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Emergency Services
ECC TRIS
Vienna, July 2004
Richard Stastny, ÖFEG*
* The opinions expressed here may or may not be that of my company
July 2004 Richard Stastny 1
Introduction
• The discussion in Europe on the treatment of
Emergency Services with VoIP started:
– with the Analysys Report to the EC, regarding access to ES
and PATS
– the activities in the US between IETF, NENA and the VON
Coalition
• One of the major issues is the provision of location
information of the caller to be used for call routing and
also to be displayed at the PSAP.
• On the other hand a lot has been undertaken already in
Europe, US and Japan to provide enhanced location
information to PSAPs for calls from mobile phones
• Many solutions proposed and implemented could be re-
used also for calls from VoIP.
July 2004 Richard Stastny 2
Content
• Regulatory Status in Europe
• Basic Emergency Call Problems
• Work at IETF
• Major topics
• Emergency Services Obligations
• Proposal for a staged approach
July 2004 Richard Stastny 3
EU Position on Emergency Services*
• Access to Emergency services is extremely important for
citizens, irrespective of how a telephone service may be
classified for legal and regulatory purposes.
• The Universal Service Directive has an explicit requirement
that access to emergency services has to be offered by
providers of PATS, but there is no similarly explicit obligation
for providers of ECS who may be offering a telephone service.
• From a public policy point of view it is desirable that
access to emergency services is available from as wide
a range of electronic communications services as
possible.
• This calls for an evolutionary approach in cooperation with the
emergency authorities.
• In principle, National Regulatory Authorities could
impose an obligation on certain „non-PATS‟ service
providers to offer emergency service access, under
Condition (8) of Annex A of the Authorisation Directive
on “Consumer Protection Rules specific to the
electronic communications sector”.
* The Treatment of VoIP under the EU Regulatory Framework
http://europa.eu.int/information_society/topics/ecomm/doc/useful_information/library/com
miss_serv_doc/406_14_voip_consult_paper_v2_1.pdf
July 2004 Richard Stastny 4
Proposal of consulation paper
• However the practicalities of call routing and handling
have not yet been resolved by the market, and until
they are, such an obligation may not be technically
feasible and could be disproportionate.
• It is proposed that:
– NRAs could require suppliers of VoIP services that include
access to the public telephone network to give precise
information to customers on how the VoIP supplier deals
with access to emergency services and caller location.
– Such information should be provided in the customer
contract drawn up in accordance with Article 20 of the
Universal Service Directive.
• The Commission will regularly review evolution in this
area.
July 2004 Richard Stastny 5
… on Routing of Emergency Calls
• The possibility to route a call to the nearest Emergency
Service centre implies that the service provider (either
publicly available ECS or PATS) has sufficient
information to allow the call to be correctly routed.
• This is only possible if the location of the user making
the emergency call is known in some way or another,
and the service provider knows the nearest emergency
service centre to which the call should be routed.
• Currently, with some VoIP based services, in particular
„nomadic‟ services, the VoIP service provider has no
knowledge of the physical location of the caller nor of
the nearest emergency service centre.
• It would be disproportionate at the present stage of
market development to impose such routing obligations
on all VoIP providers.
July 2004 Richard Stastny 6
… on PATS and PAECS
• in the case of PATS,
– the actual making of an emergency call, and the
provision of caller location information to emergency
services, should be possible without the user having
to input any location information either before
making the emergency call or when initially installing
the terminal device.
– This probably means that the provider of such
service needs to conclude some agreement
with the provider of the underlying transport
infrastructure (!)
• in the case of publicly available ECS,
– NRAs could require that the making of a call to the
emergency services happens without the user having
to provide any location information.
– The user may be invited to provide location
information when initially installing the terminal
device at a particular location.
July 2004 Richard Stastny 7
… expects solutions from market players
• At the current state of the market, it is advisable not to
present an undue burden on market players, but it will
be necessary to follow developments in this area closely
as the market evolves.
• In the case of those ECS and PATS services where users
have the possibility to move their terminal, and where
this causes a problem for the undertaking to determine
the users‟ location, users need to be warned that when
moving their terminals from agreed fixed location, they
can not be guaranteed to be provided with emergency
services.
• Market players offering VoIP based services are
encouraged to devise and rapidly implement
operational solutions for the effective handling of
calls to emergency services (ok, will do).
July 2004 Richard Stastny 8
… on Caller Location
• In the context of PATS, Member States are to ensure
that undertakings that operate public telephone
networks make caller location information available to
authorities handling emergencies for calls to the
European Emergency call number „112‟.
