The Next Generation 9-1-1 Proof-of-Concept System

Jong Yul Kim

Wonsang Song

Henning Schulzrinne

SIP 2009 (Paris, January 2009)

Talk Outline

• Background– why is emergency calling difficult for VoIP?– numbers, call routing, …

• High level proof-of-concept architecture

• Location configuration

• Call routing

• Lessons learned

3

Modes of emergency communications

emergency call

civic coordination

emergency alert(“inverse 911”)

dispatch

information“I-am-alive”

4

Background on 9-1-1

• Established in Feb. 1968– 1970s: selective call routing– late 1990s: 93% of population/96% of area covered by 9-1-1– 95% of 9-1-1 is Enhanced 9-1-1– US and Canada

• Roughly 200 mio. calls a year (6 calls/second)– 1/3 wireless

• 6146 PSAPs in 3135 counties– most are small (2-6 call takers)– 83.1% of population have some Phase II (April 2007)

• “12-15 million households will be using VoIP as either primary or secondary line by end of 2008” (NENA)

http://www.nena.org/

IEEE NY 5

Local Switch

Automatic Number Identification

Automatic Location Identification

Collaboration between local phone providers and local public safety agencies

6

What makes VoIP 112/911 hard?POTS PSTN-emulation VoIP end-to-end VoIP

(landline) phone number limited to limited area

landline phone number anywhere in US (cf. German 180)

no phone number or phone number anywhere around the world

regional carrier national or continent-wide carrier

enterprise “carrier” or anybody with a peer-to-peer device

voice provider = line provider (~ business relationship)

voice provider ≠ ISP voice provider ≠ ISP

national protocols and call routing

probably North America + EU

international protocols and routing

location = line location mostly residential or small business

stationary, nomadic, wireless

7

Emergency numbers

• Each country and region has their own– subject to change

• Want to enable– traveler to use familiar home

number– good samaritan to pick up cell

phone

• Some 3/4-digit numbers are used for non-emergency purposes (e.g., directory assistance) Emergency number

8

Service URN• Idea: Identifiers to denote emergency calls

– and other generic (communication) services• Described in IETF ECRIT RFC 5031• Emergency service identifiers:

sos General emergency services sos.animal-control Animal control sos.fire Fire service sos.gas Gas leaks and gas emergencies sos.marine Maritime search and rescue sos.mountain Mountain rescue sos.physician Physician referral service sos.poison Poison control center sos.police Police, law enforcement

“EMERGENCY HELP. Anytime, anywhere, any device.”™National Emergency Number Association (NENA)

Technical standardsIETF ECRIT Working GroupIETF GEOPRIV Working Group

The NG9-1-1 POC System

High level requirements

Use of multimediaData delivery and sharing

Recording and incident detailsCall taker user interface

Technical standards

System architectureBehavior of components

Format of location objects

IETF ECRIT Working GroupIETF GEOPRIV Working Group

NENA

The POC system is deployed in 5 real PSAPs and 3 labs across the USA.PSAP: Public Safety Answering Point (=Emergency call center)

Fort Wayne, IN

Rochester, NY

Bozeman, MT

King County, WA

St. Paul, MN

BAH Lab

Columbia Univ. Lab

TAMU Lab

Emergency Services Network (ESN)Network used by emergency caller to ask for help

Examples: PSTN, Cellular, Residential VoIP

Role1. Determine location of caller2. Route call to ESN

9-1-1

Access Network

Emergency Services Network (ESN)

Emergency Services Routing Proxy (ESRP) Call Distributor

SIP Back-to-back User Agent

PSAP A

PSAP SIP Proxy

.

.

.

Location-to-Service Translation (LoST)

Server

.

.

.

Call Takers

PSAP Z

PSAP SIP Proxy

.

.

.

Call TakersCall DistributorSIP Back-to-back

User Agent

Public Safety Answering Points (PSAP)

Conference Server

POC system is divided into two networks

SIP-based network of PSAPs managed by the emergency authorities

Why is location important?• Send help to the site of emergency• Route call to the correct destination

Cell Tower

LLDP-MED

GPS

DHCP

Manual Entry

Skyhook Wireless

How do I send my location?•Sent along with SIP INVITE •Formatted as PIDF-LO XML object

① ②

14

Location determination optionsMethod CDP or LLDP-

MEDDHCP HELD GPS manual entry

Layer L2 L3 L7 (HTTP) - user

advantages • simple to implement

• built into switch• direct port/room

mapping

• simple to implement

• network locality

• traverses NATs

• can be operated by L2 provider

• accurate• mobile

devices• no carrier

cooperation

• no infrastructure changes

• no carrier cooperation

problems may be hard to automate for large enterprises

mapping MAC address to location?

mapping IP address to switch port?

