1. Working Group 4B: Network Timing Single Source Risk Reduction Status Update December 3, 2015 Jennifer A. Manner, Chair

2. 2 WG4B Objectives Working Group Description: Synchronized network timing (time of day, standard time intervals, standard frequencies, and corrections) is a crucial element of a communications network management. However, given the high dependence of the communications sector on GNSS, the Commission is interested in identifying ways to increase the resilience of communications networks by exploring complementary or backup solutions that could be employed to offer similar time precision as GNSS in the event that GNSS signals are lost. These solutions need to be independent of GNSS to reduce risk and solutions need to be employed across the sector. Deliverables: The Working Group will make recommendations on acquiring and implementing back-up precision timing solutions that are independent of GPS. – Define the problem, including vulnerability of the GNSS systems, and what is the impact of the result of any failure – Define required characteristics for back-up solution – Identify what technologies are possible to solve the problem and the pros and cons of each

3. 3 WG4B Members Ahmad Armand, T-Mobile Bill Check, NCTA Emil Cherian, FCC Dennis Coleman, CenturyLink Lee Cosart, Microsemi (ATIS) Bill Coward, Cox Trey Fogarty, NENA Alexander Gerdenitsch, EchoStar Ethan Lucarelli, Iridium (Wiley Rein) Jennifer A. Manner, EchoStar (Chairman) Chris Oberg, Verizon David Overdorf, AT&T Walter Rausch, Sprint Bill Ryan, DHS Rob Seastrom, TWC George Turetsky, Intel (ATIS) Joan Vaughn, T-Mobile Sameer Vuyyuru, TCS

4. 4 WG4B draws on a wide range of expertise on the issue of timing – Technical, operational, legal, process expertise – Across all technologies – wireline, terrestrial, space-based We have defined our deliverables Started to work on Report 1 – Draft in early stage We have completed defining the problem that may impact telecommunications networks We are currently defining the requirements for the solutions we are evaluating Following this, we will begin work on the options and our recommendations WG4B Status

5. 5 Bi-weekly conference calls with members June 2016: Report on options on acquiring and implementing backup precision timing solutions that are independent of GPS and submission of WG4B Report 1 on Options December 2016: Report on recommendations on acquiring and implementing backup precision timing solutions that are independent of GPS and Submission of Final WG4B Report WG4B Schedule

6. 6 Next Steps Continue bi-weekly calls and technical discussions NASA presentation on impact of space weather on GPS – scheduled for Dec. 7 Presentation on Ethernet Networks and Time Division Management Networks – scheduled for Dec. 21 Completing research on requirements Define Recommendations on acquiring and implementing backup precision timing solutions that are independent of GPS Provide periodic status updates to Steering Committee and Council