• In the Directives the provision of this location
information is made dependant of the technical
feasibility.
• Considering the importance of providing location
information it is proposed that:
– NRAs encourage all undertakings offering PATS at fixed
locations to provide location information.
– This may imply some form of agreement between the
operator offering the PATS service and the underlying
provider of the transport infrastructure.
• The Privacy Directive foresees that, where Calling-Line
Identification is offered, an undertaking may override a
users‟ elimination of the presentation of this CLI, for
calls to organisations dealing with emergency calls.
July 2004 Richard Stastny 9
… on Caller Location (cont.)
• Given the importance for emergency services
of both the location and CLI information,
Member States should encourage the provision
of this information, both for PATS and for
publicly available ECS.
• Market players offering VoIP based
services are encouraged to devise and
rapidly implement operational solutions
for the effective transmission of caller ID
and the provision of location information
for calls to emergency services
• The Commission will regularly review evolution
in this area.
July 2004 Richard Stastny 10
Or in other words
• a flawed (best-effort) access to emergency
services is better than none
• new technologies should be given some time
to evolve
– e.g. mobile services took more than 10 years*
• because they may finally provide better
services then currently available and possible
• much of the work done already for
providing caller location to PSAPs for
E112 could also be used for VoIP
(databases, interfaces, …)
July 2004 Richard Stastny 11
Status of mobile networks
• Mobile phones have no power supply
• Reachability of emergency services is
not guarantied
• Ok, could route the call to the correct
ECC, but:
• No location information for 10 years
• No identification for SIM-less calls (on
the contrary, this is a requirement)
• 200.000.000 pre-paid cards out in
Europe without identification
July 2004 Richard Stastny 12
Statements
• “The ability to call for help in times of
an emergency is not „voluntary‟ – it‟s
mandatory.”
– David F. Jones, VP NENA (Testimony at the
FCC Hearing)
• “The use of IP protocols could provide
the emergency systems with …
expanded services, more resilient
networks and faster response times“
– Henning Schulzrinne
July 2004 Richard Stastny 13
The basic Emergency Call Problems
• Determine a call is an emergency call
• 4 basic requirements:
– Locate the caller
– Route the call to the correct ECC (PSAP)
– Include the location of the caller so help can be
dispatched to the right place
– Include a way to call back if disconnected
• In addition:
– Provide caller identity
– Guaranty ECC (PSAP) reachability
July 2004 Richard Stastny 14
Some work has already be done
• IETF
• US
– E911 (NENA, APCO, VON Coalition, …)
• Europe
– E112 (CGALIES, LOCUS, ETSI, LIF, …)
– UK (EISEC)
–…
July 2004 Richard Stastny 15
Current IETF drafts
• draft-taylor-sipping-emerg-scen-01
– scenarios, e.g., hybrid VoIP-PSTN
• draft-schulzrinne-sipping-emergency-arch-00
– overall architecture for emergency calling
• draft-ietf-sipping-sos-00
– describes „sos‟ SIP URI
• draft-rosen-dns-sos-00
– new DNS resource records for location mapping
July 2004 Richard Stastny 16
Major topics
• Common URI for emergency calls
sip:sos@home.domain (and 112 and 911)
• Use the global DNS to store information on
emergency numbers, ESRP, ECC service areas
• Use different means to retrieve location
information (DHCP, GPS, RFID, GSM, …)
• Push location information to ECC or let ECC
subscribe to location information
• Use authentication and TLS during call setup
• For more info see presentations of Brian Rosen
and the current work of IETF
July 2004 Richard Stastny 17
Architectural assumptions and goals by
IETF
• SIP-based for interchange
• International (global)
– devices bought anywhere can make emergency calls
anywhere
– limit biases in address formats, languages, …
– avoid built-in bias for “911” or “112” (mostly)
• Support other communications modes
– IM, SMS, MMS, video, email
• Support access for callers with disabilities
– real-time text
– video for sign language
July 2004 Richard Stastny 18
Common URL for emergency services
• Emergency numbers may be dialed from many different
places
– about 60 (national) different emergency service numbers in the
world
– many are used for other services elsewhere (e.g., directory
assistance)
• IETF draft suggests “sip:sos@home-domain”
– home-domain: domain of caller
• Can be recognized by proxies along the way
– short cut to emergency infrastructure
• If not, it reaches home proxy of subscriber
• Call can be routed from there easily
– global access to routing information (see later)
• allows also service identification “sip:sos.fire@home-domain”
• 112 and 911 should always be available (VoIP dialing plans
needed)
• Default configuration if no other information available:
– 000, 08, 110, 999, 118 and 119
– needs definitely further study
July 2004 Richard Stastny 19
Using the global DNS
• Emergency number configuration
• Determining the PSAP/ECC where the
call should be routed to
• service area of PSAP/ECC
• new infrastructure domain sos.arpa
proposed
July 2004 Richard Stastny 20
Determining locations
• Either network-provided or terminal-provided
• Conveyed via DHCP from IP-level provider
– Formats:
• geospatial (longitude, latitude, altitude or floor)
• civil (country, administrative units, street)
– Provider usually knows
– Does not depend on being a voice service provider
• 802.11 triangulation
• GPS (for ALL mobile devices)
• RFID tags in rooms
• Via configuration protocol (XCAP)
– relies on VSP having accurate service location
information
• User-configured (last resort)
July 2004 Richard Stastny 21
How does the ECC find the caller‟s
location?
