TELECOMMUNICATIONS

FCC Should Improve 

Monitoring of Industry 

Efforts to Strengthen 

Wireless Network 

Resiliency

Report to the Ranking Member, 

Committee on Energy and Commerce, 

House of Representatives 

December 2017

GAO-18-198

United States Government Accountability Office
United States Government Accountability Office

Highlights of GAO-18-198, a report to the 

Ranking Member, Committee on Energy and 

Commerce, House of Representatives

December 2017

TELECOMMUNICATIONS

FCC Should Improve Monitoring of Industry Efforts to 

Strengthen Wireless Network Resiliency

What GAO Found

The number of wireless outages attributed to a physical incident—a natural 

disaster, accident, or other manmade event, such as vandalism—increased from 

2009 to 2016, as reported to the Federal Communications Commission (FCC). 

During this time, the number of outages substantially increased from 189 to 

1,079 outages, with most of the increase occurring from 2009 to 2011. FCC 

officials said this increase was due in part to growth in wireless customers and 

wireless infrastructure. Almost all outages attributed to a physical incident were 

due to an accident, such as damage to a cable due to a digging error (74 

percent) or a natural disaster (25 percent). However, outages due to a natural 

disaster had a longer median duration (ranging from 19 to 36 hours), which was 

more than twice as long as outages caused by an accident. Power failures and 

failures in other providers’ networks also play a role in wireless outages 

attributed to physical incidents. For instance, carriers reported that 87 percent of 

wireless outages attributed to a physical incident were due to a failure in another 

provider’s network on which they rely.

Since 2013, federal agencies and industry have taken actions to improve the 

resiliency of wireless networks. For example, the Department of Homeland 

Security (DHS) and FCC charter federal advisory committees that have 

examined resiliency issues and potential solutions, such as sharing infrastructure 

during emergencies. FCC also proposed a rule that would disclose how

individual wireless carriers’ networks performed during emergency events. In 

response, an industry coalition announced an initiative—the Wireless Network 

Resiliency Cooperative Framework—whereby carriers agreed to allow roaming

on each other’s networks and aggregated statistics to be published on how 

networks performed during emergency events. This initiative prompted FCC to 

not adopt its proposed rule. FCC said it would engage with industry about the 

framework’s implementation and use, but FCC has limited formal plans to 

oversee or spread knowledge of the framework:

• FCC developed a plan to track the completion of initial implementation tasks

outlined in the framework, but this plan does not include steps to track or 

evaluate any outputs or outcomes from the framework. 

• FCC and industry documents describe broad goals for the framework, such 

as advancing information sharing during and after emergency events, but 

neither FCC nor industry has set any specific measures to help determine 

whether the framework achieves these broad goals. 

• Although some public safety officials and other stakeholders GAO contacted 

were not aware of the framework, FCC did not have plans to actively 

communicate information about the framework to these audiences. 

More robust measures and a better plan to monitor the framework would help 

FCC collect information on the framework and evaluate its effectiveness. Such 

steps could help FCC address any challenges or decide whether further action is 

needed. Also, by promoting awareness about the framework, FCC would help 

public safety officials and other industry participants to be well positioned to use 

the framework to help them prepare for or respond to emergency events. 

View GAO-18-198. For more information, 

contact Mark L. Goldstein at (202) 512-2834 

or goldsteinm@gao.gov.

Why GAO Did This Study

Americans increasingly rely on mobile 

wireless communications for safetyrelated communications like calling 911 

and receiving weather alerts. Mobile 

wireless networks face risks from 

physical incidents including extreme 

weather events and intentional and 

accidental damage. For example, in 

2017 several major hurricanes 

damaged wireless network 

infrastructure, leaving many U.S. 

citizens without reliable access to 

wireless communications.

GAO was asked to review federal 

efforts to improve the resiliency of 

wireless networks following natural 

disasters and other physical incidents. 

This report examines: (1) trends in 

mobile wireless outages reported to 

FCC since 2009 and (2) actions federal 

agencies and industry have taken 

since 2013 (after Hurricane Sandy) to 

improve wireless network resiliency,

among other objectives. GAO analyzed 

wireless outage data from 2009 to 

2016 (4 years before and after 

Hurricane Sandy); reviewed FCC, 

DHS, and industry documents; and 

interviewed stakeholders who 

represented a variety of perspectives, 

such as industry, public safety, and

consumer groups. GAO assessed 

FCC’s efforts to monitor an industry

initiative to improve wireless network 

resiliency against federal internal 

control standards.

What GAO Recommends

FCC should work with industry to 

develop specific performance 

measures for the Wireless Network 

Resiliency Cooperative Framework,

monitor the framework’s outcomes, 

and promote awareness of it. FCC 

agreed with the recommendations.
Page i GAO-18-198 Wireless Network Resiliency

Letter 1

Background 4

Wireless Outages Caused by Physical Incidents Have Increased 

since 2009, and Outages due to Natural Disasters Lasted 

Longest 10

Federal Agencies and Industry Have Taken Some Actions to 

Improve Wireless Network Resiliency, but FCC’s Oversight of 

Industry Actions Is Limited 19

Stakeholders Cited Advantages and Disadvantages for Options 

Aimed at Improving Wireless Network Resiliency 30

Conclusions 35

Recommendations for Executive Action 36

Agency Comments 36

Appendix I Objectives, Scope, and Methodology 38

Appendix II Analysis of FCC Data on Wireless Outages 47

Appendix III Comments from the Federal Communications Commission 53

Appendix IV GAO Contact and Staff Acknowledgments 55

Tables

Table 1: Description of and Steps Taken to Implement the 

Wireless Network Resiliency Cooperative Framework, as 

of October 2017 24

Table 2: Preparedness Options to Improve Wireless Network 

Resiliency and Examples of Advantages and 

Disadvantages 31

Table 3: Response Options to Improve Wireless Network 

Resiliency and Examples of Advantages and 

Disadvantages 32

Table 4: Awareness Options to Improve Wireless Network 

Resiliency and Examples of Advantages and 

Disadvantages 34

Contents
Page ii GAO-18-198 Wireless Network Resiliency

Table 5: GAO Categories for Wireless Outage Causes for All 

Outages 39

Table 6: GAO Categories for Wireless Outage Causes for 

Physical Incidents 40

Table 7: List of Interviewed Stakeholders 43

Figures

Figure 1: Example of Mobile Wireless Network Components 5

Figure 2: Number of Reported Wireless Outages and Wireless 

Outages with a Physical Incident as the Root Cause, 

2009–2016 11

Figure 3: Number of Reported Wireless Outages for Which a 

Physical Incident Was Cited as a Cause or Contributing 

Factor by Month, 2009–2016 14

Figure 4: Median Duration of Reported Wireless Outages due to a 

Physical Incident, in Hours, by Root Cause, 2009–2016 15

Figure 5: Number of Wireless Outages with a Physical Incident as 

the Root Cause, by State and Region, 2009–2016 17

Figure 6: Number of Reported Wireless Outages by Month with 

Major Natural Disasters, 2009–2016 49

Figure 7: Annual Reported Wireless Outage Rates, 2009–2016 50

Figure 8: Number and Percentage of Wireless Outages by 

Reported Root Cause, 2009–2016 50

Figure 9: Reported Direct Causes of Wireless Outages, Grouped 

by Reported Root Cause, 2009–2016 51

Figure 10: Duration and Number of Users Affected by Reported 

Wireless Outages, Grouped by Root Cause, 2009–2016 52
Page iii GAO-18-198 Wireless Network Resiliency

Abbreviations

CSRIC Communications Security, Reliability, and 

Interoperability Council

DHS Department of Homeland Security

DIRS Disaster Information Reporting System

ESF-2 Emergency Support Function #2 – Communications

FCC Federal Communications Commission 

FEMA Federal Emergency Management Agency 

NCC National Coordinating Center for Communications 

NIST National Institute of Standards and Technology 

NORS Network Outage Reporting System 

VoIP Voice over Internet Protocol 

VoLTE Voice over Long-Term Evolution

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Page 1 GAO-18-198 Wireless Network Resiliency

441 G St. N.W.

Washington, DC 20548

December 12, 2017

The Honorable Frank Pallone, Jr.

Ranking Member

Committee on Energy and Commerce

House of Representatives

Dear Mr. Pallone:

Americans are increasingly reliant on mobile wireless communications in 

their day-to-day lives to make phone calls and share information through 

the Internet, including for safety-related communications, such as making 

911 calls and receiving weather alerts. The nation’s mobile wireless 

networks face risks from a variety of physical incidents including extreme 

weather events and accidents, such as backhoe cuts to cables 

connecting cell towers to the broader network. In recent years, major 

storms have caused outages in mobile wireless networks, severely 

impairing safety communications when they were most needed. For 

example, several major hurricanes made landfall in the United States in 

August and September 2017, damaging wireless network infrastructure 

and causing power outages that led to localized wireless outages. This 

included Hurricane Irma—which caused extreme damage in the U.S. 

Virgin Islands, Puerto Rico, and Florida, among other states—and 

Hurricane Maria that severely affected infrastructure including wireless 

networks in Puerto Rico and the U.S. Virgin Islands. As a result of 

Hurricane Maria, a majority of all cell sites were knocked out of service for 

months, leaving residents without reliable and continuous access to voice 

and data communications.1

As citizens and public safety officials—such as police officers, firefighters, 

and emergency medical-services personnel—are increasingly dependent 

on wireless communications, federal agencies and the communications 

sector have stressed the importance of resilient mobile wireless 

communications during times of emergency. As of 2016, over 65 percent 

of households in the United States relied solely or mostly on wireless 

 1

A cell site is defined as the entire set of equipment needed to receive and transmit radio 

signals for cellular voice and data transmission.

Letter
Page 2 GAO-18-198 Wireless Network Resiliency

phones to make and receive phone calls.2 Further, according to the 

Federal Communications Commission (FCC), about 70 percent of calls to 

911 are made from wireless devices. The private sector owns and 

operates the nation’s wireless networks as well as other communication 

networks and is primarily responsible for managing and protecting these 

assets. However, the federal government plays a role in promoting 

wireless network resiliency—that is, the ability to prepare for and adapt to 

changing conditions and withstand and recover rapidly from disruptions.3

FCC is the federal regulatory agency for communications and its mission 

includes promoting the safety of life and property through the use of radio 

communications. The Department of Homeland Security (DHS) is 

responsible for coordinating the federal effort to promote the security and 

resilience of the nation’s critical infrastructure, which includes the 

communications sector, and also serves as the lead agency for 

coordinating and prioritizing security and resiliency activities in the 

communications sector. Further, communications networks are especially 

important due to the enabling functions they provide across all critical 

infrastructure sectors; the loss of communications facilities could have 

cascading effects on other critical infrastructures due to 

interdependencies among sectors.4

You asked us to review efforts that have been taken since Hurricane 

Sandy in late 2012 to improve the resiliency of mobile wireless networks 

as well as options that federal agencies could take to enhance wireless 

resiliency following natural disasters and other physical incidents. This 

report examines: (1) trends in mobile wireless outages attributed to 

physical incidents since 2009 as reported to FCC, (2) the actions federal 

agencies and industry have taken since 2013 to improve wireless network 

resiliency, and (3) options that federal agencies could take to improve 

network resiliency and their advantages and disadvantages. This report 

focuses on the physical risks facing wireless networks; in other words, the 

 2

Centers for Disease Control and Prevention, U.S. Department of Health and Human 

Services, Wireless Substitution: Early Release of Estimates From the National Health 

Interview Survey, July–December 2016 (Atlanta, GA: May 2017). 

3

The White House, Presidential Policy Directive/PPD-21: Critical Infrastructure Security 

and Resilience (Washington, D.C.: Feb. 12, 2013).

4

According to a presidential directive, there are 16 critical infrastructure sectors that are so 

vital to the United States that their incapacitation or destruction would have a debilitating 

effect on security, national economic security, national public health, or safety. The 

directive also identified lead federal agencies to coordinate and prioritize security and 

resiliency activities in each sector. Presidential Policy Directive/PPD-21.
Page 3 GAO-18-198 Wireless Network Resiliency

potential for an unwanted effect from an incident on a network’s 

infrastructure such as towers, antennas, and switches. Therefore, we did 

not examine cyber risks facing wireless networks.5

To address these objectives, we analyzed data submitted by wireless 

carriers to FCC’s Network Outage Reporting System (NORS) on wireless 

outages that occurred from 2009 through 2016 (that is, to cover 4 years of 

data before and after Hurricane Sandy).6 In particular, we determined the 

total number and causes of wireless outages that were reported as 

having occurred during that time period and identified the share of all 

wireless outages attributed to a physical incident. We analyzed other 

characteristics of wireless outages such as location, duration, and 

whether the failure occurred in another company’s network. We took 

several steps to assess the reliability of NORS data, such as reviewing 

FCC documentation and interviewing agency officials responsible for 

collecting and analyzing NORS data, and found the data were sufficiently 

reliable for the purposes of describing trends in wireless outages.

