) shall, if the call destination provided by the ECSP does not uniquely identify a PSAP, determine
the correct PSAP identifier to which to direct the emergency call;
PSP-R4) shall determine a network access where the identified PSAP is connected;
NOTE 2: In the most simple case the PSP is provided the identity of the desired PSAP by the ECSP. However,
PSAP selection inside the PSP may employ more complex policies for destination selection. Such
policies may be used to avoid congestion or to ensure that the provisions of the emergency caller are
better accommodated. These provisions may include the
...

SLOVENSKI STANDARD
01-oktober-2015
)XQNFLMVNDDUKLWHNWXUDHYURSVNLKGRORþE]DXJRWDYOMDQMHNUDMDNOLFDWHOMDYVLOLLQ]D
WUDQVSRUW
Functional architecture to support European requirements on emergency caller location
determination and transport
Ta slovenski standard je istoveten z: ES 203 178 V1.1.1
ICS:
33.030 Telekomunikacijske Telecommunication services.
uporabniške rešitve Applications
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

ETSI STANDARD
Functional architecture to support European requirements
on emergency caller location determination and transport

2 ETSI ES 203 178 V1.1.1 (2015-02)

Reference
DES/E2NA-00001-M493-stage2
Keywords
emergency, location, VoIP
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3 ETSI ES 203 178 V1.1.1 (2015-02)
Contents
Intellectual Property Rights . 5
Foreword . 5
Modal verbs terminology . 5
1 Scope . 6
2 References . 6
2.1 Normative references . 6
2.2 Informative references . 6
3 Definitions and abbreviations . 7
3.1 Definitions . 7
3.2 Abbreviations . 9
4 Descriptions and assumptions . 9
4.1 Introduction . 9
4.2 Location information descriptions . 10
4.2.1 General . 10
4.2.2 Location value . 10
4.2.3 Location identifier. 10
4.2.4 Location reference . 11
5 Functional architecture to support European requirements on emergency caller location
determination and transport . 11
5.1 Overview . 11
5.2 Architectural requirements . 12
5.2.1 General . 12
5.2.2 ANP - Access Network Provider . 13
5.2.3 VSP - Voice Service Provider. 13
5.2.4 ECSP - Emergency Call Service Provider . 13
5.2.5 PSP - PSAP Service Provider . 14
5.3 Interfaces . 14
5.3.1 Interface definitions . 14
5.3.2 Information flows . 16
5.3.2.1 ia interface . 16
5.3.2.2 ib interface. 17
5.3.2.3 ic interface . 17
5.3.2.4 id interface. 18
5.3.2.5 ie interface . 18
5.3.2.6 if interface . 18
5.3.2.7 ig interface. 19
5.3.2.8 ih interface. 19
5.3.2.9 ii interface . 20
5.3.2.10 ij interface . 21
5.3.2.11 ik interface. 22
5.3.2.12 il interface . 22
5.3.2.13 im interface . 23
5.3.2.14 in interface. 23
5.4 Functional entities . 24
5.4.1 ANP . 24
5.4.1.1 Location Server (LS) . 24
5.4.2 VSP . 25
5.4.2.1 VSP Call Control . 25
5.4.3 ECSP . 26
5.4.3.1 ESRF . 26
5.4.3.2 LS Proxy . 26
5.4.3.3 Other entities . 26
5.4.4 PSAP Service Provider . 27
ETSI
4 ETSI ES 203 178 V1.1.1 (2015-02)
5.4.4.1 Emergency Service Routeing Proxy. 27
5.4.4.2 Route Server . 27
5.4.4.3 Other entities . 27
5.4.5 other functional entities . 28
5.4.5.1 Location Server Discovery Function . 28
5.4.5.2 User Equipment . 28
5.4.5.3 IP-PSAP . 28
5.4.5.4 PSTN-PSAP . 28
5.5 Information flow diagrams . 29
5.5.1 Introduction. 29
5.5.2 ANP provides a location value . 29
5.5.3 ANP provides location reference to the VSP and the ECSP pulls location value . 31
5.5.4 ANP provides to the VSP a location identifier . 32
5.5.5 ANP provides location identifier to the VSP and the PSAP pulls location value . 34
5.6 Extension of the Functional Architecture for Networks with VPN, NAT/PAT and other components
which change Packet Flow Identity . 35
5.7 Extension of the Functional Architecture to support VSP Aggregation Providers . 35
6 Protocol and other requirements . 36
6.1 Generic requirements . 36
6.2 Trust relationships . 36
Annex A (normative): Extension of the Functional Architecture for Networks with VPN,
NAT/PAT and other components which change Packet Flow Identity . 37
A.1 General . 37
