911 services wireline wireless and Vo IP Prof

911 services: wireline, wireless and Vo. IP Prof. Henning Schulzrinne Dept. of Computer Science Columbia University, New York FCC Solutions Summit March 18, 2004

Overview n n n E 911 for wireline E 911 for wireless (Phase II) Short-term 911 service for Vo. IP Differences between PSTN and Vo. IP Objectives Internet standardization efforts

Components of emergency calling n Three core components that need to be replicated – everything else are implementation details 1. 2. identifying emergency calls (“ 911”) determining the right PSAP for current caller location n n 3. coarse-grained location currently, ALI and MSAG deliver caller location to PSAP n fine-grained location

E 911 for wireline CAMA or SS 7 555 -1234 313 Main St CO Switch LEC network PSAP #1 CAMA or PRI delivers ANI (555 -1234) Tandem Switch (911 Selective Router) 555 -1234 PSAP #1 MSAG ANI: 555 -1234 313 Main ALI 100 -500 Main Street ESN 1789 private data link 555 -1234 PSAP #1, 313 Main St provisioned updates verify address validity

Wireless 911 n Phase I (April 1998) n n Route all call to the appropriate PSAP based on call sector Provide cell/sector location data to PSAP Provide call back number to PSAP Phase II (October 2001) n Phase I + latitude and longitude 67% 95% handset 50 m 150 m network 100 m 300 m

Wireless 911: Phase 2 MSC p. ANI ISUP r s i l t r i y N et LEC selective router Wireless Tower PDE MPC/SCP E 2 S A-GPS, UTDOA, … t w. a p dynamic updates . c o ESRK = unique for call ESRD = unique for location ALI ESRK or ESRD coordinates callback number

Problems with existing 911 system n 1970 s technology: n n n gets complicated if multiple providers n n CAMA trunks induce long call setup delays limited in ability to transfer information (10 digits) ILEC vs. CLEC multiple wireless providers tied to ILEC rate centers and other PSTN routing artifacts hard to move PSAPs on short notice (e. g. , emergency evacuation) n can’t just plug into any network termination

PSTN vs. Internet Telephony PSTN: Signaling & Media Internet telephony: Signaling & Media China Signaling Media Belgian customer, currently visiting US Australia

n n Telephone companies are no longer needed n n new location, but same identifier there are still carriers for DSL and cable “IP dial tone” but unaware of type of data carried (voice, web, IM, …) VSP may be in another state or country Corporations and universities don’t have email carriers, either Yahoo All devices are nomadic voice service provider MCI n ISP (IP) NYSERNET How does Vo. IP differ from landline and wireless PSTN? dark fiber provider (λ) (TCP, RTP, SIP)

The role of phone numbers and identifiers n n n Wireline line, device, subscriber & location Wireless device, but not location Vo. IP (phone number and URIs): n mostly identifies person, not device n n n multiple devices located in different states can share the same number however, may not have a phone number if it does, area code may be from different state than customer billing address multiple devices device can move, while number stays the same not related to ISP

Why is Vo. IP ≠ wireless? n Vo. IP devices may not have phone numbers as lookup keys n n e. g. , sip: hgs@cs. columbia. edu Location information for devices is civil, not longitude/latitude n n e. g. , service address for VSPs GPS not available (nor functional) on indoor devices n n n Cell phones don’t work in our building… n n plus, accuracy of 50 m (67%) or 150 m spans many buildings… no floor information so A-GPS is unlikely to work there, either Plus, wireless E 911 complexity due to old signaling mechanism n n expensive and complicated to connect to multiple wireless operators proposals to use IP-based solutions 50 m

Objectives for IP-based 911 n International n n n Multimedia n n integrity, confidentiality, protection against denial-of-service attacks Technology-independent n n users can test operation without tying up operator resources Secure n n easily re-route calls to any number of backup PSAPs Testable n n avoid repeat of CAMA trunks Resilient n n Integrate alternate modalities such as text (TDD) and video (sign language) COTS n n devices must work anywhere independent of local emergency number do not depend on (e. g. , ) specific wireless or link technology Pro-competitive n does not require carriers or gatekeepers

Vo. IP and 911 – Two stages n Short term: n n n work with existing PSAPs may not support nomadic devices Longer term: n n n upgrades in PSAP CPE opportunity for improved overall architecture support nomadic devices support multimedia provide framework for simpler & cheaper circuitswitched landline and wireless architecture

Short-term solutions n Emulate wireline n n every subscriber has phone number capture Vo. IP subscriber address and enter into ALI DB gateway calls 10 -digit number and provides ANI Emulate wireless n n Vo. IP provider = another wireless carrier use similar dynamic updates for ALI DB

IETF standardization efforts n IETF = Internet Engineering Task Force = international open standardization body “ 911” sip: sos@ include civil and/or geo 911 sos 112 sos sip: psap@leonia. nj. gov provide location (civil or geo) DHCP cn=us, a 1=nj, a 2=bergen

Conclusion n Existing 911 system closely tied to PSTN history n n number as universal identifier close affiliation with PSTN switches incremental, constrained evolution Vo. IP offers opportunity to increase robustness and decrease costs Initial international standardization efforts in progress