NG 911 technology Henning Schulzrinne henning schulzrinne fcc gov

NG 911 technology Henning Schulzrinne henning. schulzrinne@fcc. gov

What is NG 911 technically? (One-slide version) • Successor (replacement) for circuit-switched technology • Same user interface (dial 9 -1 -1), different back end – Internet protocols (IP) – COTS technology: IP, RTP, SIP, XML, HTTP, … – Location information generated locally at terminal • GPS or network-based information – Full support of stationary, nomadic and mobile devices – Any number of media streams, with dynamic addition and deletion – Capability-based call routing (e. g. , language, media capabilities) • e. g. , supports American Sign Language as language tag Jan. 14, 2011 EAAC 2

IETF and NENA standards • “phone BCP” (draft-ietf-ecrit-phonebcp-16) • PSAPs MUST support RTT and video: – BCP: ED-76 Endpoints supporting real-time text MUST use [RFC 4103]. The expectations for emergency service support for the real-time text medium are described in [RFC 5194], Section 7. 1. – It must be possible to place an emergency call using To. IP and it must be possible to use a relay service in such a call. The emergency service provided to users utilising the real-time text medium must b equivalent to the emergency service provided to users utilising speech or other media. A text gateway must be able to route real-time text calls to emergency service providers when any of the recognised emergency numbers that support text communications for the country or region are called, e. g. , "911" in the USA and "112" in Europe. Routing real-time text calls to emergency services may require the use of a transcoding service. A text gateway with cellular wireless packet-switched services must be able to route real-time text calls to emergency service providers when any of the recognized emergency numbers that support real-time text communication for the country is called. Jan. 14, 2011 EAAC 3

Real-Time Text • RTT refresher: – (typically) one character at a time – immediate upon entry – bi-directional (full duplex) • Technology: RFC 4103 (Internet standard) – support international characters (e. g. , Chinese or Russian) • Just another media session in SIP session • Negotiated by both sides – Caller: “I support real-time text” – Callee: “Great – so do I” Jan. 14, 2011 EAAC 4

Video in NG 911 • Allow calls directly to PSAP • Bridge in VRS add VRS to call (dialout) receive call: video + sign language MCU Internet (conference bridge) use normal NG 911 call routing Jan. 14, 2011 EAAC 5

SMS • SMS as transitional technology • Challenges: – SMS is not reliable (but better than nothing) – Delivery can be delayed – SMS don’t include caller location information – SMS are datagrams need to maintain session to same call taker • Requirements: – All wireless carriers need to implement N 11 routing – If indirect, gateway providers would need to upgrade protocols – Phone number to location mapping or in-band protocol

SMS SMSC 9 -1 -1 SMS GMSC HTTP (no information about carrier or location) could insert location Needs to be upgraded message can get lost or delayed SMS don’t contain location information 3 -digit codes are carrier specific Each message is limited to 160 characters (larger messages combined at receiver) 7 external entity (ESInet) SMS modem (no short code)

Conclusion • Non-audio media well integrated into NG 911 – “first class participants” • SMS challenging requires large-scale mobile system modification – special-purpose clients may be easier • Transition video, relay services and RTT to NG 911 early – avoid building transient conversion infrastructure