A.2 LS chaining solution . 37
A.2.1 Location chaining interface impacts . 39
A.3 HOST_ID solution . 39
Annex B (informative): M/493 Scope . 43
Annex C (normative): Extension of the Functional Architecture to support an aggregating
VSP . 44
C.1 General . 44
C.2 Architectual requirements for VSP Aggregation Provider (VAP) . 44
C.3 Extended Interface definition . 45
C.4 VSP Aggregating Entity . 45
Annex D (informative): Avoiding authentication between the VSP and the ANP. 46
History . 48

ETSI
5 ETSI ES 203 178 V1.1.1 (2015-02)
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://ipr.etsi.org).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. 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 ETSI Standard (ES) has been produced by ETSI Project End-to-End Network Architectures (E2NA).
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI
6 ETSI ES 203 178 V1.1.1 (2015-02)
1 Scope
The present document describes the unified functional architecture to support requirements as outlined in European
Commission (EC) mandate M/493 [i.4] on emergency caller location determination and transport, in particular for the
case where the VoIP service provider and one or several network operators - all serving the customer in the
establishment of an emergency call - are independent enterprises needing to co-operate to determine the location of the
(nomadic) caller. The architecture identifies all necessary interfaces, which are needed to fulfil the requirements
outlined in EC Mandate M/493 [i.4], and provides a basis for the specification of the protocols to be used on those
interfaces.
The present document is applicable to both NGN and pre-NGN IP-based networks. The architecture defined in the
present document is intended to be compatible with IMS-based deployments but does not require compliance to IMS
specifications.
This architecture does not intend to replace existing deployed solutions. It should enable operators and undertakings
providing services to realize transmission of location information to the Public Safety Answering Point.
2 References
2.1 Normative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are necessary for the application of the present document.
Not applicable.
2.2 Informative references
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
reference document (including any amendments) applies.
NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee
their long term validity.
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI TS 123 167: "Universal Mobile Telecommunications System (UMTS); LTE; IP Multimedia
Subsystem (IMS) emergency sessions (3GPP TS 23.167)".
[i.2] IETF RFC 6967: "Analysis of Potential Solutions for Revealing a Host Identifier (HOST-ID) in
Shared Address Deployments".
[i.3] Draft-boucadair-intarea-host-identifier-scenarios-03 (March 2013): "Host Identification: Use
Cases".
[i.4] M/493: "Standardisation Mandate to the European Standards Organisations (ESO) in support of
the location enhanced emergency call service".
ETSI
7 ETSI ES 203 178 V1.1.1 (2015-02)
[i.5] IETF RFC 6753: "A Location Dereference Protocol Using HTTP-Enabled Location Delivery
(HELD)".
[i.6] ETSI TS 102 181: "Emergency Communications (EMTEL); Requirements for communication
between authorities/organizations during emergencies".
[i.7] ETSI TS 102 650: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); Analysis of Location Information Standards produced by
various SDOs".
[i.8] Directive 2002/22/EC of the European Parliament and of the Council of 7 March 2002 on
universal service and users' rights relating to electronic communications networks and services
(Universal Service Directive).
[i.9] Commission Recommendation 2003/558/EC of 25 July 2003 on the processing of caller location
information in electronic communication networks for the purpose of location-enhanced
emergency call services (notified under document number C(2003)2657).
[i.10] IETF RFC 5222: "LoST: A Location-to-Service Translation Protocol".
