Internet outages can disrupt emergency services, business transactions and basic communication. Here are few things to know about the nation's Internet infrastructure and its vulnerabilities.
HOW IT WORKS
In many cases, information is transmitted at high speeds through light waves carried in slender glass fibers that are bundled together and strung along rights of way such as highways, railroads and pipelines. When covering long distances, these fiber-optic cables often are shared, meaning they might carry Internet, telephone, television and data services for a variety of companies.
In major cities, the demand for high-speed Internet means there are typically multiple fiber-optic cables delivering service. If a main line is damaged, Internet traffic can be routed to another path. But in rural areas and smaller cities, these network redundancies sometimes don't exist because they are viewed as too costly. When a fiber-optic cable gets cut in those places, it can take much longer to restore service.
The number of outages affecting high-capacity lines has been steadily rising, from 221 in 2010 to 418 in 2012 and 487 in 2014, according to figures from the Federal Communications Commission. That comes as the nation's fiber-optic network also has been expanding by about 10 million miles of fiber annually, according to an industry group. More fiber-optic cables means there are more chances for them to get accidently cut, vandalized or develop problems.