We also reviewed reports and documents from FCC, DHS, and the 

National Institute of Standards and Technology (NIST); federal advisory 

committees and partnership councils that cover wireless network 

resiliency; and industry. We interviewed officials from FCC, NIST, and 

several DHS component agencies responsible for protecting and securing 

the communications infrastructure, as well as representatives from 24 

stakeholders, selected to ensure we covered different perspectives. 

Stakeholders included five wireless carriers and two owners of other 

wireless network infrastructure, seven industry associations, three 

consumer groups, five state and local government officials, one 

partnership council, and one representative from academia. We selected 

wireless carriers and owners of other wireless network infrastructure to 

ensure variety in company size and industry role. We selected state 

agencies to include states directly affected by two events in 2016—

flooding in Louisiana and Hurricane Matthew—for which industry had 

 5

We have previously examined cyber risks facing communications networks and critical 

infrastructure sectors. See GAO, Communications Networks: Outcome-Based Measures 

Would Assist DHS in Assessing Effectiveness of Cybersecurity Efforts, GAO-13-275 

(Washington, D.C.: Apr. 3, 2013), and GAO, Critical Infrastructure Protection: SectorSpecific Agencies Need to Better Measure Cybersecurity Progress, GAO-16-79 

(Washington, D.C.: Nov. 19, 2015).

6

Our analysis of NORS data does not include any outages from 2017 (such as outages 

caused by hurricanes Harvey, Irma, or Maria). 
Page 4 GAO-18-198 Wireless Network Resiliency

implemented elements of the framework at the time we began our review. 

However, the views presented in our report are not generalizable to those 

of all stakeholders.

We assessed FCC’s efforts to monitor an industry initiative to improve 

wireless network resiliency against federal standards for internal control 

and FCC’s current strategic plan.7 We identified options for improving 

wireless network resiliency by examining federal agency reports, 

literature, and other sources. We obtained stakeholder views on the 

advantages, disadvantages, and feasibility of the identified options by 

using open-ended questions to solicit input. Appendix I describes our 

scope and methodology in greater detail.

We conducted this performance audit from January 2017 to December 

2017 in accordance with generally accepted government auditing 

standards. Those standards require that we plan and perform the audit to 

obtain sufficient, appropriate evidence to provide a reasonable basis for 

our findings and conclusions based on our audit objectives. We believe 

that the evidence obtained provides a reasonable basis for our findings 

and conclusions based on our audit objectives.

Mobile devices use wireless networks to enable voice and data 

communications. Mobile wireless networks comprise several components 

and provide coverage based on dividing a large geographic area into 

smaller areas of coverage known as “cells.” Each cell contains a cell 

site—a base station equipped with an antenna—to receive and transmit 

radio signals to mobile devices within its coverage area. (See fig. 1.) The 

cell sites are often located on a tower, rooftop, or other structure to 

provide coverage to a wide area.8 For a mobile device to transmit and 

receive signals, it must be within range of a cell site antenna. In many 

areas, a mobile device is able to transmit and receive signals from 

 7

GAO, Standards for Internal Control in the Federal Government, GAO-14-704G 

(Washington, D.C.: September 2014) and FCC, Strategic Plan, 2015–2018 (Washington, 

D.C.).

8

In some areas, small cell infrastructure is used to add capacity or expand coverage, 

including the use of distributed antenna systems and small cell technologies. A distributed 

antenna system is a network of antennas that is generally connected by fiber optic cables 

to the broader wireless network. Small cells refer to low-powered access nodes deployed 

at a particular location. Small cells typically have a range from about 10 to several 

hundred yards. Large cell sites, by contrast, can have a range of about 20 miles. 

Background
Page 5 GAO-18-198 Wireless Network Resiliency

multiple cell sites. Each cell site is linked to a base station controller that 

manages communications between the cell site and the mobile switching 

center (e.g., routes and hands over calls). The mobile switching center 

then directs voice and data traffic to landline phones, other cell phones 

via a carrier’s network, or the Internet. Backhaul facilities provide 

transport for this voice and data traffic, and backhaul can be provided 

over fiber optic or copper cables or wirelessly via microwave facilities.

Figure 1: Example of Mobile Wireless Network Components 

According to FCC, there are four “nationwide” mobile wireless carriers—

AT&T, Verizon, T-Mobile, and Sprint—with networks that cover most of 

the United States. The industry also includes dozens of other carriers, 

many of which provide service in a specific, sometimes rural, geographic 

area.9 According to an FCC report on the wireless industry, most 

consumers in the United States have the ability to choose among multiple 

carriers with wireless network coverage in their area, and wireless 

carriers typically compete on price, network quality, and the availability of 

mobile devices with innovative features. Federal law states that FCC 

 9

The wireless industry also includes resellers and mobile virtual-network operators, which 

purchase mobile wireless service wholesale from facilities-based carriers and resell the 

service to consumers. Since these operators do not own or operate their own facilities and 

our focus is on physical risks to wireless networks, these operators are not a focus of this 

report.
Page 6 GAO-18-198 Wireless Network Resiliency

must take into account whether its actions will encourage competition in 

mobile wireless networks.10 Some wireless carriers own a portion or all of 

the structures that host cell sites, but wireless carriers mostly lease space 

from independent companies that own or operate a majority of the towers 

and other structures that host cell sites.

Mobile wireless networks face several kinds of risks that could affect the 

network’s physical components, resulting in disrupted service or an 

outage. Government reports generally identify three types of physical 

risks facing wireless networks:

• Natural disasters, such as hurricanes, tornados, wildfires, and 

earthquakes.

• Manmade events, such as terrorist attacks and damage associated 

with theft or another malicious act.

• Accidents, such as cable damage due to digging or locating errors 

and damage associated with a vehicle accident.

The potential effects related to these physical risks include damage to 

wireless network components that requires wireless carriers and other 

providers to make repairs or replace equipment to restore service. For 

example, flooding, which can occur with a hurricane or heavy rain, could 

damage the cable or other equipment submerged in water. Wildfires can 

damage network components like antennas and backhaul facilities 

(including fiber optic and copper lines and microwave towers) as well as 

equipment in buildings if the buildings are damaged or destroyed.

In addition to physical risks, wireless networks face risks stemming from 

their dependence on other sectors and providers. One key dependency 

identified by several government and industry reports is the reliance on 

commercially provided electricity, referred to in this report as commercial 

power.11 Several components—including the mobile switching center, 

antennas at cell sites, and consumer devices—may rely on commercial 

power. Therefore, loss of electric power may result in a loss of wireless 

communications. Another key dependency for wireless networks is 

backhaul used to get data from an end user to a major network. Wireless 

 1047 U.S.C. § 332.

11We previously examined federal efforts to improve the resiliency of the electricity grid. 

See GAO, Electricity: Federal Efforts to Enhance Grid Resilience, GAO-17-153 

(Washington, D.C.: Jan. 25, 2017).
Page 7 GAO-18-198 Wireless Network Resiliency

carriers can provide backhaul but typically obtain it from another 

communications provider, such as a local telephone company or cable 

company. An outage in the backhaul network can cause an outage that 

affects one or more cell sites or a portion of the wireless network. FCC 

has reported that the loss of backhaul service is a major cause of a cell 

site’s unavailability, which can lead to wireless outages. Also important is 

having clear roads and highways, as wireless carriers’ personnel or 

contractors need to be able to access cell sites to repair or replace 

equipment, or deliver fuel for generators that are sometimes located at 

cell sites.

Resilience is the ability to prepare for and adapt to changing conditions 

and withstand and recover rapidly from disruptions, according to 

Presidential Policy Directive 21.

12 Owners and operators of wireless 

networks can take a variety of actions to manage different risks, including 

various physical risks, according to the Communications Sector-Specific 

Plan.

13 These actions can be designed to achieve different aims, 

including to

• prepare for incidents, like creating and exercising disaster recovery 

plans;

• reduce a specific vulnerability, like elevating or moving a mobile 

switching center in a flood-prone area to a higher location;

• mitigate the consequences of an incident, like installing backup 

power—using batteries with a limited supply of power or generators 

that run on diesel or other fuel sources—to support continued wireless 

service during a commercial power outage; or

• enable efficient response and restoration following an incident, such 

as deploying portable cell sites on trucks and other equipment after an 

incident to provide wireless communications when the network 

experiences an outage or a significant disruption.

FCC, pursuant to the Communications Act of 1934, as amended, is 

charged with regulating interstate and international communications 

throughout the United States, which means that FCC regulates wireless 

 12Presidential Policy Directive/PPD-21.

13DHS, Communications Sector-Specific Plan, An Annex to the NIPP 2013 (Washington, 

D.C.: 2015). This plan sets goals to guide the sector’s voluntary efforts to improve security 

and resilience over the following 4 years. 
Page 8 GAO-18-198 Wireless Network Resiliency

networks and carriers, among other responsibilities.14 It develops and 

administers policies and rules to advance the security and reliability of the 

nation’s communications infrastructure; this responsibility includes, 

among other topics, network resiliency, public safety communications, 

and communications infrastructure protection.15 FCC administers two 

web-based outage-reporting systems to help it oversee network reliability 

and resiliency:

• NORS: Carriers are required to report details about service 

disruptions or outages (e.g., cause, location, and duration) to their 

communications systems that meet specified thresholds set forth in 

regulation.16 FCC uses NORS data to monitor trends in 

communications outages and to try to identify and address any 

shortcomings or issues going forward.

• Disaster Information Reporting System (DIRS): Carriers can 

voluntarily report on the status of communications infrastructure 

during an emergency event in DIRS. For example, wireless carriers 

report daily on the number of cell sites, by county, that are out of 

service by reason (e.g., power outage, physical damage). FCC 

activates DIRS in response to an event and then uses these data to 

track network restoration during and after an emergency event.

DHS also plays a role in wireless network resiliency as the lead agency 

for coordinating and prioritizing security and resilience activities for the 

communications sector. Presidential Policy Directive 21 establishes 

national policy to strengthen the security and resilience of critical 

infrastructure and states that the federal government shall work with 

critical infrastructure owners and operators to do so. DHS’s Office of 

Cybersecurity and Communications, within the National Protection and 

Programs Directorate, leads this coordination for the communications 

sector as the sector-specific agency, and this office works with the 

Communications Sector Coordinating Council and the Communications 

Government Coordinating Council to set goals, objectives, and activities 

 1447 U.S.C. §§ 151 et seq.

15As part of its programs on reliability and security, FCC also requires 911 service 

providers to take reasonable measures to provide reliable 911 service. 47 C.F.R. §12.4(c).

These requirements were outside the scope of this review.

1647 C.F.R. § 4.9. According to FCC, this outage data are presumed to be confidential and 

protected from routine public disclosure given their sensitive nature to both national 

security and commercial competitiveness.
Page 9 GAO-18-198 Wireless Network Resiliency

for the sector.17 During a national emergency or disaster, DHS also 

coordinates response efforts for communications systems in its role as 

the coordinator for Emergency Support Function #2 – Communications 

(ESF-2).18 Specifically, two DHS components—the Federal Emergency 

Management Agency (FEMA) and Office of Cybersecurity and 

Communications—lead the federal government’s work to support the 

restoration of communications infrastructure, coordinate response efforts, 

and facilitate the delivery of information to emergency-management 

decision makers.19 DHS has direct access to FCC’s NORS and DIRS 

data to support its work. Other DHS components also have 

responsibilities related to wireless network resiliency. For example, the 

Science & Technology Directorate conducts research in the area of 

wireless and other communications network resiliency, although its focus 

is on communications for the public-safety community.

Within the Department of Commerce, NIST also plays a role in promoting 

network resiliency by sponsoring the Community Resilience Panel. 

According to NIST, the Community Resilience Panel is sponsored by 

NIST and co-sponsored by other federal agencies to promote 

collaboration among stakeholders to strengthen the resiliency of 

infrastructure that communities rely on, including communications 

infrastructure.20 As part of this mission, the panel seeks to identify policy 

and standards-related impediments to community resiliency, raise 

 17Presidential Policy Directive 21 also notes that FCC is to partner with DHS and other 

agencies as appropriate on (1) identifying and prioritizing communications infrastructure, 

(2) identifying communications sector vulnerabilities and working with industry and other 

stakeholders to address those vulnerabilities, and (3) working with stakeholders to 

increase the security and resilience of the communications sector and facilitating the 

development and implementation of best practices promoting the security and resilience of 

critical communications infrastructure. 

18The National Response Framework identifies 14 emergency support functions, broken

out by functional area like communications or energy, that serve as the federal 

government’s primary coordinating structure for building, sustaining, and delivering 

response capabilities. DHS, National Response Framework Third Edition (Washington, 

D.C.: June 2016).

19In addition to communications, energy, which includes commercial power, is another 

critical infrastructure sector. As such, it is also subject to similar oversight from DHS and 

its sector-specific agency, the Department of Energy. 