• Largest difference to existing E911 system
• In-band, as part of call setup
– carried in body of setup message
– rather than by reference into external database
• May be updated during call
– moving vehicles
– late availability of information (GPS acquisition
delay)
• Also possible: subscribe to location
information (proposed method – see below)
July 2004 Richard Stastny 22
Privacy and authentication
• Want to ensure privacy of call setup
information
• prevent spoofing of call origins
– but can‟t enforce call authentication
• need to authenticate call destination
– ideally, certificate for ECCs
– but initially just verify that reached DNS-indicated
destination
• use TLS (SSL), as in https://
• host certificates widely available
– just need a domain name and a credit card
July 2004 Richard Stastny 23
Testing emergency calls
• Current E911 system has no good way
to test 911 reachability without
interfering with emergency services
• With VoIP, more distributed systems
more need for testing
• Use SIP OPTIONS request route
request, but don‟t reach call taker
• Also, DNS model allows external
consistency checking
– e.g., nationwide 911 testing agency
July 2004 Richard Stastny 24
How does VoIP (IPC) differ from
landline and wireless PSTN?
• Telephone companies are no longer
needed
– there are still carriers for DSL and
Yahoo
cable “IP dial tone” voice service provider
– but unaware of type of data carried (RTP)
– IPCSP may be in another state or
country
– Corporations and universities don‟t Backbone
MCI
have email carriers, either (IP)
– even residential users may have
servers
• Addresses (Names) may be non-
Starbucks
Access
numeric (not E.164)
(WiFi
• Media is not necessarily voice
User
July 2004 Richard Stastny 25
Take away messages
• Phones (terminals) must change
– Learn location (GPS, DHCP,..)
– Learn local emergency number from DNS
– Recognize emergency call
– Include location on the emergency call
• Proxy servers must change
– Recognize emergency call
– Route to ECC based on location (using DNS)
• All elements must implement sips: (TLS)
• ISPs must implement DHCP location
July 2004 Richard Stastny 26
Emergency Services Obligations
• Currently telephony service providers have
obligations regarding emergency services
• This should be reconsidered with VoIP
(IP Communications in general) and
especially if Broadband may be
considered as the Universal Service of the
future
– In this case contact to emergency services could also
be multimedia and made in addition to voice also by
messaging, video and even via a web browser
– depending on terminal capabilities
July 2004 Richard Stastny 27
There will be obligations to
• terminal providers:
– to receive, store and forward location information (GPS)
• access providers, ISPs and enterprises:
– to provide location information via DHCP and/or other
means (mobile)
• operating systems and application SW:
– to provide minimum set of capabilities and recognize
emergency requests (sos in browser?)
• building infrastructure:
– to provide RFIDs in rooms
• DNS infrastructure (sos.arpa.):
– to provide ECC/PSAP locations and emergency numbers
• communications service providers:
– to handle and route emergency calls properly
• emergency routing proxies
– to feed location databases, provide pseudo CLIs, route
calls to ECC/PSAPs or other ESRP.
• ECC/PSAPs:
– be able to use information provided
July 2004 Richard Stastny 28
How location information is retrieved
• All location information is gathered by the
terminal
• either network provided
– DHCP
– Mobile triangulation
– WiFi triangulation
• or by the terminal itself
– From the user
– Via GPS
– Via RFID
• and transmitted in an emergency call at call
setup (INVITE) or during the call (NOTIFY)
• together with the location information also the
source is transmitted, multiple information is
possible.
