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Thursday, 12 November 2015 06:00

When Communications Infrastructure Fails During a Disaster

Written by  Christina Richards

As seen by this summer’s severe weather in Texas and across the southwestern United States, one of the most immediate and significant impacts of flooding and natural disasters is the sudden and wide-scale breakdown or interruption of communications infrastructure. When public communication networks fail, the impact can be widely felt and has the ability to wipe out access to standard mobile or landline telecommunications, in addition to Internet and even satellite-based emergency communication devices.

Whether these systems are completely or just partially knocked offline, communications systems during a natural disaster can be the difference between life and death for those affected. Locating those who may be trapped or injured becomes nearly impossible for emergency responders, and rescue efforts are further complicated by the inability to coordinate via standard methods of communication.

How Communications Infrastructure Fails During a Disaster

Physical Damage to Network Devices

Perhaps the most common cause of communications failures during disasters is the physical damage to devices or components that make up the network infrastructure. Hurricane-force winds, floodwaters, and seismic activity can all create physical disturbances that have the power to do significant damage to cities and the vulnerable communications equipment that’s responsible for supporting these areas.

Disruptions caused by physical damage have the potential to be incredibly costly and time consuming to restore, as they require maintenance or sometimes replacement of complex network hardware to re-establish communications. This is especially problematic if major installations such as cell towers or fiber-optic cables are involved. If a cell tower is severely damaged or even knocked down, it not only causes major disruptions in the area’s wireless communications but is extremely expensive to replace and will remain a significant problem until the service provider is able to get a repair crew into the affected area.

Likewise, damage to fiber-optic cables can be an even greater challenge to repair. Because the cables are concealed underground, large portions of earth and roadway may need to be excavated just to pinpoint the exact location of the damage.

Wireless links are also susceptible to disruption or damage during disasters, as different wavelength signals can be cut off by heavy rain, snow, or fog. The transmitter itself can also receive damage or be knocked out of alignment with its receiver. While these issues are sometimes cheaper and less difficult to correct than damage to wired infrastructure, it nonetheless remains a serious obstacle to rescue efforts if knocked offline during a disaster.

Network Congestion

When disaster strikes, the “pipes” that make up our communications networks often become congested with exceptionally high levels of data traffic, as those impacted seek to contact family and friends, emergency personnel work to coordinate relief efforts, and hundreds more upload pictures and videos of the damage.

Aggregation hubs are often the failure point for congested networks. This occurs when data from a number of smaller sources flows into a central processing point and creates bottlenecks. When this happens, communications can be severely limited or even cut off completely, and important messages are often lost under the buildup of data queued to funnel through to their intended destinations. What’s more, these bottlenecks often go undiscovered until crises or other situations when the network’s peak capacity is pushed beyond its upper limit, and by then it is too late to fix the issue.

Consequences of Communications Infrastructure Failure

Preventing Emergency Response

In the immediate hours and days following a disaster, the top priority for emergency responders is to prevent any further loss of life, and if possible, mitigate damage to property and public infrastructure. During this time, it is critical that rescue workers and government officials coordinate their efforts and locate victims who may be injured or trapped, but relief efforts can be paralyzed or severely delayed if the responding agencies are unable to communicate with one another.

Major relief efforts involve a multitude of agencies – federal, municipal, and independent – all needing to work in unison. Because each of these groups has its own organizational structure, coordinating efforts is a daunting and complex task even under the best circumstances. When network connections are limited or unavailable, effective coordination becomes further complicated, and the lack of an overarching command structure can create miscommunications and delays in action. In time-sensitive situations such as these, even those few minutes lost can mean the difference between life and death for victims in need of rescue.

Spread of False Information and Confusion

In both public and private networks, there can be an imbalance in the volume of information flowing out of a disaster zone versus the information going into it. Those within the area, of course, have extremely limited access to communications, and any reports or images they are able to share are quickly repurposed by outside news organizations and disseminated to the national audience. This can mean that outside observers often have access to far more information about what is taking place than many of the individuals within the affected area.

While not as dangerous as a delay in emergency response efforts, the rumors that may result from the imbalance of communication channels here has the potential to create a great deal of confusion. Without an organized flow of information, conflicting reports of casualties, damage to property, and other dangers can spread misinformation and panic at a time when organization and level-headedness are key to carrying out rescue operations as quickly and efficiently as possible.

Preventative Measures to Keep Networks Intact

Network Path Diversity

Network path diversity is one of the most effective tactics to reduce the risk of communications failure during a disaster. This is accomplished by establishing two or more network connections that use either a different type of technology or follow a different physical path, minimizing the chance that both connections will be knocked out at the same time. These pathways must also be secure and completely redundant in the data they process, so that in the event one path fails, the flow of information is neither interrupted nor reduced.

So which methods of network path diversity are most effective to keeping communications intact during a disaster? While some companies rely on alternate leased-line dark fiber paths, the supposedly diverse pathways in reality are often still travelling along the same physical conduit. This creates the potential for a single point of failure, as any impact to the physical conduit that causes a fiber break will immediately sever all connectivity, leaving critical network connections vulnerable and making true path diversity very difficult to achieve.

It is often far more effective to use one or more wireless links to complement existing fiber-optic cable connections, as the technologies for millimeter wave and other wireless transmissions utilize entirely separate network pathways. At the same time, however, it is also important that operators use a wireless solution that can meet the reliability and capacity requirements of the network, otherwise a loss of the primary connection may result in severely limited communications, regardless of the back-up connection.

Ad-Hoc Networks

Because network connections cannot always be preserved in a disaster scenario, another effective method for maintaining and/or restoring communications in the hours immediately following the event is to establish one or more ad-hoc network links. Ad-hoc networks allow for the rapid deployment of fiber-like connectivity in situations where capacity is needed on an expedited basis, and they allow both victims and emergency workers to communicate when it is most important.

These network connections can be established quickly, even in areas where regular infrastructure has been devastated, by using a wireless transport device atop a mobile platform such as a COW (cellular on wheels) or a COLT (cellular on light trucks). The vehicle simply maneuvers into the area and can begin transmitting within a matter of hours, much faster than the time it takes to repair or replace existing network infrastructure equipment. In fact, a number of COWs were deployed in the aftermath of Hurricane Katrina to provide critical phone service to rescue and recovery workers when the area’s cellular networks had otherwise been completely cut off, and allowed the responders to organize their efforts and focus on the areas most devastated by the storm.

The failure of communications networks is a common occurrence during many disaster scenarios, and yet we have continued to see this preventable sequence of events play out time after time with deadly, expensive, and potentially preventable consequences. By working to better understand the implications of the loss of communications during a disaster, and how alternative technologies can help secure networks against failure during these events, we can ensure we are prepared for whenever the next disaster may strike.

Richards-ChristinaChristina Richards, vice president of marketing at AOptixis is responsible for AOptix’s strategic marketing vision and execution. She also leads awareness efforts for the company's laser radio technology. Richards is a 20-year veteran of the wireless communications industry.