20These agencies include the Department of Housing and Urban Development; 

Commerce’s National Oceanic and Atmospheric Administration; DHS’s FEMA and the 

Office of Infrastructure Protection; the Environmental Protection Agency; and the National 

Academies of Sciences, Engineering, and Medicine. 
Page 10 GAO-18-198 Wireless Network Resiliency

awareness of sector dependencies and of the cascading effects of 

disasters, and identify potential resiliency metrics.

The number of wireless outages attributed to a physical incident 

increased from 2009 to 2016 (see fig. 2). Specifically, the number of 

outages with a physical incident reported as a root cause increased from 

189 outages in 2009 to 1,079 in 2016.21 The number of outages 

increased substantially during the first few years of this period and then 

was relatively stable, which mirrored the trend for all wireless outages. 

According to FCC officials, the increase in reported outages was due to 

increases in both the number of wireless customers and wireless 

infrastructure over this period, as well as due to FCC’s outreach to 

wireless companies to clarify the thresholds for which carriers are 

required to report wireless outages to help ensure that carriers were 

consistently and fully reporting outages.22 From 2009 to 2016, about one-

 21We primarily used the reported root cause to determine the cause for each wireless 

outage in this section, unless otherwise noted. The root cause is the underlying reason 

why an outage occurred or was reportable and is the key problem, which once identified 

and corrected, will prevent the same or a similar problem from recurring, according to 

FCC’s NORS glossary. When reporting an outage, a wireless carrier is supposed to select 

the best fitting root cause from a list of options. Appendix I provides further information on 

how we identified outages attributed to physical incidents using the root cause field. 

22For example, one threshold for which carriers are required to report a wireless outage is 

that the outage potentially affects at least 900,000 user minutes (e.g., affects 100,000 

individual users for 9 minutes). 47 C.F.R. § 4.9(e).

Wireless Outages 

Caused by Physical 

Incidents Have 

Increased since 2009, 

and Outages due to 

Natural Disasters 

Lasted Longest

Trends in Number and 

Reported Causes of 

Wireless Outages
Page 11 GAO-18-198 Wireless Network Resiliency

third of all wireless outages reported to FCC (6,002 of 18,325) were 

attributed to physical incidents.23

Figure 2: Number of Reported Wireless Outages and Wireless Outages with a 

Physical Incident as the Root Cause, 2009–2016

Note: “Other” includes outages caused by planned maintenance to upgrade a network or equipment 

failure (e.g., a failed circuit card).

 23The other two-thirds of wireless outages that occurred during this period were attributed 

to other factors, such as planned maintenance to upgrade a network or equipment failures 

(e.g., a failed circuit card). See appendix II for more information on the trends in and 

characteristics of all wireless outages that occurred from 2009 to 2016. 
Page 12 GAO-18-198 Wireless Network Resiliency

Of wireless outages reported to FCC that were attributed to physical 

incidents, most were due to accidents, described below:

• Accidents—which include cable damage due to a backhoe cut, among 

other causes—were the root cause for 74 percent of wireless outages 

attributed to a physical event.

• Natural disasters—including tornados and wildfires—were the root 

cause for 25 percent of wireless outages attributed to a physical 

incident.

• Manmade events—which include damage associated with theft or 

other intentional damage to facilities—were the root cause for the 

remaining 1 percent of these outages.24

FCC typically suspends NORS reporting requirements in areas where 

FCC activates DIRS reporting for an emergency event, generally a 

natural disaster. For example, when FCC activated DIRS reporting for all 

counties in Puerto Rico and the U.S. Virgin Islands in response to 

Hurricane Maria in September 2017, FCC suspended NORS reporting 

requirements for those counties. As a result, FCC officials said that 

NORS data can undercount the number of wireless outages due to 

natural disasters. For a large natural disaster, however, FCC still can 

receive NORS reports for wireless outages outside the DIRS reporting 

area that are due to the natural disaster.

Looking beyond root cause reported for wireless outages, accidents 

remain the most common type of physical incident causing a wireless 

outage. Though root cause represents the underlying reason for an 

outage, FCC officials said an outage is often due to multiple events, so 

wireless carriers report a root cause and direct cause and can report two 

contributing factors when submitting information for an outage. Therefore, 

to better understand the number of outages linked to a physical incident, 

we looked at the number of outages citing a physical incident in any of the 

 24FCC’s NORS data also includes a field where carriers report whether an outage was 

related to a malicious physical event. On average, carriers reported that 16 outages each 

year (less than 1 percent) were related to a malicious physical event.

Hurricane Maria

Hurricane Maria made landfall in Puerto Rico 

and the U.S. Virgin Islands only 2 weeks after 

Hurricane Irma, compounding damage to 

wireless networks and other infrastructure. 

The storm, which had sustained winds of 

nearly 175 miles per hour before it made 

landfall, severely damaged many roads, 

homes, and utilities. After landfall, Puerto Rico 

faced extensive power outages and limited 

communications capabilities. The President 

issued a disaster declaration for Puerto Rico 

and the U.S. Virgin Islands, and to support 

response and recovery from the hurricane, 

FEMA reported that more than 19,500 civilian

personnel and military service members were 

on the ground in both locations. 

Communications networks, including wireless 

networks, were significantly impacted by 

Hurricane Maria. In the days immediately 

following the hurricane’s landfall, wireless 

carriers reported that 95 percent of cell sites 

in Puerto Rico were out of service, while over 

65 percent of cell sites in the U.S. Virgin 

Islands were out of service. Given the scale of 

damage, 2 weeks later, about 85 percent and 

60 percent of cells sites were out of service in 

these locations, respectively. FCC reported 

that wireless carriers deployed mobile cell 

sites (called cells on wheels and cells on light 

trucks) in Puerto Rico to help provide service. 

In addition, four wireless carriers opened up 

roaming on each other’s networks to provide 

the maximum service possible and worked to 

coordinate repair work and placement of 

temporary assets to maximize the coverage 

for all subscribers. 

Source: GAO based on FCC and other government reports. | 

GAO-18-198
Page 13 GAO-18-198 Wireless Network Resiliency

cause and contributing factor fields.25 Looking across cause fields, 

wireless outages citing an accident were most common, particularly from 

2010 to 2016, as shown in figure 3. Wireless outages citing a natural 

disaster were less common, although there were several spikes in the 

number of outages citing a natural disaster. Some of these spikes 

correspond with major natural disasters like the derecho affecting 

Midwest and Mid-Atlantic states in 2012 or Hurricane Matthew in 2016.26

Manmade events were rarely reported as the cause or contributing factor.

 25According to FCC’s NORS glossary, the direct cause is the immediate event that results 

in an outage and is the event, action, or procedure that triggered the outage, and 

contributing factors are problems or causes that are closely linked to an outage. This 

paragraph and figure 3 describe the number of wireless outages, by month, that cited a 

natural disaster, accident, or manmade event in at least one of the cause or contributing 

factor fields.

26According to the National Weather Service, a derecho is a widespread, long-lived wind 

storm that is associated with a band of rapidly moving showers or thunderstorms. 

Hurricane Irma 

In September 2017, Hurricane Irma made 

landfall as a Category 3 hurricane in Florida, 

having previously tracked near Puerto Rico 

and the U.S. Virgin Islands. The hurricane 

produced sustained winds of nearly 115 miles 

per hour as it made landfall in Florida. In the 

days that followed, the hurricane’s impact was 

felt over the southeastern United States, with 

nearly 16 inches of rain falling over portions of 

Florida and high winds observed in five states. 

The President issued disaster declarations 

covering portions of Puerto Rico, the U.S. 

Virgin Islands, Florida, and Georgia. 

The damage from Hurricane Irma—both 

damage to wireless network infrastructure and 

damage resulting in power outages—created 

wireless service disruptions and outages in 

certain impacted areas. In particular, over half 

of cell sites were out of service for 3 or more 

consecutive days in five counties in Puerto 

Rico and in two counties in the U.S. Virgin 

Islands, according to data from wireless 

carriers reported to FCC. Within a week, only 

6 percent of cell sites were out of service in 

reporting counties in Puerto Rico, but a 

majority of cell sites remained non-operational 

in the U.S. Virgin Islands; in one county, St. 

John, 90 percent of cell sites remained out of 

service a week and a half after landfall. In 

southern Florida, three counties had more 

than half of cell sites out of service for 4 

straight days. The number of out-of-service 

cell sites decreased over time, so that less 

than 20 percent of cell sites were out of 

service in these counties within a week. 

Looking more broadly across all counties for 

which FCC collected data in Florida, Georgia, 

and Alabama, about 13 percent, 2 percent, 

and 1 percent of cell sites in the reporting 

area were out of service 4 days after 

Hurricane Irma’s landfall, respectively. 

Source: GAO based on FCC and other government reports. | 

GAO-18-198
Page 14 GAO-18-198 Wireless Network Resiliency

Figure 3: Number of Reported Wireless Outages for Which a Physical Incident Was Cited as a Cause or Contributing Factor 

by Month, 2009–2016

Note: This figure shows the monthly number of wireless outages that cited a natural disaster, 

accident, or manmade event in at least one of the cause or contributing-factor fields.

While less common than accidents, wireless outages attributed to natural 

disasters lasted much longer than outages attributed to other physical 

incidents. Specifically, figure 4 shows that outages where a natural 

disaster was cited as the root cause were often twice as long as outages 

attributed to an accident or manmade event. From 2009 to 2016, the 

annual median duration of wireless outages attributed to accidents 

ranged from 8 hours to 16 hours, compared to natural disasters, which 

ranged from 19 to 36 hours.27 Due to this longer duration, wireless 

outages attributed to natural disasters have a greater impact on the public 

as it is left without key means of communication for longer periods of 

 27Outages attributed to a power failure also had a relatively long median duration—the 

median duration for outages attributed to power failure ranged from 13 to 26 hours from 

2009 to 2016.

Duration of Wireless 

Outages Attributed to 

Physical Incidents
Page 15 GAO-18-198 Wireless Network Resiliency

time. In addition, an industry association told us that even though public 

safety officials primarily use dedicated communication networks, like land 

mobile radio networks, to carry out their work, they also rely on their 

mobile devices that use commercial wireless networks for maps and other 

applications.28

Figure 4: Median Duration of Reported Wireless Outages due to a Physical Incident, in Hours, by Root Cause, 2009–2016

Note: Accidents include outages caused by cable damage due to digging or locating errors and 

damage associated with a vehicle accident. Natural disasters include outages caused by tornados, 

wildfires, and earthquakes. Manmade includes outages caused by damage associated with theft or 

another malicious act.

 28DHS administers the Wireless Priority Service program that authorizes communications 

providers to prioritize calls made over wireless networks by public safety officials and 

other priority users following a disruption of service.
Page 16 GAO-18-198 Wireless Network Resiliency

Ten of 24 stakeholders we interviewed said that natural disasters pose 

the greatest risk to wireless networks as they have the most intense 

consequences.29 Natural disasters can result in physical damage to or 

flooding of critical network components, and fallen trees and debris can 

temporarily block transportation routes, keeping repair crews from 

inoperable cell sites and other network components, as described in the 

Community Resilience Planning Guide for Buildings and Infrastructure 

Systems. Further, the failure of other systems like commercial power 

upon which wireless networks depend can lead to cascading failures in 

communications networks.30 One industry association we spoke with said 

that natural disasters are the primary risk to wireless network resiliency as 

these events usually create the largest outages with the longest 

durations. 

By location, the number of wireless outages attributed to physical 

incidents increased from 2009 to 2016 in some states, including several 

of the most populous states such as California and Texas (see fig. 5). 

Most of the recent expansion of wireless networks has tended to be in the 

most populous states, as those states contain the most customers and 

the highest densities of customers, according to FCC officials. In addition, 

the thresholds for which carriers are required to report wireless outages in 

NORS are such that many outages that affect primarily rural areas will not 

accumulate enough user minutes to be reportable. However, the number 

of wireless outages with a physical incident as the root cause was 

relatively steady in many states or had spikes that generally 

corresponded with major natural disasters like the 2012 derecho.

 29We asked all stakeholders to comment on the types of physical risks facing wireless 

networks and whether any type posed a greater risk. The remaining stakeholders did not 

identify a primary risk or rank the types of physical risks.

30U.S. Department of Commerce, NIST Special Publication 1190: Community Resilience 

Planning Guide for Buildings and Infrastructure Systems, Volume I and II (Washington, 

D.C.: May 2016).

Hurricane Harvey 

Hurricane Harvey made landfall as a Category 

4 hurricane in Texas in August 2017 bringing 

record-breaking rainfall and strong winds to 

communities in its path. In the week following 

landfall, 30 to more than 40 inches of rain fell 

over thousands of square miles in the week 

that followed. The President issued a disaster 

declaration for over 40 counties in the area. 

According to data from wireless carriers 

reported to FCC, some counties experienced 

a high number of out-of-service cell sites, a 

situation that can lead to limited service 

coverage or capacity. In four counties, more 

than 40 percent of cell sites were out of 

service for 3 straight days. The number of outof-service cell sites decreased over time, so 

that less than 20 percent of cell sites were out 

of service in each of these counties within one 

week. Other counties in Texas and Louisiana 

had a much lower percentage of out-ofservice cell sites, and across all counties, 

about 4 percent of cell sites were out of 

service in the week following the hurricane’s 

landfall.