July 2004 Richard Stastny 29
Proposal for a staged approach
to access emergency services from IP-
based networks
0. the existing situation
1. from the Internet via VoIP to PSAPs/ECCs on
the PSTN/ISDN with enhancements
2. from the Internet to PSAPs/ECCs also
connected to the Internet using IPC
3. both PSAP/ECC and User are using NGN
July 2004 Richard Stastny 30
Stage 0
• No problem for VoIP provided at a fixed location using
geographic numbers or for users with FXO life-line
• For nomadic users:
– Emergency calls always routed to home PSAP/ECC for a
given subscriber or
– emergency calls only possible if location is provided to
VoIP SP manually, but
• how can this information be provided to PSAP/ECC in time?
– recognition by PSAP/ECC via CLI of non-geographic
number
• better then nothing
• but problem of call routing to correct PSAP/ECC still exists
• No access to emergency services for IP-only providers with
no E.164 number?
July 2004 Richard Stastny 31
Stage 0
IPCSP need access to local gateway operators
Gateway
DNS
Operator
Internet PSAPs/
IPCSPs PSTN
ECCs
Terminal Adapter
with FXO life-line
nomadic users fixed users
July 2004 Richard Stastny 32
Proposed Architecture Stage 1
• PSAPs/ECC still on PSTN, using existing technology
• All emergency calls are routed via the (Home)
Emergency Service Routing Proxy (ESRP)
• Users may subscribe directly, giving his
preferences
– in this case the ESRP is also a SIP- and presence server
• Subscriber needs to identify himself at subscription
time
• ESRP guaranties the subscriber to disclose identity
and location information only to emergency
services (or on user push)
• ESRP implements the local (national) policy
July 2004 Richard Stastny 33
Stage 1 (cont.)
• Location information is either entered manually by user
or transmitted from the device
• ESRP is able to map location information to routing
information to proper PSAP/ECC by using local
databases or the DNS
• ESRP is able to provide PSAP/ECC with screened CLI
• For calls from users without E.164 number a pseudo
number (CLI) may be set up
• PSAPs/ECCs need only to have narrow-band Internet
access to retrieve the presence information indexed by
CLI (watcher)
• If location of user is out-side of ESRP boundary, the call
may be routed easily (and trusted) to other ESRPs
• These ESRP may be found via sos.arpa
• Devices or applications need to be able to support more
then one line – indication of availability of ES
recommended
July 2004 Richard Stastny 34
Stage 1 direct
ECC looks up name and location information
ESRP
Gateway
DNS
Operator
IPCSP
CLI presented to ECC
lookup ECC
Internet PSAPs/
PSTN
ECCs
location
Terminal Adapter
with FXO life-line
July 2004 Richard Stastny 35
Usage of existing databases
• If a database for providing location
information for fixed and mobile calls is
already existing
• this database and the related interfaces
may be used for VoIP too
• e.g. in UK
– Enhanced Information Service for
Emergency Calls (EISEC SIN 278) and
– Emergency Location Information Interface
ND1013:2002/11
July 2004 Richard Stastny 36
Stage 1 via IPCSP
lookup ECC ECC looks up name and location information
ESRP
Gateway
DNS
Operator
IPCSP
location and CLI presented to ECC
identity
Internet PSAPs/
PSTN
ECCs
location
Terminal Adapter
with FXO life-line
July 2004 Richard Stastny 37
Forward to foreign ESRP
ECC looks up name and location information
foreign
lookup ECC
DNS ESRP Gateway
home Operator
ESRP CLI presented to ECC
Internet PSAPs/
PSTN
ECCs
location
Terminal Adapter
with FXO life-line
July 2004 Richard Stastny 38
Advantages of this approach
• IPCSP need not to be involved in
emergency services
• Users may not trust IPCSP regarding
identity and location information
• Reachability of ES may be better
guarantied
• No E.164 number required
• Identity also possible with prepaid services
• Global connectivity achieved more easily
• Implementation of local policies possible
• Call back to contact address possible
July 2004 Richard Stastny 39
Migration to Stage 2
• No or minor changes required in ESRP
• If PSAP/ECC decides to migrate to VoIP,
calls are not routed via the gateway,
but directly to the SIP-server of the
PSAP/ECC
• Name and location information will be
transmitted directly
• Location information may be dispatched
directly to emergency vehicles
July 2004 Richard Stastny 40
Stage 3
• Left to ETSI and EMTEL
• Stage 3 would be the full support of
emergency services in NGN
environments for which various work
items have been opened. ETSI needs to
ensure that they are aligned with NENA
for this future network scenario.
July 2004 Richard Stastny 41
The End
Thank you
Richard Stastny
ÖFEG
+43 664 420 4100
richard.stastny@oefeg.at
July 2004 Richard Stastny 42