[i.11] IETF RFC 4848: "Domain-Based Application Service Location Using URIs and the Dynamic
Delegation Discovery Service (DDDS)".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
access network: portion of the telecommunications network that provides access to the switching function and
terminates the user access signalling
Access Network Provider (ANP): service provider that provides physical and IP connectivity to a user equipment
(UE) via a fixed or mobile access
NOTE: The access network may be provided by a single organization or it may be provided by a number of
different organizations, BUT the interfaces between these organizations are not relevant to the scope of
the present document as it is matter of contractual relations between the parties.
emergency: urgent need for assistance or relief
emergency call: call from a user to an emergency call centre, PSAP or similar agency charged with routeing calls to the
relevant emergency response organization
emergency call facilities: mechanisms provided by public or private communications networks, emergency telephone
stanchions/boxes, fire alarms, etc. the use of which enables emergency calls to be made
Emergency Call Service Provider (ECSP): service provider that acts as a mediator between the voice service
providers and the public safety answering point service providers
emergency caller: individual placing an emergency call to reach the suitable PSAP
emergency response organization: local or national force established to provide assistance to citizens in the event of
their being involved in an emergency situation and requiring specialized help, for example, the police, fire service and
emergency medical services
emergency service: service that provides immediate and rapid assistance in situations where there is a direct risk to life
or limb, individual or public health or safety, to private or public property, or the environment but not necessarily
limited to these situations
emergency situation: abnormal situation of serious nature that develops suddenly and unexpectedly, of which the
evolution is uncertain and which may turn into a crisis or cause damage and casualties
ETSI
8 ETSI ES 203 178 V1.1.1 (2015-02)
FlowChanger: device in an IP flow, which changes the packet flow identity, for example changing the IP address
and/or port, so the UE can no longer be identified in the original access network
location identifier: public network identifier, which provides a location value
EXAMPLE: A cell ID or line ID (see ETSI TS 123 167 [i.1]).
NOTE: A location value can be obtained from a location identifier by applying a static mapping or the location
identifier may be encoded in such a way that it contains a location value (e.g. a ZIP code).
location information: location value, and/or a location identifier and/or a location reference
location reference: identifies a location server and provides sufficient information to allow the location server to
provide the location value for the UE
EXAMPLE: https://ls.example.com:49152/uri/w3g61nf5n66p0, IETF RFC 6753 [i.5].
location value: civic or geodetic position
network-provided location information: any location information pertaining to the calling device that is determined,
provided or verified by the ANP
Next Generation Network (NGN): packet-based network able to provide telecommunication services and able to
make use of multiple broadband, QoS-enabled transport technologies and in which service-related functions are
independent from underlying transport-related technologies
nomadic: having the ability to move across network access points
NOTE: A nomadic user can make calls from different locations. However, unlike a mobile user, the location of a
nomadic user cannot change during a specific call.
originating network: access network in which the emergency call was placed
packet flow identity: all network parameters, which unambiguously identify a IP flow
PSAP address: URI or an E.164 number identifying a PSAP or a group of PSAPs
PSAP Service Provider: service provider that provides connectivity to Public Safety Answering Points (PSAPs) and
directs emergency calls from the ECSP to the PSAP
Public Safety Answering Point (PSAP): physical location where emergency calls are received under the responsibility
of a public authority
NOTE: See Commission Recommendation C(2003)2657 [i.9] and ETSI TS 102 181 [i.6].
regulatory domain: geographical area where a set of regulatory rules applies
telecommunication: any transmission, emission, or reception of signs, signals, writing, images, sounds or intelligence
of any nature, by wire, radio, optical fibre or other electromagnetic system
user access: point of connection to a telecommunication network from which a call can be placed
NOTE: This includes public telephones and "emergency call facilities".