Source: GAO based on FCC and other government reports. | 

GAO-18-198

Location of Wireless 

Outages Attributed to 

Physical Incidents
Page 17 GAO-18-198 Wireless Network Resiliency

Figure 5: Number of Wireless Outages with a Physical Incident as the Root Cause, by State and Region, 2009–2016
Page 18 GAO-18-198 Wireless Network Resiliency

For more detailed information on the location of all reported wireless 

outages that occurred from 2009 through 2016, including the cause and 

number of users associated with these outages, see an interactive 

graphic which can be viewed at http://www.gao.gov/products/gao-18-198.

Power failures and failures in other providers’ networks (e.g., backhaul) 

played a role in the majority of wireless outages attributed to physical 

incidents. When an accident, natural disaster, or manmade event was the 

root cause for an outage, we found that wireless carriers often also 

reported a failure in one of these two key dependencies for wireless 

networks:

• Regarding power, 8 percent of wireless outages with a physical 

incident as the root cause (465 of 6,002 outages) cited power failure 

as the direct cause of the outage.31 Nearly all these outages were 

attributed to a natural disaster.

• Regarding failures in other providers’ networks, 87 percent of outages 

attributed to a physical incident (5,206 of 6,002 outages) were due to 

a failure in another provider’s network, which includes backhaul 

connecting cell sites to mobile switching centers and onto the broader 

network. Most of these outages—4,111—cited an accident (i.e., a 

digging error resulting in cable damage) as the root cause. In 2014, a 

working group from an FCC-chartered federal advisory committee 

concluded that there is little to no shared, last-mile transport 

infrastructure for backhaul that wireless carriers (or other providers) 

could share dynamically to mitigate the effect of a backhaul failure. 

Thus, a backhaul outage will often result in a wireless outage. 

However, the working group identified existing best practices that 

providers can employ to help reduce or lessen the impact of failure in 

last-mile backhaul.32

 31Conversely, of wireless outages with power failure as the root cause, 40 percent (554 of 

1,390 outages) listed an environmental event as the direct cause, further demonstrating 

the relationship between natural disasters and power outages in causing wireless 

outages. See appendix II for more on reported root and direct causes for all wireless 

outages from 2009 to 2016.

32Communications Security, Reliability, and Interoperability Council, Infrastructure Sharing 

During Emergencies, Transport Subcommittee, Shared Services (Washington, D.C.: 

December 2014).

Wireless Network 

Dependencies
Page 19 GAO-18-198 Wireless Network Resiliency

Since 2013, FCC and DHS have both continued to take action using a 

range of existing mechanisms to improve wireless network resiliency. 

These mechanisms include leading communications-specific planning 

activities and topic-specific research to develop and to share best 

practices. While these mechanisms are not new, FCC and DHS report 

updating and adapting these activities based on emerging needs and 

lessons learned from exercises and emergency events. FCC and DHS 

actions include the following:

• Chartering advisory committees that examine resilience: DHS and 

FCC charter federal advisory committees that have studied how 

agencies and industry could improve resiliency. For example, one 

such committee is FCC’s Communications Security, Reliability, and 

Interoperability Council (CSRIC), whose members include 

representatives from wireless carriers and other communications 

companies, industry associations, and federal, state, and local 

agencies. CSRIC working groups often develop best practices for 

industry and make recommendations to wireless carriers, FCC, and 

others to improve network resiliency. One example is a working group 

that studied how industry could share backup power resources in 

2014. FCC maintains a database of best practices and publicizes 

these through presentations at conferences and in public reports, as it 

did in a report on communications outages caused by the 2012 

derecho. Six stakeholders we interviewed said best practices 

represent a valuable means to improve resiliency, as for example, 

best practices are flexible and enable providers to adapt practices as 

communications networks evolve. One stakeholder attributed 

CSRIC’s effectiveness in issuing and promoting best practices and 

information in part to its affiliation with the industry’s regulator, FCC. 

Federal Agencies and 

Industry Have Taken 

Some Actions to 

Improve Wireless 

Network Resiliency, 

but FCC’s Oversight 

of Industry Actions Is 

Limited

Federal Agencies Largely 

Continue to Use Existing 

Mechanisms to Improve 

Resiliency
Page 20 GAO-18-198 Wireless Network Resiliency

Other advisory committees that examined resiliency include DHS’s 

National Security Telecommunications Advisory Committee and 

FCC’s Technological Advisory Council.

• Developing and implementing procedures to respond to physical 

incidents: DHS leads emergency communications response and 

recovery efforts, as coordinator for ESF-2. For example, within DHS, 

the National Coordinating Center for Communications (NCC) holds 

weekly calls with government and industry partners to exchange 

information as part of NCC’s work to continuously monitor events that 

may affect communications.33 These weekly calls sustain 

relationships and promote readiness that can be leveraged to 

coordinate a response to an emergency incident, according to DHS 

and FCC officials and members of the Communications Sector 

Coordinating Council. During an incident, NCC reports that it holds 

these calls on a daily basis to understand the status of wireless and 

other networks—along with FCC outage data and other information 

collected from carriers—and to support industry response efforts. For 

instance, NCC officials said that during an incident they can help 

carriers find available generators or work with local governments to 

enable carriers to enter disaster areas to make repairs if carriers are 

denied access. Two carriers we interviewed said the NCC works well 

to support industry response to and recovery from incidents, as NCC 

has established response processes to help the communications 

sector to coordinate with the power industry. According to DHS, NCC 

participates in the Energy Priority Restoration Group that is dedicated 

to determining power restoration priority following an incident.34 While 

this group includes many sectors, it enables communications 

providers to help prioritize power restoration for critical 

communications components, like mobile switching centers.35

• Analyzing wireless outage data to identify trends and areas for further 

study: As noted above, FCC collects and regularly analyzes data on 

wireless outages during the regular course of business and during 

emergency events. FCC meets with each nationwide wireless carrier 

 33According to DHS, 11 federal government agencies (including FCC) and over 60 

private-sector-communications and information-technology companies (including major 

wireless carriers) routinely share critical communications information and advice to 

support the NCC’s mission.

34This group is part of the emergency support function for the energy sector.

35To further improve this coordination, FEMA is finalizing a Power Outage Incident Annex 

to supplement existing national response and recovery plans.
Page 21 GAO-18-198 Wireless Network Resiliency

annually to discuss trends in the carrier’s outages and any issues 

related to how the carrier completes NORS reports, according to FCC 

officials and an industry association we interviewed. FCC also 

analyzes and shares its analysis of NORS data with industry at 

quarterly meetings of the Alliance for Telecommunications Industry 

Solutions’ Network Reliability Steering Committee.36 Specifically, FCC 

presents trends in NORS outage data for the last 3 years for different 

types of outages. Such data include trends in the total number and 

duration of wireless outages. The Network Reliability Steering 

Committee, at FCC’s request or its own initiative, establishes teams to 

examine NORS trends and to make recommendations that may 

increase network reliability and reduce network outages.37 Based on 

this work, the team may identify relevant best practices that carriers 

could use to reduce or eliminate outages or suggest refining or 

creating a new best practice. Representatives from two industry 

associations said that FCC meets with industry to discuss outage data 

and is receptive to feedback on how to improve data-reporting 

processes and data quality.

In addition to these existing mechanisms, federal agencies have initiated 

some new activities to enhance wireless network resiliency since 2013.

• Community Resilience Panel: NIST issued the Community Resilience 

Planning Guide for Buildings and Infrastructure Systems in October 

2015 and sponsors the Community Resilience Panel, which aims to 

reduce barriers to achieving community resilience by promoting 

collaboration among stakeholders to strengthen the resilience of 

buildings, infrastructure, and social systems upon which communities 

rely. The panel held its first meeting in November 2015.38 The 

 36The Alliance for Telecommunications Industry Solutions is a global standards 

development and technical planning organization that supports the creation and adoption 

of international technical and operational standards for information, entertainment, and 

communications technologies. Its Network Reliability Steering Committee provides 

consensus-based technical and operational guidance and best practices to help ensure 

the reliability of communications networks. This committee provides feedback to FCC on 

NORS and DIRS, among other efforts.

37The Alliance for Telecommunications Industry Solutions maintains a list of industry best 

practices at http://www.atis.org/bestpractices/Default.aspx. This list matches FCC’s best 

practice database. 

38The panel has more than 350 members and membership is open to anyone with an 

interest in community resilience. Members include representatives from private 

companies, including communications companies; universities; local governments; and 

federal agencies. 
Page 22 GAO-18-198 Wireless Network Resiliency

planning guide provides a process that communities can use to 

improve their resilience by setting priorities and allocating resources 

to manage risks based on their prevailing hazards. The guide also 

devotes sections to key infrastructures; the communications section 

describes components of communications networks, the regulatory 

environment, and industry standards that can help inform community 

planning. The Community Resilience Panel also has a 

Communication Standing Committee comprised of industry and 

government members. This committee is currently creating additional 

resources to support communities, including a methodology that 

communities could use to involve wireless carriers and other 

communications providers in resilience planning activities. While 

communities have started to use the guide, NIST officials said it is too 

soon to measure or point to specific outcomes attributable to the 

Community Resilience Panel’s work.

• Post Hurricane Sandy hearings and proposed rule: In 2013, FCC held 

field hearings on network reliability and continuity. The goals of the 

hearings were to improve network resiliency, improve restoration, 

empower the public, and unleash technological solutions. The two 

hearings included a wide range of panelists including representatives 

from FCC and FEMA, state and local agencies, consumer groups, 

wireless carriers, and other communications providers. Following the 

hearings, FCC issued a notice of proposed rulemaking to promote 

transparency to the public on how wireless carriers compare in 

keeping their networks operational during emergency events. 

Specifically, FCC’s proposed rule would publicly report the number 

and percentage of each carrier’s cell sites that remained operational 

during an emergency event to enable consumers to compare wireless 

carriers when purchasing service.39 Based on our review of 

comments, public safety and consumer groups tended to support the 

proposed rule while industry expressed concerns, in particular, that 

the public reporting in the proposed rule would not accurately portray 

the service available during an emergency or be a useful measure to 

help consumers choose among wireless carriers. FCC decided not to 

issue a final rule, stating in December 2016 that a voluntary industry 

 39In the Matter of Improving the Resiliency of Mobile Wireless Communications Networks, 

28 FCC Rcd 14373 (2013).
Page 23 GAO-18-198 Wireless Network Resiliency

approach, described below, provided a more appropriate path to 

improve network resiliency.40

We asked stakeholders about the results of the actions taken by FCC and 

DHS, and across the 24 stakeholders we interviewed, there was no 

consensus regarding needed improvements in DHS and FCC guidance, 

coordination, or research on wireless resiliency.41 Seven stakeholders 

said they did not think there were any gaps or needed improvements from 

FCC, and six stakeholders said they did not think there were any gaps or 

needed improvements from DHS. Although most stakeholders identified a 

need for further federal agency action, they tended to identify dissimilar 

actions. However, the three state and two local agencies we interviewed 

noted that more real-time data on wireless outages would help aid their 

efforts to respond to an incident, which we discuss further below.

In April 2016, an industry coalition consisting of CTIA, a wireless industry 

association, and five wireless carriers announced the Wireless Network 

Resiliency Cooperative Framework (framework) in response to FCC’s 

2013 notice of proposed rulemaking on wireless network resiliency.42 The 

framework is a voluntary initiative designed to advance wireless service 

continuity and information sharing during and after emergencies by 

enhancing coordination and communication, both among carriers and 

between carriers and government.

The framework has five elements; some elements are specific to disaster 

response while other elements focus on preparedness and education. 

Industry has taken steps related to all five elements of the framework, as 

described in table 1. Furthermore, CTIA representatives told us they have 

ongoing meetings with representatives from the public-safety community, 

the outcome of which they expected to be a series of best practices 

concerning planning before disasters, addressing coordination during and 

after emergencies, and developing education and awareness strategies in 

 40In the Matter of Improving the Resiliency of Mobile Wireless Communications Networks, 

31 FCC Rcd 13745 (2016). 

41We did not ask stakeholders about guidance or research from NIST because its 

Community Resiliency Planning Guide for Buildings and Infrastructure Systems was 

recently issued and its resilience work does not focus solely on the communications 

sector. 

42The carriers were AT&T, Sprint, T-Mobile, US Cellular, and Verizon.

Voluntary Industry 

Framework Aims to 

Improve Wireless Network 

Resiliency, but FCC Has 

Limited Plans to Monitor 

This Framework
Page 24 GAO-18-198 Wireless Network Resiliency

fall 2017. The threshold to trigger the response elements is when DHS 

activates ESF-2 and FCC activates DIRS. At the time of our review, four 

events—Hurricane Matthew in October 2016 and hurricanes Harvey, 

Irma, and Maria in late 2017—had met the threshold to trigger the 

response elements.43 Prior to the three events in 2017, FCC officials and 

three stakeholders we interviewed told us it was too soon to know the 

effectiveness or results of the framework.44

Table 1: Description of and Steps Taken to Implement the Wireless Network Resiliency Cooperative Framework, as of October 

2017

Element Description Steps taken

Response elements

Providing for roaming 

under disasters

Wireless carriers commit to working with one another to 

implement roaming arrangements for the duration of an 

event.

