The Next Generation 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 Established in Feb –1970s: selective call routing –late 1990s: 93% of population/96% of area covered by –95% of is Enhanced –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)

IEEE NY5 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? POTSPSTN-emulation VoIPend-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 carriernational or continent- wide carrier enterprise “carrier” or anybody with a peer- to-peer device voice provider = line provider (~ business relationship) voice provider ≠ ISP national protocols and call routing probably North America + EU international protocols and routing location = line locationmostly 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.marineMaritime search and rescue sos.mountainMountain rescue sos.physicianPhysician referral service sos.poisonPoison control center sos.policePolice, law enforcement

“EMERGENCY HELP. Anytime, anywhere, any device.”™ National Emergency Number Association (NENA) Technical standards IETF ECRIT Working Group IETF GEOPRIV Working Group The NG9-1-1 POC System High level requirements Use of multimedia Data delivery and sharing Recording and incident details Call taker user interface Technical standards System architecture Behavior of components Format of location objects IETF ECRIT Working Group IETF 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 Role 1. Determine location of caller 2. Route call to ESN Access Network 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 ①②

14 Location determination options MethodCDP or LLDP- MED DHCPHELDGPSmanual entry LayerL2L3L7 (HTTP)-user advantagessimple 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 problemsmay 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 UseEthernet LANsEnterprise LANs Some ISPs DSL, cablemobile devicesfall 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 cluster serves VSP 2 NY US NJ US Bergen County NJ US 123 Broad Ave Leonia Bergen County NJ US cluster serving VSP 1 replicate root information search referral root nodes Leonia NJ US VSP 1 LoST

17 LoST Architecture T1 (.us) T2 (.de) T3 (.dk) G G G G G broadcast (gossip) T1:.us T2:.de resolver seeker 313 Westview Leonia, NJ US Leonia, NJ  tree guide

18 LoST: Query example Uses HTTP or HTTPS <findService xmlns="urn:…:lost1” recursive="true" serviceBoundary="value" > Germany Bavaria Munich Neu Perlach 96 urn:service:sos.police

19 LoST “Find Service” response/warning example München Polizei-Abteilung urn:service:sos.police Germany Bavaria Munich

RTP LoST Cellular Access Network SIP

LoST SMS Access Network SIP “Bank robbery!” S

RTP LoST Telematics Access Network SIP Crash Data

RTP LoST Access Network SIP “All call takers are busy…” All Busy

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?