user equipment: device allowing a user access to network services
user-provided location information: any location information originating from user-equipment that is not
independently verified by the ANP
Voice Service Provider (VSP): specific type of application service provider that provides voice related services and
optionally text and video-related services, on IP
VSP Aggregation Provider (VAP): provider that a VSP or group of VSPs can use to support call routing to remote
ECSPs and for the generation of related call data records
ETSI
9 ETSI ES 203 178 V1.1.1 (2015-02)
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ANP Access Network Provider
AP Access Point
CGN Carrier Grade NAT
DHCP Dynamic Host Configuration Protocol
DNS Domain Name Server
EC European Commission
ECSP Emergency Call Service Provider
ESO European Standards Organization
ESRF Emergency Service Routing Function
ESRP Emergency Service Routeing Proxy
ETSI European Telecommunications Standards Institute
FID Flow Identity
th
FID-N N Flow Identity
FQDN Fully Qualified Domain Name
IETF Internet Engineering Task Force
IMS IP Multimedia Subsystem
IP Internet Protocol
ISDN Integrated Services Digital Network
LS Location Server
th
LS-N N Location Server
NAPTR Naming Authority Pointer
NAT Network Address Translation
NGN Next Generation Network
PAT Port and Address Translation
PBX Private Branch Exchange
PCRF Policy and Charging Rules Function
PSAP Public Safety Answering Point
PSP PSAP Service Provider
PSTN Public Switched Telephone Network
RFC Request For Comment
SIP Session Initiation Protocol
TCP Transmission Control Protocol
UDP User Datagram Protocol
UE User Equipment
URI Uniform Resource Identifier
VAE VSP Aggregating Entity
VAP VSP Aggegation Provider
VoIP Voice over Internet Protocol
VPN Virtual Private Network
VSP Voice Service Provider
4 Descriptions and assumptions
4.1 Introduction
ETSI TS 102 650 [i.7] states that:
"In order to effectively deliver emergency services to the location of a reported incident, it is essential for the
emergency response organization to have timely and accurate information that enables them to correctly identify the
location of the incident.
The ability to initiate an emergency communication to summon help when needed is regarded by the European
Commission as a right of all citizens and this ability should ideally be independent of the network and access
technologies deployed or the physical abilities of the citizen.
ETSI
10 ETSI ES 203 178 V1.1.1 (2015-02)
The rights of individual users to privacy shall be adhered to according to European regulations and it is therefore
essential that all information derived from emergency calls shall only be used for management of the related incident.
Location information for non-emergency calls is out of scope of the present document.
In many circumstances, citizens reporting an incident requiring urgent assistance are unable to provide the emergency
service with accurate information about the location of the emergency. This may be due either due to the nature of the
emergency, the callers' lack of local knowledge, their disabilities or lack of linguistic ability, etc. Young children or
cognitively impaired people may not have the language skills to explain their location, speech and/or hearing impaired
users may not be able to use voice terminals, visually impaired or otherwise disabled people may not be able to use text
terminals, elderly or confused people may not be able to use any form of terminal, etc. For these significantly large
categories of users the successful outcome of an emergency call could make the difference between life and death. It is
therefore essential for the emergency responders to be provided with accurate location information via an automated
process based on the communications network being used by the caller.
Implementation of caller location systems is also likely to result a welcome positive impact on the reduction of
malicious calls made by criminal or anti-social persons when they realize that the automatic provision of their location
information to the emergency services could enable their almost instant apprehension."
The M/493 standardization mandate [i.4] is issued on the basis of the European Regulatory Framework for the
electronic communication networks and services. The Universal Service Directive, Article 26, Paragraph 2 states, that
"Member States . shall ensure that undertakings providing end-users with an electronic communications service for
originating national calls to a number or numbers in a national telephone numbering plan provide access to emergency
services". This includes providing emergency caller location.The service addressed by the Universal Service Directive
includes telephony and any publicly available voice service using E.164 numbers, independently from the specific
network technology (i.e. traditional or VoIP network technologies). The architecture in the present document includes
provisions for the universal service directive obligations as described above and emergency calling using emergency
service URNs.
The scope of the M/493 mandate [i.4] is directly reproduced in annex B.
4.2 Location information descriptions
4.2.1 General
Location information is crucial in emergency calling in determining which PSAP needs to receive the call and also
where to dispatch emergency crews to ensure that help is received where it is needed. The definition clause of the
present document defines three types of location information, a location value, a location identifier and a location
reference. Each of the location information types represents a different kind of information about the caller's location
and each can be used by the emergency call service in a different way.
4.2.2 Location value
A location value describes a physical area in which the caller is likely to be present. This may be a civic location, which
describes some kind of street address, or it may be represented as a geodetic location, which uses latitude, longitude and
uncertainty parameters that result in the defining of an area or volume.