Roaming would occur when a requesting carrier’s 

network is inoperable (after taking steps to restore the 

network), when roaming is technically feasible, and 

when the roaming will not adversely affect the nonrequesting carrier’s network.

Two of the signatory wireless carriers implemented 

roaming arrangements during Hurricane Matthew 

(2016).

Following Hurricane Maria (2017), the Federal 

Communications Commission (FCC) reported that 

four wireless carriers had opened up roaming in 

Puerto Rico so that they could collectively serve the 

maximum population of the islands with the current 

coverage available. This included both signatory 

and non-signatory wireless carriers.

Fostering mutual aid Wireless carriers commit to establish mutual aid 

arrangements with one another to provide aid, such as 

sharing physical assets, during and after an event. 

According to FCC, some national carriers 

implemented mutual aid arrangements during 

Hurricane Matthew, Hurricane Irma (2017), and 

Hurricane Maria. For example, one carrier allowed 

another carrier to use its facilities in the U.S. Virgin

Islands during Hurricane Irma.

Improving public 

awareness regarding 

service and restoration

Wireless carriers will support FCC making data on the 

number of out-of-service cells sites, aggregated across 

carriers, publicly available. Data will be posted for 

counties covered by an FCC Disaster Information 

Reporting System (DIRS) activation notice.

FCC posted daily data on the number of out-ofservice cells sites by county for 8 days for Hurricane 

Matthew, 11 days for Hurricane Harvey (2017), 12 

days for Hurricane Irma, several weeks for 

Hurricane Maria, and 1 day for Hurricane Nate 

(2017).a

 43Industry also implemented two of the response elements of the framework—roaming 

under disasters and mutual aid—during flooding in Louisiana in August 2016, though this 

event did not meet the threshold to trigger the framework.

44In October 2017, FCC announced that it would form an internal task force to support the 

restoration of communications services affected by the 2017 hurricane season with a 

particular emphasis on addressing challenges in Puerto Rico and the U.S. Virgin Islands.
Page 25 GAO-18-198 Wireless Network Resiliency

Element Description Steps taken

Preparedness and education

Enhancing municipal 

preparedness and 

restoration

Wireless carriers will convene select local governments’

public safety representatives to develop best practices 

to facilitate coordination before, during, and after events 

to maintain and restore wireless service.

Wireless carriers will also provide contact information 

for a carrier/public safety answering point database, to 

be made available to a state emergency operations 

center during an event.

CTIA, a wireless industry association, convened a 

working group that includes officials from state and 

local governments, according to CTIA 

representatives. The working group is carrying out 

its work to identify best practices in three subgroups: (1) pre-event planning, (2) coordination 

during and after an event, and (3) education and 

awareness. 

Increasing consumer 

readiness and 

preparation

Wireless carriers will conduct consumer education to 

ensure consumers are properly prepared for 

emergencies and disasters. In particular, CTIA will 

develop a Consumer Readiness Checklist and 

strategies to disseminate the checklist. 

CTIA created a website titled How to Prepare 

Wireless Devices for Emergencies that includes a 

video and list of steps for consumers to take to 

prepare for an emergency.b

Select carriers have also issued press releases to 

consumers, for example, on carrier and consumer 

efforts to prepare for hurricane season.

Source: GAO review of FCC documents, CTIA documents, and interviews. | GAO-18-198

Note: The response elements are triggered by an emergency or disaster for which (1) the Federal 

Emergency Management Agency activates Emergency Support Function 2, and (2) FCC activates 

DIRS.

a

FCC posted data for each event at a dedicated website—https://www.fcc.gov/matthew, 

https://www.fcc.gov/harvey, https://www.fcc.gov/irma, and https://www.fcc.gov/maria. The posted data 

were submitted by the five signatory carriers to the framework and several companies that agreed to 

allow FCC to include their data. FCC officials noted that for Hurricane Irma, four carriers that provide 

service to Puerto Rico and the U.S. Virgin Islands all agreed to allow FCC to use their data in the 

aggregated data.

b

The CTIA website is at https://www.ctia.org/consumer-tips/emergency-preparedness-wireless-tips.

FCC is responsible for administering policies to improve resiliency, which 

include monitoring actions taken by industry, and federal standards for 

internal control state that management should establish and operate 

monitoring activities, evaluate and document the results of ongoing 

monitoring, and then identify changes that either have occurred or are 

needed.45 Federal standards for internal control also state that agencies 

should define objectives clearly and that objectives should be in specific 

and measurable terms that allow for the assessment of performance.46

In December 2016, FCC said it would continue to engage with industry on 

the implementation and use of the framework, and FCC has taken some 

steps to monitor the framework’s implementation. Specifically, FCC 

 45GAO-14-704G.

46GAO-14-704G.
Page 26 GAO-18-198 Wireless Network Resiliency

developed a plan to track certain tasks related to the framework in August 

2017. This plan

• tracks the completion of initial tasks related to the framework, such as 

tracking industry’s publication of best practices to enhance municipal 

preparedness and resiliency, and confirming the five signatory 

wireless carriers’ commitment to the framework, and

• notes that FCC will update its emergency response documents to 

ensure that the documents reflect the framework and include 

checklists to validate that carriers take these actions during 

emergency events (e.g. instituting roaming, providing mutual 

assistance).47

In August 2017, FCC also issued a public notice inviting carriers beyond 

the five signatory wireless carriers to sign on to the framework.

However, we found FCC’s plan does not include any steps to document 

and assess the effect of the framework on the resiliency of wireless 

networks. In particular, FCC’s plan does not track any outputs or 

outcomes over time that speak to the results of the framework, such as 

the number of roaming requests made and fulfilled during an emergency 

event.48 FCC’s plan to monitor the framework is still new. According to 

FCC officials, FCC did not decide what division would lead its monitoring 

of the framework until August 2017 because it needed to determine which 

division should have responsibility for the framework.

49 Since the plan 

was created, FCC has met with industry groups and individual carriers to 

gather additional information and has updated its plan with this 

information to track implementation tasks.

 47In particular, FCC plans to update its Incident Management Plan, used leading up to and 

during emergencies, following the 2017 hurricane season. In addition to reflecting the 

framework, FCC officials said the update will incorporate lessons learned from hurricanes 

Harvey, Irma, and Maria. FCC officials said it is also participating in DHS’s efforts to 

update the ESF-2 concept of operations document.

48Outputs can be defined as the direct products and services delivered by a program or 

initiative, while outcomes are the results of those products and services.

49Specifically, FCC officials said the framework was initially the responsibility of the 

Cybersecurity and Communications Reliability Division with support from the Office of 

Emergency Management; in August 2017, FCC transitioned full responsibility for the 

framework to the Cybersecurity and Communications Reliability Division.
Page 27 GAO-18-198 Wireless Network Resiliency

Overall, by monitoring the outputs and outcomes of the framework, FCC 

could determine where further changes are needed to help ensure that 

wireless networks are resilient. In 2016, FCC reported that the framework 

could produce benefits such as bolstering FCC’s situational awareness 

and providing consumers with a means to hold carriers accountable for 

service continuity during emergency events. Yet, seven stakeholders we 

interviewed, including wireless carriers, said the framework largely 

codified actions that carriers already generally take to prepare for and 

respond to an emergency event. In addition, comments submitted to FCC 

in 2016 were split on whether the framework represented a sufficient path 

forward, and some stakeholders noted specific issues that they believed 

could limit the effectiveness of the framework, for example:

• Four stakeholders we interviewed—an industry association, local 

agency, state agency, and consumer group—cited the lack of federal 

agency enforcement or monitoring.

• Two industry associations stated in joint comments that there was no 

assurance that all carriers would conduct adequate testing to enable 

roaming under disasters.50

• A local agency said in comments that the threshold to trigger the 

response elements was too high; as such, carriers would not beobligated to implement the elements for more local events.51

Therefore, monitoring the outputs and outcomes of the framework would 

help FCC understand the effect of industry formalizing these actions in 

the framework.

Furthermore, although FCC and industry documents that describe and 

endorse the voluntary framework include broad goal statements, there 

are no specific measures for what the framework hopes to achieve. As a 

 50In comments, the associations said that entering a roaming agreement requires 

negotiating the terms of the agreement and testing the roaming functionality on the 

involved wireless networks. According to these associations, which represent small and 

rural carriers, nationwide carriers only conduct unilateral testing for roaming agreements 

(i.e., that the other carrier’s subscribers can use the nationwide carrier’s network), as they 

often restrict their subscribers from roaming on the networks of smaller carriers. 

Therefore, in an emergency situation, the nationwide carrier’s subscribers may not be able 

to roam on the other carrier’s network as testing has not been conducted to ensure that 

roaming can occur. 

51Since 2009, DHS had activated ESF-2 for 10 incidents, and FCC had activated DIRS for 

11 incidents.
Page 28 GAO-18-198 Wireless Network Resiliency

result, FCC lacks specific and measurable terms to monitor the effect of 

the framework. The CTIA- and carrier-released public summary of the 

framework said it aims to advance wireless service continuity and 

information sharing during and after emergencies and disasters, as well 

as help consumers be better prepared for future disasters. FCC, when 

endorsing the framework, said it was a reasonable approach to achieve 

FCC’s stated goals for the 2013 proposed rule, including promoting 

availability of wireless mobile services in the event of natural disasters 

and increasing provider transparency around wireless resiliency. FCC 

officials told us they have not discussed possible measures to monitor the 

effect of the framework with industry participants. As the creators of the 

framework, industry participants could provide insight into such 

measures. However, FCC officials acknowledged that it will be important 

to determine what the results of the framework have been in light of the 

2017 hurricanes, and that developing measures to assess industry’s 

efforts under the framework would be beneficial.

In addition, FCC has not communicated the framework to all state and 

local public-safety officials and wireless carriers, potentially limiting its 

effectiveness. At the time of our review, CTIA and the signatory wireless 

carriers had released a high-level summary of the framework but no 

additional documentation on the scope of wireless carriers’ obligations 

under the framework.52 Based on our interviews, we found that 

knowledge of the framework was not widespread. Six stakeholders we 

interviewed, including representatives of state agencies we interviewed 

and a non-signatory wireless carrier, were either unaware of the 

framework or unaware of whether industry had taken actions on any 

elements of the framework since its announcement. For example, a state 

emergency manager in one state affected by Hurricane Matthew was 

unaware of the framework and that FCC, based on one element of the 

framework, had posted daily status updates on wireless service following 

the hurricane. This manager noted that those updates would be useful for 

response efforts.

Federal standards for internal control state that federal agencies should 

externally communicate necessary, quality information to achieve the 

agency’s objectives and that open communication can also help enable a 

federal agency to obtain information from external parties.53 Among the 

 52In the Matter of Improving the Resiliency of Mobile Wireless Communications Networks, 

PS Docket 13-239, Ex Parte Presentation, CTIA et al. (2016).

53GAO-14-704G.
Page 29 GAO-18-198 Wireless Network Resiliency

stated objectives of FCC is to advise and assist public safety entities on 

wireless communications issues and to develop and administer policy 

goals and plans to promote reliable communications for public safety and 

disaster management.54 Moreover, one of FCC’s current strategic 

objectives is to promote access to effective public-safety communications 

services used by government as well as all consumers in need. To 

address this and other objectives, FCC stated that it will facilitate 

discussions and share information among key constituencies.55 FCC uses 

several mechanisms and standing forums to share information and 

educate constituencies. For example, FCC gives presentations about 

FCC activities at conferences on public safety communications that 

include state and local officials.56 In addition, FCC participates in the 

regular conference calls hosted by DHS’s NCC through which 

government and industry exchange information and the Network 

Reliability Steering Committee’s public quarterly meetings, as noted 

above.

Without greater awareness of the framework, state and local public safety 

officials may continue to be unaware of tools or other improvements 

available through the framework that could help them prepare for or 

respond to an emergency, such as the posting of daily updates on the 

number of out-of-service cell sites or best practices that could aid 

resilience. Also, smaller and rural (non-signatory) wireless carriers might 

be unaware of commitments made by the signatory carriers, such as 

committing to roaming under disasters that could benefit them and the 

citizens they serve during an emergency event but may require entering 

into and testing a roaming arrangement. By actively communicating 

information about the framework, FCC could also increase the likelihood 

of receiving information from industry or state and local public-safety 

officials about any implementation issues or positive results from the 

framework. In August 2017, FCC created a website that summarized the 

framework and, as noted above, issued a public notice inviting additional 

carriers to sign on to the framework. Only two carriers, as of October 

2017, beyond the carriers involved in creating the framework publicly 

 5447 C.F.R. § 0.191 (a) and (f).

55FCC Strategic Plan, 2015-2018.