• indoor coverage

• acquisition time

• fails for mobile devices

• unreliable for nomadic

Use Ethernet LANs Enterprise LANs

Some ISPs

DSL, cable mobile devices fall back

LoST

• LoST = Location-to-Service Translation

• LoST lets you find a PSAP

• RFC 5222 from IETF ECRIT WG

Caller’s location

Service identifier

(urn:service:sos)

+Service provider

(PSAP URL)

Emergency Dial String

+

16

LoST: Location-to-URL Mapping

clusterserves VSP2

NYUS

NJUS

Bergen CountyNJ US

123 Broad AveLeoniaBergen CountyNJ US

cluster serving VSP1replicateroot information

searchreferral

rootnodes

LeoniaNJ US

sip:psap@leonianj.gov

VSP1

LoST

17

LoST Architecture

T1

(.us)

T2

(.de) T3

(.dk)

G

G

GG

G broadcast (gossip)T1: .us

T2: .de

resolver

seeker313 Westview

Leonia, NJ US

Leonia, NJ sip:psap@leonianj.gov

tree guide

18

LoST: Query example

• Uses HTTP or HTTPS

<findService xmlns="urn:…:lost1”recursive="true" serviceBoundary="value">

<location profile="basic-civic"> <civicAddress> <country>Germany</country> <A1>Bavaria</A1> <A3>Munich</A3> <A6>Neu Perlach</A6> <HNO>96</HNO> </civicAddress> </location> <service>urn:service:sos.police</service></findService>

19

LoST “Find Service” response/warning example

<findServiceResponse xmlns="urn:ietf:params:xml:ns:lost1"> <mapping expires=“1990-12-31T23:59:60Z” lastUpdated=“2006-11-01T01:00:00Z”> <displayName xml:lang="de">München Polizei-Abteilung</displayName> <service>urn:service:sos.police</service> <serviceBoundary profile=”civic”> <civicAddress xmlns="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr"> <country>Germany</country> <A1>Bavaria</A1><A3>Munich</A3><PC>81675</PC> </civicAddress> </serviceBoundary> <uri>sip:munich-police@example.com</uri> <serviceNumber>110</serviceNumber> </mapping> <path> <via source=“lost:esgw.uber-110.de.example”/> <via source=“lost:polizei.munchen.de.example”> </path></findServiceResponse>

Emergency Services Network (ESN)

Emergency Services Routing Proxy (ESRP) Call Distributor

SIP Back-to-back User Agent

PSAP A

PSAP SIP Proxy

.

.

.

Location-to-Service Translation (LoST)

Server

.

.

.

Call Takers

PSAP Z

PSAP SIP Proxy

.

.

.

Call TakersCall DistributorSIP Back-to-back

User Agent

Public Safety Answering Points (PSAP)

Conference Server

RTP

LoST

Cellular

Access Network

SIP

9-9-1-19-1-9-1-1

Emergency Services Network (ESN)

Emergency Services Routing Proxy (ESRP) Call Distributor

SIP Back-to-back User Agent

PSAP A

PSAP SIP Proxy

.

.

.

Location-to-Service Translation (LoST)

Server

.

.

.

Call Takers

PSAP Z

PSAP SIP Proxy

.

.

.

Call TakersCall DistributorSIP Back-to-back

User Agent

Public Safety Answering Points (PSAP)

Conference Server

LoST

SMS

Access Network

SIP

9-9-1-19-1-9-1-1

“Bank robbery!”

S

Emergency Services Network (ESN)

Emergency Services Routing Proxy (ESRP) Call Distributor

SIP Back-to-back User Agent

PSAP A

PSAP SIP Proxy

.

.

.

Location-to-Service Translation (LoST)

Server

.

.

.

Call Takers

PSAP Z

PSAP SIP Proxy

.

.

.

Call TakersCall DistributorSIP Back-to-back

User Agent

Public Safety Answering Points (PSAP)

Conference Server

RTP

LoST

Telematics

Access Network

SIP

9-9-1-19-1-9-1-1

Crash Data

Emergency Services Network (ESN)

Emergency Services Routing Proxy (ESRP) Call Distributor

SIP Back-to-back User Agent

PSAP A

PSAP SIP Proxy

.

.

.

Location-to-Service Translation (LoST)

Server

.

.

.

Call Takers

PSAP Z

PSAP SIP Proxy

.

.

.

Call TakersCall DistributorSIP Back-to-back

User Agent

Public Safety Answering Points (PSAP)

Conference Server

RTP

LoST

Access Network

SIP

“All call takers are busy…”

All Busy

9-9-1-19-1-9-1-1

24

Calltaker screen• Columbia SIPc as SIP UA

• Mapping software to display caller’s location– Geolynx– Google Maps

25

NG911 trial: Lessons learned• Tested NG911 prototype in 3 PSAPs in TX and VA• Surprise: PSAP is really a conferencing system

– LanguageLine, first responders, …

• Surprise: no uniform incident description– every jurisdiction uses their own variation and level of detail

• What is desirable behavior– rather than current behavior– e.g., for transfer, overflow

• Need to integrate call taker management– presence (availability)– a specialized call center

• Special requirements: partial mute– not typically supported on conference servers

26

Challenges for NG911

• Technically, much simpler than E911 Phase II– hopefully, cheaper, too– but security challenges: location and identity verification– co-existence between E911 and NG911– integrating external data (e.g., OnStar) -- from silo to NG911

SOA

• Logistical challenges– deployment of new infrastructure

• location and LoST servers

• Legal and regulatory challenges– will ISPs give out location information to VSPs or customers?– liability for misrouted calls?

Final Comments

• We are beginning to understand what an emergency response system should look like

• Lots of interesting network problems in emergency communication systems– Geographic Location of network devices– “Call setup time (dialing of last digit to ring at the

PSAP), under expected peak load shall be less than 2 seconds.”

– Reliable communications in large scale disasters

mDNS?