Romy Arroyo Fernandez/NurPhoto via Getty Images)

For the most up-to-date news and information about the coronavirus pandemic, visit the WHO website

Cities throughout the US have emptied out amid the coronavirus outbreak. Millions of people are working from home, children are attending school remotely, and no one's heading to ballparks, nightclubs or movie theaters. They've all turned to their home broadband connections to stay connected.

With California mandating "shelter in place" across the entire state, New York City on total lockdown and other states and cities to follow suit, home broadband networks across the nation will be under tremendous pressure as we enter a second week of school and office closures across the country.

So far networks in the US and across the world have been holding up even as usage spikes. But will it continue?

European officials last week streaming service Netflix to dial back its resolution to help conserve bandwidth. Broadband companies in the US say their networks can handle whatever traffic is thrown their way. But some broadband policy experts are skeptical.

"To be honest, I think we just don't know the answer," said Jon Sallet, a senior fellow at the Benton Institute for Broadband & Society, and a former general counsel at the Federal Communications Commission. "But that's something the FCC should be asking the nation's broadband providers and telling the American people the answer."

Now playing: Watch this: Will coronavirus crash the internet?

FCC Commissioner Jessica Rosenworcel agrees. In a tweet on Friday she said the agency "needs to report daily on the state of communications networks in this country" just as it does following natural disasters, like hurricanes and power outages. "It needs to do this here. Now. Because these are the networks we are all counting on for some semblance of modern life."

Traffic is spiking

There's no question that broadband providers in the US saw huge spikes in usage last week as many Americans began telecommuting and schools closed around the country.

In a week-over-week comparison, Verizon said voice usage between March 12 and March 19 on its network was up 25%. And total web traffic was up 22%.

On Wednesday, the company said week-over-week usage patterns showed demand for streaming video services, like Netflix and Amazon, increased 12%. These are the most bandwidth-intensive applications on the internet. Meanwhile, web traffic climbed 20%, virtual private network jumped 30%. And online gaming skyrocketed 75%. Social media usage didn't change compared with the prior week.

Anticipating the need for Americans to get online, US carriers and broadband providers have already suspended data caps on service.

Verizon CEO Hans Vestberg told CNBC on Thursday that the company, which operates the Fios fiber-optic network and is the largest US wireless provider by number of users, is well positioned to handle the onslaught.

"In less than a week, we have transformed this company dramatically," he said. "We're always built for being prepared for different types of changes in the network, and that's why we're coping so good so far in the network."

Verizon isn't the only carrier that's confident. AT&T and Comcast have also said they've seen traffic skyrocket, but they're confident their networks can handle the surge in usage.

"We've been watching the network very closely," said Joel Shadle, a spokesman for Comcast. "We're seeing a shift in peak usage. Instead of everyone coming home and getting online, we're seeing sustained usage and peaks during the day."

AT&T reported Monday that on Friday and again on Sunday it hit record highs of data traffic between its network and its peers, driven by heavy video streaming. The company also said it saw all-time highs in data traffic from Netflix on Friday and Saturday with a slight dip on Sunday.

And the company reported that its voice calling traffic has been way up, too. Wireless voice calls were up 44% compared to a normal Sunday; Wi-Fi calling was up 88% and landline home phone calls were up 74%, the company said in its press release Monday.

AT&T also said it has deployed FirstNet portable cell sites to boost coverage for first responders in parts of Indiana, Connecticut, New Jersey, California and New York.

Cloudflare, which provides cloud-based networking and cybersecurity services and which has been tracking worldwide data usage, noted in a blog post last week that it had seen network usage increase as much as 40% in Seattle, where the coronavirus first broke out in the US. Key internet exchanges in cities like Amsterdam, London and Frankfurt also saw 10% to 20% spikes in usage in the week of March 9, just two days before the World Health Organization declared the coronavirus outbreak a pandemic.

"A 40% increase in peak usage sounds like a lot," said Matthew Prince, co-founder and CEO of Cloudflare. "But that's about what you'd expect for a big event like the Super Bowl or the Olympics."

Based on data Cloudfare has collected, he said, the networks are holding up remarkably well. Cloudflare hasn't detected any "noticeable jitter, latency or packet loss, which are things that would indicate the networks are overloaded."

Still, streaming services in Europe are already proactively ratcheting down the resolution of their streams to make sure they don't overwhelm broadband networks and choke off access to important services. Amazon, Netflix and YouTube have agreed to a European Union request to tap the brakes on streaming services, switching from high definition to standard for the next 30 days in an effort to reduce the strain on the internet.

Cloudfare

The companies haven't yet announced whether they'll take a similar approach in the US. But Prince said it would make sense if they did.

"The truth is that most people won't notice if they're getting their stream in 4K or not," he said. "So if they did it in the US, too, it would be a prudent action to make sure all the critical bits are getting through."

Network choke points

But some broadband policy experts are unconvinced it will be smooth sailing for all broadband users as traffic ramps up.

"The fact that things are holding up reasonably well so far doesn't mean it will remain so," said Harold Feld, senior vice president at Public Knowledge, a consumer advocacy group. "The fact is that we're putting a lot of pressure on a system that wasn't designed to take it."

Feld says there are several potential choke points in the internet that could hurt network performance. The most obvious depends on the type of technology used to access service.

"These are the networks we are all counting on for some semblance of modern life." FCC Commissioner Jessica Rosenworcel

For instance, older cable broadband networks and DSL networks use infrastructure that was primarily designed to send information in one direction -- downstream. As a result, the broadband service offered is asynchronous, which means that the download speed is much faster than the upload speeds. This may be fine for watching a movie or sending a tweet, but it is likely to be problematic for households using multiple videoconferencing applications like Zoom, which need a lot of capacity upstream as well as downstream.

Mobile wireless networks, fixed wireless networks in rural areas and satellite broadband services are also likely to have similar capacity constraints. Recognizing the need for additional capacity, AT&T, Verizon and T-Mobile sought and were granted approval last week from the FCC to strike a commercial deal with satellite TV provider Dish to borrow the company's unused wireless spectrum to help boost their network capacity during times of congestion. Feld applauded the carriers and the FCC for taking this step.

While some access networks may struggle, Feld acknowledged that newer cable broadband networks and fiber networks, which don't have the same upload constraints, will likely perform fine.

"I don't think the whole internet is going to come crashing down," he said. "But there's likely going to be some unevenness in experiences."

This is exactly why Feld and other broadband policy experts, like former FCC official Jon Sallet, say it's crucial that the FCC collect data to know how the networks perform during this crisis.

"This is a really important question that needs answering," Sallet said. "As Congress looks at how to rebuild our economy and a stimulus package, broadband will play an essential role. But we need to know what worked and what didn't."