56For instance, FCC officials said they attend and present at conferences hosted by 

APCO International, an organization of public safety communications professionals, and 

the National Emergency Management Association, an association of the emergency 

management directors from states, territories, and the District of Columbia.
Page 30 GAO-18-198 Wireless Network Resiliency

informed FCC of their intent to participate in the framework. As of October 

2017, FCC officials told us they did not have additional plans to promote 

awareness of the framework, but noted that it would be important to 

inform relevant stakeholder groups about the framework, especially those 

who might remain unaware of it.

We identified options that federal agencies could take to further improve 

wireless network resiliency based on agency reports, federal advisory

committee recommendations, peer-reviewed literature, and other reports. 

The options we identified could be implemented either alone or in 

combination and are not meant to be exhaustive. We categorized them by 

their aim—preparedness, response, and awareness. FCC, as the 

regulator for wireless communications, would be the likely agency to 

implement many of the options, although DHS or other federal agencies 

could play a role in implementing some of the options. We asked 

stakeholders to comment on the advantages and disadvantages, 

including the feasibility—technical, legal, or other—of each option. The 

tables below describe identified options by category, along with the most 

frequently cited advantages and disadvantages.

FCC has previously suggested and discussed some of these options, 

most recently during its notice of proposed rulemaking in 2013. FCC 

noted that its proposed rule sought to comply with guidance from the 

Office of Management and Budget to use disclosure requirements or 

transparency measures where possible in place of prescriptive 

regulations. However, as noted above, FCC declined to issue a final rule, 

stating that the proposed rule was problematic in light of substantial 

concerns raised about proposed metrics and disclosure requirements.

Two options identified in agency reports and literature intend to improve 

resiliency by focusing on actions to be taken ahead of an emergency or 

disaster, as described in table 2.

Stakeholders Cited 

Advantages and 

Disadvantages for 

Options Aimed at 

Improving Wireless 

Network Resiliency

Preparedness
Page 31 GAO-18-198 Wireless Network Resiliency

Table 2: Preparedness Options to Improve Wireless Network Resiliency and Examples of Advantages and Disadvantages

Option description Advantages cited by stakeholders Disadvantages cited by stakeholders

Require wireless carriers to 

provide a minimum amount 

of backup power at cell sites 

or other critical 

communications facilities.a

Backup power would help mitigate the effects 

from wireless outages due to commercial power 

outages.

Backup power requirements would help ensure 

continued service given the increased 

dependency of the public on wireless phone 

service for public safety.

Public safety officials would know how long cell 

service would last during power outages if there 

were specific backup power requirements.

Technological advances in backup power have 

made this requirement more feasible.

Not all cell sites are suitable for backup power 

(e.g., a cell site on a rooftop is subject to space 

and weight constraints) so a requirement could 

discourage carriers from deploying more cell sites, 

lowering network redundancy.

This requirement could be costly and 

burdensome, and costs could be passed onto 

consumers.

Long power outages (i.e., outages that exceed the 

minimum amount of backup power) would still 

likely lead to wireless outages.

Several carriers and infrastructure owners already 

provide backup power at specific components, like 

macro cell sites that provide key coverage to an 

area, based on a particular network’s needs.

Zoning, permitting, and environmental protection 

rules make installing backup power difficult in 

some locations.

Issue guidance to states 

and localities regarding 

policies for siting or 

construction standards that 

would allow for easier 

deployment of 

telecommunications 

infrastructure, such as 

towers that host cell sites.

This option could address difficulties (cost and 

time) carriers and other infrastructure providers 

can face from inconsistent rules or rules that 

hinder deployment and thus could enable 

wireless carriers to deploy more sites to help 

make networks more resilient.

This option was generally seen as cost effective 

when compared with other options (e.g., options 

that set new network requirements). 

Since the implementation of this guidance would 

be left to states and localities, this option may 

have limited impact.

There are concerns that guidance could lead to 

calls for federal rules to pre-empt state and local 

rules.

Guidance may not be flexible enough to consider 

the different needs and vulnerabilities facing 

different states and localities; for example, 

different areas in the country are more at risk for 

earthquakes than other areas.

Source: GAO analysis of Federal Communications Commission (FCC), Department of Homeland Security, federal advisory committee, and other reports, and interviews of selected stakeholders. |

GAO-18-198

a

In 2013, FCC sought comments on options to improve wireless network resiliency in addition to its 

proposed rule to disclose the percentage of a carrier’s cell sites that are operational during major 

emergencies. FCC suggested and sought comment on this option in its order but did not take any 

further action on this or other options when it closed the proceeding in 2016.

Twelve stakeholders we interviewed raised concerns about the feasibility 

of the option to require a minimum level of backup power at cell sites due 

to technical or legal issues. In 2007, FCC adopted a requirement for 

wireless carriers to provide 8 hours of backup power at cell sites. That 

requirement was vacated after the Office of Management and Budget 

disapproved the rule’s information collection requirements. In contrast, 

nine stakeholders we interviewed were more positive about the feasibility 

of guidance. Further, FCC created the Broadband Deployment Advisory 

Committee in January 2017 to provide recommendations on how to 
Page 32 GAO-18-198 Wireless Network Resiliency

accelerate broadband deployment. Two of the committee’s five working 

groups focus on state and local regulatory barriers and model language 

for state and municipal code, both of which could provide a model for 

wireless network infrastructure.

As shown in table 3, agency reports and literature also included options 

related to response activities during and after an emergency event.

Table 3: Response Options to Improve Wireless Network Resiliency and Examples of Advantages and Disadvantages

Option description Advantages cited by stakeholders Disadvantages cited by stakeholders

Require wireless carriers 

(and other communications 

providers like cable 

companies) to open Wi-Fi 

hotspots usually limited to a 

carrier’s subscribers in 

emergency situations, or 

facilitate communities or 

other organizations to 

create resilient Wi-Fi 

networks.a

Wi-Fi hotspots can provide a lifeline to citizens, 

such as allowing them to obtain emergency 

information via the Internet and call 911.

Wireless carriers have opened their Wi-Fi 

networks in prior emergency situations, enabling 

communications between citizens and public 

safety agencies.

Communities could sponsor Wi-Fi hotspots to 

keep people connected during emergencies.

Opening Wi-Fi hotspots normally subject to 

authentication requirements could create network 

security concerns.

Wi-Fi hotspots also rely on commercial power and 

thus may be unavailable during some emergency 

events.

Wi-Fi hotspots could be prone to overloading.

Wi-Fi would not be feasible to provide service in 

lower-density areas, since Wi-Fi signals have a 

limited range.

Communities could face difficulties funding and 

maintaining community Wi-Fi networks in the long 

term. 

Require wireless carriers to 

disclose information about 

service outages to local 

authorities with public safety 

duties.

Real-time outage information improves the 

situational awareness of first responders and 

allows them to identify where additional 

resources are needed, for instance, by informing 

them where citizens cannot reach 911 by 

wireless phones.

The Federal Communications Commission 

(FCC) already collects some data on outages, 

such as FCC’s Disaster Information Reporting 

System (DIRS) data, that could be used for this 

purpose.

Information sharing would keep both the public 

safety community and public informed of the 

recovery process. 

Industry is concerned about the potential release 

of sensitive, proprietary data. For instance, FCC 

treats outage data as confidential, and data 

shared with local public safety agencies could be 

obtained using open records laws in some 

jurisdictions.

Requiring such disclosures could be costly and 

burdensome and could divert resources from 

restoring service to meeting disclosure 

requirements.

Not all public safety groups would be able to 

process or interpret this information; for example, 

requiring such disclosures could potentially 

overwhelm a public safety agency if it lacked the 

capacity to handle the high volume of disclosures.

Source: GAO analysis of FCC, Department of Homeland Security, federal advisory committee, and other reports and interviews of selected stakeholders. | GAO-18-198

a

Some but not all wireless carriers operate Wi-Fi hotspots, so this requirement would not apply to all 

carriers. Other communications providers, like cable providers, sometimes also operate Wi-Fi 

hotspots.

Response
Page 33 GAO-18-198 Wireless Network Resiliency

For the first option, FCC officials and six stakeholders we interviewed 

noted that wireless carriers have on occasion opened up their networks in 

prior emergency situations, which indicates that the option is technically 

feasible. For the second option, every state and local agency we spoke 

with noted the value of having real-time information on wireless outages 

during an emergency event. FCC collects DIRS data, and these data are 

confidential when provided to FCC. According to FCC, if outage data 

were shared with a state or local agency, it may be subject to open 

records laws that provide a means for the public to gain access to 

government documents.

Other options are intended to improve wireless network resiliency by 

fostering transparency, as described in table 4. For some options below, 

transparency would involve making information publicly available so 

consumers could use this information when choosing a wireless carrier. 

Such transparency could give industry an incentive to improve the 

resiliency of their networks. For example, by setting performance 

standards or requiring wireless carriers to disclose their efforts to improve 

resiliency, consumers could compare the performance or practices of 

wireless carriers. However, some of these options would require defining 

specific parameters, whether a metric or the specific information to 

disclose, and seven stakeholders we interviewed noted this could be 

difficult given factors such as the variation in carriers’ wireless networks 

and the pace of technological change. For other options below, 

transparency would involve more selectively sharing information with 

other public safety agencies to improve coordination and aid planning for 

possible disruptions to wireless networks during emergencies.

Awareness
Page 34 GAO-18-198 Wireless Network Resiliency

Table 4: Awareness Options to Improve Wireless Network Resiliency and Examples of Advantages and Disadvantages

Option description Advantages cited by stakeholders Disadvantages cited by stakeholders

Require wireless carriers to 

report and disclose information 

about practices designed to 

promote network resiliency, 

such as extent of backup power 

and supplementary 

infrastructure a carrier can 

deploy to provide service.a

Information about carriers’ response 

capabilities could assist public safety officials 

with emergency preparation processes.

More data available to the public about 

resiliency practices taken by carriers could 

help consumers make informed choices when 

purchasing wireless service.

Accurate information about network 

components, such as cell tower location and 

the points of interconnection for network-tonetwork coverage, could help facilitate and 

monitor roaming between carriers under 

disasters. 

Industry is concerned about the potential 

release of business confidential and sensitive 

information to competitors or malicious actors.

The public may not be able to understand or 

use the disclosed information on a carrier’s 

practices.

This disclosed information may lead to unfair 

comparisons between carriers, particularly 

between large and small or urban and rural 

carriers.

This information is less useful to public safety 

agencies than real-time outage information. 

Use crowd-sourced data to track 

the performance of wireless 

carriers in providing reliable, 

resilient service, specific to or 

including emergency and 

disaster events, and make the 

information publicly available.a

More data available could help consumers 

make informed choices based on the 

performance of carriers’ networks.

Using crowd-sourced data is less burdensome 

to carriers than requiring new data disclosures.

Crowd-sourced data could be a useful tool for 

emergency management agencies as it 

provides a picture of where damage occurs 

and where to dispatch resources. 

Stakeholders raised concerns about the 

accuracy, reliability, and completeness of 

crowd-sourced data.

Consumers may not find the information useful 

or understandable.

Data on network performance is currently 

available from commercial sources, which may 

make federal involvement unnecessary.

Crowd-sourced data would not enable reliable 

comparisons across carriers of different types 

(e.g., nationwide and rural) or networks.

Design a reliability metric so 

federal agencies can track 

wireless network resiliency, 

based on existing data sources 

such as the Network Outage 

Reporting System (NORS) and 

Disaster Information Reporting 

System (DIRS), or on new data 

sources. 

A resiliency metric would make it easier for 

government and consumers to track network 

resilience over time against a common 

benchmark.b

Data gathered over time can help industry, 

government, and researchers improve 

forecasting, predictive modeling, and planning 

for wireless network outages.b

Emergency managers could use this 

information to formulate disaster response 

plans. 

It would be difficult to develop a simple metric 

that would be useful and remain relevant as 

technology changes.

A metric would be of limited use if only for 

federal agency use and not for the public.

Any new data collected for a metric would 

impose additional compliance costs on carriers.
Page 35 GAO-18-198 Wireless Network Resiliency

Option description Advantages cited by stakeholders Disadvantages cited by stakeholders

Formulate and implement 

wireless network resiliency 

performance standards that 

establish minimum levels of 

network reliability, including 

incentives for achieving them or 

penalties for failing to achieve 

them.a

More consumers are depending on wireless 

networks as their primary or only means of 

communication, so setting minimum 

performance standards analogous to other 

utility services may be appropriate.

Performance standards could ensure that 

wireless networks continue working during 

disasters.

Performance standards could make it easier 

for consumers and others to compare carriers.

The competitive nature of the wireless industry 

already provides incentives for carriers to 

improve resiliency without performance 

standards; for instance, carriers already 

compete on resiliency, and the public indicates 

how much it values resiliency based on its 

willingness to purchase more resilient service.

Performance standards would impose costs on 

carriers and the federal agency charged with 

enforcing the standards.