However, a location value that is accurate enough to allow routeing of a call to the correct PSAP may not be good
enough to enable dispatch of responders to provide assistance to those in need. Further discussions on accuracy are
beyond the scope of the present document.
The location value describes where the caller is as a consequence of this a location value needs to be considered private
and only made available to authorized entities.
4.2.3 Location identifier
A location identifier is a datum that is public or semi-public and is used to derive a serving area where the UE is present
or the position of a network termination point to which the UE is attached. The area and prescribed identifier may be
associated with the physical access network, such as a mobile Cell-ID, WiFi AP or line identifier. However, the location
identifier does not have to be tied to an access network termination point, provided that the defined area includes the
termination point to which the UE is attached.
ETSI
11 ETSI ES 203 178 V1.1.1 (2015-02)
A location value derived from a location identifier can be accurate enough to allow routeing to occur to the correct
PSAP but is often not good enough to allow accurate dispatch or emergency responders to provide assistance to those in
need. Further discussions on accuracy are beyond the scope of the present document.
Since a location identifier can be translated into a physical area in which a caller is likely to be they should be used with
care to ensure that the physical location of the caller is not inadvertently provided to an unauthorized entity.
4.2.4 Location reference
A location reference is a key, often a URI, which identifies a location server and provides sufficient information to
allow the location server to provide the location value of the UE. The location reference does not explicitly represent a
physical location, the location is returned when the reference is used allowing a location reference to be accessed
multiple times resulting in location updates being provided. This is not possible with a location value or location
identifier.
Unlike a location value or location identifier, a location reference does not in and of itself contain the location of the
caller. This attribute allows a location reference to be used in a range of network environments as long as suitable
authentication and authorization policies are implemented on the location server.
5 Functional architecture to support European
requirements on emergency caller location
determination and transport
5.1 Overview
The functional architecture to support EC requirements on emergency caller location determination and transport
identifies four service provider roles as represented in figure 5.1:
• Access network provider (ANP);
• Voice service provider (VSP);
• Emergency call service provider (ECSP); and
• PSAP service provider (PSP).
The ANP, ECSP and PSP are in the same regulatory domain. The VSP can be inside or outside this domain.
NOTE: On the basis of the European Regulatory Framework the emergency services provision inside a country is
in charge of its administration; so the term "regulatory domain" typically coincides with a single country.
In some cases a specific agreement can be defined between neighbouring countries to correctly manage
the provision of the emergency services, for example in areas close to the common border.
This architecture is neutral regarding deployment and business models. It defines the functional roles of different
network segments. Multiple roles can be played by a single actor or by multiple actors, each actor managing its own
resources to fulfil a role.
Clause 5.2 specifies the functional requirements to be fulfilled by a service provider when playing these roles.
Clause 5.3 specifies the interfaces used to support communication between these roles and interfaces with user
equipment and PSAPs.
For each interface the functional description is provided in clause 5.3.1, while clause 5.3.2 provides, without going into
the details of the protocols, the description of the information flows that the functional entities need to exchange to
implement the service.
The communication is specified with reference to the functional entities, defined in clause 5.4, that each role needs to
implement and are explicitly evidenced in figure 5.1.
ETSI
12 ETSI ES 203 178 V1.1.1 (2015-02)
Clause 5.5 finally provides the information flow diagrams needed to implement the service in different conditions, with
reference to the information elements defined in clause 5.3 and without addressing protocol aspects.
The architecture covers two methods for transmission of location values to the PSAPs, the push and the pull method:
• In the push method the location values are transmitted via the ii or ij interface as part of the call setup
signalling information or via the ik or im interface directly to the PSAP as soon as the emergency call request
is sent to the PSAP.
• In the pull method the PSAP receives via the ii or ij interface the information required to acquire a location
value from the LS or the LS Proxy via the ik, il or im interface. The request is triggered manually by the PSAP
operator on a case by case basis or automatically in the PSAP entity with every emergency call request
received.
The method, or combination of methods, for getting a location value from the ECSP to a PSAP is decided via prior
agreement between the ECSP and the PSAP authority.
