nena ng911 arch for sdo workshop

8/6/2019 NENA NG911 Arch for SDO Workshop

http://slidepdf.com/reader/full/nena-ng911-arch-for-sdo-workshop 1/17

NENA Next Generation 9-1-1Architecture

Brian Rosen

Senior Director, NeuStar

Chair, NENA Long Term

Definition WG



Background

NENA = North American Emergency Number Association

Sets standards (among many other things) for emergency calls in U.S./Canada

Next Generation 9-1-1 project ± Complete overhaul of the entire 9-1-1 system

± Based on IP ± Includes changes to processes, funding, training, etc, etc

± The initial version of the technical standards part is knownas ³i3´



i3 is based on IETF Emergency CallMechanisms

Endpoint (phone) ³determines´ its location by measurement(e.g. GPS) or from the access network via a ³Location

Configuration Protocol´ Endpoint ³maps´ the location to the URI of the PSAP with a new

protocol, LoST

Endpoint learns LOCAL dialstring (9-1-1, 1-1-2) from LoST

Endpoint recognizes emergency call dialstring when dialed

Call is marked with service urn (urn:service:sos) Call is sent to PSAP with mapped URI

Location is ³conveyed´ with the call

Call arrives at PSAP with location and call back info

Works for all media (voice, video, text, IM, «)



Location Configuration Protocols

How the access network provides location

Exchange an identifier of some kind, implicitly (e.g. what port on

the switch) or explicitly (e.g. MAC address, IP address) for location

Location can be civic or geo

Current discussion on whether it can be a reference (e.g. URI)which must be dereferenced by some other protocol, or must

be a value DHCP is an example LCP

There is a ³Layer 7´ LCP in development

LLDP-MED is another example of an LCP



Marking an Emergency Call

Single global standard to denote an emergency call(does not rely on local dialstrings)

Uses a newly defined Service urn Local dialstring is detected, and call is then marked

with the service urn

Single number countries (9-1-1) use urn:service:sos

Number-per-service countries (1-1-6=police) use e.g.urn:service:sos.police

Extends to commercial location based routing, e.g.urn:service:restaurant.pizza.pizzahut)

Normally endpoint does dialstring to service URNtranslation, network can do it



Routing Emergency Calls

Location to Service Translation = LoST

Service URN + Location in, URI out

A ³Mapping´ function

Accepts civic/geo and service urn, returns URI, e.g.SIP and/or XMPP URI of where to route the call

Normal (SIP) routing of that URI

LoST is global, distributed, and replicated Normally endpoint maps, network can do it

LoST will also supply the dialstring(s) for a location

LoST will also validate a civic location



Back to NENA i3

All calls answered as IP calls at PSAP

Implies gateways between older TDMswitches and PSAPs

All calls routed with LoST

Implies TN to location lookup prior to routing All calls arrive at PSAP with location and call

back address (can be URI or e.164)



Emergency Services IP Network

An IP network FOR ALL OF PUBLIC SAFETY, not just 9-1-1

A regular routed IP network DOES have (firewalled) connections to the Internet

Conceived as LOCAL networks (e.g. County level)interconnected with neighbors, perhaps a backbonefor efficiency

Most local carriers will have private connections tothe local ESInet

Option of using the Internet to introduce calls



Multi-Stage Routing

Emergency Services Routing Proxies at edge

of ESInet onward route calls to PSAP Uses LoST with authentication

User LoST query may return URI of ESRP

ESRP will foreward to PSAP Could have more than one level of ESRP



More Data will be accepted

Additional Information about the call ± Includes carrier contact info, subscriber class of service, etc

±

Call marked with URI of a datastructure to be retrieved by the PSAP ± Also used for pointer to telematics data

Additional Information about the caller ± Refers to the person, independent of home/office/mobile telephone

± Could be medical info, ³in emergency, please contact´, «)

± Also a URI (anonymous), supplied by subscriber to carrier

Additional Information about the location

± Comes from LoST ± Two calls from same location will have same info, regardless of caller or

carrier

± Could be floor plans, hazardous materials, surveillance video, «



i3 PSAPs will be multimedia

Voice, Video, Text

Will support a variety of codecs (but not all of them,carriers don¶t decide)

Will support both IM and interactive (character at atime codecs)

Full Offer/Answer negotiation

Will use codec choice to automatically engage relayoperators if needed

Will use Language preference info to route calls toappropriate call takers, and automatically engageinterpreters



3rd Party Calls

Used when user contacts a call center first

± Text/Video/IP Relay ± Telematics (OnStar)

± Central Alarm Monitoring

Authorized 3rd parties can directly introduce

calls, routed by location of user, with all 3parties conferenced at the PSAP



PSAPs use LoST to route toresponders

A PSAP will make LoST dips with caller¶s

location to determine the responding police,fire, ems, « services

A different service urn

Requires authentication

Same underlying database This replaces the ³ESN´ of the current

system



Notes to endpoint vendors

Read ±phonebcp (will be draft-ietf-ecrit-phonebcp-00)

Implement ALL OF a short list of LCPs

Map location to PSAP URI and cache it

Recognize local (and maybe home) dialstrings as emergencycalls

Mark emergency calls with service URN

Try to update location and LoST mapping at call time, use

cached values if needed Several other SIP things to support PSAP operations on calls

Support manual override of determined location, but make itpossible, not easy to use



Notes to Access Network Providers

Need to choose one of the LCPs the phones willimplement and deploy it

The only way to choose something not on the ±phonebcp list is to force every endpoint to dosomething else ± But watch out for Ethernet connected phones behind a

router/switch with an uplink to your network; you may not beable to control them

Probably will be asked to supply a hint to a localLoST service

Validate (use LoST) civic locations when you putthem in your location server



Notes to Communications (e.g. VoIP)

Carriers

Prepare to route marked emergency calls to

PSAP/ESRP Prioritize marked emergency calls in softswitches

Deploy connections to local ESInets

Add the ³Info about the call´ URI with your contact

data, etc. Support Interactive Text & Video codecs all the way

through the system for the disabled

nena ng911 arch for sdo workshop

Documents