Developing appropriate performance standards 

could be difficult, especially with changing 

technology.

Source: GAO analysis of Federal Communications Commission (FCC), Department of Homeland Security, federal advisory committee, and other reports and interviews of selected stakeholders. |

GAO-18-198

a

In 2013, FCC sought comments on options to improve wireless network resiliency in addition to its 

proposed rule to disclose the percentage of a carrier’s cell sites that are operational during major 

emergencies. FCC suggested this option in its order but did not take any further action on this or 

other options when it closed the proceeding in 2016.

b

In analyzing stakeholder responses, we identified only one advantage cited by multiple stakeholders; 

therefore, we also included advantages identified in federal agency and federal advisory committee 

reports.

During natural disasters and other emergencies, wireless network 

outages can make emergency communications, such as making 911 

calls, nearly impossible for the vast number of people who rely solely on 

wireless communications. The wireless industry sought to enhance 

resiliency by improving the continuity of wireless service and information 

sharing during and after emergency events by introducing a voluntary 

framework. Although FCC stated that this voluntary framework would 

have many benefits, neither industry nor FCC has identified any specific, 

measurable objectives that could be used to determine whether the 

framework meets its broad goals, and FCC has limited plans to monitor 

the framework’s implementation and use. Absent sufficient monitoring, 

including identifying specific, objective measures for the framework, FCC 

lacks information on the framework’s outcomes and overall effectiveness; 

such information could help FCC identify whether it needs to take steps to 

address challenges or take other action to further promote wireless 

network resiliency. Furthermore, FCC does not have any plans to actively 

communicate information about the framework to public safety officials 

and industry representatives. A concerted effort by FCC to promote 

awareness of the framework could help more public safety officials and 

other industry participants use the framework to prepare for or help 

mitigate the risks to wireless networks posed by natural disasters and 

other emergencies.

Conclusions
Page 36 GAO-18-198 Wireless Network Resiliency

We are making the following three recommendations to FCC:

The Chairman of FCC should work with industry, to the extent practical, to 

develop specific and measurable objectives for the Wireless Network 

Resiliency Cooperative Framework, such as outputs to measure the 

extent of the framework’s use. (Recommendation 1)

The Chairman of FCC should develop a plan to monitor the outputs and 

outcomes of the Wireless Network Resiliency Cooperative Framework 

and document the results of its monitoring to evaluate its effectiveness 

and identify whether changes are needed. (Recommendation 2)

The Chairman of FCC should promote awareness about the elements of 

and any outcomes from the Wireless Network Resiliency Cooperative 

Framework among state and local public safety officials and other 

industry stakeholders, such as through existing outreach mechanisms 

and government-industry forums. (Recommendation 3)

We provided a draft of this report to FCC, DHS, and the Department of 

Commerce for comment. In its comments, reproduced in appendix III, 

FCC agreed with the recommendations. FCC also provided technical 

comments, which we incorporated as appropriate. DHS and the 

Department of Commerce had no comments. 

As agreed with your office, unless you publicly announce the contents of 

this report earlier, we plan no further distribution until 30 days from the 

report date. At that time, we will send copies to the appropriate 

congressional committees, the Chairman of FCC, the Secretary of 

Homeland Security, and the Secretary of Commerce. In addition, the 

report will be available at no charge on the GAO website at 

http://www.gao.gov.

Recommendations for 

Executive Action

Agency Comments
Page 37 GAO-18-198 Wireless Network Resiliency

If you or your staff have any questions about this report, please contact 

me at (202) 512-2834 or goldsteinm@gao.gov. Contact points for our 

Offices of Congressional Relations and Public Affairs may be found on 

the last page of this report. GAO staff who made key contributions to this 

report are listed in appendix IV.

Sincerely yours,

Mark L. Goldstein

Director, Physical Infrastructure
Appendix I: Objectives, Scope, and 

Methodology

Page 38 GAO-18-198 Wireless Network Resiliency

This report examines federal agency and industry efforts to improve the 

resiliency of mobile wireless networks in response to natural disasters 

and other physical incidents since Hurricane Sandy, a natural disaster 

that caused significant communications outages across several states in 

late 2012. Specifically, this report examines: (1) trends in mobile wireless 

outages attributed to physical incidents since 2009 as reported to the 

Federal Communications Commission (FCC), (2) the actions federal 

agencies and industry have taken since 2013 to improve wireless network 

resiliency, and (3) options that federal agencies could take to improve 

network resiliency and their advantages and disadvantages. This report 

focuses on the physical risks facing wireless networks; that is, the 

potential for an unwanted effect from an incident on a network’s 

infrastructure like towers, antennas, and switches. Therefore, we did not 

examine cyber risks facing wireless networks.

To determine the trends in wireless outages, we analyzed data from 

FCC’s Network Outage Reporting System (NORS) on wireless outages 

that occurred from 2009 through 2016. We chose this timeframe to cover 

4 years of data before and after Hurricane Sandy. Communications 

providers, including wireless carriers, are required in regulation to submit 

outage reports in NORS for network service disruptions that reach certain 

thresholds.1 Given our focus on wireless outages, we examined reports in 

NORS for outages (1) that were reported by wireless companies that 

identified themselves as either a wireless carrier or Voice over Internet 

Protocol (VoIP) provider2 and (2) that were cited, as the reason the 

outage was reportable, a reporting requirement applicable to a wireless 

carrier or VoIP provider in 47 C.F.R. Part 4.3

We analyzed NORS data for wireless outages to determine the total 

number and the causes of wireless outages that occurred from 2009 

through 2016. FCC provides carriers a list of 19 main categories from 

which a carrier selects a root cause, direct cause, and contributing 

factor(s) for an outage. We examined the root cause and direct cause for 

 1

47 C.F.R. § 4.

2

Some wireless carriers have implemented Voice over Long-Term Evolution (also known 

as VoLTE) networks and thus could report an outage on these wireless networks as a 

VoIP outage. 

3

We included outages that listed one of the following as the reason for reporting the 

outage: 1350 DS3 minutes, blocked calls, E911, mobile switching center, other special 

facilities, VoIP-900,000 user minutes, VoIP-E911, Wireless-900,000 user minutes, and 

Wireless-E911.

Appendix I: Objectives, Scope, and 

Methodology
Appendix I: Objectives, Scope, and 

Methodology

Page 39 GAO-18-198 Wireless Network Resiliency

each wireless outage reported to FCC. We collapsed several of the FCC 

categories to create 9 categories for ease of presentation. Table 5 shows 

the crosswalk between the 19 FCC categories and our 9 collapsed 

categories.

Table 5: GAO Categories for Wireless Outage Causes for All Outages

GAO combined category FCC categories

Cable damage/failure Cable Damage

Cable Damage/Malfunction

Equipment failure Design-Firmware

Design-Hardware

Design-Software

Hardware Failure 

Network robustness Diversity Failure

Simplex Condition

Maintenance Spare

Procedural-Other Vendor/Contractor

Procedural-Service Provider

Procedural-System Vendor

Planned Maintenance 

External environmental Environment-External

Internal environmental Environment-Internal

Other/Insufficient data Insufficient Data

Other/Unknown

Power failure Power Failure

Traffic/System overload Traffic/System Overload 

Source: GAO. | GAO-18-198

We also analyzed the data to identify the share of all wireless outages 

attributed to a physical incident—that is, a natural disaster (e.g., flooding, 

earthquake, wildfire); accident (e.g., backhoe cut); or manmade event 

(e.g., theft, malicious act). FCC provides carriers a list of categories from 

which they select a root cause, direct cause, and contributing factor(s) for 

an outage. Using these FCC categories, we created three new categories 

for natural disasters, accidents, and manmade events (see table 6). We 

based these three new categories on the description and categorization 
Appendix I: Objectives, Scope, and 

Methodology

Page 40 GAO-18-198 Wireless Network Resiliency

of physical risks in FCC and DHS reports, including the Communications 

Sector-Specific Plan.4

Table 6: GAO Categories for Wireless Outage Causes for Physical Incidents

GAO category FCC category FCC subcategory

Natural disaster Environment –

External

Earthquake

Fire

Flood

Ice/Storm

Lightning/Transient Voltage

Other

Storm-Water/Ice

Storm-Wind/Trees

Accident Cable Damage Cable Unlocated

Digging Error

Inaccurate/Incomplete Cable Locate

Inadequate/No Notification

Other

Shallow Cable

Environment –

External

Vehicular Accident

Animal

Manmade Environment –

External

Vandalism/Theft

Source: GAO. | GAO-18-198

To understand the distribution of causes across all wireless outages in 

our time frame, we focused primarily on the root cause for each wireless 

outage. However, we also examined the root and direct cause reported 

for each outage to better understand the multiple factors that may have 

led to an outage and to understand wireless network dependencies (e.g., 

power, backhaul). Finally, we examined the number of outages, by month 

and by year, for which a wireless carrier reported a physical event as the 

root cause, direct cause, or contributing factor to better understand the 

 4

U.S. Department of Homeland Security, Communications Sector-Specific Plan: An Annex 

to the NIPP 2013 (Washington, D.C.: 2015).
Appendix I: Objectives, Scope, and 

Methodology

Page 41 GAO-18-198 Wireless Network Resiliency

total number of outages related to a physical incident during our time 

period.5

We also analyzed other characteristics of wireless outages such as 

location, duration, and whether the failure occurred in another company’s 

network. To examine location, we focused on three NORS fields—city, 

state, and description of location—to identify a city(ies) and state for each 

outage, and then we determined the latitude and longitude for each 

outage.6 We also examined NORS data in conjunction with two other data 

sets. First, data on events for which FCC activated its Disaster 

Information Reporting System (DIRS) or “DIRS-lite” to understand any 

correlation between wireless outages and major physical incidents.7

Second, data from CTIA’s annual wireless survey on the number of 

wireless subscribers and other measures of wireless networks’ size to 

understand any correlation between wireless outages and the size of the 

wireless industry.

To assess the reliability of NORS data, we reviewed FCC’s data glossary 

and other FCC documentation on the NORS data system and data 

elements. We interviewed agency officials responsible for collecting and 

analyzing NORS data to understand the manual and automated controls 

used to review carrier-reported outage information and any potential 

limitations in the data. We also reviewed relevant data elements for 

missing data, outliers, and errors. We found the data were sufficiently 

 5

According to FCC’s NORS glossary, the root cause is the underlying reason why the 

outage occurred or why the outage was reportable and the key problem which, once 

identified and corrected, will prevent the same or a similar problem from recurring, and the 

direct cause is the immediate event that results in an outage and is the event, action, or 

procedure that triggered the outage.

6

We created and applied an algorithm to identify a city and state in these fields for which 

we could assign a latitude and longitude; the algorithm enabled us to assign a latitude and 

longitude for a majority of outages (15,637 of 18,325). When the algorithm could not 

identify a valid city and state, we manually reviewed information in the outage report to 

identify a city. When only a county was provided, we identified the county seat as the city 

for the outage; when an outage was reported as statewide, we identified the state capital 

as the city for the outage.

7

DIRS-lite is a scaled back version of DIRS used to determine the status of major wireline 

and wireless assets, like switches. DIRS is activated only for major disasters while DIRSlite is activated for smaller-scale disasters. DIRS-lite collects information through email 

and phone calls. FCC has activated DIRS 14 times and DIRS-lite 6 times since DIRS was 

created in 2007; 2 of the 14 DIRS activations were later downgraded to DIRS-lite 

activations. Each activation was for a natural disaster, primarily hurricanes.
Appendix I: Objectives, Scope, and 

Methodology

Page 42 GAO-18-198 Wireless Network Resiliency

reliable for the purpose of describing the number and type of wireless 

outages reported to FCC that were attributed to a physical incident.

To determine the actions federal agencies have taken since 2013 to 

improve the resiliency of mobile wireless networks, we reviewed reports 

and documents from FCC, the Department of Homeland Security (DHS), 

and the National Institute of Standards and Technology (NIST) within the 

Department of Commerce. Specifically, we reviewed transcripts and 

papers from hearings and a workshop FCC held in 2013 on 

communications reliability and continuity. We also analyzed agency 

orders and comments submitted in FCC’s 2013 proceeding on wireless 

resiliency.8 In addition, we reviewed communications sector planning 

reports, such as the 2015 Communications Sector-Specific Plan and 

2013 National Infrastructure Protection Plan,

9 and other DHS 

communications sector-specific documents, as well as the NIST 

Community Resilience Planning Guide for Buildings and Infrastructure 

Systems and related documents.10 We also examined reports from 

federal advisory committees and partnership councils that cover wireless 

network resiliency, including reports from the Technological Advisory 

Council; Communications, Security, Reliability, and Interoperability 

Council; National Security Telecommunications Advisory Committee; and 

the Communications Sector Coordinating Council.

