Transcript Network-PSAP_IF_032602

Network to PSAP Interface: Signaling
Needs
Prepared For:
SBC and BellSouth
In support of NENA
Migration WG
Telcordia Contacts:
Nadine Abbott
(732) 758-5257
[email protected]
March 27, 2002
Selvam Rengasami
(732) 758-5260
[email protected]
An SAIC Company
Telcordia Technologies Proprietary – Internal Use Only
This document contains proprietary information that shall be distributed, routed or made available only
within Telcordia Technologies, except with written permission of Telcordia Technologies.
Overview
 Summary of E911 Functionality (from Bernard Brabant’s
presentation to NENA TDC)
 Summary of issues raised during Migration discussion at NENA
TDC
 Summary of signaling functions required by network to PSAP
interface, extracted from Telcordia contribution
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E911 Functionality
(from Bernard Brabant summary at NENA TDC)
 Voice grade quality line
 ANI (or some other indicator or key)
 Call Delivery (voice routed to designated SR)
 Call Routing (routable number)
 Call Priority (voice packets)
 Selective Routing and Transfer (IP-based SR)
 Default routing when ANI/KEY is not available
 Security (voice/data content)
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E911 Functionality (cont.)
(from Bernard Brabant summary at NENA
TDC)
 Emergency Call Trace (power active or not)
 Location Determination and Identification
 Call Back (recall an IP-device)
 Ringback, Caller Hold,
 Reverse ALI Search
 X & Y coordinates
 TTY and TDD
 Busy Line Verification and Busy Line Interrupt
 etc. . .
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Summary of Issues Identified during Q&A at
NENA TDC
 Location
– Information for selective routing/assisted dispatch
– Of PSAPs
 Security
– Database access
– Calls
 Power – sensitivity
 Quality of Service
– Voice call related (e.g., jitter, latency, delay)
– Traffic related
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Shortage of qualified staff/training to support VoIP?
Reliability/Outages
Bandwidth requirements
Availability of IP network access (geographic distribution is uneven)
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Summary of Issues Identified during Q&A at
NENA TDC
 E9-1-1 PSAP Feature comparability with existing E911 tandems
 E9-1-1 PSAP Feature uniformity
 Interoperability with existing premise based ACDs
 PSAP alarms
 Overflow to alternate PSAPs
 New PSAP operational and performance measurement
requirements
 Request for technical course in IP technology
 Concern about possible additional delays for conversion of MF
signaling to packet
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Possible Motivations for Considering VoIP
Access at PSAP (from Telcordia)
 Convergence of Voice and Data on PSAP access
– Efficient use of bandwidth on access to reduce costs?
– Reduce number of equipment interfaces that have to be maintained
and tested.
– Support of multi-media calls (e.g., transferring CAD data with voice
call to a secondary PSAP or dispatch center)
– Possible to leverage public network facilities, while retaining secure
access.
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Some Strategic Issues (from Telcordia)
 Network Terminating Office Functionality for converged
voice/data access could be provided by, for example:
– Legacy E911 Tandem [Selective Router] with traditional CAMA or
Enhanced MF trunks (or Custom ISDN) terminated on an E911
capable Media Gateway.
– Legacy E911 Tandem [Selective Router] with integrated E911
gateway functionality supporting converged access and VoIP
signaling (Nortel proposal at NENA TDC)
– AIN End Office with custom ISDN interface
– Softswitch based VoIP network with Selective Routing functionality
and E911 gateways
 Additional delays for converting CAMA/Enhanced MF signaling
to packet may be unacceptable—migration to converged
access may not be feasible without changes to signaling from
terminating office.
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Some Strategic Issues (from Telcordia,
cont.)
 Will converged access support both emergency call
terminations and administrative calling?
 Quality of Service for emergency calls.
– Support of voice call delivery to PSAPs should be provided over
managed IP networks that can provide QoS guarantees.
– Emergency calls are received in a distracting environment, and the
effects of any degradation in voice quality would be unacceptable.
– If VoIP is also implemented on the PSAP LAN, coordination of QoS
measures is required among the public and private parts of the
packet network.
 Security
– Need secure intranet for PSAPs that share information, e.g., via
servers.
– Various approaches have been proposed for providing security on
VoIP networks. This will require careful evaluation. Some
combination of approaches may be needed.
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Some Strategic Issues (from Telcordia,
cont.)
 What are the survivability and real-time redundancy
requirements for the IP PSAP and supporting packet network
access? (E.g., component and route redundancy?) What
impacts are there on the packet-based architectures?
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Summary of Functions/Signaling Needs for
Network to PSAP Interface (from Telcordia)
 Delivery of call to appropriate work station
– Interwork with existing Customer Premise Equipment (CPE)
Automatic Call Distribution (ACD) functions
– Interwork with existing CPE Key Telephone System arrangements
– Interface support of network-based call distribution functions?
– Need to signal called party number to distinguish emergency calls
from administrative calls, if access is shared to support both.
 Delivery of Callback Number to PSAP
 Delivery of ANI/Location Information (Phase 1)
 Delivery of Location Information (Phase 2)
 Delivery of “flashing” indication with emergency call (e.g., to
indicate alternate routing)
 Ability to provide inband audible ringing tone toward emergency
caller (provided today by PSAP equipment)
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Summary of Functions/Signaling Needs for
Network to PSAP Interface (from Telcordia,
cont.)
 ALI controller function—where?
– ALI queries/responses
– PSAP based queries (as today)
– Network supported queries (e.g., via a server) to deliver ALI earlier
 Ability to provide access for archival voice recording functions
for emergency calls
 Alternate Routing (to another PSAP)
– Signaling to invoke/revoke alternate routing to pre-specified PSAP
– Signaling to indicate request to accept alternate routing
– Signaling to indicate alternate routing is active (to invoking and
target PSAP)
– (Future) Capability to specify target PSAP explicitly
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Summary of Functions/Signaling Needs for
Network to PSAP Interface (from Telcordia,
cont.)
 Support for Central Office Transfer capabilities
– Signaling required to request transfer
 Manual Transfer
 Fixed Transfer
 Selective Transfer
– Conference bridge—where should this functionality be supported?
By a server in the network? At the PSAP?
 Transfer of associated data with COTs to other PSAPs
– Via multi-media calls?
– Via Server based sharing of data: e.g., sending of “key” with
transferred voice call to allow retrieval of transfer-related data (e.g.,
from intra-net server/web site)
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Summary of Functions/Signaling Needs for
Network to PSAP Interface (from Telcordia,
cont.)
 Callback (to reach emergency caller)
 Ringdown
 PSAP Alarms
 Support for TDD and TTY
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Possible Future Functions/Signaling for
Network to PSAP Interface
 Requests by the IP PSAP for updates of location information for
an emergency caller during a call?
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Possible Next Steps?
 Develop Motivations
– Identify additional motivations for each step of migration strategy
 Strategic Issues Analysis
– Identify any other issues?
– Prioritize
– Plan for how strategic questions should be addressed? And by
whom?
 Signaling Needs Analysis
– Identify any other feature/functions required for access interface?
– Prioritize capabilities.
– Draft Stage 1 service description, and Stage 2 description of
functional elements and information flows.
– Draft liason to be sent to IETF, ANSI T1S1, ITU, including above
descriptions and requesting protocol support (Stage 3).
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