A network fault at Time Warner Cable (TWC) has cut off millions of US customers from the internet.
The incident comes a day after the company was hit with a $1.1m penalty in connection with previous network outages.
TWC said the incident was under investigation and gave no further details on what caused the outage.
The outage started at 4.30am on Wednesday, affecting the company’s 11.4 million internet subscribers in all 29 states in which it operates.
In July, KPMG business resilience expert Stephen Bonner told Computer Weekly he expected a total internet failure within five years as the web grows beyond all initial expectations.
A total internet failure is the one thing that could stop any business in its tracks, yet few are preparing for this possibility, said Bonner.
TWC claimed the problem was “largely resolved” within 90 minutes, but services continued to be intermittent for some users for up to five hours, according to reports.
The day before the outage, TWC was hit with a $1.1m penalty by the Federal Communications Commission (FCC) for failing to report earlier network disruptions in a timely manner.
The FCC requires network operators to provide information about the security and operation of crucial segments of the national telecommunications infrastructure.
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The notifications are intended to enable the FCC to prevent disruptions in service that could threaten national security, public health and safety, and national economic wellbeing.
“TWC failed to file a substantial number of reports with respect to a series of reportable wireline and voice over internet protocol network outages,” the FCC’s report said.
“TWC admits that its failure to timely file the required network outage reports violated the commission’s rules.”
In addition to paying the penalty, TWC has agreed to implement a three-year plan to ensure compliance with the FCC’s network outage reporting rules.
The FCC is currently reviewing a deal for TWC to be acquired by rival cable and internet firm Comcast.
TWC accepted Comcast’s offer of $45.2bn after turning down a $60bn offer from Charter Communications, which threatened to unseat TWC’s board of directors, according to The Guardian.
The deal is opposed by some consumer groups because of fears that a merger will further reduce competition in an already-monopolised market.
But TWC and other communications firms are facing increased competition from internet such as Google, which is building its own fibre-optic networks in several US cities.
Google's fibre project was announced in 2010, with more than 1,000 towns and cities applying to take part.
The Google project uses dark fibre acquired from US telecoms firms to link Google’s datacentres around the country.
Google has also been investing in cheap fibre laid by companies that have gone bankrupt before completing broadband roll-outs.
Industry pundits have suggested that Google wants people to pressure ISPs and the government to improve the quality of their connection to generate more revenue for the company.