To ensure we covered relevant agency actions and to seek any 

information on the results of these actions, we interviewed officials from 

DHS’s Office of Cybersecurity and Communications within the National 

Protection and Programs Directorate, including officials from the 

Stakeholder Engagement and Cyber Infrastructure Resilience division—

the sector-specific agency that leads federal efforts to protect and secure 

the communications critical infrastructure—and National Cybersecurity 

and Communications Integration Center—the center that continuously 

monitors incidents that may impact communications. We also interviewed 

 8

In the Matter of Improving the Resiliency of Mobile Wireless Communications Networks, 

28 FCC Rcd 14373 (2013)

9

Communications Sector-Specific Plan, 2015, and DHS, National Infrastructure Protection 

Plan, Partnering for Critical Infrastructure Security and Resilience (Washington, D.C.: 

2013).

10U.S. Department of Commerce, NIST Special Publication 1190: Community Resilience 

Planning Guide for Buildings and Infrastructure Systems, Volume I and II (Washington, 

D.C.: May 2016).
Appendix I: Objectives, Scope, and 

Methodology

Page 43 GAO-18-198 Wireless Network Resiliency

officials from DHS’s Federal Emergency Management Agency and 

Science and Technology Directorate, FCC, and NIST.

Beyond federal agency officials, we interviewed 24 stakeholders to further 

understand federal agency and related industry actions to improve 

wireless network resiliency since 2013 and any results from these 

actions. Stakeholders included wireless carriers and other owners of 

wireless network infrastructure, industry associations, consumer groups, 

and state and local government officials. We selected stakeholders to 

ensure we covered different perspectives (e.g., industry and consumer 

groups, associations that represent state and local public safety officials). 

In particular, we selected industry associations and individual companies 

to cover both wireless carriers—which operate networks and own some 

network infrastructure—and communications tower companies—which 

own and operate towers and sites and then lease space to wireless 

carriers. We selected wireless carriers to include both nationwide and 

regional carriers. We selected state agencies to include states directly 

affected by two events—flooding in Louisiana and Hurricane Matthew—

for which industry had implemented elements of the framework at the 

time we began our review. The views presented in our report are not 

generalizable to those of all stakeholders. See table 7 for a list of 

interviewed stakeholders.

Table 7: List of Interviewed Stakeholders

Academic

David Turetsky, professor, University at Albany, State University of New York 

Consumer groups

Consumers Union

New America, Resilient Communities Program

Public Knowledge

Industry associations

Alliance for Telecommunications Industry Solutions – Network Reliability Steering 

Committee

Association of Public-Safety Communications Officials International

Competitive Carriers Association

CTIA

National Emergency Management Association

NTCA - The Rural Broadband Association and Rural Wireless Association

Wireless Infrastructure Association
Appendix I: Objectives, Scope, and 

Methodology

Page 44 GAO-18-198 Wireless Network Resiliency

Infrastructure owners

American Tower

Crown Castle

Partnership council

Communications Sector Coordinating Council

State and local agencies

Georgia Emergency Management and Homeland Security Agency 

Louisiana Governor’s Office of Homeland Security and Emergency Preparedness 

New York City Department of Information Technology and Telecommunications 

San Francisco Office of Resiliency and Capital Planning 

South Carolina Department of Administration 

Wireless carriers

AT&T

GCI 

Pioneer 

T-Mobile 

Verizon 

Source: GAO. | GAO-18-198

We reviewed documents describing the Wireless Network Resiliency 

Cooperative Framework (framework)—a voluntary, industry initiative 

announced in April 2016. We interviewed CTIA and three of the five 

wireless carriers that collectively proposed the framework to learn about 

the impetus for, status of, and any outcomes or lessons learned from use 

of the framework to date. We also interviewed FCC and DHS about each 

agency’s awareness of and role monitoring industry use of the framework, 

and we reviewed FCC plans to monitor and share information about the 

framework. Finally, we asked stakeholders we interviewed, as described 

above, about their knowledge of and experience with the framework, 

including any observed outcomes from its use to date. We assessed 

FCC’s efforts to monitor implementation of the framework against 

Standards for Internal Control and FCC’s current strategic plan.11

To determine what options exist for federal agencies to improve wireless 

network resiliency, we examined federal agency reports, literature, and 

 11GAO, Standards for Internal Control in the Federal Government, GAO-14-704G 

(Washington, D.C.: September 2014) and FCC, Strategic Plan, 2015-2018 (Washington, 

D.C.).
Appendix I: Objectives, Scope, and 

Methodology

Page 45 GAO-18-198 Wireless Network Resiliency

other sources. First, we reviewed filings in FCC’s 2013 proceeding 

examining wireless resiliency, including FCC’s orders and comments filed 

by various parties, for proposed options that federal agencies could 

take.12 Second, we conducted a literature review of peer-reviewed 

articles, government reports, industry publications, and think tank 

publications from the last 5 years to identify additional options.13 Third, we 

examined reports from the aforementioned federal advisory committees 

on wireless network resiliency, the NIST Community Resilience Planning 

Guide for Buildings and Infrastructure Systems, and the Hurricane Sandy 

Rebuilding Task Force for recommendations made to federal agencies to 

enhance wireless network resiliency. From these sources, we identified 

11 proposed options that federal agencies could take to improve wireless 

network resiliency. We eliminated one option—requiring wireless carriers 

to disclose outage information to the public—as this was the only option 

that FCC specifically proposed as a new rule in its 2013 proceeding, but 

ultimately FCC decided not to move forward on this proposal when it 

decided to not issue a final rule. The identified options were primarily 

those that FCC could implement, as FCC is the regulatory agency for 

wireless communications, although DHS or NIST could implement several 

of the options.

We interviewed a variety of stakeholders, described above, to obtain their 

views on the advantages, disadvantages, and feasibility of each of the 

identified options. We used open-ended questions to solicit input on each 

option rather than provide a list of advantages and disadvantages to 

stakeholders. We also asked stakeholders if there were additional options 

for federal agencies to ensure we had a thorough list of options for federal 

agencies. Based on interviews with stakeholders and federal agencies, 

we decided not to present two options in our report—establish more 

formal, ongoing collaboration between wireless carriers and power 

companies and create a program to facilitate collaborative restoration 

between wireless carriers and power companies—as federal agencies 

told us they were already taking actions on these fronts. Therefore, we 

included federal agencies’ actions related to these two options while 

describing actions taken by federal agencies since 2013. We analyzed 

information collected through the interviews with stakeholders to identify 

 12In the Matter of Improving the Resiliency of Mobile Wireless Communications Networks, 

28 FCC Rcd 14373 (2013).

13For the literature review, we searched ProQuest, Scopus, and Science.gov, among 

other databases.
Appendix I: Objectives, Scope, and 

Methodology

Page 46 GAO-18-198 Wireless Network Resiliency

the most commonly cited advantages and disadvantages, and to 

determine the number of stakeholders that supported or did not support 

each option. The information collected from stakeholder interviews is not 

generalizable to all industry stakeholders.
Appendix II: Analysis of FCC Data on Wireless 

Outages

Page 47 GAO-18-198 Wireless Network Resiliency

The figures below provide results from our analysis of Federal 

Communications Commission (FCC) data on wireless outages from 2009 

through 2016. The data is from the Network Outage Reporting System 

(NORS), the system that wireless carriers and other communications 

providers use to report information on outages meeting certain threshold 

as required by regulation. The figures below present information on the 

number, cause, and duration of all wireless outages reported to FCC for 

this period.

To describe wireless outages by cause, we use nine categories that 

collapse several of the FCC categories from which wireless carriers select 

the root cause, direct cause, and contributing factor(s) when reporting an 

outage.1 The following provides a brief description of these nine 

categories. Appendix I contains information on the scope and 

methodology for this analysis, including these nine collapsed categories.

• Cable damage/failure includes outages caused by an error locating or 

digging that resulted in cable damage, by an aerial cable that was 

damaged or ceased to function, and by loss of transmission in a cable 

due to aging, among other causes. FCC categories: cable damage, 

cable damage/malfunction.

• Equipment failure contains outages caused by the failure of a 

hardware component (e.g., circuit pack or card in a processor) or by a 

problem with the design of firmware, hardware, or software (e.g., 

failure for firmware to reset or restore after initialization, logical errors 

in software). FCC categories: design-firmware, design-hardware, 

design-software, hardware failure.

• Network robustness includes outages caused by, for example, a 

failure to provide or maintain diversity, thus preventing single points of 

failure. FCC categories: diversity failure, simplex condition.

• Maintenance includes outages caused by a needed spare part not 

being on hand or available, a vendor or contractor lacking updated 

procedures for its work, a service provider not providing adequate or 

up-to-date training, and scheduled maintenance to upgrade a network

component or fix a known problem, among other causes. FCC 

categories: spare, procedural-other vendor/contractor, proceduralservice provider, procedural-system vendor, planned maintenance.

 1

FCC, Network Outage Reporting System, Glossary of Fields in NORS Reports, Version 1

(Washington, D.C., July 25, 2016). 

Appendix II: Analysis of FCC Data on 

Wireless Outages
Appendix II: Analysis of FCC Data on Wireless 

Outages

Page 48 GAO-18-198 Wireless Network Resiliency

• External environmental contains outages caused by earthquakes, 

wildfires, flooding, and other natural disasters as well as vandalism, 

theft, vehicle accidents that impair or destroy a component, and 

animal damage. FCC category: environment (external).

• Internal environmental contains outages caused by contamination due 

to dirt or dust that leads to overheating, by water entering manholes or 

vaults that destroys or impairs a component, and by other damage 

related to the condition of buildings and structures housing network 

equipment. FCC category: environment (internal).

• Other/Insufficient data includes outages for which there is not enough 

information for a failure report or investigation to determine the cause 

of the failure, service was restored before the cause could be 

determined, and the cause cannot be determined or proven. FCC 

categories: insufficient data, other/unknown.

• Power failure includes outages due to a commercial power failure 

(including power failures that extend beyond any backup power 

capabilities), a generator running out of fuel, a power system that was 

insufficiently sized for its purpose, and batteries not functioning as 

designed. FCC category: power failure (commercial and/or backup).

• Traffic/System overload contains outages where a network is 

overloaded or congested because of an unplanned, external event, or 

because of under-engineering the network due to changing demand 

or technologies. FCC category: traffic/system overload.
Appendix II: Analysis of FCC Data on Wireless 

Outages

Page 49 GAO-18-198 Wireless Network Resiliency

Figure 6: Number of Reported Wireless Outages by Month with Major Natural Disasters, 2009–2016

Note: FCC typically suspends NORS reporting requirements in areas where FCC activates DIRS 

reporting for an emergency event, generally a natural disaster. Therefore, FCC officials said that 

NORS data can undercount the number of wireless outages due to natural disaster. For a large 

natural disaster, however, FCC still can receive NORS reports for wireless outages outside the DIRS 

reporting areas that are due to the natural disaster.
Appendix II: Analysis of FCC Data on Wireless 

Outages

Page 50 GAO-18-198 Wireless Network Resiliency

Figure 7: Annual Reported Wireless Outage Rates, 2009–2016

Figure 8: Number and Percentage of Wireless Outages by Reported Root Cause, 2009–2016
Appendix II: Analysis of FCC Data on Wireless 

Outages

Page 51 GAO-18-198 Wireless Network Resiliency

Figure 9: Reported Direct Causes of Wireless Outages, Grouped by Reported Root Cause, 2009–2016

Note: The large labeled boxes in this graphic represent the root cause reported for an outage, and the 

smaller boxes within a large box represent the direct cause reported for an outage. The size of a box 

is determined by the number of outages. Therefore, for root cause, the most commonly reported root 

causes for wireless outages were equipment failure and cable damage/failure. For outages where 

equipment failure was the root cause, the most commonly reported direct cause was also equipment 

failure.
Appendix II: Analysis of FCC Data on Wireless 

Outages

Page 52 GAO-18-198 Wireless Network Resiliency

Figure 10: Duration and Number of Users Affected by Reported Wireless Outages, Grouped by Root Cause, 2009–2016

Note: The size of each block represents the number of users affected by wireless outages with that 

root cause, and the shading of the block represents the median duration.
Appendix III: Comments from the Federal 

Communications Commission

Page 53 GAO-18-198 Wireless Network Resiliency

Appendix III: Comments from the Federal 

Communications Commission
Appendix III: Comments from the Federal 

Communications Commission

Page 54 GAO-18-198 Wireless Network Resiliency

.
Appendix IV: GAO Contact and Staff 

Acknowledgments

Page 55 GAO-18-198 Wireless Network Resiliency

Mark L. Goldstein, (202) 512-2834 or goldsteinm@gao.gov

In addition to the contacts named above, Sally Moino (Assistant Director); 

Joanie Lofgren (Analyst in Charge); Enyinnaya David Aja; Stephen 

Brown; David Hooper; Richard Hung; Joshua Ormond; Amy Rosewarne; 

Andrew Stavisky; and Timothy Young made key contributions to this 

report. Jon Ludwigson, John Mortin, Mark Pross, Pam Snedden, James R 

Sweetman, Jr., and Joe Thompson also made contributions to this report.

Appendix IV: GAO Contact and Staff 

Acknowledgments

GAO Contact

Staff 

Acknowledgments

(101344)
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