As a general remark, if an interface is internal to an operator (e.g. the "in" interface as presently depicted in figure 5.1),
its functional description does not mandate the implementation of the corresponding protocols, provided this does not
impact on the functionality of the external interfaces.
Anywhere
Country A
Voice Service
Provider
Emergency Call
Service Provider
VSP Call
Control
(ECSP)
ESRF
ie (Emergency
Service Routeing
in
Function)
LS
ib
LS
Proxy
Discovery
ig
if
ia
ic
ih ik
Route
PSAP
Server
Service
id
Provider
ESRP (Emergency
Access Network
LS (Location
Service Routeing
Provider im
Server)
Proxy)
ii
ij
il
UE
IP-PSAP
PSTN-PSAP
Emergency
Caller
Figure 5.1: High level Functional Architecture
5.2 Architectural requirements
5.2.1 General
The following technical requirements describe the set of actions performed by the different roles that can be involved in
the provision of an emergency service. It is the responsibility of national Administrations and Governments to decide on
national implementations for emergency services. Specific attention ought to be paid to the roles that have access to
sensitive end user information like caller identity and caller location.
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13 ETSI ES 203 178 V1.1.1 (2015-02)
5.2.2 ANP - Access Network Provider
The ANP:
ANP-R1) shall provide IP-based connectivity for the UE to the VSP so that an emergency call can be made;
ANP-R2) shall provide location information to the VSP;
ANP-R3) shall provide routeing information to the VSP when routeing information is requested, so that an
emergency call can be delivered to the ECSP;
ANP-R4) shall provide (push or pull) the UE location information to the ECSP;
ANP-R5) shall provide (push or pull) the current UE location information to the PSAP or LS proxy; and
ANP-R6) shall provide information to location server discovery functions such that the ANP can be
contacted using that information.
NOTE: The management of location information requests to an ANP's LS by VSPs presents challenges to an
ANP as there are many VSPs that may make such requests and the ANP needs to protect itself against any
suspicious requests. A method to manage this without requiring VSP authentication is outlined in
annex D.
5.2.3 VSP - Voice Service Provider
The VSP:
VSP-R1) shall determine that the call is to be classified as an emergency call and, if applicable, its
emergency category;
VSP-R2) shall obtain the identity of the ECSP, in the same regulatory domain as the UE, to handle the call
from the UE;
VSP-R3) shall direct the call to the identified ECSP;
VSP-R4) shall obtain the caller location information provided by the ANP;
VSP-R5) shall convey the caller location information to the ECSP; and
VSP-R6) should convey information provided by the UE to the ECSP.
5.2.4 ECSP - Emergency Call Service Provider
The ECSP:
ECSP-R1) shall be capable of receiving emergency calls from a trusted sender (e.g. a VSP or VAP);
NOTE 1: The VAP is defined in annex C.
ECSP-R2) shall obtain location information from the Access Network Provider if location information is not
included in the emergency call request received from the VSP or VAP or additional location
information is required to select the appropriate destination;
ECSP-R3) shall provide interconnection with IP-based PSPs;
ECSP-R4) shall provide call interworking with existing PSP implementations;
ECSP-R5) shall determine the correct PSAP address to which to direct the emergency call;
NOTE 2: The PSAP address determined by the ECSP may identify a PSAP or a group of PSAPs.
NOTE 3: Determination of the PSAP address is based on location and type of emergency, and not on busy/free
status of the individual PSAP identified by the PSAP address.
ECSP-R6) shall direct the emergency call towards the selected PSAP address;
ETSI
14 ETSI ES 203 178 V1.1.1 (2015-02)
ECSP-R7) shall convey the caller location information to the PSAP Service Provider network; and
ECSP-R8) should convey information provided by the UE via the VSP and VAP to the PSAP Service
Provider network.
NOTE 4: Conveyance of information provided in the user plane may not always be possible (e.g. conveyance of
non-voice band data to a circuit-switched PSP network).
5.2.5 PSP - PSAP Service Provider
The PSP:
PSP-R1) shall accept emergency calls from Emergency Call Service Providers;
PSP-R2) shall acquire all information not provided in the call signalling that is necessary for the selection of
the correct PSAP to which to direct the emergency call;
NOTE 1: In some cases the PSP will have been
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