network reliability steering committee (nrsc) overview and nrsc 9-1-1 cama trunk throughput...
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Network Reliability Steering Committee (NRSC) Overview and NRSC 9-1-1 CAMA Trunk Throughput
Optimization Analysis
Stacy Hartman – CenturyLink
Robin Howard – Verizon
NRSC Co-Chairs
September 23, 2011
CSRICSeptember 23, 2011
ATIS and Standards Development
• ATIS is the leading technical planning and standards development organization committed to the rapid development of global, market-driven standards for the Information Communication Technologies (ICT) industry.
• More than 600 industry professionals from approximately 250 companies actively participate in ATIS’ Committees, Forums, Focus Groups and Incubators. – These groups are comprised of leading subject matter experts and
develop global technical and operational standards for communications using a pragmatic, flexible and open approach.
– The groups focus on issues such as Emergency Communications, IPTV, Cloud Services, M2M, mHealth, Next Generation Networks and Services, Interconnection, etc.
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CSRICSeptember 23, 2011
Network Reliability Steering Committee
• Addresses network reliability improvement opportunities in an open environment and advises the communications industry through the development of standards, technical requirements, technical reports, bulletins and best practices.
• Addresses critical trends in the reliability of our nation’s wireless and wireline communications networks by: – identifying potential network reliability issues through an
opportunity evaluation process; – establishing subteams to work specific reliability issues; – providing industry feedback to the FCC on network reliability and the
FCC’s Network Outage Reporting System (NORS) and Disaster Information Reporting System (DIRS); and
– serving as an educational resource on network outage trends and the industry’s ongoing efforts to resolve network reliability concerns.
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CSRICSeptember 23, 2011
• The NRSC also initiates special studies related to critical infrastructure reliability. Over the past 24 months, these special studies have included:– Cyber Security Best Practice Review – NRSC Proposed and Modified Best Practices (submitted to CSRIC II)– Best Practices Tutorial – Normalization of Reliability Metrics for FCC-Reportable Outage Data – NRSC CAMA Trunk Throughput Optimization Analysis
• The NRSC actively partners with other industry groups to share knowledge. Joint efforts included:– EastWest Institute Worldwide Cybersecurity Summit– Telecom Energy Alliance – North American Telecommunications Damage Prevention Council – Association for Information Communications Technology Professionals
in Higher Education
Network Reliability Steering Committee
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CSRICSeptember 23, 2011
• CSRIC II Participation – NRSC participation on WG2A – Cyber Security Best Practices, WG4A -
Best Practices for Reliable 9-1-1 and E9-1-1, WG4C - Technical Options for E9-1-1 Location Accuracy, WG6 - Best Practice Implementation, WG7 - Pandemic Planning - Priority Service Requirements
• Best Practice Subcommittee – Partnering with the FCC to review the modified and new Best
Practices ratified by CSRIC to:• Identify duplication and/or overlap within the existing Network Reliability
Interoperability Council (NRIC) Best Practices; • Ensure each Best Practice has a subject title and/or tagline’• Identify applicable keywords; and• Evaluate the Best Practices for additional ways to group them and/or
make them more user friendly.
• ATIS NRSC Best Practice Website, put online with enhanced features: http://www.atis.org/bestpractices/Default.aspx.
Network Reliability Steering Committee
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CSRICSeptember 23, 2011
• Member Companies:– Alcatel-Lucent– AT&T– CenturyLink– Cox Communications– MetroPCS– National Communications Systems (NCS)– Sprint– Telcordia– T-Mobile– Verizon
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Network Reliability Steering Committee
NRSC 9-1-1 CAMA TRUNK THROUGHPUT OPTIMIZATION ANALYSIS
CSRICSeptember 23, 2011
• The NRSC was asked by the FCC on May 4, 2011, to review a 9-1-1 service-affecting issue that may occur during a sustained Mass Calling Event to 9-1-1 that causes a Focused Overload of the 9-1-1 system.
• A NRSC subteam was created with participants from AT&T, CenturyLink, Cox, Telcordia, T-Mobile and Verizon. – Numerous subject matter experts from these companies participated
in semi-weekly calls.• As part of this review, incidents of high call volume and the current
9-1-1 architecture were reviewed, as were situations in which certain 9-1-1 Selective Router (SR) platforms could remove 9-1-1 PSAP trunks from service during periods of heavy emergency call volume.
Overview
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CSRICSeptember 23, 2011
• Wink Failures can occur during heavy call volume events to 9-1-1 PSAPs and result in a 9-1-1 SR removing PSAP trunks from service during call setup.
• These Wink Failures occur when a SR presents a new call to the PSAP over an idle trunk and the SR does not receive a supervisory OFF-HOOK Wink to signify the Customer Premise Equipment’s (CPE’s) ability to receive the ANI digits using MF Signaling Tones.
Architecture
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CSRICSeptember 23, 2011
• Upon two successive No-Wink conditions, certain legacy 9-1-1 SRs will remove the trunk from service. – This would result in fewer trunks remaining to receive and handle
additional calls.– There is a potential that all trunks can be taken out of service due to a
No-Wink condition; in this case, all incoming 9-1-1 calls would be routed to treatment if the PSAP has not requested an overflow route to another PSAP, administrative line, or other location to receive the call.
• The root cause originates from a timing or synchronization offset between the SR and the 9-1-1 CPE that can occur during periods of high call volume in which abandoned calls allow new calls to be presented before the 9-1-1 CPE is ready to receive the call.– All CPE types may be susceptible to this condition and this problem is
likely shared by many 9-1-1 SR Service Providers.
Data Analysis and Root Cause
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CSRICSeptember 23, 2011
• ATIS published its NRSC 9-1-1 CAMA Trunk Throughput Optimization Analysis Standard (ATIS-0100034), which provides recommendations to mitigate the condition of the double wink failure and to maximize 9-1-1 call throughput to PSAPs during high call volume conditions.Short Term Recommendations, such as:
– Where available, 9-1-1 system providers should modify translations in their SRs to disallow the complete trunk group to be removed from service due to double wink failures.
– 9-1-1 SR Service Providers should update procedures to be more proactive in response to periods of high call volume to 9-1-1.
Long Term Recommendations, such as:– Update the PSAP trunk standards documents that are silent on the inter-call
timing so that the industry, SR vendors, and CPE vendors are clear on PSAP trunk inter-call behavior in the future.
– As possible, migrate off of the legacy SR to PSAP signaling standard to alternative industry compliant standards (such as NG 9-1-1 networks).
NRSC Recommendations
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CSRICSeptember 23, 2011
• It is impossible to accurately forecast periods of high call volume, prevent a period of high call volume from flooding a 9-1-1 system with more emergency traffic than they can handle, or install enough network capacity to be able to handle all emergency calls during such an event. – With changing call patterns and more calls shifting from wireline to
wireless, this situation may occur more often. • The industry believes that if 9-1-1 SR Service Providers and Public
Safety Agencies take the steps outlined in the ATIS Standard, the 9-1-1 network will continue to operate as designed, and not inadvertently (or excessively) remove PSAP trunks from service.
• The ATIS Standard is available to industry at no cost from the ATIS Document Center at: http://www.atis.org/docstore/product.aspx?id=25661.
Summary
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CSRICSeptember 23, 2011
Contact Information
NRSC Co-Chairs ATIS
Stacy HartmanCenturyLink – Director Public Policy(303) [email protected]
Tom GoodeATIS – General Counsel(202) [email protected]
Robin Howard Verizon – Network Operations Manager(972) [email protected]
Jackie VossATIS – Manager(202) 662-2545 [email protected]
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